Refer to Park's textbook of PSM (communicable diseases)and give me the following information Causative organism Incubation period Mode of transmission Host factors Environmental factors Clinical features complications Diagnosis Treatment Prevention Programmes and schemes if any About following diseases Measles Rubella Influenza SARS COVID TB Polio Diarrheal diseases Typhoid Dengue Malaria Filariasis Rabies Japanese encephalitis Ebola Make a table

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Here is the comprehensive table compiled directly from Park's Textbook of Preventive and Social Medicine (PSM):

Communicable Diseases - Park's PSM Summary Table

Source: Park's Textbook of Preventive and Social Medicine, 26th Edition (ISBN 9789382219163)

1. MEASLES (Rubeola)

Parameter	Details
Causative Organism	Paramyxovirus (RNA virus, group Myxoviruses). No animal reservoir.
Incubation Period	10-14 days (range 7-18 days). Pre-rash catarrhal stage lasts 3-5 days.
Mode of Transmission	Droplet infection; airborne spread via droplet nuclei; direct contact with nasal and throat secretions. Most communicable from onset of catarrhal symptoms to 4 days after rash appears.
Host Factors	Children 1-5 years most affected. One attack confers lifelong immunity. Infants protected by maternal antibodies up to 6-9 months. Unimmunized children in crowded settings are most vulnerable.
Environmental Factors	Endemic worldwide; epidemic every 2-3 years. Urban populations cycle faster. Rainy/cold seasons favour spread. Overcrowding and malnutrition increase severity.
Clinical Features	3 stages: (1) Incubation stage, (2) Pre-eruptive/catarrhal stage - fever, coryza, cough, conjunctivitis, Koplik's spots on buccal mucosa (pathognomonic), (3) Eruptive stage - maculopapular rash beginning at hairline, spreading down to face, trunk, extremities.
Complications	Bronchopneumonia (most common cause of death), otitis media, laryngotracheobronchitis (croup), encephalitis, diarrhoea, subacute sclerosing panencephalitis (SSPE - late complication), blindness (in Vitamin A deficiency).
Diagnosis	Clinical diagnosis (Koplik's spots + rash). Lab: serological (ELISA IgM), virus isolation, RT-PCR.
Treatment	Supportive: antipyretics, Vitamin A (2 doses), adequate nutrition. Antibiotics for secondary bacterial infections.
Prevention	Measles vaccine (MCV); two-dose schedule (MCV1 at 9-12 months, MCV2 at 16-24 months); SIAs (Supplementary Immunization Activities). Vitamin A supplementation reduces CFR.
Programmes/Schemes	Universal Immunization Programme (UIP); Mission Indradhanush; Measles-Rubella (MR) Campaign; Global Measles and Rubella Strategic Framework 2021-2030 (target: measles elimination).

2. RUBELLA (German Measles)

Parameter	Details
Causative Organism	RNA virus of the Togavirus family (Rubivirus genus). Only one antigenic type.
Incubation Period	14-21 days (average 16-18 days).
Mode of Transmission	Droplet infection from nose and throat; droplet nuclei (aerosols). Infective from 1 week before to 1 week after rash appears. Congenitally infected infants shed virus for months. Portal of entry: respiratory route.
Host Factors	Mainly 3-10 years age group. One attack gives lifelong immunity. Infants of immune mothers protected for 4-6 months. 10-40% may reach adulthood without natural infection if no immunization. Women of childbearing age are an important risk group.
Environmental Factors	Worldwide; epidemics every 4-9 years in pre-vaccination era. Seasonal - late winter and spring in temperate zones.
Clinical Features	Mild illness: low-grade fever, lymphadenopathy (post-auricular, suboccipital, posterior cervical nodes), maculopapular rash for ~3 days. Often subclinical (25-50%). Congenital Rubella Syndrome (CRS): cataracts, congenital heart disease (PDA, VSD), deafness, microcephaly, mental retardation, purpura, hepatosplenomegaly.
Complications	CRS (most serious) - risk highest if infection in 1st trimester (up to 85% risk). Encephalitis (rare in children), thrombocytopenic purpura, arthritis (young women).
Diagnosis	Clinical. Lab: ELISA for rubella-specific IgM and IgG; virus isolation from throat/urine; HI test. Prenatal diagnosis: rubella IgM in fetal blood.
Treatment	Symptomatic/supportive. No antiviral treatment. Termination of pregnancy offered if rubella occurs in first trimester.
Prevention	Rubella vaccine (live attenuated RA 27/3 strain); given as MR or MMR vaccine. Vaccination of women of childbearing age. Pregnancy should be avoided for 3 months after vaccination.
Programmes/Schemes	MR (Measles-Rubella) Campaign in India since 2017; MMR in UIP; Global Rubella elimination goal by 2020 in at least 5 WHO regions.

