1. Discuss the epidemiology of kala-azar. Describe the strategies for its control under NVBDCP/NCVBDC. 2. Classify leprosy. Discuss the management of leprosy and the strategies under the National Leprosy Eradication Programme (NLEP). 3. Describe the modes of transmission of HIV. Discuss the National AIDS Control Programme (NACP) and Post-Exposure Prophylaxis (PEP). 4. Describe post-exposure prophylaxis following a dog bite. Discuss the prevention and control of rabies. 5. Define Acute Encephalitis Syndrome (AES). Discuss its causes, diagnosis and management. 6. Discuss the sources of hospital-acquired (nosocomial) infections. Describe the measures for prevention and control. 7. Define emerging and re-emerging infectious diseases. Discuss their causes, examples and control measures.

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I now have all the material I need. Let me update todos and write the comprehensive answer.Here is the comprehensive, exam-ready answer to all seven questions, drawn primarily from Park's Textbook of Preventive and Social Medicine and supported by Harrison's Principles of Internal Medicine 22E and Sherris & Ryan's Medical Microbiology.

1. Kala-Azar: Epidemiology and NVBDCP/NCVBDC Control Strategies

Epidemiology

Agent factors

Causative organism: Leishmania donovani (an intracellular parasite infecting macrophages)
Vector: Female sandfly (Phlebotomus argentipes in India)
In India, kala-azar is an anthroponotic (non-zoonotic) infection - man is the sole reservoir, distinguishing it from other parts of the world where animal reservoirs (dogs, rodents) exist.

Host factors

All age groups susceptible; peak age in India is 5-9 years
Males affected twice as often as females
Socio-economic status: strikes the poorest sections of society
Population movement between endemic and non-endemic areas facilitates spread

Environmental factors

Sandfly P. argentipes breeds in dark, damp places with organic debris - cracks in mud walls, rubble, leaf litter
Rainfall, humidity and temperature influence sandfly breeding density
Endemic in specific geographical zones of the Indian subcontinent

Disease burden in India

Endemic in 33 districts of Bihar, 4 of Jharkhand, 11 of West Bengal, and 6 of Uttar Pradesh
Sporadic cases in a few other UP districts
The centrally-sponsored programme launched in 1990-91 brought incidence down from 77,102 cases in 1992 to 5,758 cases in 2017

Post-Kala-Azar Dermal Leishmaniasis (PKDL)

Caused by L. donovani; appears 1 to several years after apparent cure
Multiple nodular infiltrations of the skin without ulceration; parasites numerous in lesions
Acts as an important human reservoir maintaining transmission

Strategies for Kala-Azar Elimination under NVBDCP/NCVBDC

(a) Enhanced case detection and complete treatment

Introduction of rK39 rapid diagnostic kits (immunochromatographic assay; result in 5 minutes)
Active case searches increased from annual to quarterly, conducted during the "Kala-Azar Fortnight" - door-to-door search by peripheral health workers
ASHA incentive: Rs. 300 for identifying a case; Rs. 100/Rs. 200 for ensuring one/two rounds of insecticide spraying; patient gets Rs. 500 as daily wage compensation during hospitalization, Rs. 2,000 for PKDL

Treatment Guidelines (2017):

Single dose Liposomal Amphotericin B (LAMB) IV: 10 mg/kg bw - drug of choice across all age groups (including paediatric, pregnant, elderly); WHO supplies free of cost
Miltefosine (oral): Adults >12 yr, weight >25 kg - 100 mg/day (two 50 mg doses) after meals for 28 days; children 2-11 yr - 2.5 mg/kg once daily × 28 days; NOT for pregnant/lactating women
Amphotericin B deoxycholate: 1 mg/kg bw on alternate days × 15 doses (IV)
Combination therapy: Paromomycin IM + Miltefosine

(b) Interruption of transmission through vector control

DDT being replaced with synthetic pyrethroid (pyrethroids) for indoor residual spraying (IRS) due to emerging sandfly resistance to DDT
Indoor residual spray of all villages reporting cases; vegetation, breeding sites, and animal shelters included
Two rounds of IRS per year recommended

(c) Communication for behavioural impact and intersectoral convergence

IEC campaigns; community participation

(d) Capacity building

Training of health workers and volunteers in case detection

(e) Monitoring, supervision and evaluation

Key indicators: detection rate, treatment completion rate, coverage rate of vector control, final cure rate, treatment failure rate

Key Indicators for Monitoring:

Indicator	Formula
Detection rate	New cases/year ÷ total population × 100
Treatment completion rate	Patients completing full course ÷ all new cases started × 100
Vector control coverage	Households protected ÷ households at risk × 100
Final cure rate	Patients with final cure ÷ total started treatment × 100

(Source: Park's Textbook of Preventive and Social Medicine)

2. Leprosy: Classification, Management, and NLEP

Classification of Leprosy

A. Ridley-Jopling Classification (Immunological/Histological) Based on host immune response and bacterial load:

Type	Immunity	Skin lesions	Nerve involvement	Bacteriology
Tuberculoid (TT)	High	1-2, well-defined, hypopigmented, dry, anaesthetic	Pronounced, single nerve	AFB negative
Borderline Tuberculoid (BT)	Good	Few, satellite lesions	Marked	Few AFB
Mid-Borderline (BB)	Variable	Multiple, "punched out" lesions	Moderate	Moderate AFB
Borderline Lepromatous (BL)	Poor	Many, less defined	Multiple nerves	Many AFB
Lepromatous (LL)	Absent	Numerous, bilateral, symmetric nodules, leonine facies	Diffuse, late, glove-and-stocking anaesthesia	AFB ++
Indeterminate (I)	?	Single hypopigmented macule	None/minimal	AFB negative

B. WHO Operational Classification (Field Use)

Type	Skin lesions	Nerve involvement	Smear
Paucibacillary (PB)	1-5 lesions	Up to 1 nerve trunk	Negative
Multibacillary (MB)	>5 lesions	>1 nerve trunk	Positive or negative

Cardinal features for diagnosis:

Hypopigmented patches with loss/reduction of sensation
Thickened peripheral nerves
Presence of AFB in skin smears/nasal smears
Acid-fast bacilli on skin biopsy

Management of Leprosy

Multi-Drug Therapy (MDT) Regimens (WHO-Recommended)

Multibacillary Leprosy (Adults):

Rifampicin: 600 mg once monthly (supervised)
Dapsone: 100 mg daily (self-administered)
Clofazimine: 300 mg once monthly (supervised) + 50 mg daily (self-administered)
Duration: 12 months (within 18 months)

Paucibacillary Leprosy (Adults):

Rifampicin: 600 mg once monthly (supervised)
Dapsone: 100 mg daily (self-administered)
Duration: 6 months (within 9 months)

Children (10-14 years):

MB: Rifampicin 450 mg monthly + Dapsone 50 mg daily + Clofazimine 150 mg monthly + 50 mg every other day
PB: Rifampicin 450 mg monthly + Dapsone 50 mg daily

Lepra Reactions:

Type 1 (Reversal reaction): Treat with corticosteroids (prednisolone)
Type 2 (ENL): Thalidomide (not in women of childbearing age) or corticosteroids, clofazimine

Note: MDT is NOT contraindicated in pregnancy or HIV co-infection; response to MDT is the same in HIV-positive leprosy patients.

National Leprosy Eradication Programme (NLEP)

History:

National Leprosy Control Programme (NLCP) started in 1955 using DDS (dapsone) monotherapy
Renamed National Leprosy "Eradication" Programme (NLEP) in 1983 when MDT was introduced
Goal: reduce prevalence to <1 per 10,000 population
World Bank support: Phase 1 (1993), Phase 2 (2001-2004)
Integrated with general health system in 2002-03: leprosy services now available at all PHCs and government hospitals
Target achieved at national level by December 2005

Components of NLEP:

Decentralized, integrated leprosy services through general health care system
Capacity building of general health services functionaries
Intensified IEC (Information, Education and Communication)
Prevention of disability and medical rehabilitation
Intensified monitoring and supervision

Major Initiatives:

Sparsh Leprosy Awareness Campaign: Awareness drives, stigma reduction
Special action in 209 high-endemic districts; house-to-house surveys in 1792 blocks and 150 urban areas
Achievement: Case load reduced from 57.6/10,000 in 1981 to <1/10,000 in 2005

Goals of Leprosy Control:

Interrupt transmission to reduce incidence
Treat patients to achieve cure and rehabilitation
Prevent the development of deformities

(Source: Park's Textbook of Preventive and Social Medicine)

3. HIV: Modes of Transmission, NACP, and PEP

Modes of Transmission of HIV

HIV (Human Immunodeficiency Virus) is transmitted through three main routes:

1. Sexual Transmission (most common globally)

Unprotected vaginal, anal, or oral sexual intercourse with an infected person
Anal intercourse carries the highest risk
Concurrent STIs (especially ulcerative, e.g., syphilis, herpes) greatly increase transmission risk
Heterosexual transmission is predominant in India (especially in southern states)

2. Blood-borne Transmission

Sharing of contaminated needles/syringes (intravenous drug users - IDUs)
Transfusion of infected blood or blood products
Use of unsterilized medical/dental instruments
Occupational exposure (needle-stick injuries in health care workers)
Organ/tissue transplantation from infected donors

3. Mother-to-Child (Vertical) Transmission

During pregnancy (transplacental) - accounts for about 5-10%
During delivery (intrapartum) - the most common route of MTCT
Through breastfeeding (postnatal) - risk of 10-15% if breastfed

Factors increasing transmission risk:

High viral load in source
Advanced HIV disease in source
Low CD4 count
Presence of genital ulcers/STIs
Unprotected receptive anal intercourse

HIV is NOT transmitted by: casual contact, coughing, sneezing, sharing utensils, mosquito bites, toilets, or swimming pools.

