TYPHOID FEVER - Agent, Incubation Period, Mode of Transmission & Control Measures

I. INTRODUCTION

II. AGENT FACTORS (Causative Organism)

• A Gram-negative, non-spore-forming, facultatively anaerobic bacillus belonging to the family Enterobacteriaceae.
• S. typhi is the major causative agent; S. paratyphi A, B, and C cause paratyphoid, which is milder.
• The organism possesses three main antigenic components:
  • O antigen (somatic, cell wall lipopolysaccharide)
  • H antigen (flagellar)
  • Vi antigen (virulence antigen - a polysaccharide capsule that inhibits phagocytosis and complement activation)
• At least 80 phage types have been identified; phage typing is a useful epidemiological tool for tracing the source of outbreaks.
• S. typhi can survive intracellularly in tissues of the liver, spleen, bone marrow, and lymph nodes - this is key to its pathogenesis and persistence.
• Resistance: It is readily killed by drying, pasteurization (60°C for 30 minutes), and common disinfectants (phenol, chlorine). However, it can survive for days to weeks in contaminated water, ice, and food, especially in cold conditions.
• The infecting dose and virulence of the organism are the key factors influencing onset of disease; as few as 10^3 - 10^7 organisms can cause infection depending on the vehicle.

• Cases (active cases): May be mild, subclinical, or severe. A case is infectious as long as bacilli appear in stools or urine.
• Carriers: These are critically important in perpetuating the disease:
  • Temporary (incubatory) carriers: Excrete organisms before onset of illness.
  • Convalescent carriers: Excrete bacilli for 6-8 weeks after illness; numbers diminish rapidly. By 3 months, only ~4% still excrete; by 1 year, ~3%.
  • Chronic carriers: Those who excrete bacilli for more than 1 year after a clinical attack. Organisms persist in the gallbladder and biliary tract (often in association with gallstones). Chronic carriage develops in 2-5% of cases and may last for several decades (50 years in extreme cases). The notorious "Typhoid Mary" (Mary Mallon) was a chronic carrier responsible for >1300 cases in her lifetime.
  • Fecal carriers are more common than urinary carriers; chronic urinary carriers often have an underlying structural abnormality of the urinary tract or concurrent Schistosoma haematobium infection.
  • Chronic carriage is more common in women, the elderly, and those with biliary abnormalities.

• Primary sources: Faeces and urine of cases or carriers.
• Secondary sources: Contaminated water, food, fingers ("the 5 Fs"), and flies.
• There is no evidence that typhoid bacilli are excreted in sputum or milk.

III. INCUBATION PERIOD

• The incubation period of typhoid fever is typically 1 to 3 weeks (7-21 days), with an average of 10-14 days.
• It can range from 3 days to 60 days depending on:
  • The inoculum size (infecting dose) - smaller doses lead to longer incubation
  • The virulence of the strain
  • The host's immune status and gastric acid level (low gastric acidity = shorter incubation)
  • The vehicle of infection (waterborne outbreaks tend toward longer incubation)
• The disease is communicable as long as the bacilli appear in excreta - typically from the first week through the convalescent period, and indefinitely in carriers.

IV. MODE OF TRANSMISSION

A. Water-Borne Transmission (MOST IMPORTANT)

• The most common and important mode of transmission globally.
• Contamination of drinking water supplies with sewage is the classic mechanism.
• Responsible for most large-scale epidemics (e.g., "explosive epidemics" with a characteristic epidemic curve peaking rapidly).
• Ice made from contaminated water, and floods contaminating water supplies, are important vehicles.
• Risk correlates directly with mixing of drinking water with human sewage.

B. Food-Borne Transmission

• The most common mode in developed countries.
• Any food can be contaminated by:
  • Carriers handling food (cooks, food handlers - e.g., Typhoid Mary)
  • Raw fruits and vegetables grown in fields fertilized with sewage ("night soil")
  • Shellfish and seafood from contaminated water
  • Milk and milk products contaminated by carriers
  • Street vendor foods
• Food-borne outbreaks tend to be smaller and more prolonged compared to waterborne outbreaks.

C. Fly-Borne Transmission

• Flies can mechanically transfer the organism from infected faeces to food.
• Important in areas with open defecation and poor sanitation.
• Flies carry organisms on their legs, body, and in their vomit.

D. Contact Transmission (Person-to-Person)

• Direct feco-oral contact - unhygienic handling
• Fomites - contaminated utensils, latrines, etc.
• Sexual transmission between male partners has been described.
• Healthcare workers can acquire infection from infected patients or clinical specimens.
• Relatively less common than water/food-borne routes.

E. Fomites

• Contaminated clothing, bedding, utensils, and other objects can serve as vehicles, especially in institutional settings.