3. INFLUENZA

Parameter	Details
Causative Organism	Influenza virus types A, B, C, D. All known epidemics due to types A and B. Influenza A is further classified by hemagglutinin (H1-H18) and neuraminidase (N1-N11) subtypes. SARS-CoV-2 (COVID-19) belongs to a different family. Currently circulating: A(H1N1), A(H3N2), B viruses.
Incubation Period	1-3 days (range 1-4 days).
Mode of Transmission	Droplet infection; airborne (droplet nuclei); contact transmission. Infective 1 day before to 7 days after onset. Attack rates 5-10% in adults, 20-30% in children.
Host Factors	All ages susceptible. Elderly (>65), young children (<2 years), pregnant women, and immunocompromised are at high risk of complications. No long-lasting immunity due to antigenic drift/shift.
Environmental Factors	Temperate: winter epidemics. Tropics: year-round activity. Epidemics every 2-3 years (Influenza A), 3-6 years (Influenza B). Pandemics every 10-40 years due to major antigenic shift. Overcrowded settings, schools, workplaces amplify spread.
Clinical Features	Sudden onset of fever (39-40°C), chills, headache, severe myalgia, malaise, anorexia, dry cough, sore throat, rhinitis. Illness self-limited in 3-7 days. "Influenza-like illness (ILI)" definition: fever ≥38°C + cough or sore throat.
Complications	Primary viral pneumonia, secondary bacterial pneumonia (S. aureus, S. pneumoniae, H. influenzae), myocarditis, encephalitis, Reye's syndrome (in children given aspirin), ARDS. Excess mortality in elderly (cardiac/pulmonary disease exacerbation).
Diagnosis	Rapid Influenza Diagnostic Tests (RIDTs); RT-PCR (gold standard); viral culture; serology (HI/CF tests).
Treatment	Antivirals: Oseltamivir (Tamiflu) - 75 mg BD x 5 days; Zanamivir (inhaled); Amantadine/Rimantadine (type A only). Supportive care; avoid aspirin in children.
Prevention	Annual influenza vaccine (trivalent or quadrivalent); WHO recommends vaccine composition annually. Non-pharmaceutical: hand hygiene, masks, respiratory etiquette, isolation of cases.
Programmes/Schemes	WHO Global Influenza Surveillance and Response System (GISRS); Influenza Surveillance Network in India; National Influenza Centres (NICs). Pandemic preparedness plans under IHR 2005.

4. SARS (Severe Acute Respiratory Syndrome)

Parameter	Details
Causative Organism	SARS coronavirus (SARS-CoV), a novel coronavirus. Natural reservoir: horseshoe bat; amplifying host: palm civet.
Incubation Period	2-7 days, commonly 3-5 days. Maximum 10 days.
Mode of Transmission	Primarily droplet/contact transmission. Direct or indirect contact with mucous membranes (eyes, nose, mouth) with respiratory droplets or fomites. Aerosol-generating procedures (intubation, bronchoscopy, nebulization) amplify nosocomial transmission. Faecal-oral route possible. Virus survives hours on surfaces, up to 4 days in stool, 24+ hours on plastic.
Host Factors	Healthcare workers at highest risk. Attack rate higher in adults; children generally less severely affected. Superspreaders documented (single case infecting many).
Environmental Factors	Hospital settings: major amplification sites. Cold temperatures favour viral survival. First emerged November 2002 in Guangdong, China; spread to 30 countries by August 2003 with 8,422 cases and 916 deaths.
Clinical Features	Prodrome: fever (>38°C), chills, rigors, headache, malaise, myalgia. Respiratory phase (days 3-7): dry non-productive cough, dyspnoea, hypoxemia. Radiographic infiltrates in most patients. 10-20% require ICU admission. ARDS is the severe end-stage.
Complications	ARDS, acute respiratory failure, secondary infections (nosocomial pneumonia), multi-organ dysfunction, death. CFR approximately 10% (higher in elderly).
Diagnosis	Clinical case definition (fever + respiratory illness + epidemiological link). Lab confirmation: RT-PCR (nasopharyngeal aspirate, urine, stool), serological tests (ELISA, IFA), viral culture (BSL-3 facility).
Treatment	Supportive. Ribavirin + steroids used in the epidemic (efficacy uncertain). Oxygen, mechanical ventilation for severe disease. Strict infection control.
Prevention	No vaccine available. Contact tracing; isolation of suspected/confirmed cases; appropriate PPE for healthcare workers; hand hygiene; exit screening of international travellers; timely reporting under IHR 2005.
Programmes/Schemes	IHR (International Health Regulations) 2005 notification; WHO SARS case reporting system; GOARN (Global Outbreak Alert and Response Network).

5. COVID-19 (Coronavirus Disease-2019)

Parameter	Details
Causative Organism	SARS-CoV-2 - a betacoronavirus, single-stranded RNA virus (ssRNA), 60-140 nm diameter, crown-shaped spikes. Closely linked to SARS-CoV. Sensitive to UV rays, ethanol (75%), chlorine-based disinfectants.
Incubation Period	2-14 days (most commonly 5-6 days). Infectivity begins 1-3 days before symptom onset.
Mode of Transmission	Respiratory droplets (>5-10 μm) within 1 metre; airborne via aerosols/droplet nuclei (≤5 μm) - especially in poorly ventilated indoor settings and aerosol-generating procedures. Fomite transmission via contaminated surfaces. Faecal-oral route possible (SARS-CoV-2 detected in urine and faeces). RT-PCR positivity: 1-2 weeks in asymptomatic, up to 3+ weeks in moderate/severe cases.
Host Factors	All age groups susceptible. Severe disease more likely in elderly (>60 years), males, those with comorbidities (DM, HTN, CVD, CKD, chronic lung disease, obesity, immunosuppression). Children generally less severely affected.
Environmental Factors	Poorly ventilated indoor settings, large gatherings, crowded places amplify spread. Cold, dry weather may enhance aerosol survival. R0 initially estimated at 2-3 (Delta ~5-6, Omicron ~8-10 for later variants).
Clinical Features	Asymptomatic (40%); Mild (fever, cough, myalgia, fatigue, anosmia, ageusia, sore throat, headache); Moderate (pneumonia without hypoxia); Severe (SpO2 <90%, RR >30/min, infiltrates >50% of lungs); Critical (ARDS, septic shock, multi-organ failure). WHO 3-tier severity classification used.
Complications	ARDS, acute kidney injury, cardiac injury (myocarditis, arrhythmias), liver dysfunction, DVT/PE, cytokine storm, secondary infections, neurological complications. Post-COVID syndrome (fatigue, dyspnoea, cognitive impairment lasting >12 weeks).
Diagnosis	RT-PCR (gold standard) from nasopharyngeal/oropharyngeal swab; Rapid Antigen Test (RAT); Chest CT (ground glass opacities); HRCT severity scoring; Antibody tests (not for acute diagnosis).
Treatment	Mild: symptomatic; home isolation. Moderate-Severe: oxygen supplementation, remdesivir, dexamethasone (for severe with oxygen requirement), anticoagulation (low-molecular-weight heparin), prone positioning, tocilizumab (in severe). ICU: mechanical ventilation, vasopressors.
Prevention	COVID-19 vaccines (mRNA: Pfizer-BioNTech, Moderna; viral vector: AstraZeneca/Covishield; inactivated: Covaxin/BBV152; protein subunit: Novavax). Non-pharmaceutical interventions: masking, physical distancing (1 metre), hand hygiene, ventilation, isolation, quarantine.
Programmes/Schemes	India: National COVID-19 Vaccination Programme (Co-WIN platform); Ayushman Bharat Health Infrastructure Mission; PM CARES Fund. Global: COVAX facility (Gavi + CEPI + WHO); WHO Emergency Use Listing (EUL). IHR 2005 - COVID declared PHEIC in January 2020, pandemic in March 2020.