National AIDS Control Programme (NACP)

India launched NACP under the National AIDS Control Organization (NACO). Currently, NACP-IV is operational.

National Strategic Plan for HIV/AIDS and STI (2017-2024)

Vision: An AIDS-free India
Goal: Zero new infections, zero AIDS-related deaths, zero AIDS-related stigma and discrimination

Six Objectives:

Reduce 80% new infections by 2024 (baseline 2010)
Ensure 95% of estimated PLHIV know their status by 2024
Ensure 95% PLHIV have ART initiation and retention by 2024 for sustained viral suppression
Eliminate mother-to-child transmission (MTCT) of HIV and syphilis by 2020
Eliminate HIV/AIDS-related stigma and discrimination by 2020
Facilitate sustainable NACP service delivery through 100% domestic funding by 2024

Expected outcomes by 2024:

<50 cases of congenital syphilis per 100,000 live births
HIV/AIDS perceived as a chronic, manageable disease without stigma

Strategic Approaches based on Epidemiological Context:

States with 'mature' epidemics (high HIV incidence among key populations): targeted interventions
States with 'emerging' epidemics (rising rates): outreach and prevention
States with 'low/stable' epidemics: maintain low rates, focus on key populations

Key Programme Components:

Prevention outreach: Condom promotion, needle/syringe exchange for IDUs (Harm Reduction), Targeted Interventions for high-risk groups (FSW, MSM, IDU, truckers, migrants)
Testing and counselling: ICTC (Integrated Counselling and Testing Centres); VCTC
Treatment: Free ART at ART centres nationwide; 95-95-95 target
PPTCT: Prevention of Parent to Child Transmission - all pregnant women offered HIV testing; nevirapine + AZT prophylaxis; safe delivery; replacement/exclusive breastfeeding
Care and support: Community Care Centres, Positive Prevention
IEC/Behaviour Change Communication:
- Adolescence Education Programme (AEP): 16-hour sessions in schools, Class IX and XI; implemented in 23 states
- Red Ribbon Clubs (RRCs) in colleges: peer-to-peer messaging, voluntary blood donation
Surveillance and M&E

Post-Exposure Prophylaxis (PEP) for HIV

PEP for HIV applies to:

Healthcare workers after occupational needle-stick/splash exposures
Non-occupational exposures (sexual assault, unprotected sex, IDU needle sharing)

Principles:

Must be started as early as possible, ideally within 2 hours and no later than 72 hours after exposure
Prophylaxis after 72 hours is NOT recommended
Duration: 28 days of antiretroviral therapy

Risk Assessment before PEP:

Nature of exposure (percutaneous > mucous membrane > intact skin)
Volume of infectious material
Viral load of source patient
HIV status of source

Recommended PEP Regimen (current WHO/NACO guidelines):

Preferred: Tenofovir (TDF) + Lamivudine (3TC) or Emtricitabine (FTC) + Dolutegravir (DTG) for 28 days
Alternative: TDF + 3TC + Lopinavir/ritonavir (LPV/r)

Steps after exposure:

Immediate local wound care (wash with soap and water for 15 minutes; flush mucous membranes with water)
Report to occupational health/emergency immediately
Risk assessment
Baseline HIV test of exposed person
Start PEP (if indicated)
Follow-up HIV testing at 6 weeks, 3 months, and 6 months
Counselling and psychological support

(Source: Park's Textbook of Preventive and Social Medicine)

4. Rabies: Post-Exposure Prophylaxis after Dog Bite and Prevention/Control

Post-Exposure Prophylaxis (PEP) Following Dog Bite

Every instance of human exposure to a suspected rabid animal must be treated as a medical emergency. The aim of PEP is to neutralize inoculated virus before it enters the nervous system.

WHO Wound Category Classification

Category	Type of exposure	Recommended action
I	Touching/feeding animals; licks on intact skin	Wash exposed skin; no PEP needed
II	Nibbling of uncovered skin; minor scratches without bleeding; licks on broken skin	Wound treatment + vaccine
III	Single or multiple transdermal bites or scratches; licks on mucous membranes; bat bites/scratches	Wound treatment + RIG + vaccine

Steps of PEP

1. Local Wound Treatment (most important first step)

Immediate, thorough flushing and washing with plenty of soap and water under running tap for at least 15 minutes - this alone can reduce the chance of developing rabies by up to 80%
If soap unavailable: flush with copious water
Apply: povidone-iodine (Betadine), or 70% alcohol, or quaternary ammonium compounds
Suturing should be avoided if possible; if necessary, suture loosely after RIG infiltration
Anti-tetanus prophylaxis and antibiotics for wound infection as indicated
Do NOT apply irritants (chilli powder, lime, plant juices) to wound

2. Rabies Immunoglobulin (RIG) - Passive Immunization

Indicated for Category III exposures (and Category II in immunocompromised)
Administer only once, preferably at or as soon as possible after the first vaccine dose
NOT indicated after the 7th day (active antibody response is expected to have occurred)
Dose:
- Human RIG (HRIG): 20 IU/kg body weight
- Equine RIG (ERIG)/F(ab')2 products: 40 IU/kg body weight
As much as anatomically possible should be infiltrated into/around the wound; remaining RIG given IM at a site distant from vaccine
ERIG: small risk of anaphylaxis (1/45,000); skin test NOT reliable - give regardless

3. Rabies Vaccine (Active Immunization)

Modern Cell Culture/Embryo-based vaccines (CCEEVs):

Purified Chick Embryo Cell Vaccine (PCECV)
Human Diploid Cell Vaccine (HDCV)
Purified Vero Cell Vaccine (PVCV)

Standard IM regimen (Essen protocol): 5 doses - days 0, 3, 7, 14, 28

Abbreviated Intradermal (ID) regimen (Zagreb/2-1-1):

Day 0: 2 sites ID
Day 7: 1 site ID
Day 21: 1 site ID

For previously vaccinated individuals:

Only 2 doses (days 0 and 3); RIG NOT required

For immunocompromised (including HIV/AIDS):

Full 5-dose IM course + RIG for Category II and III exposures
Check antibody titres 2-4 weeks after vaccination

Prevention and Control of Rabies

1. Prevention in Humans (Pre-exposure Prophylaxis)

Pre-exposure prophylaxis (PrEP) recommended for:

Laboratory workers handling rabies virus/lyssaviruses
Veterinarians and animal handlers
Children in rural high-risk areas
Travellers with extensive outdoor exposure

PrEP schedule: IM (1 ml or 0.5 ml depending on vaccine) or ID (0.1 ml) on days 0, 7, and 21 or 28

2. Animal Reservoir Control

Control of Urban Rabies:

Elimination of stray and ownerless dogs combined with mass immunization of at least 80% of the entire dog population in the shortest possible time
Registration and licensing of all domestic dogs
Restraint of dogs in public places
Immediate destruction of dogs and cats bitten by rabid animals
Quarantine (~6 months) of imported dogs
Health education about care of dogs

Control of Wildlife Rabies:

Oral vaccine baits placed in fox habitats (successful in Canada, Germany, Switzerland)
Wildlife population control

3. Health Education

Teaching public to avoid contact with unknown animals
Reporting all bites promptly

(Source: Park's Textbook of Preventive and Social Medicine)

5. Acute Encephalitis Syndrome (AES): Definition, Causes, Diagnosis, and Management

Definition

AES (suspected case): A person of any age, at any time of year with the acute onset of fever (not more than 5-7 days duration) AND change in mental status (including confusion, disorientation, coma, or inability to talk), WITH or WITHOUT new-onset seizures (excluding simple febrile seizures), AND other early clinical findings including irritability, somnolence, or abnormal behaviour greater than that expected with a usual febrile illness.

Following the 2005 JE outbreak in Gorakhpur and Basti divisions (eastern UP), the NVBDCP developed surveillance guidelines advising that all JE cases be reported under the broader AES umbrella (as they share common clinical manifestations and follow a common management protocol).

Case Classification

Category	Definition
Laboratory-confirmed case	AES + any one of: IgM antibody in serum/CSF to specific virus; 4-fold IgG titre rise in paired sera; virus isolation from brain tissue; antigen detection by immunofluorescence; nucleic acid by PCR
Probable case	Suspected case in close geographic and temporal relationship to a lab-confirmed case during an outbreak
AES due to other agent	Suspected AES with an aetiological agent other than JE identified
AES due to unknown agent	No diagnostic testing done/no agent identified/results indeterminate

Causes of AES

AES is caused by a wide range of infectious and non-infectious agents:

Viral causes (most common):

Japanese Encephalitis (JE) virus - single-stranded RNA virus, commonest identifiable cause in India
Enteroviruses (EV71, Coxsackievirus A16)
Herpes Simplex Virus (HSV-1, HSV-2)
Dengue virus
Nipah virus
West Nile virus
Influenza viruses
Measles, Mumps, Varicella, Rabies

Bacterial causes:

Bacterial meningitis (Neisseria meningitidis, Streptococcus pneumoniae, H. influenzae)
Tuberculous meningitis

Parasitic causes:

Cerebral malaria (P. falciparum) - AES with symmetrical signs and fever suggests this
Cerebral cysticercosis

Toxic/Nutritional causes:

Scrub typhus (Orientia tsutsugamushi)
Lychee fruit toxicity (hypoglycin A) - linked to Muzaffarpur, Bihar outbreaks

Differential diagnosis tip: Presence of rash on the body EXCLUDES Japanese Encephalitis. AES with symmetrical signs and fever is likely cerebral malaria.