Conditions Favoring Transmission:

• Absence of safe drinking water
• Inadequate sanitation and sewage disposal
• Open defecation practices
• Lack of handwashing facilities
• Overcrowding
• Poor food hygiene practices
• Previous H. pylori infection (associated with reduced gastric acidity, lowering the infective dose needed)

V. CONTROL MEASURES

A. MEASURES DIRECTED AT THE SOURCE (Reservoir / Cases / Carriers)

1. Case Management

• Early diagnosis and prompt treatment with appropriate antibiotics (see below) reduces the duration of infectivity and prevents spread.
• Isolation: Cases should be subject to enteric precautions - isolation of excreta (faeces and urine), disinfection of contaminated articles, and strict handwashing. Full ward isolation is not required, but barrier nursing is essential.
• Treatment options:
  • Fluoroquinolones (ciprofloxacin 500 mg BD x 10-14 days) - first line for sensitive strains
  • Third-generation cephalosporins (ceftriaxone IV, cefixime oral) for MDR and fluoroquinolone-resistant cases
  • Azithromycin (1g on day 1, then 500 mg OD x 6 days) - effective for uncomplicated cases and XDR strains
  • Chloramphenicol, ampicillin, and cotrimoxazole are unreliable due to widespread resistance (first-line in the past but no longer recommended as empiric therapy)
  • Dexamethasone is added for severe cases with meningitis, encephalitis, or shock (reduces mortality)
• Notification: Typhoid is a notifiable disease in India and most countries. Cases must be reported to public health authorities for epidemiological investigation.

2. Carrier Detection and Management

• Food handlers, water workers, milk handlers, and healthcare workers should be screened for carrier status.
• Stool and urine cultures (minimum 3 negative cultures) are required to certify freedom from carriage.
• Carriers must be excluded from handling food, water supplies, and patient care until declared free.
• Treatment of carriers:
  • Ciprofloxacin 750 mg twice daily for 4 weeks can eliminate carriage in ~80% of cases.
  • Amoxicillin + probenecid for 3 months was previously used.
  • In cases where carriage is due to gallbladder disease (cholelithiasis), cholecystectomy may be needed for eradication.
• Health education on handwashing and personal hygiene for carriers who cannot be treated.

3. Disinfection of Excreta

• Faeces, urine, and vomit from cases must be disinfected with bleaching powder, cresol, or carbolic acid before disposal.
• Soiled linen and articles should be disinfected by boiling or autoclaving.
• Terminal disinfection of the patient's room after recovery or death.

B. MEASURES DIRECTED AT THE ROUTES OF TRANSMISSION (Environmental)

1. Safe Water Supply

• Provision of safe, potable water is the single most important measure in controlling typhoid.
• Chlorination of public water supplies (residual chlorine 0.2-0.5 mg/L at the consumer's end).
• Boiling of water at household level in endemic areas.
• Regular testing and bacteriological surveillance of water sources.
• Prevention of cross-connections between water mains and sewage pipes.
• Protection of wells, tanks, and reservoirs from contamination.
• During floods and natural disasters, emergency chlorination and distribution of safe water.

2. Sanitary Disposal of Sewage (Excreta Disposal)

• Construction and use of sanitary latrines (water seal latrines, pour flush latrines).
• Sewage treatment plants to prevent fecal contamination of water bodies and agricultural fields.
• Prevention of open defecation, especially near water sources.
• Promotion of Total Sanitation Campaigns (Swachh Bharat Mission in India).
• Preventing use of untreated human excreta as agricultural fertilizer.

3. Food Hygiene and Safety

• Supervision of food handlers - regular health examinations, periodic stool cultures.
• Thorough cooking of food; avoiding raw vegetables fertilized with sewage.
• Proper pasteurization of milk and dairy products.
• Control of street food vendors and public eating establishments.
• Proper storage and refrigeration of food to prevent multiplication of organisms.
• Handwashing with soap before handling food and after using the toilet.

4. Control of Flies

• Fly control measures: fly-proof latrines, screening of windows and food, use of insecticides.
• Elimination of fly breeding sites (proper garbage disposal, composting pits with covers).
• Keeping food covered.
• Use of fly traps and sticky strips.

5. Personal Hygiene

• Thorough handwashing with soap after defecation and before eating - the single most effective personal hygiene measure.
• Safe disposal of infant stools (often overlooked).
• Avoiding ice, raw foods, and unpeeled fruits in endemic areas.

C. MEASURES DIRECTED AT THE HOST (Immunization)

1. Typhoid Vaccines Currently Available:

• TCV (Typhoid Conjugate Vaccine) is now the WHO-preferred vaccine and is recommended for routine immunization of children ≥6 months in endemic countries. It is the only typhoid vaccine approved for children under 2 years. India introduced TCV in the national immunization program.
• ViPS vaccine provides no protection in children under 2 years (T-cell independent response).
• Ty21a is contraindicated in immunocompromised individuals and children under 5.