6. TUBERCULOSIS (TB)

Parameter	Details
Causative Organism	Mycobacterium tuberculosis (human type); M. bovis (bovine type - through milk). Acid-fast bacillus (AFB), non-spore forming, non-motile.
Incubation Period	4-12 weeks from infection to primary lesion or positive tuberculin test. Risk of developing clinical disease: 5-10% in lifetime of an infected person.
Mode of Transmission	Airborne via droplet nuclei (1-5 μm) produced by coughing, sneezing, speaking, singing. One infectious case can infect 10-15 persons/year. Bovine TB via ingestion of unpasteurized milk.
Host Factors	Age: all ages; peaks in 15-44 years (adults), young children. Males>females. HIV co-infection (8.2% of all TB cases in 2019). Malnutrition, diabetes mellitus, silicosis, immunosuppression, poverty, overcrowding, and alcoholism are risk factors.
Environmental Factors	Poverty, overcrowding, poor ventilation, urban slums, mining, prison settings. Annual Risk of Infection (ARI) 0.5-2% in high-burden countries. About one-third of world population is latently infected.
Clinical Features	Pulmonary TB: chronic productive cough (>3 weeks), haemoptysis, fever, night sweats, anorexia, weight loss, fatigue. Extra-pulmonary: lymphadenitis (most common EPTB), pleural effusion, meningitis (TB meningitis), spinal TB (Pott's disease), renal TB, miliary TB.
Complications	Lung cavitation, spontaneous pneumothorax, cor pulmonale, haemoptysis, ARDS, spread to other organs (miliary TB), adrenal insufficiency (Addison's disease), TB meningitis, death. MDR-TB and XDR-TB are major complications of inadequate treatment.
Diagnosis	Sputum AFB smear (Ziehl-Neelsen); Sputum culture (gold standard - LJ medium); Nucleic acid amplification - Xpert MTB/RIF (CBNAAT); Chest X-ray; Tuberculin skin test (TST/Mantoux); IGRA (interferon gamma release assay); GeneXpert Ultra.
Treatment	DOTS: 6-month regimen - 2HRZE (initial/intensive phase 2 months) + 4HR (continuation phase 4 months). H=Isoniazid, R=Rifampicin, Z=Pyrazinamide, E=Ethambutol. MDR-TB: 18-24 months (fluoroquinolones + injectable agents). Bedaquiline/Delamanid for XDR-TB.
Prevention	BCG vaccination (newborn); DOTS strategy; case finding; contact tracing; chemoprophylaxis (isoniazid) for high-risk contacts; treatment of LTBI; nutritional improvement; housing improvement.
Programmes/Schemes	Revised National Tuberculosis Control Programme (RNTCP) - now National Tuberculosis Elimination Programme (NTEP); End-TB Strategy (WHO, 2016-2030 - target 90% reduction in incidence, 95% reduction in deaths by 2030); India's target: TB-free India by 2025 (TB Harega, Desh Jeetega). Nikshay portal (patient tracking). Pradhan Mantri TB Mukt Bharat Abhiyaan.

7. POLIOMYELITIS

Parameter	Details
Causative Organism	Poliovirus - RNA virus (Enterovirus, Picornaviridae family). 3 serotypes: type 1 (most common cause of paralysis), type 2, type 3. Type 2 eradicated (1999), type 3 eradicated (2012).
Incubation Period	7-14 days (range 3-35 days).
Mode of Transmission	Faecal-oral route (primary); oral-oral (respiratory) route in areas with good sanitation. The virus enters via pharynx/GI tract, replicates in lymphoid tissue, then viremia.
Host Factors	Children under 5 years most susceptible (hence "infantile paralysis"). Males more likely to develop paralytic disease. Immunity: type-specific and lifelong after infection. Tonsillectomy increases risk of bulbar involvement. Pregnancy increases susceptibility.
Environmental Factors	Poor sanitation, open defecation, contaminated water supply. Warm climates and summer season in temperate countries. Overcrowding. India certified polio-free: 27 March 2014.
Clinical Features	4 forms: (1) Inapparent infection (90-95%): no symptoms; (2) Abortive poliomyelitis (4-8%): fever, sore throat, headache, vomiting - no CNS involvement; (3) Non-paralytic poliomyelitis (1-2%): aseptic meningitis; (4) Paralytic poliomyelitis (<1%): spinal, bulbar, or bulbospinal form. Flaccid asymmetric paralysis, maximal within 2-3 days. No sensory loss.
Complications	Permanent flaccid paralysis (lower motor neuron type), respiratory failure (bulbar/spinal involvement), post-polio syndrome (30-40 years later - new muscle weakness, fatigue).
Diagnosis	Stool/rectal swab for virus isolation (gold standard - collected within 14 days of onset of paralysis). Paired serum for neutralizing antibodies. CSF in non-paralytic form.
Treatment	No specific antiviral treatment. Supportive: bed rest in acute phase, physiotherapy, orthopaedic management of residual paralysis, respiratory support (iron lung/ventilator for bulbar).
Prevention	OPV (oral polio vaccine - Sabin): trivalent/bivalent types; IPV (inactivated polio vaccine - Salk): given IM. IPV produces humoral immunity; OPV provides intestinal + humoral immunity. Both herd immunity.
Programmes/Schemes	Global Polio Eradication Initiative (GPEI) 1988; Pulse Polio Immunization Programme (PPIP) in India since 1995-96 (National Immunization Days - NIDs on Sundays); India polio-free since 2014. Switch from tOPV to bOPV (2016). IPV added to UIP. Polio Eradication and Endgame Strategic Plan 2013-2018.

