Typhoid fever progresses through four distinct stages over approximately four weeks: incubation, continuous high fever (1st week), rose spots and complications (2nd–3rd week), and convalescence (4th week). It is caused by the bacterium Salmonella typhi, transmitted through contaminated food and water. Early diagnosis and antibiotic treatment are critical to prevent life-threatening complications.
Typhoid fever is caused by Salmonella typhi, a gram-negative bacterium.
The four stages are: incubation, continuous fever (week 1), rose spots (week 2), and convalescence (week 4).
Rose spots are a pathognomonic feature appearing in 20–30% of typhoid patients.
Intestinal perforation in the 3rd week is the most dangerous complication of typhoid.
Relative bradycardia (Faget's sign) is a classic clinical feature of typhoid fever.
Blood culture is the gold standard diagnostic test, most positive in the first week.
The Widal test detects antibodies against Salmonella typhi antigens (O and H antigens).
Chronic carriers harbor bacteria in the gallbladder and continue to shed Salmonella in their faeces.
The incubation period lasts 7–14 days (range: 3–30 days) after ingestion of Salmonella typhi. During this stage, the bacteria multiply in the intestinal lymph nodes (Peyer's patches) and spread to the bloodstream. The patient may experience mild malaise, loss of appetite, and headache. No fever is present at this stage.
In the first week of illness, the characteristic stepwise rising fever appears, reaching 39–40°C (103–104°F). Symptoms include:
During the second week, symptoms reach their peak. Key features include:
In the third week, serious complications may arise:
Treatment: Antibiotics such as ciprofloxacin, azithromycin, or ceftriaxone are used depending on antibiotic sensitivity. Supportive care includes hydration and nutritional support.
Prevention:
The four stages of typhoid fever are: (1) Incubation period (7–14 days, no symptoms), (2) First week — stepwise rising fever, headache, constipation, and relative bradycardia, (3) Second week — continuous high fever, rose spots, hepatosplenomegaly, and risk of intestinal perforation, (4) Third to fourth week — complications arise or the patient enters convalescence and gradually recovers.
Rose spots are small (2–4 mm), pink, flat macules that appear on the chest and abdomen during the second week of typhoid fever. They represent bacterial emboli in the skin capillaries and are found in about 20–30% of patients. They fade on pressure and disappear within 3–4 days.
Intestinal perforation is the most dangerous complication of typhoid fever, occurring in approximately 1–3% of cases during the third week. The bacteria cause necrosis of Peyer's patches in the ileum, leading to a hole in the intestinal wall, peritonitis, and septic shock. It requires emergency surgical intervention.
Blood culture is most positive in the first week (bacteraemia stage). Stool and urine cultures are most positive in the second and third weeks. The Widal test (antibody detection) becomes positive from the second week onward. Bone marrow culture is the most sensitive test at any stage.
Typhoid fever is prevented by vaccination (oral Ty21a or injectable Vi polysaccharide vaccine), drinking safe treated water, maintaining proper sanitation, practicing regular hand hygiene, and avoiding consumption of raw or street food in endemic areas. Identifying and treating chronic carriers also prevents spread.
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