Diagnosis

Clinical:

Acute fever + altered sensorium (>2 hours duration with focal seizure or paralysis) = encephalitis in epidemic setting

Laboratory:

IgM Capture ELISA for JE/Enterovirus - preferred in sentinel surveillance network
Virus isolation: National Reference Laboratory
CSF examination (cell count, protein, glucose, culture)
Blood smear/RDT for malaria
Blood culture, scrub typhus serology
Blood glucose (to exclude hypoglycaemia)
CT/MRI brain

Management (NVBDCP Guidelines 2014)

Management is essentially SYMPTOMATIC - no specific antiviral is available for JE.

At Community Level (PHC) - Initial Management:

Identify danger signs: abnormal posturing, apnoea, Cheyne-Stokes breathing, papilloedema, focal neurological deficit
Maintain airway; Oxygen therapy
Control seizures: Diazepam IV/rectal (first line); Phenobarbitone
Reduce fever: Paracetamol; tepid sponging
Maintain blood glucose - give IV glucose if hypoglycaemic
Refer to FRU/district hospital - early referral is key

At FRU/District Hospital:

Maintain blood pressure at ~95th centile for age (use dopamine drip if needed) - autoregulation failure makes cerebral circulation dependent on systemic BP
Avoid fluid overload (risk of cerebral oedema)
Manage raised intracranial pressure: head elevation 30°, mannitol
Nutritional support (nasogastric feed if unconscious)
Prevent infections: mouth care, bladder care, pressure sores

Treatment of Specific Causes (if identified):

HSE: Acyclovir IV 10 mg/kg 8-hourly × 14-21 days
Bacterial meningitis: Appropriate antibiotics
Cerebral malaria: Artesunate IV
Scrub typhus: Doxycycline
Hypoglycaemia: IV dextrose

(Source: Park's Textbook of Preventive and Social Medicine)

6. Nosocomial (Hospital-Acquired) Infections: Sources, Prevention and Control

Definition

A nosocomial infection is an infection acquired during hospital care that was not present or incubating at the time of admission. Infections occurring more than 48 hours after admission are generally considered nosocomial. The definition now encompasses infections in any health care setting (including outpatient and long-term care), infections that appear after discharge, and infections among hospital staff.

Common examples: Surgical site infections (SSI), urinary tract infections (catheter-associated), hospital-acquired pneumonia (ventilator-associated), primary bloodstream infections (central line-associated), hepatitis B.

Sources of Nosocomial Infections

Nosocomial infections may be viewed from three angles: Source, Routes of Spread, and Recipients.

1. Sources

(a) Patients (most important source):

Patients suffering from infectious diseases: viral infections (measles, rubella, influenza, viral hepatitis), skin infections (discharging wounds, infected lesions, eczema, psoriasis, boils, bed sores), respiratory infections (pulmonary TB, sore throat, chest infections), and urinary tract infections

(b) Hospital Staff:

Doctors, nurses, ward boys in close contact with patients can transmit infection
Staphylococcus aureus nasal carriage in staff is a classic example
Staff with skin diseases, sore throat, diarrhoea, or other infections are a risk

(c) Environment:

Inanimate environment: contaminated linen, clothing, bedpans, floors, walls
Air: Hospital air contaminated with dust (bacteria, viruses released during sweeping, dusting, bed-making)
Water and food: Contaminated water/food supply
Medical equipment: Catheters, endoscopes, IV lines, ventilators
Medications: Contaminated IV fluids or medications

Endemic vs Epidemic Nosocomial Infections:

Endemic: Most common; constant background level of HAI
Epidemic: Unusual increase above baseline of a specific infection/organism; constitutes an outbreak

Routes of Spread

Contact transmission (most common): Direct contact (hands of staff) or indirect contact (contaminated instruments/surfaces)
Droplet transmission: Large respiratory droplets from coughing/sneezing (TB, influenza, measles)
Airborne transmission: Small particles remaining suspended in air (TB, chickenpox, measles)
Vehicle transmission: Contaminated food, water, medications, blood products
Vector-borne: Rare in hospital settings

Prevention and Control

Specific Measures

(a) Isolation

Infectious patients must be isolated; susceptible patients should not be placed next to infectious patients
Intensive care units, urological wards, geriatric wards, and special baby care units - highest risk

(b) Hospital Staff

Staff with skin diseases, sore throat, cold, ear infection, diarrhoea should be kept away from work until cured
Regular changes of aprons and outer clothing; personal hygiene

(c) Hand Hygiene (single most important intervention)

Hands are the most common route of cross-infection
Thorough hand-washing with soap and water; alcohol-based hand rub when hand-washing insufficient
WHO guidelines: "Clean Care is Safer Care" (2009)
WHO's "5 Moments for Hand Hygiene": before patient contact, before aseptic procedure, after body fluid exposure, after patient contact, after contact with patient surroundings

(d) Dust Control

Hospital dust contains numerous bacteria and viruses
Wet dusting and vacuum cleaning (suppress dust during sweeping/dusting/bed-making)

(e) Disinfection and Sterilization

Proper disinfection of articles used by patients (urine, faeces, sputum)
Sterilization of surgical instruments (autoclave, ETO, glutaraldehyde)
Spaulding classification: Critical items (sterilize) > Semi-critical (high-level disinfection) > Non-critical (low-level disinfection)

(f) Control of Droplet/Airborne Infection

Face masks, proper bed spacing (minimum 1 metre)
Prevention of overcrowding; adequate lighting and ventilation
Negative-pressure isolation rooms for airborne infections (TB, measles)

(g) Nursing Techniques

Barrier nursing (protective isolation)
Task nursing to minimize cross-infection

Standard (Universal/Routine) Precautions

Apply to ALL patients regardless of diagnosis:

Gloves for all contacts with secretions, body fluids, blood, mucous membranes
Gown, mask, eye protection where contamination of clothes/face is anticipated

The four most common nosocomial infections are:

Urinary tract infections (catheter-associated)
Surgical wound infections
Pneumonia (ventilator-associated)
Primary bloodstream infections (central line-associated)

Each is associated with an invasive device or procedure.

Administrative Measures

Hospital Infection Control Committee: formulates policies on admission of infectious cases, isolation facilities, disinfection procedures
Antibiotic stewardship programmes
Surveillance of HAI rates
Regular audit and feedback

(Source: Park's Textbook of Preventive and Social Medicine)

7. Emerging and Re-emerging Infectious Diseases

Definitions

Emerging infectious disease: An infectious disease that has newly appeared in a population, or that has existed but is rapidly increasing in incidence or geographic range. The agent may be newly recognized or may have been known previously but whose significance was newly recognized.

Re-emerging infectious disease: An infectious disease that was previously under control or declining but has reappeared and is now increasing in incidence, sometimes in a new geographic area, in a drug-resistant form, or in association with a new host.

Causes / Determinants

1. Microbial/Agent Factors

Genetic mutations and evolution: Rapid mutation rates (especially RNA viruses like influenza) lead to new strains evading host immunity (e.g., influenza pandemics)
Antigenic shift and drift in influenza
Antimicrobial resistance (e.g., MDR-TB, MRSA, XDR TB, carbapenem-resistant Enterobacteriaceae - CRE, drug-resistant N. gonorrhoeae)
Recombination between animal and human viral strains

2. Host Factors

Increased immunocompromised populations: HIV/AIDS, organ transplants, cancer chemotherapy - susceptibility to opportunistic infections
Ageing populations: Greater susceptibility
Behavioural factors: Sexual practices, IVDU, bushmeat hunting

3. Environmental/Ecological Factors

Deforestation and land use change: Bringing humans into contact with new animal reservoirs (Nipah, Ebola, Hendra)
Climate change: Expanding the geographic range of vector-borne diseases (dengue, Zika, chikungunya, Lyme disease)
Agricultural practices: Factory farming, use of antibiotics in livestock

4. Human/Social Factors

International travel and trade: Rapid global spread of pathogens (SARS, COVID-19, influenza pandemics)
Urbanization: High-density populations, inadequate sanitation
Population displacement: Refugees, migrants moving pathogens across borders
Breakdown of public health infrastructure: Re-emergence of previously controlled diseases
Bioterrorism: Deliberate release of agents (anthrax, smallpox concerns)

5. Healthcare/Technological Factors

Medical procedures introducing new transmission routes (blood transfusion → HIV, hepatitis B; organ transplants → CMV, West Nile virus)
Hospital environments fostering antimicrobial resistance

Examples

Category	Examples
Truly emerging (new)	HIV/AIDS (1980s), SARS-CoV (2003), SARS-CoV-2/COVID-19 (2019), Nipah virus, Hendra virus, vCJD (variant Creutzfeldt-Jakob disease)
Re-emerging	Dengue (global spread), Chikungunya, Zika virus, Drug-resistant TB (XDR-TB), MDR malaria, Ebola, West Nile virus, Plague
Antimicrobial resistance	MRSA, VRE, CRE, XDR-TB, drug-resistant gonorrhoea, Clostridioides difficile
Vector-borne (expanding range)	Dengue (temperate zones), Chikungunya, Lyme disease, SFTS virus
Zoonotic spillover	Avian influenza (H5N1, H7N9), Monkeypox, Nipah, MERS-CoV, Hantavirus