8. DIARRHOEAL DISEASES

Parameter	Details
Causative Organism	Multiple organisms: Bacteria (Vibrio cholerae, E. coli - ETEC, EPEC, EIEC, EHEC, Shigella, Salmonella, Campylobacter); Viruses (Rotavirus - most common in children, Norovirus, Adenovirus); Parasites (Entamoeba histolytica, Giardia lamblia, Cryptosporidium).
Incubation Period	Varies: Cholera 2 hrs-5 days; Rotavirus 1-3 days; Shigella 1-4 days; ETEC 1-3 days; Salmonella 6-72 hours; Entamoeba 2-4 weeks.
Mode of Transmission	4 Fs: Faeces - Fingers - Flies - Food/Fluid; Faecal-oral route; Contaminated water and food; Person-to-person contact.
Host Factors	Children under 5 years most affected (3 episodes/child/year globally). Malnutrition, HIV, crowding, low breastfeeding rates increase severity. Infants of non-immune mothers more susceptible.
Environmental Factors	Poor water supply, inadequate sanitation, open defecation, poor food hygiene, floods and natural disasters, warm/humid climate (increases fly breeding and pathogen survival), overcrowding.
Clinical Features	4 clinical types: (1) Acute watery diarrhoea (main risk: dehydration), (2) Acute bloody diarrhoea/dysentery (Shigella - intestinal damage, sepsis), (3) Persistent diarrhoea (≥14 days - risk: malnutrition), (4) Diarrhoea with severe malnutrition. WHO dehydration scale: no dehydration, some dehydration, severe dehydration.
Complications	Severe dehydration (hypovolaemic shock), electrolyte imbalance (hyponatraemia, hypokalaemia), metabolic acidosis, malnutrition, intussusception (rotavirus), HUS - haemolytic uraemic syndrome (EHEC O157:H7), septicaemia, death (>0.48 million child deaths in 2016).
Diagnosis	Stool examination (microscopy, culture, sensitivity); ORS assessment (dehydration signs); ELISA for rotavirus; Widal test not appropriate here; Stool PCR for specific pathogens.
Treatment	ORT (Oral Rehydration Therapy) - cornerstone: ORS (WHO/UNICEF formula: NaCl 2.6g, KCl 1.5g, Na citrate 2.9g, glucose 13.5g per litre); IV fluids for severe dehydration (Ringer's lactate); Zinc supplementation (10-20 mg/day x 14 days); Continued breastfeeding; Selective antibiotics (cotrimoxazole/ciprofloxacin for shigellosis; azithromycin for cholera).
Prevention	Safe water supply (chlorination); adequate sanitation and sewage disposal; hand washing with soap; food hygiene; breastfeeding promotion; Rotavirus vaccine (Rotavac, Rotarix, RotaTeq); proper excreta disposal.
Programmes/Schemes	Diarrhoeal Diseases Control Programme (WHO, 1980); CDD (Control of Diarrhoeal Diseases) Programme in India; Integrated Management of Childhood Illness (IMCI); National Oral Rehydration Programme; Jal Jeevan Mission (safe water supply); Swachh Bharat Mission (sanitation).

9. TYPHOID FEVER

Parameter	Details
Causative Organism	Salmonella typhi (S. typhi) - Gram-negative bacillus. Paratyphoid: S. paratyphi A, B, C. Collectively = enteric fever. Found only in man.
Incubation Period	1-3 weeks (average 2 weeks). Short in large-dose/water-borne outbreaks.
Mode of Transmission	Faecal-oral route via contaminated water and food (the main route). Flies as mechanical vectors. Carriers (convalescent, chronic) - important source. No animal reservoir.
Host Factors	All ages; school-age children and young adults in endemic areas. Chronic carriers (gallbladder reservoir): 1-5% especially females with gallbladder disease. Vi antigen helps escape host defences. Gastric achlorhydria increases susceptibility.
Environmental Factors	Poor water supply and sanitation, open defecation, contaminated street food, flooding, inadequate sewage disposal. Endemic in South and Southeast Asia, Africa, Latin America.
Clinical Features	Week 1: Stepladder fever (Wunderlich curve), headache, abdominal pain, rose spots (10-30% on trunk), relative bradycardia, splenomegaly. Week 2: Sustained fever (39-40°C), toxic appearance, coated tongue, constipation → diarrhoea (pea-soup), hepatosplenomegaly. Week 3: Complications may arise. Week 4: Defervescence.
Complications	Intestinal perforation (most dangerous - ileum), intestinal haemorrhage, typhoid hepatitis, cholecystitis, myocarditis, encephalopathy (typhoid state), lobar pneumonia, thrombophlebitis. MDR typhoid (resistance to chloramphenicol, ampicillin, cotrimoxazole).
Diagnosis	Blood culture (1st week - gold standard, positive in 80%); Widal test (significant titre: O ≥1:160, H ≥1:160 - not reliable alone); Bone marrow culture (most sensitive, positive even with prior antibiotics); Stool and urine culture (2nd-3rd week); ELISA/PCR. Typhidot: IgM anti-OMP antibodies.
Treatment	Ciprofloxacin (1st line, 500 mg BD x 14 days); Ceftriaxone (IV for severe/resistant); Azithromycin; Dexamethasone for severe toxaemia. MDR cases: ciprofloxacin or ceftriaxone. XDR (extensively drug resistant typhoid): azithromycin + carbapenems.
Prevention	Safe water supply; sanitary disposal of excreta; food hygiene; identification and treatment of carriers; anti-typhoid vaccination.
Programmes/Schemes	Anti-Typhoid Vaccines: (1) Ty21a (live oral vaccine, 4 doses on days 1,3,5,7 - from 6 years), (2) Vi polysaccharide vaccine (Vi CPS - single IM dose for ≥2 years), (3) Typhoid Conjugate Vaccine (TCV - Typbar-TCV, single dose from 6 months, recommended by WHO 2018, recently introduced in UIP in India). Swachh Bharat Mission (prevention).