2. Target Groups for Vaccination:

• Children 6 months to 15 years in endemic areas (highest risk group)
• Travelers to endemic areas
• Laboratory workers handling S. typhi cultures
• Household contacts of known carriers
• Military personnel
• Food handlers in high-risk settings

3. Mass Immunization Campaigns:

• Targeted vaccination campaigns in epidemic settings and endemic urban areas have shown significant impact.
• School-based vaccination programs are highly cost-effective.

D. OTHER GENERAL PUBLIC HEALTH MEASURES

1. Health Education: Community education on safe water use, food hygiene, handwashing, recognition of symptoms, and importance of seeking early treatment.
2. Surveillance and Epidemiological Investigation:
   • Mandatory notification and reporting of all cases.
   • Investigation of every case/cluster to identify the source and route of transmission.
   • Contact tracing and surveillance of household contacts for 21 days (the maximum incubation period).
   • Stool cultures from contacts who are food handlers.
3. International Measures:
   • Under International Health Regulations (IHR), typhoid is a reportable condition.
   • Surveillance of travelers from endemic to non-endemic areas.
   • Vaccination of travelers to high-risk areas.
   • Inspection of ships and aircraft originating from endemic areas.
4. Multidrug Resistance (MDR) and Extensively Drug-Resistant (XDR) S. typhi:
   • MDR strains (resistant to chloramphenicol, ampicillin, cotrimoxazole) emerged in the 1980s and are widespread in Asia.
   • XDR S. typhi (additionally resistant to fluoroquinolones and third-generation cephalosporins) first emerged in Hyderabad, Pakistan (2016) and is spreading.
   • XDR typhoid is treated with azithromycin (oral) or carbapenems (parenteral).
   • Combating MDR/XDR requires antibiotic stewardship, rational prescribing, and accelerated TCV rollout.

VI. SUMMARY TABLE

TUBERCULOSIS - Agent, Incubation Period, Mode of Transmission & Control Measures

I. INTRODUCTION

II. AGENT FACTORS (Causative Organism)

(a) The Organism - Mycobacterium tuberculosis

• A rod-shaped, non-spore-forming, thin aerobic bacterium measuring 0.5 μm × 3 μm.
• It is Gram-neutral (neutral on Gram staining) but, once stained, cannot be decolorized by acid alcohol - hence classified as Acid-Fast Bacilli (AFB).
• Acid fastness is due to the high content of mycolic acids and long-chain fatty acids in the cell wall, which also confers remarkable resistance to harsh environmental conditions.
• The genome consists of 4.4 million base pairs with 65.6% guanine-plus-cytosine content, reflecting its aerobic lifestyle.
• M. tuberculosis can survive intracellularly within macrophages - a critical mechanism underlying latency, chronicity, and drug resistance.
• The organism grows very slowly (doubling time ~15-20 hours; colonies take 4-8 weeks on Lowenstein-Jensen medium), which explains the prolonged course of disease and treatment.

• M. bovis (bovine tubercle bacillus) - transmitted via unpasteurized milk; resistant to pyrazinamide
• M. africanum - causes TB in West, Central, and East Africa
• M. caprae, M. pinnipedii, M. microti - rare zoonotic causes

(b) Reservoir of Infection

• In pulmonary TB: Man is the primary reservoir - specifically sputum-positive (smear-positive) cases.
• Bovine reservoir: Cattle with bovine TB; transmitted via unpasteurized milk or meat. Of lesser importance in India due to the practice of boiling milk before consumption.
• An infected individual with open (cavitating) pulmonary TB can infect 10-15 persons per year on average.

(c) Source of Infection

• Primary source: Sputum of smear-positive pulmonary TB cases (the most infectious).
• Secondary source: Infected milk/dairy (bovine TB).
• Patients are infectious as long as they remain untreated. Effective anti-microbial treatment reduces infectivity by 90% within 48 hours of initiation - a critical public health fact.

(d) Communicability

• The disease is communicable from the time bacilli appear in sputum (often before diagnosis).
• A person with latent TB infection (LTBI) is infected but NOT infectious - they cannot transmit the disease.
• Only active smear-positive pulmonary TB cases are the primary source of transmission.

III. INCUBATION PERIOD

Phase 1: Primary Infection to Tuberculin Conversion

• The time from initial infection to development of tuberculin sensitivity (primary TB infection) is approximately 2-10 weeks (average 4-8 weeks).
• During this period, the organism multiplies and spreads, and the host mounts a cell-mediated immune response.