Control Measures

1. Surveillance and Detection

Global surveillance networks: WHO Global Outbreak Alert and Response Network (GOARN), IHR (International Health Regulations 2005)
Enhanced sentinel surveillance at entry points (airports, seaports)
Early warning systems; event-based surveillance
Laboratory capacity building for rapid pathogen identification

2. Prevention of Spread

Quarantine and isolation during outbreaks
Infection prevention and control (IPC) in health facilities
Vector control: insecticide use, environmental management
Travel advisories and screening at ports of entry
Safe food handling and food safety regulations

3. Response Measures

Rapid response teams (national and international)
Contact tracing and ring vaccination
Stockpiling of vaccines, antivirals, and PPE
Emergency use authorization of investigational vaccines/treatments (e.g., Ebola vaccines)

4. Research and Development

Development of broad-spectrum antivirals and new vaccines
One Health approach: integrated human-animal-environment health surveillance
International collaboration: CEPI (Coalition for Epidemic Preparedness Innovations), GAVI

5. Antimicrobial Resistance (AMR) Control

Antibiotic stewardship programmes
Restricting antibiotic use in agriculture
Surveillance of resistance patterns (WHO GLASS)
Development of new antibiotics and alternatives

6. Addressing Root Causes

Sustainable land use and deforestation control
Climate change mitigation
Poverty reduction and improved sanitation
Strengthening health systems in low- and middle-income countries

(Sources: Park's Textbook of Preventive and Social Medicine; Sherris & Ryan's Medical Microbiology, 8th Edition)

Quick Reference Summary Table

Question	Key National Programme	Drug/Vaccine Highlight
1. Kala-azar	NVBDCP (Kala-azar elimination initiative)	LAMB single dose; Miltefosine; rK39 RDT
2. Leprosy	NLEP (since 1983, integrated 2002)	MDT: Rifampicin + Dapsone ± Clofazimine
3. HIV	NACP-IV (NSP 2017-2024); NACO	TDF+3TC+DTG for PEP; ARV for PMTCT
4. Rabies	NRCP; integrated into NVBDCP	Cell culture vaccine (5-dose Essen); RIG 20 IU/kg
5. AES	NVBDCP (2014 guidelines)	Symptomatic; Acyclovir for HSE
6. Nosocomial	Hospital Infection Control Committee	Hand hygiene ("Clean Care is Safer Care")
7. Emerging diseases	IHR 2005; One Health; GOARN	Surveillance + rapid response

1. Discuss the strategies for measles elimination in India. Describe the steps in the investigation and control of a measles outbreak. 2. Classify Acute Respiratory Infection (ARI)/pneumonia according to IMNCI. Discuss its management and preventive measures. 3. Describe the diagnostic algorithm of tuberculosis under NTEP. Discuss the management of tuberculosis. 4. Define food poisoning. Describe the investigation and control of a food poisoning outbreak. 5. Classify dehydration in children with diarrhoea. Discuss the management of dehydration and measures to prevent future episodes of diarrhoea. 6. Discuss the National Drug Policy for malaria. Describe the strategies for malaria control under NVBDCP/NCVBDC and the investigation of a malaria outbreak. 7. Describe the clinical features, diagnosis and management of dengue. Discuss the dengue control strategies under NVBDCP/NCVBDC and outbreak investigation.

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I now have sufficient content to write comprehensive answers for all 7 questions. Let me update the todos and write the full response.Here is the comprehensive, exam-ready answer to all seven questions, drawn primarily from Park's Textbook of Preventive and Social Medicine.

1. Measles Elimination in India: Strategies and Outbreak Investigation

Strategies for Measles Elimination

Problem statement: Measles is endemic virtually in all parts of the world and tends to occur in epidemics when the proportion of susceptible children reaches about 40%. The primary reason for continuing high childhood measles morbidity and mortality is the failure to deliver at least one dose of measles-containing vaccine (MCV) to all infants. The challenges for measles elimination in India include weak immunization systems, the high infectiousness of measles, populations inaccessible due to conflict, refusal of immunization, the need to provide catch-up vaccination to >130 million children, and gaps in human and financial resources.

A. Vaccination Strategy

Two-dose schedule (routine):

MCV1: Given at 9 months of age in countries with ongoing transmission and high mortality risk (India)
MCV2: Given at 15-18 months of age; the minimum interval between MCV1 and MCV2 is 4 weeks
Every contact with health services must be used to vaccinate children who missed one or both doses, particularly those under 15 years

Vaccine properties:

Only live attenuated vaccines are recommended; available as monovalent (measles only), MR (measles-rubella), MMR, or MMRV
Stored at 2-8°C (freeze-dried); reconstituted vaccine loses 50% potency after 1 hour at 20°C, and almost all potency at 37°C; sensitive to sunlight
Route: Subcutaneous (also effective intramuscularly); dose 0.5 ml

MR Campaign (India's Measles-Rubella Campaign):

India launched the MR mass vaccination campaign targeting children aged 9 months to <15 years (covering approximately 324 million children in phases)
Aim: Accelerate measles elimination and control congenital rubella syndrome (CRS)

B. Supplementary Immunization Activities (SIAs)

Conducted periodically to fill immunity gaps across all age groups
Includes catch-up campaigns in high-risk areas, schools, slums
Target: 95% vaccination coverage at national level and 80% in every district

C. Surveillance Strengthening

Case-based surveillance: All suspected measles cases must be laboratory confirmed
Sentinel surveillance: At district hospital level
Outbreak investigation: Every suspected case investigated, serology (IgM ELISA) confirmed
Epidemiological link confirmed by RT-PCR or virus isolation
Link tracking to determine genotype/origin

D. WHO/WHA Targets (endorsed 2010, measles elimination roadmap)

Raise routine MCV1 coverage to ≥90% nationally and ≥80% in every district
Reduce annual measles incidence to <5 cases per million population
Reduce measles mortality by ≥95% compared to 2000 levels

For eradication: Requires immunization coverage of at least 96% of children under one year AND prevention of accumulation of the immunity gap.

E. Additional Strategies

Vitamin A supplementation: 100,000 IU for infants 6-11 months; 200,000 IU for children 12-59 months; reduces complications and mortality
Case management: No specific antiviral; supportive care including antipyretics, nutritional support, treatment of bacterial superinfections; antibiotics for bacterial pneumonia
Passive immunization (immunoglobulin) for contacts: Immunoglobulin given within 6 days of exposure in unvaccinated immunocompromised individuals, infants <6 months, pregnant women

Investigation and Control of a Measles Outbreak

Step 1: Confirm the Diagnosis

Verify clinical diagnosis in index cases: fever, catarrhal symptoms (coryza, cough, conjunctivitis), Koplik's spots, maculopapular rash spreading from head downward
Laboratory confirmation: Measles-specific IgM antibody by ELISA in serum or oral fluid; or RT-PCR from throat swab/nasopharyngeal mucus/urine
Rule out other causes of fever with rash (rubella, roseola, drug reactions)

Step 2: Confirm the Outbreak

Define "outbreak" in context: ≥2 epidemiologically linked confirmed cases in a defined area within 30 days
Establish line listing of all suspected/confirmed cases

Step 3: Describe the Outbreak (Descriptive Epidemiology)

Time: Plot epidemic curve (determine whether common source, propagated, or mixed)
Place: Map cases by residence, school, health facility
Person: Age, sex, vaccination status, vitamin A status, nutritional status, HIV status

Step 4: Identify Source and Mode of Transmission

Review immunization records and coverage data for the affected area
Identify susceptible clusters (unvaccinated cohorts, pockets with low coverage)
Identify primary case and exposure event if possible

Step 5: Immediate Control Measures

(a) Ring vaccination (reactive vaccination):

Vaccinate all susceptible persons in the affected area and surrounding areas regardless of prior vaccination history
Vaccine should be administered within 3 days of exposure if given to contacts
Immunoglobulin for contacts who are contraindicated for vaccine (immunocompromised, pregnant, infants <6 months)

(b) Case management:

Isolation of cases for 4 days after onset of rash (droplet and contact precautions)
Vitamin A supplementation for all cases
Treat complications (pneumonia, diarrhoea, encephalitis)

(c) Enhanced surveillance:

Active case search in affected area (house-to-house, schools, hospitals)
Zero-reporting by health facilities

Step 6: Long-Term Control

Conduct vaccination coverage rapid assessment in affected area
Identify reasons for low coverage and address gaps
Conduct SIAs if coverage gap is large
Health education to community

Step 7: Reporting and Documentation

Report to district/state health authority
Submit outbreak investigation report to IDSP (Integrated Disease Surveillance Programme)

(Source: Park's Textbook of Preventive and Social Medicine)

2. ARI/Pneumonia Classification under IMNCI, Management and Prevention

IMNCI Classification of ARI/Pneumonia

IMNCI (Integrated Management of Neonatal and Childhood Illness) classifies ARI/pneumonia in children aged 2 months to 5 years based on clinical signs at the peripheral level (no chest X-ray or lab tests required):