10. DENGUE FEVER

Parameter	Details
Causative Organism	Dengue virus - RNA virus (Flavivirus family). 4 serotypes: DENV-1, DENV-2, DENV-3, DENV-4. DENV-2 and DENV-3 associated with severe dengue.
Incubation Period	4-10 days (extrinsic incubation in mosquito: 8-12 days).
Mode of Transmission	Bite of infected female Aedes aegypti mosquito (primary vector); Aedes albopictus (secondary vector). Diurnal biter. No person-to-person transmission (except vertical/rare blood-borne).
Host Factors	All ages susceptible. Immunity is serotype-specific and lifelong. Secondary infection with different serotype = severe dengue (antibody-dependent enhancement). Children in endemic areas most affected.
Environmental Factors	Tropical and subtropical regions. Stagnant water collections (flower pots, tyres, coolers, containers) near human habitation as mosquito breeding sites. Rainy season, urban/semi-urban settings, 25-35°C temperature, high humidity.
Clinical Features	3 forms: (1) Classical Dengue Fever (DF): Sudden high fever (39-40°C), severe headache, retro-orbital pain, arthralgia, myalgia ("break-bone fever"), maculopapular rash (3rd-4th day), lymphadenopathy, biphasic fever curve, tourniquet test positive; (2) Dengue Haemorrhagic Fever (DHF): 3 phases - febrile (1-3 days), critical/plasma leakage (days 3-6), recovery. Thrombocytopenia (platelets <100,000), haematocrit rise ≥20%, haemorrhagic manifestations; (3) Dengue Shock Syndrome (DSS): DHF + circulatory collapse (narrow pulse pressure <20 mmHg or hypotension).
Complications	Severe dengue: severe plasma leakage leading to shock, severe bleeding (haematemesis, melena), severe organ impairment (liver, CNS, heart, kidneys). DHF CFR: 1-5% with good management; up to 20% without treatment.
Diagnosis	NS1 antigen (days 1-5 of fever - highly specific); IgM antibody ELISA (from day 5); IgG (secondary infection); RT-PCR (gold standard for early diagnosis); CBC (thrombocytopenia, leucopaenia, haemoconcentration); Tourniquet test.
Treatment	No specific antiviral. Supportive: paracetamol for fever (avoid NSAIDs/aspirin); IV fluids for dehydration/shock; platelet transfusion if <10,000 or active bleeding; close monitoring of haematocrit and platelet count; WHO dengue management protocol.
Prevention	Vector control: source reduction (eliminate breeding sites); biological control (Bacillus thuringiensis israelensis); chemical control (larvicides - temephos; adulticicides - pyrethrin sprays); personal protection (repellents, long clothing, mosquito nets). Dengue vaccine: Dengvaxia (CYD-TDV, Sanofi Pasteur) - only for seropositive persons ≥9 years; Qdenga (TAK-003, Takeda) - approved in 2023.
Programmes/Schemes	National Vector-Borne Disease Control Programme (NVBDCP); National Dengue Day (16 May); IDSP (Integrated Disease Surveillance Programme) for surveillance; WHO Global Strategy for Dengue Prevention and Control 2012-2020.

11. MALARIA

Parameter	Details
Causative Organism	Plasmodium species: P. vivax (most common in India, 47% cases), P. falciparum (most lethal, 53% in India), P. malariae, P. ovale, P. knowlesi. Transmitted by infected female Anopheles mosquito.
Incubation Period	P. vivax: 14 days (10-17 days); P. falciparum: 12 days (9-14 days); P. malariae: 28 days; P. ovale: 14-16 days. Extrinsic incubation in mosquito: 10-12 days at 25°C.
Mode of Transmission	Bite of infected female Anopheles mosquito (primary). Congenital malaria (trans-placental). Blood transfusion malaria. Syringe transmission (IV drug users). Main vectors in India: A. culicifacies (rural), A. stephensi (urban), A. fluviatilis, A. minimus.
Host Factors	All ages susceptible. Natural/acquired immunity develops in endemic areas. Sickle cell trait (HbAS), G6PD deficiency, thalassemia, Duffy antigen negativity offer partial protection. Pregnant women and children under 5 at highest risk. Splenomegaly index (SI) measures endemicity.
Environmental Factors	Tropical/subtropical regions. Breeding sites: rice fields, stagnant water, irrigation canals, swamps (A. culicifacies); urban water storage, construction sites (A. stephensi). Temperature 20-30°C, humidity >60%, rainfall for Anopheles breeding. Rainy season = peak transmission. Altitude <2500m generally safe. Malaria endemicity: Hypo-Meso-Hyper-Holoendemicity based on spleen rate and parasite rate.
Clinical Features	Classical malarial paroxysm: Cold stage (15-60 min) → Hot stage (2-6 hours) → Sweating stage (2-4 hours) → afebrile interval. Periodicity: Tertian (P. vivax/ovale - every 48 hrs), Quartan (P. malariae - every 72 hrs), Quotidian (P. falciparum - irregular). Splenomegaly, anaemia, headache. Severe/complicated falciparum: cerebral malaria (coma), severe anaemia (Hb<5g/dL), blackwater fever (haemoglobinuria), renal failure, hypoglycaemia, ARDS, hyperparasitaemia (>5%).
Complications	Cerebral malaria (P. falciparum - convulsions, altered sensorium, coma), algid malaria, blackwater fever, severe malaria anaemia, thrombocytopenia, splenic rupture, pulmonary oedema, hypoglycaemia, renal failure. Relapses in P. vivax/ovale (due to hypnozoites).
Diagnosis	Peripheral blood smear (gold standard): thick smear (screening), thin smear (species identification, parasitaemia). Rapid Diagnostic Tests (RDTs): HRP-2 antigen (P. falciparum), pLDH (P. vivax); PCR for low parasitaemia; QBC (quantitative buffy coat); Malaria antigen tests.
Treatment	P. vivax: Chloroquine (25 mg/kg over 3 days) + Primaquine (0.25 mg/kg/day x 14 days - radical cure/anti-relapse; G6PD screening needed); P. falciparum: Artemisinin-based Combination Therapy (ACT) - Artesunate + Amodiaquine or Artesunate + Sulfadoxine-Pyrimethamine (AS+SP); Severe malaria: IV Artesunate (drug of choice), IV Quinine + Doxycycline.
Prevention	Personal protection: insecticide-treated bednets (ITNs/LLINs), repellents, protective clothing; Indoor Residual Spraying (IRS) with DDT/synthetic pyrethroids; Larval source management; Biological control (Gambusia fish - larvivorous); Chemoprophylaxis for travellers; Malaria vaccines: RTS,S/AS01 (Mosquirix - first approved malaria vaccine, recommended by WHO in 2021 for children in Sub-Saharan Africa).
Programmes/Schemes	National Framework for Malaria Elimination (NFME) 2016-2030; National Malaria Control Programme (NMCP) since 1953; Enhanced Malaria Control Project (World Bank funded); National Anti-Malaria Programme; Urban Malaria Scheme (UMS); Malaria Elimination Demonstration Project (MEDP - Mandla district, MP). India target: malaria-free by 2030. NVBDCP umbrella.