Phase 2: Infection to Active Disease (Latent Period)

• The incubation period in the conventional sense (infection to clinical disease) is highly variable.
• Short incubation: Active disease can develop within weeks to months in immunocompromised individuals (e.g., HIV-positive patients) following primary infection.
• Long incubation (reactivation TB): Up to 10% of infected, immunocompetent persons will develop active TB over their lifetime. Of these, half do so within 18 months of infection (i.e., relatively early); the rest may develop disease years to decades later through reactivation.
• Overall, the incubation period is stated as 4-12 weeks for primary disease; the conventional definition used in communicable disease control is 2 to 10 weeks for the appearance of tuberculin sensitivity after infection.
• In the Indian context and for exam purposes: the incubation period is commonly stated as 4-12 weeks.

Why is Incubation Complex in TB?

IV. MODE OF TRANSMISSION

A. Airborne Transmission (PRIMARY AND MOST IMPORTANT MODE)

1. A sputum-positive patient with pulmonary TB coughs, sneezes, speaks, sings, or laughs, generating respiratory droplets of varying sizes.
2. Large droplets (>5 μm) settle rapidly and are not inhaled into the alveoli; they are trapped by upper airway defenses.
3. Droplet nuclei - tiny particles of 1-5 μm diameter - remain suspended in the air for hours, travel over long distances with air currents, and are directly inhaled into the alveoli where infection begins.
4. Coughing generates the largest number of droplets of all sizes; it is the most important mechanism.
5. The frequency and vigor of cough, and the ventilation of the environment, critically influence transmission.

• Bacillary load in sputum: Smear-positive (AFB visible on microscopy) patients are far more infectious than smear-negative cases.
• Duration of exposure: Close, prolonged exposure (household contacts) carries the highest risk.
• Degree of ventilation: Enclosed, poorly ventilated spaces concentrate infectious droplet nuclei.
• Host susceptibility: Immune status of the contact person.
• Type of activity: Procedures that generate aerosols (bronchoscopy, intubation, sputum induction, autopsy) carry high occupational risk.

B. What Does NOT Transmit TB

• TB is NOT transmitted by fomites (dishes, clothing, bedding, books, utensils, etc.) - this is a common misconception.
• TB is NOT spread by shaking hands, sitting near an infected person in open air, or touching surfaces.
• Bovine TB (M. bovis) is transmitted by ingestion of unpasteurized milk - an exception to airborne-only rule.
• Rare routes: Direct inoculation (skin TB), transplacental (congenital TB), and direct GI inoculation.

C. Factors Favoring Transmission

• Overcrowding and poor ventilation (slums, prisons, hostels, barracks)
• High bacillary load (cavitating smear-positive cases)
• Delayed diagnosis and treatment
• Poverty, malnutrition, poor housing
• Smoking and alcohol abuse (both increase risk)
• HIV co-infection (most potent single risk factor)
• Indoor air pollution
• Migration from high-burden to low-burden areas

D. Risk Factors for Progression from Infection to Active Disease

V. CONTROL MEASURES

A. MEASURES DIRECTED AT THE SOURCE (Case Finding & Treatment)

1. Case Finding (Early Diagnosis)

• Passive case finding: Symptomatic patients presenting to health facilities (the standard approach in India under the National TB Elimination Programme [NTEP]). Any person with cough ≥2 weeks is a "presumptive TB" case and must be investigated.
• Active case finding: Systematic screening of high-risk populations:
  • Household contacts of sputum-positive cases
  • People living with HIV (PLHIV)
  • Residents of prisons, slums, homeless shelters
  • Migrant workers and tribal populations
  • Persons with diabetes, silicosis, end-stage renal disease
  • Healthcare workers

• Sputum smear microscopy (ZN stain / Ziehl-Neelsen): Cheapest and most widely used; detects AFB. Two sputum specimens (spot + morning) are examined.
• LED fluorescence microscopy: More sensitive than conventional ZN; recommended by WHO to replace ZN.
• CBNAAT/Xpert MTB-RIF (TrueNat): Rapid molecular test (results in 90 minutes); detects both MTB and rifampicin resistance simultaneously. Recommended as the initial diagnostic test for all presumptive TB under NTEP.
• Line Probe Assay (LPA): Detects resistance to rifampicin (rpoB), isoniazid (katG, inhA), fluoroquinolones, and second-line injectables.
• Culture (LJ medium / MGIT-BACTEC): Gold standard; 4-8 weeks (conventional), 2-6 weeks (liquid culture); used for drug sensitivity testing.
• Tuberculin Skin Test (TST/Mantoux): Indicates infection (not necessarily active disease); not useful alone for diagnosis of active TB; used for LTBI diagnosis and contact tracing.
• Interferon Gamma Release Assay (IGRA): Blood test; detects TB-specific immune response; not affected by BCG vaccination; used for LTBI diagnosis.
• Chest X-ray: Useful for smear-negative pulmonary TB, pleural TB, miliary TB, and pediatric TB.

