🦠 Typhoid Fever: Causes, Symptoms, Treatment & How to Stay Safe

Typhoid fever remains a major public health concern in India, particularly in areas with poor sanitation and limited access to clean drinking water. Caused by the bacterium Salmonella Typhi, it presents as a gradually worsening fever with abdominal symptoms and a characteristic slow heart rate relative to the height of the fever. If untreated, it can lead to life‑threatening intestinal perforation. Dr. Ravi Sishir Reddy explains how typhoid spreads, its classic symptoms, how it is diagnosed, and the crucial role of appropriate antibiotic treatment.

1. What Causes Typhoid Fever?

Typhoid fever is caused by the bacterium Salmonella enterica serotype Typhi (often abbreviated as S. Typhi). It is exclusively a human pathogen — meaning it only infects and is carried by humans. The bacteria are shed in the faeces and, in some cases, the urine of infected individuals. Transmission occurs through the faecal‑oral route:

• Drinking water contaminated with sewage containing S. Typhi.
• Eating food prepared by an infected person who did not wash their hands properly after using the toilet.
• Consuming raw vegetables or fruits washed with contaminated water.
• Eating street food or food from unhygienic establishments where sanitation is compromised.

Once ingested, the bacteria invade the intestinal lining, enter the bloodstream, and spread throughout the body — particularly to the liver, spleen, bone marrow, and lymph nodes. A small percentage of people (about 3‑5%) who recover from typhoid become chronic carriers — they continue to shed the bacteria in their stool for months or years without showing any symptoms themselves. Chronic carriers are a reservoir for continued transmission in the community.

2. The Step‑Ladder Fever: Classic Typhoid Symptoms

Typhoid has an incubation period of about 6‑30 days after exposure. The illness typically progresses over four weeks if untreated, although antibiotic therapy dramatically alters this course:

• Week 1: The fever rises in a "step‑ladder" pattern — each day, the peak temperature is slightly higher than the previous day. The patient experiences headache, dry cough, malaise, and a dull frontal headache. There may be nosebleeds. A key sign is relative bradycardia — the heart rate is slower than expected for the height of the fever (normally, the pulse increases by about 10 beats per minute for every 1°F rise in temperature; in typhoid, this doesn't happen). The tongue is coated white centrally with red edges ("typhoid tongue").
• Week 2: The fever plateaus at 103‑104°F (39‑40°C). The patient becomes more toxic — lethargic, confused, and profoundly weak. Rose spots — faint, salmon‑pink, blanching spots 2‑4 mm in diameter — may appear on the lower chest and upper abdomen, though they are seen in only about 30% of cases. The abdomen becomes distended and tender. Constipation is more common than diarrhoea, though children may have a pea‑soup diarrhoea.
• Week 3 (the danger zone): Without treatment, this is when severe complications occur. The most feared is intestinal perforation and haemorrhage. The bacteria‑laden Peyer's patches (lymphoid tissue in the small intestine) ulcerate, and the ulcers can erode through the bowel wall, causing leakage of intestinal contents into the abdominal cavity. This presents as sudden, severe abdominal pain, a rigid abdomen, and signs of shock. Intestinal haemorrhage manifests as black, tarry stools or passage of fresh blood. Both are surgical emergencies.
• Week 4: If the patient survives, the fever gradually subsides, and recovery begins, though it is slow and the patient is extremely weak and wasted.

With timely antibiotic treatment, the fever typically resolves within 3‑5 days, and the prolonged course and complications are avoided entirely.

3. How Is Typhoid Diagnosed?

Dr. Reddy outlines the tests used to confirm typhoid:

• Blood culture: The gold standard. A blood sample is incubated in a culture medium to see if S. Typhi grows. It is most likely to be positive during the first week of illness. Results take 2‑3 days, but it also provides antibiotic sensitivity testing, which is critical because drug‑resistant typhoid is increasingly common.
• Bone marrow culture: The most sensitive test (positive in 80‑90% of cases), but it is invasive, painful, and reserved for difficult‑to‑diagnose cases where blood cultures are negative.
• Widal test: A serological test that detects antibodies against S. Typhi antigens (O and H antigens). It is widely available and inexpensive. However, it has significant limitations: false positives can occur from previous typhoid, vaccination, or other infections, and false negatives can occur if done too early (before antibodies have developed). A single high titer (≥1:160 for O antigen or ≥1:320 for H antigen) is suggestive, but a fourfold rise in titers between two samples taken 7‑10 days apart is more diagnostic. Dr. Reddy cautions that the Widal test should be interpreted in the context of the clinical picture — a positive Widal alone does not confirm typhoid, especially in endemic areas like India.
• Complete blood count (CBC): Often shows a normal or low total white blood cell count (leukopenia), which is unusual for a bacterial infection but typical of typhoid.