Classification Based on Respiratory Signs

Classification	Clinical Criteria	Action
Severe Pneumonia or Very Severe Disease	Cough or difficult breathing PLUS: any danger sign (unable to drink/breastfeed, vomits everything, convulsions, lethargic/unconscious) OR chest indrawing OR stridor in calm child	REFER URGENTLY to hospital; give first dose of antibiotic; treat to prevent low blood sugar
Pneumonia	Cough or difficult breathing PLUS fast breathing* ONLY (NO chest indrawing, NO danger sign)	Give oral antibiotic (Co-trimoxazole or Amoxicillin) for 5 days; treat fever; soothe throat
No Pneumonia: Cough or Cold	Cough or difficult breathing BUT no fast breathing, no chest indrawing, no danger signs	Home treatment; soothe throat with safe remedy; treat fever; no antibiotic

*Fast breathing (age-specific cut-offs):

2 months - <12 months: ≥50 breaths/minute
12 months - <5 years: ≥40 breaths/minute

For Children Aged 0-2 Months (Young Infants - Separate Protocol)

Classification	Criteria
Very Severe Disease	Stopped feeding well; convulsions; fast breathing (≥60/min); severe chest indrawing; fever/low body temperature; movement only when stimulated or no movement at all
Local bacterial infection	Umbilical infection or skin pustules

Classification by Severity (WHO/Modified)

Level	Features
Very Severe Pneumonia	Cyanosis; unable to drink; severe respiratory distress; convulsions
Severe Pneumonia	Chest indrawing (lower chest wall indrawing); stridor when calm
Pneumonia	Fast breathing only
No Pneumonia	Cough/cold, no above features

Management

Mild/Moderate Pneumonia (Outpatient)

First-line antibiotic: Amoxicillin (oral) 40 mg/kg/day in 2 divided doses for 5 days (preferred over co-trimoxazole in current WHO guidelines)
Alternative: Co-trimoxazole (4 mg/kg TMP + 20 mg/kg SMX twice daily for 5 days)
Antipyretic for fever (paracetamol)
Continue feeding and fluids
Follow up after 2 days; if worsening, refer

Severe/Very Severe Pneumonia (Hospital)

Hospitalize
IV/IM antibiotics: Benzylpenicillin (Penicillin G) 50,000 units/kg IM/IV every 6 hours PLUS Gentamicin 7.5 mg/kg/day OD IM/IV; for 5-7 days
Alternative: Ampicillin 50 mg/kg IM/IV 6-hourly
Oxygen therapy (if SpO2 <90% or severe respiratory distress)
IV fluids if unable to feed; nasogastric feeding
Treat complications (empyema, meningitis)
Monitor respiratory rate, temperature, and fluid intake

At Home (No Pneumonia)

Soothe the throat with safe home remedies (honey, warm water - NOT aspirin, not antibiotics)
Increase fluids
Continue feeding
Return if worsening (fast/difficult breathing, chest indrawing, unable to eat)

Preventive Measures

Immunization

Pneumococcal Conjugate Vaccine (PCV): Introduced in India's UIP; 3 primary doses + booster; prevents Streptococcus pneumoniae pneumonia
Hib vaccine (Pentavalent): Prevents Haemophilus influenzae type b pneumonia; part of UIP
Measles vaccine: Measles is a major precipitant of pneumonia
Influenza vaccine: Annual for high-risk groups

Nutrition

Exclusive breastfeeding for 6 months: Reduces ARI incidence and severity
Adequate complementary feeding after 6 months
Vitamin A supplementation: reduces risk of severe measles-related pneumonia and all-cause respiratory mortality

Environmental Measures

Reduce household air pollution: proper ventilation, clean cooking fuels (LPG, biogas), avoid indoor burning of biomass
Reduce overcrowding
Ensure safe water and sanitation (reduces co-morbidities)

Health Education

Prompt care-seeking for fast breathing, chest indrawing
Recognition of danger signs by mothers/caregivers

(Source: Park's Textbook of Preventive and Social Medicine; WHO IMNCI guidelines)

3. TB Diagnostic Algorithm under NTEP and Management

Diagnostic Algorithm under NTEP (National Tuberculosis Elimination Programme)

India's NTEP (formerly RNTCP) follows a systematic diagnostic pathway. Universal Drug Susceptibility Testing (UDST) is now the cornerstone - every bacteriologically confirmed case must have DST done.

Step 1: Identify Presumptive TB Cases

Presumptive TB = any person with:

Cough for ≥2 weeks, OR
Fever for ≥2 weeks, OR
Significant weight loss, OR
Night sweats

High-risk groups to screen actively: HIV-positive, close contacts of TB cases, prisoners, healthcare workers, tribal populations, slum dwellers, patients on immunosuppressive therapy.

Step 2: Initial Diagnostic Tests

Microbiological Confirmation (preferred):

(a) CBNAAT (Cartridge-Based Nucleic Acid Amplification Test) / Xpert MTB/RIF:

First-line test at all designated microscopy centres (DMCs) and above
Simultaneously detects M. tuberculosis AND rifampicin resistance
Result in 2 hours
Preferred for all presumptive TB, all HIV-positive presumptive TB, and presumptive DR-TB

(b) Sputum Smear Microscopy (ZN staining):

Two sputum samples: one spot, one early morning
Used where CBNAAT is not immediately available
Detects AFB (does not distinguish species or drug resistance)

(c) Culture (LJ medium/MGIT liquid culture):

Gold standard for confirmation
Used for smear-negative/CBNAAT-negative cases with clinical suspicion
MGIT: faster (2-3 weeks) vs LJ (6-8 weeks)

(d) TrueNat MTB/MTB Plus:

Portable chip-based real-time PCR platform
Equivalent to Xpert for MTB detection; TrueNat MTB Plus also detects RIF resistance

Step 3: Drug Susceptibility Testing (DST)

Line Probe Assay (LPA):
- First-line LPA: Detects resistance to Rifampicin (RIF) and Isoniazid (INH)
- Second-line LPA: Detects resistance to fluoroquinolones and aminoglycosides/capreomycin
- Done on culture isolates or directly on smear-positive sputum
Phenotypic DST (MGIT/solid culture-based): For confirmation of resistance to second-line drugs

Step 4: Classification

Based on diagnosis:

Type	Definition
Bacteriologically confirmed	Positive by smear, culture, or molecular test (CBNAAT/TrueNat)
Clinically diagnosed	Not bacteriologically confirmed but clinical/radiological diagnosis

Based on drug resistance:

Type	Definition
Drug-susceptible TB (DS-TB)	Sensitive to RIF and INH
INH-resistant TB (Hr-TB)	Resistant to INH only, sensitive to RIF
Rifampicin-resistant TB (RR-TB)	Any resistance to RIF (includes MDR-TB)
MDR-TB	Resistant to at least INH + RIF
Pre-XDR-TB	MDR/RR-TB + resistance to any fluoroquinolone
XDR-TB	MDR/RR-TB + resistance to fluoroquinolone + at least one of bedaquiline or linezolid

Based on treatment history:

New case: Never treated or treated for <1 month
Previously treated: Relapse, treatment after loss to follow-up, treatment failure

Step 5: Radiological and Other Investigations

Chest X-ray: Supports diagnosis, assesses extent of disease (not confirmatory)
Mantoux test (TST)/IGRA: Useful in LTBI, paediatric TB, immunocompromised
CT chest: Smear-negative cases, complications, miliary TB
Fine needle aspiration (FNAC): Lymph node TB
CSF analysis: TB meningitis (protein elevated, glucose low, lymphocytic pleocytosis; Xpert MTB/RIF Ultra on CSF)

Management of Tuberculosis under NTEP

Drug-Susceptible TB (DS-TB)

Treatment regimen (weight-based dosing, fixed-dose combinations - FDCs):

Phase	Duration	Drugs
Intensive phase (IP)	2 months	HRZE (Isoniazid + Rifampicin + Pyrazinamide + Ethambutol)
Continuation phase (CP)	4 months	HR (Isoniazid + Rifampicin)

Total duration: 6 months (2HRZE + 4HR)

All patients receive daily treatment under DOPT (Daily Observed Preventive Treatment)
Treatment given as FDC tablets based on weight bands
Pyridoxine (Vitamin B6) 10 mg/day given with isoniazid to all patients to prevent peripheral neuropathy

Extended continuation phase (7 months instead of 4): For severe forms - TB meningitis, spinal TB with neurological complications, disseminated TB

Treatment of TB in special situations:

HIV-co-infection: Same anti-TB regimen; start ART within 2-8 weeks of starting ATT (or within 2 weeks if CD4 <50)
Pregnancy: HRZE regimen used; streptomycin contraindicated
Hepatic disease: Avoid pyrazinamide; use HRE or HRSt regimens
Renal disease: Ethambutol dose adjusted based on GFR

Drug-Resistant TB

MDR-TB/RR-TB Regimens under NTEP:

(a) All-oral shorter MDR regimen (9-12 months): Bedaquiline + Levofloxacin + Linezolid + Clofazimine ± Pyrazinamide (BPaL-based) - the newer preferred regimen

(b) Conventional longer MDR-TB regimen (18-24 months): Intensive phase (6 months): Bedaquiline + Levofloxacin (or Moxifloxacin) + Linezolid + Clofazimine + Pyrazinamide Continuation phase (12-18 months): Levofloxacin + Clofazimine + Pyrazinamide + Ethambutol

Key drug monitoring: Monthly sputum culture; LFTs, CBC, ECG (QTc monitoring for bedaquiline, moxifloxacin); audiometry (for aminoglycosides if used)

NTEP Programme Features

Nikshay portal: Online case notification and tracking platform
Nikshay Poshan Yojana: Rs. 500/month nutritional support to all TB patients during treatment
DOPT (Daily Observed Preventive Treatment): Direct observation at facility or home by ASHA/community volunteer
Treatment Supporter: Designated person to observe each dose
99DOTS: Digital adherence technology; patient calls a toll-free number to confirm daily dose
Universal DST: All cases undergo drug resistance testing

(Source: Park's Textbook of Preventive and Social Medicine; NTEP India guidelines)

4. Food Poisoning: Definition, Outbreak Investigation and Control

Definition

Food poisoning is an acute gastroenteritis caused by the ingestion of food or drink contaminated with either (a) living bacteria or their toxins, (b) inorganic chemical substances, or (c) poisons derived from plants and animals.