2. Treatment (Chemotherapy) - The Core of TB Control

• Isoniazid (INH/H): Most powerful; bactericidal; penetrates all body compartments including CSF; inhibits mycolic acid synthesis. Side effects: peripheral neuropathy (prevented by pyridoxine), hepatotoxicity.
• Rifampicin (RIF/R): Powerful bactericidal; excellent sterilizing activity; the only drug active against "persisters" (dormant bacilli in caseous lesions). Turns urine red-orange (useful compliance marker). Side effects: hepatotoxicity, flu-like syndrome, thrombocytopenia.
• Pyrazinamide (PZA/Z): Bactericidal in acidic environment (within macrophages); essential in the intensive phase for early sterilization. Side effects: hepatotoxicity, hyperuricemia, arthralgia.
• Ethambutol (EMB/E): Bacteriostatic; prevents emergence of resistance to other drugs; inhibits arabinosyl transferase. Side effect: optic neuritis (color vision loss - earliest sign; reversible if stopped early).
• Streptomycin (S): Injectable aminoglycoside; bactericidal; no longer a first-line drug due to resistance and toxicity; reserved for certain MDR-TB regimens.

• Regimen of 18-20 months duration using second-line drugs:
  • Group A drugs (all three should be included): Levofloxacin or Moxifloxacin; Bedaquiline; Linezolid
  • Group B drugs (at least one): Clofazimine; Cycloserine or Terizidone
  • Group C drugs (to complete regimen): Ethambutol, Delamanid, Pyrazinamide, Imipenem-cilastatin or Meropenem, Amikacin, Ethionamide, PAS

• 3HP regimen: Isoniazid + Rifapentine weekly for 3 months - currently the regimen of choice for contacts >2 years and all adults including HIV-positive
• 4R regimen: Rifampin alone daily for 4 months
• 3HR: Isoniazid + Rifampin daily for 3 months
• 6H or 9H: Isoniazid alone daily for 6-9 months (older regimen)

3. DOTS (Directly Observed Treatment, Short Course)

• The cornerstone of the NTEP (previously RNTCP) in India since mid-1990s.
• A health worker or designated person directly observes the patient swallowing each dose of anti-TB medication.
• Purpose: prevent drug resistance, ensure adherence, and achieve cure.
• India has now moved to daily fixed-dose combination (FDC) regimens under NTEP rather than intermittent DOTS.

4. Notification

• TB (all forms) is a mandatory notifiable disease in India since 2012 and under the Nikshay portal (case-based web notification system).
• Private practitioners, labs, and chemists are mandated to notify all TB cases.
• Notification drives contact tracing, LTBI treatment, and programmatic monitoring.

B. MEASURES DIRECTED AT THE ROUTE OF TRANSMISSION (Environmental Measures)

1. Ventilation and Housing

• Improving housing conditions: Elimination of overcrowding is the most powerful long-term environmental measure. TB declined in Europe primarily because of improved housing and living standards before antibiotics were introduced.
• Adequate ventilation in homes, hospitals, schools, prisons: ensures rapid dilution and removal of droplet nuclei.
• Natural light (UV radiation): Sunlight (UV component) kills M. tuberculosis rapidly; rooms with good natural light are less infectious.
• In healthcare facilities: Infection control measures including:
  • Negative pressure isolation rooms for suspected/confirmed TB patients
  • HEPA filtration and UV germicidal irradiation in high-risk areas
  • N95 respirators (not surgical masks) for healthcare workers
  • Surgical masks for suspected TB patients to reduce aerosol generation
  • Rapid triage and separation of coughing patients

2. Personal Protective Measures

• Cough hygiene: Cover mouth and nose when coughing/sneezing; use disposable tissues; handwashing.
• Sputum disposal: Sputum should never be spit in open; should be expectorated into spittoons containing disinfectant (1% phenol) and properly disposed of.

3. Occupational Measures for Healthcare Workers

• Annual TB screening for all healthcare workers
• N95 respirators during aerosol-generating procedures (bronchoscopy, intubation, sputum induction)
• LTBI treatment for tuberculin-converted healthcare workers
• Infection control committees in hospitals

C. MEASURES DIRECTED AT THE HOST (Protection)

1. BCG (Bacillus Calmette-Guérin) Vaccination

2. Chemoprophylaxis (LTBI Treatment / Preventive Therapy)

• All contacts of sputum-positive TB cases should be evaluated and, if eligible, given LTBI treatment.
• Priority groups for preventive therapy:
  • PLHIV with LTBI (regardless of age)
  • Children under 5 years who are household contacts of a TB case
  • All close contacts of MDR-TB cases (after ruling out active disease)
  • Immunocompromised individuals (transplant, anti-TNF therapy)
  • Health workers in high-burden settings
• WHO and NTEP recommend 6H (isoniazid 300 mg/day for 6 months) as standard preventive therapy for children; 3HP (weekly INH + Rifapentine for 3 months) is now preferred for adults.

