Typhoid fever, also called enteric fever, is an acute infectious disease caused mainly by Salmonella typhi. A related organism, Salmonella paratyphi, causes a milder form of illness. The infection spreads through fecal contamination of food and water, especially in regions with poor sanitation. Typhoid is rare in industrial nations but remains a significant public health problem in developing countries, including India.
Pathophysiology
After entering the body through contaminated food or water, Salmonella organisms reach the intestine, where they are engulfed by phagocytic cells. These cells carry the bacteria across the intestinal mucosa to macrophages in the lymphatic tissues.
Unlike non-typhoidal Salmonella, S. typhi has special mechanisms for survival:
- It enters through Peyer’s patches in the ileum.
- It uses fimbriae to attach to intestinal epithelium.
- Its Vi capsular antigen hides it from the immune system.
The bacteria multiply inside macrophages and travel through lymphatics to the liver, spleen, bone marrow and lymph nodes. After reaching a critical density, they destroy the macrophages and enter the bloodstream, causing bacteremia. Later, they infect the gallbladder, re-enter the intestine through bile and are shed in stool, making the person infectious.
Symptoms
Symptoms usually appear 1–3 weeks after exposure.
Common Symptoms
- High, sustained fever (up to 40°C)
- Extreme tiredness
- Headache
- Loss of appetite
- Stomach pain
- Constipation or sometimes diarrhoea
- Cough
- Sore throat
Less Common Symptoms
- Bleeding from the rectum
- Delirium
- Rose spots (pink rash) on chest and abdomen
- Severe diarrhoea
Diagnosis
Clinical Indicators
Some classic signs suggesting typhoid include:
- Fever increasing gradually with evening rise
- Headache and general malaise
- Coated tongue with red tip and edges
- Nosebleeds (epistaxis)
- Slow pulse (relative bradycardia)
- Abdominal distension and tenderness (especially in right iliac fossa)
- Splenomegaly
- Bronchial catarrh
Culture Tests
Definitive diagnosis is made by isolating the organism:
- Blood cultures: positive in 40–60% of cases; can be improved with multiple samples.
- Stool culture: useful but less sensitive.
- Bone marrow culture: most sensitive (up to 90%) even after antibiotics.
Serological Tests
The Widal test measures antibodies against O and H antigens of S. typhi.
- O antibody indicates acute infection.
- H antibody indicates past exposure or vaccination.
The test is widely used but varies in accuracy across laboratories.
Treatment
Before antibiotics, mortality was around 20%. With modern treatment, it has decreased to 1–2%. Symptoms usually begin improving within 1–2 days of starting therapy.
Antibiotics Used
- Fluoroquinolones (e.g., ciprofloxacin, ofloxacin, gatifloxacin) — commonly used in adults.
- Ceftriaxone — preferred for pregnant women or when resistance is suspected.
- Ampicillin or trimethoprim-sulfamethoxazole — effective but resistance increasing.
- Chloramphenicol — formerly first-line but now avoided due to serious side effects.
Supportive Care
- Antipyretics for fever
- Hydration and electrolyte balance
- Light, nutritious diet
Surgery
If intestinal perforation occurs, emergency surgical closure is required.
Complications
Untreated typhoid can lead to life-threatening complications.
- Intestinal hemorrhage
- Intestinal perforation (high mortality without surgery)
- Hepatitis or jaundice
- Cholecystitis or cholangitis
- Pancreatitis
- Kidney injury
- Toxic myocarditis
- Neurological complications like delirium
Prevention
- Wash hands thoroughly after using the toilet and before eating.
- Drink only boiled or safely purified water.
- Avoid ice, street food, raw salads and unpasteurized milk.
- Peel fruits and vegetables before eating.
- Keep flies away from food.
- Eat thoroughly cooked and piping-hot food.
- Avoid shellfish and raw seafood in endemic areas.
- Vaccination is available and recommended for high-risk areas.
Public Health Importance
Because typhoid spreads through contaminated water and poor hygiene, improving sanitation, waste disposal and access to clean water dramatically reduces disease spread. Community pharmacists also play a key role in educating people about early symptoms, safe water practices and the importance of completing antibiotic treatment.
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