12. LYMPHATIC FILARIASIS

Parameter	Details
Causative Organism	Wuchereria bancrofti (90% of cases, periodic form in India), Brugia malayi (semi-periodic - SE Asia), Brugia timori (Indonesia). Transmitted via infective mosquito bites.
Incubation Period	Onset of acute episodes: 8-16 months after infective bite. Microfilariae appear in blood 6-12 months post-infection.
Mode of Transmission	Bite of infected vector mosquito: Culex quinquefasciatus (urban/night biting, W. bancrofti), Mansonia species (B. malayi), Aedes and Anopheles spp. Microfilariae show nocturnal periodicity (peak in peripheral blood 10 PM-2 AM).
Host Factors	All ages susceptible; cumulative over time with repeated exposure. Males more commonly show hydrocele. Tropical pulmonary eosinophilia (TPE) - hypersensitivity state, more in males. Long-term residence in endemic area required for development of lymphatic disease.
Environmental Factors	Tropical/subtropical regions. Stagnant water (drains, ditches, cesspits, rice fields) as Culex breeding sites. Poor sanitation, urban slums favours C. quinquefasciatus.
Clinical Features	(1) Asymptomatic (most infected persons); (2) Acute manifestations: ADL (Acute Dermato-Lymphangioadenitis) - episodic fever, lymphadenitis, lymphangitis, acute hydrocele; (3) Chronic manifestations: Lymphoedema (legs, arms, genitals), Elephantiasis (brawny oedema, skin thickening), Hydrocele (scrotal), Chyluria (milky urine); (4) Tropical Pulmonary Eosinophilia (TPE): nocturnal cough, wheeze, eosinophilia >3000, high anti-filarial IgE; (5) Occult filariasis.
Complications	Severe elephantiasis causing permanent disability and disfigurement; genital disability (hydrocele, scrotal elephantiasis); chylous ascites; secondary bacterial/fungal infections of lymphoedematous limbs; psychosocial stigma.
Diagnosis	Microfilariae detection: nocturnal blood smear (10 PM - 2 AM), thick film, membrane filtration, Knott's concentration technique; Immunochromatographic test (ICT) - filarial antigen (W. bancrofti); USG (filarial dance sign - live adult worms in lymphatics); PCR; Chest X-ray in TPE (diffuse mottling).
Treatment	Diethylcarbamazine (DEC) 6 mg/kg/day x 12 days or single annual dose (MDA); Ivermectin 150 μg/kg (single dose) + Albendazole 400 mg (for MDA - two-drug regimen); Lymphoedema management: limb hygiene, exercise, elevation, compression bandages; Hydrocelectomy (surgery).
Prevention	Annual Mass Drug Administration (MDA) with DEC + albendazole (areas where onchocerciasis absent) or ivermectin + albendazole (where onchocerciasis co-endemic); vector control; personal protection.
Programmes/Schemes	National Filaria Control Programme (NFCP) since 1955; National Programme for Elimination of Lymphatic Filariasis (NPELF); Global Programme to Eliminate Lymphatic Filariasis (GPELF) since 2000 (WHO target: elimination as public health problem); MDA to cover ≥65% total population x ≥5 rounds. India target: LF elimination by 2027 (accelerated in 2021).