3. Nutrition and General Resistance

• Addressing malnutrition is essential; malnourished individuals have 2x higher risk of developing active TB.
• Control of diabetes mellitus: DM confers a 2-4x higher risk; optimal glycemic control reduces TB risk.
• HIV prevention and ART: HIV is the most potent risk factor (21->30x). Universal ART coverage for PLHIV is a critical TB control strategy. All HIV-positive TB patients must receive ART.
• Smoking cessation and alcohol reduction: Both independently increase TB risk (2-3x).
• Silicosis prevention: Silicosis increases TB risk 30x; dust control in mines and industries is essential.

D. PROGRAMMATIC AND NATIONAL LEVEL MEASURES

1. National TB Elimination Programme (NTEP), India

• Formerly Revised National TB Control Programme (RNTCP), renamed NTEP in 2020.
• Vision: TB-free India - Eliminate TB by 2025 (ahead of global 2030 target).
• Provides free diagnosis and treatment to all TB patients.
• Nikshay portal: Web-based patient management system for notification, monitoring, and treatment tracking.
• Nikshay Poshan Yojana: Rs. 500/month nutritional support to TB patients during treatment.
• Pillars of NTEP: Detect, Treat, Prevent, Build (DTPB).

2. WHO End TB Strategy (2016-2030)

• Targets: 90% reduction in TB deaths and 80% reduction in TB incidence between 2015 and 2030.
• Three pillars: (1) Integrated patient-centered TB care and prevention; (2) Bold policies and supportive systems; (3) Intensified research and innovation.
• SDG target: End TB epidemic by 2030.
• WHO 2035 target: 95% reduction in deaths and 90% decline in incidence.

3. Contact Tracing

• All household contacts of a newly diagnosed sputum-positive TB case must be evaluated.
• Children <5 years and PLHIV among contacts should receive LTBI treatment after ruling out active TB.
• Screening using TST or IGRA.

4. Social Measures (Upstream Determinants)

• Poverty alleviation, improved nutrition programs, better housing
• Safe drinking water and sanitation
• Education and health literacy
• Reducing indoor air pollution
• Gender equity (women disproportionately affected - TB kills more women in reproductive age than all maternal causes combined)

VI. SUMMARY TABLE

PRIMARY HEALTH CENTRE (PHC)

A Comprehensive 10-Mark Answer

I. INTRODUCTION

1. Primary Health Care (PHC) - the philosophy and approach (Alma-Ata Declaration, 1978)
2. Primary Health Centre (PHC) - the actual institution/health facility in India's rural health infrastructure

II. CONCEPT OF PRIMARY HEALTH CARE (Philosophy)

A. Historical Background - Alma-Ata Declaration (1978)

• Declared that the "existing gross inequality in health status between developed and developing countries and within countries is politically, socially and economically unacceptable"
• Called for acceptance of the WHO goal of "Health for All by 2000 AD"
• Proclaimed primary health care as the key to achieving Health for All

B. Definition (Alma-Ata, 1978)

• "Health by the people"
• "Placing people's health in people's hands"

C. Principles of Primary Health Care

D. Eight Essential Elements of Primary Health Care (Alma-Ata Declaration)

1. Education about prevailing health problems and methods of preventing and controlling them
2. Promotion of food supply and proper nutrition
3. Adequate supply of safe water and basic sanitation
4. Maternal and child health care, including family planning
5. Immunization against major infectious diseases
6. Prevention and control of locally endemic diseases
7. Appropriate treatment of common diseases and injuries
8. Provision of essential drugs

III. PRIMARY HEALTH CENTRE AS AN INSTITUTION IN INDIA

A. Historical Evolution

B. Definition and Coverage (IPHS 2012)

• Population coverage: 1 PHC per 20,000-30,000 population in plains; 1 PHC per 20,000 population in hilly, tribal and backward areas
• Beds: 6 beds (all PHCs)
• Location: At community development block level
• PHC serves as the first referral level for sub-centres below it and refers cases upward to Community Health Centres (CHC)

C. Types of PHC (Based on Delivery Case Load - IPHS 2012)

• Type A PHC: Less than 20 deliveries per month
• Type B PHC: 20 or more deliveries per month (designated MCH facility; must have labour room, SBA-trained ANM, newborn care corner)

IV. THREE-TIER RURAL HEALTH INFRASTRUCTURE IN INDIA

DISTRICT HOSPITAL
        ↑
COMMUNITY HEALTH CENTRE (CHC)
   - 1 per 80,000-1,20,000 population
   - 30 beds; 4 specialists
        ↑
PRIMARY HEALTH CENTRE (PHC)
   - 1 per 20,000-30,000 population
   - 6 beds; 1-2 Medical Officers
        ↑
HEALTH SUB-CENTRE
   - 1 per 5,000 (plains) / 3,000 (hilly/tribal)
   - Staffed by ANM + MPW (Male)
        ↑
VILLAGE LEVEL
   - ASHA: 1 per 1,000 population (village health activist)
   - Anganwadi Worker (AWW)