4. Treatment: Antibiotics Are Essential

Typhoid is a bacterial infection that requires appropriate antibiotic therapy. Without antibiotics, the mortality rate is about 10‑15%; with appropriate treatment, it drops to less than 1%. The choice of antibiotic depends on the sensitivity of the bacteria in your region and, ideally, on the results of blood culture and sensitivity testing. Dr. Reddy explains the commonly used agents:

• First‑line options (if the organism is sensitive):
  • Ciprofloxacin or other fluoroquinolones — but resistance is now widespread in India, so they are used only if sensitivity is confirmed.
  • Ceftriaxone (a third‑generation cephalosporin) — given intravenously or intramuscularly for 7‑14 days. It is highly effective and is often the drug of choice for hospitalised patients.
  • Azithromycin (a macrolide) — oral option for uncomplicated typhoid, particularly in children and during pregnancy (under medical supervision).
• Multi‑drug‑resistant (MDR) and extensively drug‑resistant (XDR) typhoid: Strains of S. Typhi resistant to multiple first‑line antibiotics (including fluoroquinolones) have emerged in South Asia, particularly in Pakistan and India. In some cases, even ceftriaxone resistance has been reported. Carbapenems (meropenem) or azithromycin‑ceftriaxone combinations may be required. This makes antibiotic sensitivity testing more important than ever.

Treatment is usually given for 10‑14 days. Even if the fever subsides within a few days, completing the full course is essential to prevent relapse and reduce the risk of becoming a chronic carrier. Adequate hydration, a soft, easily digestible diet (khichdi, rice, soups, curd, bananas), and complete rest are important supportive measures.

5. Complications: When Typhoid Becomes Dangerous

The most serious complication is intestinal perforation, which occurs in about 1‑3% of untreated cases. A perforated ulcer causes sudden, severe abdominal pain, board‑like rigidity of the abdominal muscles, and rapid deterioration into septic shock. This is a surgical emergency requiring laparotomy and repair of the perforation, along with broad‑spectrum intravenous antibiotics. Intestinal haemorrhage can occur without perforation and may require blood transfusions. Other complications include hepatitis, myocarditis, pneumonia, and central nervous system involvement (typhoid encephalopathy).

6. Prevention: Safe Water, Safe Food, and Vaccination

• Safe drinking water: Drink boiled, filtered, or bottled water. Avoid ice made from tap water when outside. Use clean water for brushing teeth.
• Food hygiene: Eat freshly cooked, hot food. Avoid raw salads, cut fruits sold on the street, unpasteurised milk, and street vendor food that may have been prepared in unhygienic conditions. Wash fruits and vegetables thoroughly with safe water before eating them raw at home.
• Hand washing: Wash hands with soap and water before eating, after using the toilet, and after handling anything that may be contaminated. Alcohol‑based sanitisers are a good backup but do not kill all pathogens as effectively as soap and water for S. Typhi.
• Vaccination: Two types of typhoid vaccines are available in India:
  • Typhoid conjugate vaccine (TCV): A single intramuscular injection that can be given to children as young as 6 months. It provides about 85% protection and is long‑lasting. It is now part of the routine immunisation schedule in several Indian states.
  • Vi polysaccharide vaccine: A single injection for children over 2 years and adults. It requires a booster every 3 years. It is slightly less immunogenic than the conjugate vaccine but still effective.
  • Oral live‑attenuated vaccine (Ty21a): A capsule taken every other day for 4 doses. It is less commonly used in India but is an option for those who prefer an oral vaccine.

Dr. Reddy recommends typhoid vaccination for anyone living in or travelling to areas with poor sanitation, and for households where someone has been diagnosed with typhoid. The vaccine does not provide 100% protection, so food and water precautions remain essential even after vaccination.