It is characterized by:

History of ingestion of a common food
Attack of many persons at the same time
Similarity of signs and symptoms in the majority of cases

Types of Food Poisoning

A. Non-bacterial:

Chemical contamination: arsenic, mercury, cadmium, lead, pesticides, fertilizers
Plant toxins: alkaloids, aflatoxins (Aspergillus contamination of cereals)
Animal toxins: fish (tetrodotoxin, ciguatera), shellfish toxins

B. Bacterial (most common):

Type	Agent	Incubation	Mechanism	Characteristic features
Salmonella	S. typhimurium, S. enteritidis	12-24 hrs	Infective (multiplication)	Fever, chills, diarrhoea, may persist 2-3 days
Staphylococcal	Enterotoxins of S. aureus (heat-stable)	1-6 hrs (shortest)	Toxic (preformed toxin)	Sudden nausea, profuse vomiting, cramps; no fever; toxin survives cooking
Cl. perfringens	Spore-forming anaerobe	8-24 hrs	Toxin produced in gut	Watery diarrhoea, cramps; mild vomiting; self-limiting (24 hrs)
B. cereus	Two toxin types	1-6 hrs (emetic); 6-24 hrs (diarrhoeal)	Preformed toxin (emetic) / enterotoxin	Emetic type: vomiting; Diarrhoeal type: diarrhoea, cramps
Botulism	Cl. botulinum toxin	12-36 hrs	Preformed neurotoxin	Cranial nerve palsies, descending flaccid paralysis, respiratory failure; NO diarrhoea

Investigation of a Food Poisoning Outbreak

Step 1: Initial Report and Alert

Receive report (clinical staff, community, laboratory)
Constitute outbreak investigation team
Define case (clinical criteria + temporal/geographic link to common meal)

Step 2: Secure Complete List and Detailed Histories

(a) Interview all persons who shared the common food:

Questionnaire covering: all foods eaten in previous 2 days; place and time of consumption; time of onset of symptoms; nature of symptoms in order of occurrence (nausea, vomiting, diarrhoea, abdominal pain, fever, headache, prostration); personal data (age, sex, residence, occupation)
Interview kitchen employees and food handlers in dining halls

Step 3: Laboratory Investigations

(b) Collect specimens:

Stool samples from sick persons
Vomit specimens from sick persons
Remnants of suspected food (multiple foods collected in sterile containers with refrigeration)
Stool samples from kitchen employees and food handlers
Blood for antibodies (useful for retrospective/Salmonella diagnosis)
Examinations: Aerobic and anaerobic culture; phage typing; total bacterial count; relative counts of each organism type
Animal experiments: Rhesus monkey feeding test for suspected remnants; protection tests for botulism (subcutaneous injection into mice with antitoxic sera)

Step 4: Environmental Study

(c) Inspect eating place, kitchen, food storage:

Food preparation methods; temperatures during storage/cooking
Personal hygiene of food handlers (hand-washing, skin infections, sore throat, diarrhoea)
Kitchen facilities (refrigeration, garbage disposal)
Sources of food (farms, abattoirs, suppliers)

Step 5: Data Analysis

(d) Calculate food-specific attack rates:

For each food item: attack rate among those who ate it vs those who did not
Attack rate = (no. who ate food item and fell ill / total who ate food item) × 100
The incriminated food has: highest attack rate in those who ate it AND lowest in those who did not
Case-control study may be undertaken for epidemiological association
Analyze by time (incubation period distribution), place, person
Calculate relative risk (RR) for each food item

Step 6: Identify and Control the Source

(e) Control measures:

Remove and destroy incriminated food
Thoroughly disinfect cooking/serving utensils
Exclude food handlers with infection from duty until symptom-free and stool culture negative
Improve food storage (refrigeration at <5°C), cooking temperatures, and personal hygiene
Health education to food handlers

Step 7: Treatment of Cases

Oral rehydration therapy for most cases
IV fluids for severe dehydration
Antibiotics are generally not indicated in bacterial food poisoning (except severe Salmonella with systemic spread)
Botulism: Antitoxin (polyvalent, anti-A, B, E) as soon as possible; respiratory support; gastric lavage

Step 8: Report Preparation

Final report with findings, conclusions, recommendations
Notify public health authorities

(Source: Park's Textbook of Preventive and Social Medicine)

5. Dehydration Classification and Management in Children with Diarrhoea

WHO/IMNCI Classification of Dehydration in Diarrhoea

Assessment Signs

Sign	No Dehydration	Some Dehydration	Severe Dehydration
General condition	Well, alert	Restless, irritable	Lethargic/unconscious
Eyes	Normal	Sunken	Very sunken and dry
Tears	Present	Absent	Absent
Mouth/tongue	Moist	Dry	Very dry
Thirst	Drinks normally, not thirsty	Thirsty, drinks eagerly	Drinks poorly or not able to drink
Skin pinch	Returns immediately	Slowly (< 2 sec)	Very slowly (> 2 sec)
Estimated fluid deficit	<5% body weight	5-10% body weight	>10% body weight
Management	Plan A	Plan B	Plan C

Management of Dehydration

Plan A: No Dehydration - Treat at Home

Give more fluids than usual:

After each loose stool:
- Children <2 years: 50-100 ml
- Children 2-10 years: 100-200 ml
- Children >10 years: As much as wanted

Fluid options:

ORS solution (preferred)
Home fluids: rice water, diluted yoghurt drinks, green coconut water, weak tea, soup
Avoid: commercial carbonated drinks, commercial fruit juices, sweetened tea (cause osmotic diarrhoea and hypernatraemia); avoid coffee and medicinal teas

Continue feeding: Food should NEVER be withheld; usual diet of cereals, vegetables continued during diarrhoea and increased afterwards. Never dilute the child's usual food.

Return to facility if: child worsens; cannot drink or breastfeed; develops bloody stools; becomes sicker.

Plan B: Some Dehydration - Oral Rehydration at Clinic

ORS dose: 75 ml/kg ORS over 4 hours

Administration:

Give frequently in small sips (teaspoon every 2-3 minutes for infants)
If the child vomits, wait 10 minutes then resume more slowly
Breastfeeding should continue during ORS
If the child wants more ORS than the estimated amount and does not vomit, allow more
After 4 hours, reassess and reclassify dehydration

WHO Recommended ORS Formulation (Reduced osmolarity - since 2004):

Component	Amount
Sodium chloride	2.6 g/L
Trisodium citrate	2.9 g/L
Potassium chloride	1.5 g/L
Glucose (anhydrous)	13.5 g/L
Osmolarity	245 mOsm/L

The reduced osmolarity ORS decreases stool output by 20%, reduces vomiting by 30%, and reduces need for supplemental IV therapy by 33% compared to the original ORS.

Home-made solution (if ORS packet unavailable):

1 level teaspoon of salt + 6 level teaspoons of sugar dissolved in 1 litre of safe water

Plan C: Severe Dehydration - Treat Urgently

IV rehydration (Ringer's Lactate preferred; Normal Saline if RL not available):

Age	First Give	Then Give
Infants <12 months	30 ml/kg over 1 hour	70 ml/kg over 5 hours
Children ≥12 months	30 ml/kg over 30 minutes	70 ml/kg over 2.5 hours

Total: 100 ml/kg IV fluid
Reassess every 30 minutes; if not improving, give IV drip faster
As soon as able to drink, give ORS (5 ml/kg/hour) while IV fluids continue
Switch to Plan B when child can drink; complete oral rehydration

Measures to Prevent Future Episodes of Diarrhoea

1. Breastfeeding

Exclusive breastfeeding for the first 6 months
Continue breastfeeding up to 2 years and beyond
Breastfed infants have significantly lower diarrhoea morbidity and mortality

2. Improved Weaning Practices

Introduce complementary foods safely after 6 months
Fresh, properly cooked food; use clean utensils
Do not store prepared food at room temperature for >2 hours

3. Use of Safe Water

Use clean/safe water for drinking and cooking
Boil or treat water where safe supply not available
Store water in clean, covered containers

4. Handwashing

Wash hands with soap and water before feeding children, before food preparation, after defecation, and after handling children's stools
Critical intervention reducing diarrhoea incidence by up to 47%

5. Sanitation

Use of latrines; proper disposal of stools (including children's stools)
Fly control

6. Immunization

Rotavirus vaccine: Given at 6 weeks and 10 weeks (oral); prevents severe rotavirus diarrhoea (rotavirus accounts for 15-25% of diarrhoeal cases in treatment centres)
Measles vaccine: Measles is a major precipitant of severe/fatal diarrhoea in children
Cholera vaccine where indicated

7. Zinc Supplementation (Treatment)

Zinc 20 mg/day (10 mg for infants <6 months) for 14 days with ORS
Reduces duration and severity of acute diarrhoea episode
Prevents recurrence in the following 2-3 months
Part of NTAGI and WHO guidelines

8. Vitamin A Supplementation

Reduces severity and case-fatality of diarrhoea episodes
100,000 IU for infants 6-11 months; 200,000 IU for children >1 year, given every 6 months

9. Nutrition

Adequate feeding during and after diarrhoea episode
Treatment of malnutrition (kwashiorkor/marasmus) reduces susceptibility

(Source: Park's Textbook of Preventive and Social Medicine)

6. National Drug Policy for Malaria, NVBDCP Strategies and Outbreak Investigation

National Drug Policy for Malaria (India - Updated 2013/2019)

The drug policy is governed by the Directorate of NVBDCP/NCVBDC and is based on the species of Plasmodium causing infection, confirmed by microscopy or RDT.