V. FUNCTIONS OF A PRIMARY HEALTH CENTRE

1. Medical Care

• OPD services: 4 hours morning + 2 hours afternoon/evening; minimum 40 patients per doctor per day
• 24-hour emergency services: First-aid, stabilization before referral, management of dog bite, snake bite, scorpion bite, injuries, accidents
• In-patient services: 6 beds
• 24-hour delivery services (Type B PHC: normal delivery; assisted deliveries including forceps and vacuum; manual removal of placenta)
• Referral services to CHC/First Referral Unit (FRU)

2. Maternal and Child Health (MCH) Care + Family Planning

• Antenatal care (ANC): Early registration of pregnancy; minimum 4 ANC check-ups; minimum lab investigations (Hb, blood group, Rh typing, urine albumin/sugar, RPR for syphilis); iron-folic acid supplementation; tetanus toxoid immunization; identification and management of high-risk pregnancies; referral as required
• Intranatal care: 24-hour normal delivery services; partograph monitoring; management of PPH, eclampsia, sepsis; prompt referral of complications
• Postnatal care: Post-natal check-up on day 0, 3, 7, and 42; new-born care; promotion of exclusive breastfeeding
• Child health: Immunization under Universal Immunization Programme (UIP); IMNCI (Integrated Management of Neonatal and Childhood Illness); growth monitoring; management of common childhood illnesses
• Family planning: Provision of all spacing (OCP, condoms, IUCDs/Copper-T, injectable contraceptives) and permanent methods (tubectomy, vasectomy); MTP services; counselling

3. Safe Water Supply and Basic Sanitation

• Testing of water quality (bacteriological and chemical)
• Chlorination of water sources; estimation of chlorine residual
• Surveillance of sanitation in the PHC area
• Promotion of household and community sanitation under Swachh Bharat Mission

4. Prevention and Control of Locally Endemic Diseases

• Management of malaria, dengue, chikungunya, kala-azar, lymphatic filariasis, Japanese encephalitis (JE), etc.
• Diagnosis of malaria by microscopy/RDT; treatment as per national policy
• Participation in Mass Drug Administration (MDA) for filariasis

5. Collection and Reporting of Vital Statistics

• Registration of births, deaths, and marriages
• Maintenance of relevant records
• Reporting of disease outbreaks and notifiable diseases to District Health Officer

6. Education About Health (IEC Activities)

• Health education to individuals, families, and the community
• Promotion of healthy behaviors, personal hygiene, sanitation
• School health education programmes
• Promotion of tobacco cessation, safe sex, nutrition

7. National Health Programmes (as Relevant)

8. Referral Services

• Appropriate and prompt referral of cases beyond PHC capacity to CHC/FRU/District Hospital
• Transportation facilitation (PHC vehicle; Janani Suraksha Yojana; JSSK)
• Drop-back home facility for post-delivery patients (mandatory under JSSK)
• Back-referral and follow-up of referred patients

9. Training of Health Workers

• Training of Health Guides, ANMs, ASHAs, and traditional birth attendants (trained dais)
• Continuing Medical Education (CME) for PHC doctors
• Training in emergency obstetric care, IMNCI, AYUSH
• Periodic refresher training of paramedics

10. Basic Laboratory Services

• Routine urine, stool examination
• Blood tests: Hb, CBC, blood grouping, Rh typing, blood sugar, blood cholesterol
• Bleeding time and clotting time
• Diagnosis of RTI/STDs (wet mounting, Gram stain)
• Sputum examination for TB (if designated microscopy center under NTEP)
• Blood smear examination for malarial parasite
• Rapid tests: pregnancy test, RDT for malaria, Typhidot for typhoid
• RPR test for syphilis surveillance
• Rapid kit test for fecal contamination of water
• Estimation of chlorine level in water (ortho-toluidine reagent)

VI. STAFFING PATTERN OF A PHC (IPHS 2012)

VII. INFRASTRUCTURE (IPHS 2012 Standards)

Building:

• Minimum floor area: ~3,500 sq ft (Type A); ~5,000 sq ft (Type B)
• Residential quarters for Medical Officer and staff
• OPD block, IPD ward (6 beds), labour room (Type B), emergency room, lab, pharmacy
• Clean water supply, sanitation, electricity, backup power (generator/solar)

Equipment:

• Basic surgical and obstetric instruments
• Oxygen cylinder and suction apparatus
• Cold chain equipment (vaccine refrigerator, cold boxes, ice packs)
• Weighing machines (adult and infant)
• BP apparatus, stethoscopes, fetoscopes
• Basic laboratory equipment (microscope, centrifuge, glucometer, etc.)
• Ambulance/PHC vehicle for referral transport