13. RABIES

Parameter	Details
Causative Organism	Lyssavirus type 1 (Rabies virus) - Rhabdovirus family, RNA virus. Bullet-shaped. Causes encephalomyelitis. The only communicable disease of man that is invariably fatal once clinical symptoms appear.
Incubation Period	Highly variable: 4 days to >1 year. Average 1-3 months. Shorter for head/face bites and multiple severe bites; longer for lower limb bites. Depends on: site of bite (proximity to brain), severity of bite, viral load, immune status.
Mode of Transmission	Bites or licks of rabid animals on mucous membranes or abraded skin. Dog bites responsible for 99% of human rabies. Also: cat, wolf, jackal, fox, bat, mongoose. Not transmitted through intact skin. Not airborne (except caves with bat colonies). Not transmitted person to person (except corneal transplant).
Host Factors	All age groups susceptible; most common in children <15 years (40% of post-exposure prophylaxis in 5-14 year olds). No known naturally immune person. No carrier state.
Environmental Factors	Stray dog population; lack of dog vaccination; rural settings in Asia/Africa. 55,000 deaths/year globally; 20,000 deaths/year in India. Urban rabies linked to stray dog density.
Clinical Features	4 stages: (1) Incubation period (no symptoms); (2) Prodromal stage (2-10 days): fever, headache, malaise, sensory changes at bite site (tingling, pain, burning); (3) Acute neurological stage: (a) Furious/encephalitic form (80%): hydrophobia (hallmark), aerophobia, agitation, disorientation, alternating with lucid periods, autonomic instability; (b) Paralytic/dumb form (20%): ascending paralysis, resembles GBS; (4) Coma and death within 4-6 days.
Complications	Invariably fatal once clinical rabies develops. Cause of death: cardiac/respiratory arrest, autonomic failure, raised ICP.
Diagnosis	Clinical (hydrophobia + history of bite). Lab: Negri bodies (eosinophilic intracytoplasmic inclusions in Purkinje cells and hippocampus - post-mortem); DFA test (direct fluorescent antibody) on brain tissue; RT-PCR on saliva/CSF/skin biopsy; Virus isolation. Ante-mortem: skin biopsy from nape of neck (DFA).
Treatment	Once symptoms appear: supportive/palliative only (no proven effective treatment). Milwaukee Protocol (induced coma) - not consistently effective. Pre-exposure: Rabies vaccine (HDCV/PCEC) IM on days 0, 7, 21. Post-exposure prophylaxis (PEP): (1) Wound washing (soap + water, 15 minutes); (2) Equine/human rabies immunoglobulin (ERIG/HRIG) infiltrated around wound + IM; (3) Cell culture vaccine (HDCV/PCECV) IM on days 0, 3, 7, 14 (WHO 4-dose Essen regimen) or 2-1-1 Zagreb regimen.
Prevention	3-pronged: (1) Dog control: registration, vaccination of dogs (anti-rabies vaccine), elimination of stray dogs; (2) Pre-exposure prophylaxis (PrEP) for high-risk persons (veterinarians, dog handlers, lab workers) - 3 doses on days 0, 7, 21/28; (3) Post-exposure prophylaxis (PEP) for bite victims (as above).
Programmes/Schemes	National Rabies Control Programme (NRCP) in India under NVBDCP; National Anti-Rabies Policy; WHO recommended: Zero by 30 campaign - zero human deaths from dog-mediated rabies by 2030; Strategic framework: 3 pillars - educate people, vaccinate dogs, enhance access to PEP.

14. JAPANESE ENCEPHALITIS (JE)

Parameter	Details
Causative Organism	Japanese Encephalitis virus - Group B arbovirus (Flavivirus family), RNA virus. Transmitted by Culex mosquitoes. Zoonotic disease (mainly infects animals, incidentally humans).
Incubation Period	6-8 days (range 5-15 days).
Mode of Transmission	Bite of infected Culex mosquitoes (mainly Cx. tritaeniorhynchus - breeds in rice paddies). Amplifying hosts: pigs and ardeid birds (herons, egrets). Dead-end hosts: humans. Seasonal - rainy/summer season. Transmission mainly rural, near rice-growing areas.
Host Factors	Children under 15 years most affected. ~10% cases in those >60 years. JE-immune IgG antibodies are protective. Most infections asymptomatic (~1 in 250-300 infections leads to clinical disease).
Environmental Factors	Rural agricultural areas with flooded irrigation (rice paddies). Pig farming near human habitation. Rainy season (monsoon) with peak vector density. 24 Asian/Western Pacific countries affected. India endemic in 21 states.
Clinical Features	Most infections subclinical. Clinical disease: sudden onset fever, headache, meningismus, altered sensorium, focal neurological signs, tremors, parkinsonism-like features, seizures (especially children), acute flaccid paralysis. CFR: 20-30%. 30-50% of survivors have neurological sequelae.
Complications	Permanent neurological damage (cognitive impairment, motor deficits, parkinsonism, epilepsy, behavioural disturbances) in 30-50% of survivors. Respiratory failure requiring mechanical ventilation. CFR 20-30%.
Diagnosis	Clinical + epidemiological. Lab: IgM capture ELISA on serum or CSF (gold standard - from day 5); IgM in CSF is diagnostic; CT/MRI brain (bilateral thalamic hypodensities/hyperintensities on T2); EEG (diffuse slowing); RT-PCR (low sensitivity in clinical disease); virus isolation.
Treatment	No specific antiviral therapy available. Supportive: antipyretics, anticonvulsants, management of raised ICP, respiratory support. Interferon-α and other antivirals have been tried (not proven effective).
Prevention	Vaccination: most effective prevention. Two JE vaccines licensed in India: (1) SA 14-14-2 live attenuated vaccine (single dose from 9 months - Encevac); (2) Inactivated Vero cell-derived vaccine (JENVAC - made in India; 2 doses). Vector control: source reduction, larviciding, indoor residual spraying, personal protection. Piggery relocation away from human habitation.
Programmes/Schemes	Japanese Encephalitis Vaccination Programme (national immunization under UIP since 2006 in endemic districts); Acute Encephalitis Syndrome (AES) surveillance; NVBDCP umbrella. JE vaccination extended to new districts progressively; India launched catch-up immunization campaigns in endemic states.