Treatment of P. vivax Malaria

Drug	Dose	Duration
Chloroquine	25 mg/kg total (10 mg/kg Day 1, 10 mg/kg Day 2, 5 mg/kg Day 3)	3 days
Primaquine (radical cure, prevents relapse)	0.25 mg/kg/day	14 days

Primaquine is contraindicated in: pregnant women; infants <6 months; G6PD-deficient persons

Treatment of P. falciparum Malaria

Most parts of India (except North-East):

Phase	Drug	Dose
ACT-SP	Artesunate 4 mg/kg/day	3 days
	+ Sulfadoxine-Pyrimethamine	Single dose on Day 1
	+ Primaquine (single dose, gametocyte clearance)	0.75 mg/kg on Day 2

North-Eastern States (SP resistance reported):

Drug	Dose
ACT-AL: Artemether (20 mg) + Lumefantrine (120 mg)	Age-specific weight-based dose schedule × 3 days
+ Primaquine (gametocyte clearance)	0.75 mg/kg single dose

Note: Artemisinin monotherapy is BANNED in India to prevent resistance development

Severe/Complicated Malaria (P. falciparum)

First line: Artesunate IV/IM 2.4 mg/kg at 0, 12, 24 hours, then daily until able to take oral treatment → switch to oral ACT to complete 7 days total

Alternative: Quinine IV: 20 mg salt/kg loading dose in 5% dextrose over 4 hours; then 10 mg/kg 8-hourly until oral treatment possible

Severe malaria - additional management:

Manage complications: cerebral malaria (airway/seizure management), hypoglycaemia (IV dextrose), severe anaemia (blood transfusion), acute renal failure (dialysis), pulmonary oedema
Do NOT use: corticosteroids, IV mannitol, heparin, adrenaline, or overhydrate

Malaria in pregnancy:

1st trimester: Quinine (3 days) + Clindamycin (7 days); ACT if quinine unavailable
2nd and 3rd trimester: ACT
P. vivax: Chloroquine; primaquine contraindicated in pregnancy

Mixed infection (P. vivax + P. falciparum): Treat as P. falciparum malaria

Chemoprophylaxis

For travellers to endemic areas; soldiers/labourers posted in high-endemic areas
Weekly chloroquine (for P. vivax endemic areas)
Doxycycline daily (for P. falciparum/drug-resistant areas)
Start 1 week before travel; continue for 4 weeks after leaving endemic area

Strategies for Malaria Control under NVBDCP/NCVBDC

National Framework for Malaria Elimination in India (2016); National Strategic Plan 2017-2022

Goal: Eliminate malaria from India by 2030

State categorization (by API):

Category	Definition
0 - Prevention of re-establishment	Zero indigenous cases
1 - Elimination phase	API <1, all districts API <1
2 - Pre-elimination phase	State API <1, but some districts API ≥1
3 - Intensified control phase	API ≥1

Strategies (Strategic Action Plan 2017-2022):

(a) Surveillance and Case Management

Passive case detection (PCD): All fever cases presenting to health facilities tested (microscopy/RDT)
Active case detection (ACD): House-to-house fever surveys; mass blood surveys in high-endemic areas; fortnightly surveys in epidemic-prone areas
ABER (Annual Blood Examination Rate): Target ≥10% of population
Early diagnosis and complete treatment: All confirmed cases treated within 24 hours of diagnosis
Rapid Diagnostic Tests (RDT): Bivalent RDT (introduced 2012) detects both P. falciparum (HRP-2 antigen) and P. vivax (LDH antigen); results in 20 minutes
Sentinel surveillance: At selected sites for trend monitoring

(b) Integrated Vector Management (IVM)

Indoor Residual Spray (IRS): Two rounds per year in high-endemic areas (2 rounds: before and after transmission season)
- Insecticides: Synthetic pyrethroids (replacing DDT due to resistance)
- Coverage: ≥80% of houses sprayed
Insecticide-Treated Nets (ITNs) and Long-Lasting Insecticidal Nets (LLINs): Distributed free to tribal/high-risk populations; LLINs introduced 2009; effective for 3 years
Anti-larval measures and source reduction:
- Biological: Bacillus thuringiensis israelensis (Bti); larvivorous fish (Gambusia affinis, Lebistes)
- Chemical: Temephos (Abate) for water containers; pyrethrum space spray
- Environmental: Drainage of stagnant water; filling of pits; proper management of irrigation channels

(c) Epidemic Preparedness and Early Response

Epidemic-prone areas: Forested/tribal areas, development project sites, border areas, areas affected by natural disasters
Epidemic response: Rapid case detection; mass drug administration; emergency IRS; social mobilization

(d) Supportive Interventions

Capacity building
Behavioural change communication (BCC)
Intersectoral collaboration (water/irrigation, forest, agriculture departments)
Monitoring and evaluation
Drug Distribution Centres (DDC) and Fever Treatment Depots (FTD): Community-based malaria drug dispensing by trained volunteers

Urban Malaria Scheme

Launched 1971; focuses on antilarval measures (An. stephensi breeds in overhead tanks, cisterns, water coolers)
Major cities: Chennai, Kolkata, Ahmedabad, Mumbai

Investigation of a Malaria Outbreak

Indicators for outbreak (epidemic):

API >5 in an area where normal API is <1
Sudden increase in malaria cases above the expected seasonal baseline
3 or more times the expected cases in a given time period

Steps

1. Confirm the outbreak:

Verify laboratory diagnoses (microscopy/RDT)
Establish that cases exceed the normal background rate

2. Describe the outbreak:

Time: Epidemic curve; date of onset; duration
Place: Map cases; identify focal areas, proximity to water bodies, construction sites
Person: Age, sex, occupational exposure, immunity status, travel history

3. Identify risk factors:

Identify vector: species, breeding sites, density, insecticide susceptibility
Check IRS coverage and ABER in the area
Assess drug resistance if treatment failure rate is high

4. Immediate control measures:

Active case detection: House-to-house fever surveys; blood smear collection from all fever cases
Rapid treatment: Same-day treatment of all positive cases
Emergency IRS: Focal spray of affected villages with synthetic pyrethroid
Anti-larval measures: Source reduction; Bti; larvivorous fish; oil spray
Distribution of LLINs: Especially to pregnant women, children under 5
Health education: Seek treatment for fever within 24 hours

5. Surveillance and monitoring:

Weekly reporting of cases during outbreak period
Daily fever case tracking
Monitor for drug resistance (non-response within 72 hours)
Report to district/state malaria officer

6. Investigation of contributing factors:

Environmental: Recent flooding, irrigation projects, deforestation
Vector: New breeding sites; change in vector species; insecticide resistance
Drug: Treatment failure; fake/substandard antimalarials

(Source: Park's Textbook of Preventive and Social Medicine)

7. Dengue: Clinical Features, Diagnosis, Management, NVBDCP Control and Outbreak Investigation

Clinical Features of Dengue

Dengue is caused by dengue virus (DENV 1-4) and transmitted by Aedes aegypti (primary vector) and Ae. albopictus. Incubation period: 4-6 days (range 3-14 days).