Drugs:

• Essential drugs list as per National List of Essential Medicines (NLEM)
• Vaccines for UIP
• Contraceptives and family planning supplies
• Emergency drugs for obstetric complications

VIII. URBAN PRIMARY HEALTH CENTRES (U-PHC)

• One U-PHC for every 50,000 urban population (revised to 30,000 in cities >5 lakh)
• Functions are similar to rural PHCs but with additional focus on urban-specific health issues (communicable disease control in slums, mental health, occupational health, trauma)

IX. HEALTH SUB-CENTRE (The Peripheral Unit of PHC)

Coverage Norms:

• 1 sub-centre per 5,000 population (plains)
• 1 sub-centre per 3,000 population (hilly, tribal, desert areas)
• Total sub-centres in India: 1,58,417 (March 2018)

Staffing:

• 1 Female Health Worker (ANM) - Primary functionary
• 1 Male Health Worker (MPW - Multi-Purpose Worker)
• 1 LHV (Lady Health Visitor) - supervisory role (1 per 4-6 sub-centres)

Functions:

• MCH care, immunization, family planning
• Basic health services and first-aid
• Disease surveillance and reporting
• DOTS provision for TB
• Health education and community mobilization
• Supervision of ASHA workers

X. ASHA - ACCREDITED SOCIAL HEALTH ACTIVIST

• 1 ASHA per 1,000 population (or 1 per village)
• Selected from the village itself (minimum 8th standard education, preferably married/widow/divorced woman of 25-45 years)
• ~9.15 lakh ASHAs in position across India

1. Create awareness on nutrition, sanitation, hygiene, and health services
2. Counsel on safe delivery, breastfeeding, immunization, contraception
3. Mobilize community to access services at AWC, sub-centre, PHC
4. Accompany/escort pregnant women and sick children to PHC/CHC
5. Primary medical care for minor ailments (diarrhoea, fever, first-aid)
6. DOTS provider for TB patients
7. Depot holder for ORS, iron-folic acid, chloroquine, condoms, OCP, delivery kits
8. Report births, deaths, and unusual health events/outbreaks to sub-centre/PHC
9. Promote household toilet construction (Swachh Bharat Mission)

• Incentive-based payment (not a salaried employee); receives incentives for each defined activity (e.g., institutional delivery escort, immunization mobilization)

XI. MONITORING AND EVALUATION AT PHC LEVEL

• Monitoring and supervision of sub-centres through regular visits and monthly meetings
• Monitoring of all National Health Programmes
• Monitoring of ASHA activities
• Analysis of records and reports to identify gaps in service delivery
• Village Health, Sanitation and Nutrition Committee (VHSNC) at the gram panchayat level provides community oversight
• Rogi Kalyan Samiti (RKS) / Hospital Management Committee at PHC level: a registered body responsible for improving quality of care and utilizing untied funds for PHC development

XII. CHALLENGES AND LIMITATIONS OF PHCs IN INDIA

1. Shortage of personnel - particularly doctors and specialists (31% vacancy in MO posts in rural areas)
2. Inadequate physical infrastructure in many PHCs (no 24-hour electricity, water supply)
3. Poor supply chain for drugs and equipment (frequent stock-outs)
4. High absenteeism of staff posted at rural PHCs
5. Urban concentration of health services and personnel vs. rural needs
6. Lack of accountability mechanisms
7. Inadequate community participation
8. Overburdened with curative work; insufficient attention to preventive/promotive services
9. Poor referral linkages and transport
10. Inadequate funding (India's public health expenditure ~3% of GNP vs. WHO recommendation of 5%)

XIII. RECENT REFORMS - NATIONAL HEALTH MISSION (NHM)

• IPHS (Indian Public Health Standards) formulated to set minimum quality standards for PHCs
• RKS (Rogi Kalyan Samiti): Registered society at PHC level to manage untied funds for improvements
• Untied Funds: Annual untied grants to PHCs (Rs. 75,000/year) for local health needs
• Janani Suraksha Yojana (JSY): Conditional cash transfer for institutional delivery - drives deliveries to PHC
• JSSK (Janani Shishu Suraksha Karyakram): Free delivery, C-section, newborn care, diagnostics, medicines, transport, drop-back; entitlement for all pregnant women at government health facilities
• Kayakalp Award: National quality certification for best-performing PHCs
• LaQshya Programme: Quality improvement in labour rooms of PHCs
• Transformation of PHCs into Health and Wellness Centres (HWC): Under Ayushman Bharat (2018), 1,50,000 Sub-Centres and PHCs are being upgraded to Health and Wellness Centres to provide comprehensive primary health care including 12 packages (maternal health, child health, NCDs, TB, mental health, palliative care, ENT, ophthalmology, dermatology, dental care, geriatric care, emergency care)

XIV. SUMMARY TABLE