15. EBOLA VIRUS DISEASE (EVD)

Parameter	Details
Causative Organism	Ebola virus - Filoviridae family, negative-sense ssRNA virus. 5 distinct species: Zaire ebolavirus (most lethal), Sudan ebolavirus, Reston ebolavirus (non-pathogenic to humans), Tai Forest ebolavirus, Bundibugyo ebolavirus. Natural reservoir: fruit bats (Pteropodidae family).
Incubation Period	2-21 days. Not infectious during incubation period.
Mode of Transmission	Direct contact with blood, organs, body secretions (sweat, saliva, semen, breast milk, urine, faeces) of infected symptomatic persons or carcasses of infected animals (chimpanzees, gorillas, monkeys, fruit bats). Exposure to contaminated needles/instruments. Asymptomatic persons are NOT infectious. NOT transmitted via air, water, or food. Sexual transmission possible (virus persists in semen up to 18 months).
Host Factors	All ages susceptible. Healthcare workers at high risk (nosocomial transmission). Survivors develop immunity. Asymptomatic infection may occur but those individuals are non-infectious.
Environmental Factors	First emerged 1976 in Zaire (DRC) and Sudan. Sub-Saharan Africa most affected. Dense forest-edge settings, contact with bushmeat, fruit bats. 2013-2016 West Africa epidemic (Guinea, Sierra Leone, Liberia): 28,616 cases, >11,000 deaths. CFR up to 70% in some outbreaks.
Clinical Features	Sudden onset fever, intense weakness, muscle pain, headache, sore throat → vomiting, diarrhoea, rash, impaired kidney/liver function → in some cases: internal and external bleeding (haemorrhagic manifestations - petechiae, ecchymoses, oozing from puncture sites, haematemesis, melena).
Complications	Severe dehydration, electrolyte imbalance, multi-organ failure (liver, renal), haemorrhage (haematemesis, melena, epistaxis), septic shock, death. Survivors may experience sequelae: uveitis, arthralgia, fatigue, post-Ebola syndrome.
Diagnosis	RT-PCR (gold standard - from symptom onset day 1); ELISA (IgM/IgG); antigen detection; virus isolation (BSL-4 facility); electron microscopy. Clinical: difficult to distinguish from malaria, typhoid, meningitis in early stages.
Treatment	Supportive: rehydration (oral/IV), electrolyte management, nutrition, treatment of secondary infections. Specific: Inmazeb (atoltivimab, maftivimab, odesivimab - FDA approved 2020 monoclonal antibody cocktail for Zaire ebolavirus); Ebanga (ansuvimab - FDA approved 2020); Remdesivir (some evidence).
Prevention	Strict infection control: PPE (gloves, gowns, face shields, boots), barrier nursing; safe burial practices (no touching of body); isolation of confirmed/suspected cases; contact tracing; hand hygiene; avoid contact with dead animals or bushmeat. No consumption of bushmeat.
Programmes/Schemes	rVSV-ZEBOV-GP (Ervebo - Merck) - first FDA/EMA approved Ebola vaccine (2019, WHO prequalified); licensed for adults in DRC and Guinea; ring vaccination strategy; GAVI-supported vaccination campaigns in DRC; WHO Emergency Use Listing; Global Outbreak Alert and Response Network (GOARN); IHR 2005 - Ebola declared PHEIC in 2014, 2019, 2021.

Quick Reference Summary Table

Disease	Organism	Incubation	Transmission	Key Clinical Feature	Key Prevention	Indian Programme
Measles	Paramyxovirus	10-14 days	Droplet/airborne	Koplik's spots + rash	2-dose MCV vaccine	UIP, MR Campaign
Rubella	Togavirus (RNA)	14-21 days	Droplet	Mild rash + lymphadenopathy; CRS if in pregnancy	MR/MMR vaccine	MR Campaign, UIP
Influenza	Influenza virus A/B/C/D	1-3 days	Droplet/contact	Sudden fever, myalgia, cough	Annual influenza vaccine	GISRS surveillance
SARS	SARS-CoV	2-7 days	Droplet/contact/fomite	Fever + ARDS + pneumonia	Isolation, PPE, IHR	GOARN, IHR 2005
COVID-19	SARS-CoV-2	2-14 days	Droplet/aerosol/fomite	Fever, cough, anosmia; ARDS in severe	mRNA/inactivated vaccine, masking	National Vaccination Programme, Co-WIN
TB	M. tuberculosis	4-12 weeks	Airborne (droplet nuclei)	Cough >3 wks, haemoptysis, night sweats	BCG, DOTS	NTEP (Nikshay), TB Mukt Bharat 2025
Poliomyelitis	Poliovirus (3 types)	7-14 days	Faecal-oral	Flaccid asymmetric paralysis, no sensory loss	OPV + IPV	Pulse Polio, GPEI, India polio-free 2014
Diarrhoeal Diseases	Bacteria/Viruses/Parasites	Hours-weeks	Faecal-oral (4 Fs)	Watery/bloody stools, dehydration	ORS, safe water, Rota vaccine	CDD Programme, Swachh Bharat
Typhoid	S. typhi	1-3 weeks	Faecal-oral (water/food)	Stepladder fever, rose spots, relative bradycardia	Vi/TCV/Ty21a vaccines	TCV in UIP, Swachh Bharat
Dengue	Dengue virus (4 serotypes)	4-10 days	Aedes aegypti bite	Break-bone fever, thrombocytopenia, DHF	Source reduction, Dengvaxia/Qdenga	NVBDCP, National Dengue Day
Malaria	Plasmodium spp.	12-28 days	Anopheles mosquito bite	Cold-hot-sweating paroxysm; splenomegaly	ACT, ITNs, IRS, RTS,S vaccine	NMCP/NVBDCP, NFME 2030
Filariasis	W. bancrofti / Brugia spp.	8-16 months	Culex mosquito bite	Lymphoedema, elephantiasis, hydrocele	MDA (DEC+Albendazole)	NPELF, GPELF (elimination by 2027)
Rabies	Lyssavirus type 1	1-3 months (variable)	Bite/lick of rabid animal	Hydrophobia, aerophobia - invariably fatal	PEP (vaccine + ERIG); dog vaccination	NRCP, WHO Zero by 30
Japanese Encephalitis	Flavivirus (JE virus)	6-8 days	Culex tritaeniorhynchus bite	Fever + acute encephalitis; thalamic lesions on MRI	SA14-14-2 / JENVAC vaccine	JE vaccination in UIP (endemic districts)
Ebola	Filovirus (Ebolavirus)	2-21 days	Contact with body fluids (symptomatic)	Haemorrhagic fever, multi-organ failure; CFR up to 70%	Ervebo vaccine; PPE; safe burial	GOARN, IHR PHEIC 2014/2019/2021

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