Clinical Classification (WHO 2009 - adopted by NVBDCP)

1. Dengue Fever (DF) - Undifferentiated fever / Classic dengue

Sudden onset high fever (39-40°C), often biphasic ("saddle-back" fever) lasting about 5 days
Severe headache, retro-orbital pain, severe myalgia and arthralgia ("breakbone fever")
Nausea, vomiting, anorexia, altered taste
Skin eruptions in 80% of cases: diffuse flushing on face/neck/chest in early phase; maculopapular or scarlatiniform rash on 3rd-4th day starting on chest/trunk, spreading to extremities
Rash lasts 2 hours to several days; may be followed by desquamation
Leucopenia (WBC ≤5000/mm³); thrombocytopenia (platelet <150,000)
Case fatality is exceedingly low
Full recovery usual; convalescence may be prolonged

2. Dengue Haemorrhagic Fever (DHF) - Three phases:

Phase	Features
Febrile phase (Day 1-3)	Abrupt high fever; facial flushing; headache; anorexia; vomiting; epigastric discomfort; maculopapular rash
Critical phase (Day 4-6)	Defervescence; plasma leakage; haemoconcentration; pleural effusion/ascites; rapid worsening or shock
Recovery phase (Day 7-10)	Reabsorption of plasma; bradycardia; rash with white islands on red background

WHO Criteria for DHF (ALL four required):

Acute onset of fever of 2-7 days duration
Haemorrhagic manifestations (positive tourniquet test/petechiae/ecchymoses/purpura/mucosal bleeding)
Platelet count ≤100,000/mm³
Evidence of plasma leakage: haemoconcentration ≥20% from baseline, or pleural effusion/ascites/hypoproteinaemia

3. Dengue Shock Syndrome (DSS) - DHF criteria PLUS shock:

Tachycardia, cool extremities, delayed capillary refill, weak pulse, lethargy/restlessness
Pulse pressure ≤20 mmHg (e.g., 100/80 mmHg)
Hypotension: systolic <80 mmHg (<5 years) or 80-90 mmHg (older children/adults)

WHO Grading (DF/DHF)

Grade	Classification	Features
DF	-	Fever + ≥2 symptoms; no plasma leakage
DHF Grade I	DHF	DF features + positive tourniquet test; plasma leakage
DHF Grade II	DHF	Grade I + spontaneous bleeding (petechiae, ecchymoses, epistaxis, black tarry stools)
DHF Grade III	DSS	Grade II + circulatory failure (weak pulse, pulse pressure ≤20 mmHg, hypotension, cold clammy skin, restlessness)
DHF Grade IV	DSS	Grade III + profound shock (undetectable BP/pulse)

Diagnosis of Dengue

Clinical diagnosis is based on above features + epidemiological context (known outbreak, Aedes exposure).

Laboratory diagnosis:

Test	Window of Detection	Notes
NS1 antigen detection (ELISA/RDT)	Days 1-5 of fever	High sensitivity early in illness; becomes negative after defervescence
RT-PCR (viral RNA)	Days 1-5	Highest specificity; detects all 4 serotypes; also for genotyping
Virus isolation	Days 1-6	From serum, plasma, buffy coat; confirms serotype
IgM antibody (ELISA - MAC-ELISA)	Day 5 onwards; peaks ~2 weeks	Dengue IgM; may cross-react with other flaviviruses
IgG antibody (ELISA)	Primary: Day 14+; Secondary: Day 1-2	Persists for years; useful for serosurveillance
Haemagglutination inhibition (HI) test	Paired sera (acute + convalescent)	4-fold rise confirms infection

Supportive laboratory findings:

Leucopenia
Thrombocytopenia (platelet count drop)
Rising haematocrit (≥20% from baseline = plasma leakage)
Elevated liver enzymes (SGOT/SGPT)
Prolonged PTT/coagulopathy in DHF
Chest X-ray/ultrasound: pleural effusion, ascites

Management of Dengue

No specific antiviral treatment; management is supportive.

DF (Dengue Fever - Outpatient):

Paracetamol for fever and pain (target temperature <39°C)
AVOID aspirin, ibuprofen, NSAIDs (risk of bleeding, gastric erosion)
Copious oral fluids: ORS, fruit juices, coconut water
Rest; monitor for warning signs (persistent vomiting, abdominal pain, bleeding, rapid breathing)
Outpatient follow-up daily once fever defervesces (critical period is day 3-7)

DHF Febrile Phase (Grade I-II):

Same as DF management
Paracetamol to keep temperature <39°C
Oral fluids aggressively; IV fluids if persistent vomiting or refusing feeds
Monitor closely: serial haematocrit daily from Day 3; platelet count; blood pressure

DHF Critical Phase/DSS (Grade III-IV): Hospitalize Urgently

Volume replacement (IV fluid therapy):

Crystalloids (Normal Saline, Ringer's Lactate) as first choice
Start with 10 ml/kg/hour; titrate based on haematocrit, vital signs, urine output
If haematocrit rises despite IV: add colloid (Dextran 40 or polygeline/degraded gelatin)
Monitor every hour: vital signs, urine output, haematocrit
ABCS monitoring: Acidosis, Bleeding, Calcium (Na, K), Sugar

Criteria for improvement: Haematocrit falls; pulse rate and BP stable; urine output rises Criteria for no improvement/deterioration: Haematocrit/pulse rises; pulse pressure falls; urine output falls; signs of shock

Platelet transfusion indications:

Prophylactic: platelet <10,000/mm³
Prolonged shock with coagulopathy and abnormal coagulogram
Systemic massive bleeding (with red cell transfusion)

No prophylactic platelet transfusion even at <20,000/mm³ in the absence of the above

Criteria for patient discharge:

Absence of fever for ≥24 hours without antipyretics
Return of appetite
Visible clinical improvement
Good urine output
Minimum 2-3 days after recovery from shock
Platelet count >50,000/mm³ and rising

Dengue Control Strategies under NVBDCP/NCVBDC

Global Strategy for Dengue Prevention and Control 2030 goals:

Reduce dengue mortality by ≥50% by 2020 (now 2030)
Reduce dengue morbidity by ≥25% by 2020 (now 2030)

1. Vector Control (Primary strategy)

Personal protection measures:

Full-sleeve clothing; insect repellent creams, coils, mats, liquids
Bed nets for sleeping infants and young children (protection during daytime - Aedes bites during day)
Isolation of dengue patient under bed-nets during first few days of illness (to prevent spread)

Environmental management (source reduction):

Detection and elimination of Aedes aegypti breeding places:
- Clear roof tops, porticos, sunshades of collected water
- Cover water storage containers properly
- "Weekly Dry Day": Empty and dry all containers, coolers, flower vases, tyres, discarded containers once weekly
- Proper disposal of solid waste (tins, tyres, coconut shells)
Apply temephos (Abate) larvicide to water containers that cannot be emptied

Chemical control:

Fogging/spraying with insecticides (pyrethrin/malathion) during outbreaks (space spray)
Indoor residual spray in epidemic settings

2. Case Management and Surveillance

Integrated Disease Surveillance Programme (IDSP): Mandatory notification of dengue
Weekly reporting from sentinel hospitals
Monitoring dengue serotypes/genotypes

3. Dengue Vaccine (CYD-TDV - Dengvaxia)

A live attenuated tetravalent dengue vaccine (covers all 4 serotypes)
Given as 3 subcutaneous doses at 0, 6, 12 months
WHO recommends only for seropositive individuals ≥9 years in highly endemic areas (risk of severe dengue in seronegative vaccinees)
Reconstituted vaccine: use within 6 hours; stored 2-8°C; no preservative/adjuvant
Contraindications: Immunocompromised; HIV with immune deficiency; pregnancy/breastfeeding

4. IEC and Community Mobilization

Awareness campaigns about symptoms, preventive measures, and early care-seeking
School health programmes for dengue prevention

Dengue Outbreak Investigation

Step 1: Verify and Confirm the Outbreak

Confirm laboratory diagnosis (NS1/IgM/RT-PCR)
Establish that cases exceed expected endemic baseline for the season
Determine dengue serotype(s) involved (RT-PCR/virus isolation)

Step 2: Descriptive Epidemiology

Time: Epidemic curve; date of onset; peak; duration
Place: Map cases; identify hotspots; proximity to stagnant water, construction sites
Person: Age, sex, occupation; identify high-risk groups (children, non-immune migrants)

Step 3: Entomological Investigation

Breeding site survey: Identify positive containers (Stegomyia indices)
- House Index (HI): % houses with Aedes larvae or pupae
- Container Index (CI): % positive containers
- Breteau Index (BI): Number of positive containers per 100 houses
- BI > 5 = epidemic threshold (some authorities use BI > 20)
Identify predominant breeding container types
Assess adult mosquito density (ovitrap index)

Step 4: Source Investigation

Identify index cases; trace introduction of new dengue serotype
Review case records for clusters (schools, apartments, factories)

Step 5: Control Measures During Outbreak

Focal fogging/space spray with pyrethrin in affected area (morning and evening - Aedes activity peak)
Emergency source reduction: Intensive house-to-house visits; clear stagnant water; remove discarded containers
Larviciding: Temephos in water containers
Distribute mosquito repellent; educate households
Intensify passive surveillance; set up dengue testing at all fever cases

Step 6: Monitoring and Evaluation

Track cases daily during outbreak
Monitor entomological indices weekly
Assess effectiveness of control measures (decline in new cases)

Step 7: Report

Submit outbreak investigation report to state/national authorities
IDSP-based reporting

(Source: Park's Textbook of Preventive and Social Medicine)

Quick Summary Reference Table

Question	Key Theme	Core Exam Points
1. Measles	MR campaign; SIAs; 2-dose schedule	MCV1 at 9 months; MCV2 at 15-18 months; 96% coverage for eradication; IgM ELISA for confirmation
2. ARI/IMNCI	3-level classification	Fast breathing cut-offs; chest indrawing = severe; amoxicillin; danger signs → refer
3. TB/NTEP	UDST; CBNAAT first line	2HRZE + 4HR; bedaquiline for MDR; Nikshay Poshan Rs.500/month
4. Food poisoning	Definition; attack rate analysis	Food-specific attack rate; staphylococcal = shortest IP; botulism = antitoxin
5. Diarrhoea	Plan A/B/C; zinc; ORS	Reduced osmolarity ORS 245 mOsm/L; 75 ml/kg over 4 hrs for Plan B; zinc 14 days
6. Malaria	Drug policy 2013; NVBDCP	ACT-SP for Pf; chloroquine + primaquine for Pv; API for categorization; ABER target ≥10%
7. Dengue	DHF grading; NS1; IVM	No aspirin; crystalloids; platelet only if <10,000; weekly dry day; Breteau Index >5 = epidemic

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