Typhoid fever arises from infection with a bacteria called Salmonella typhii. This bacterial strain is primarily spread via the feco-oral route. The bacteria are passed from the body of an infected individual in their feces, and can contaminate the drinking water in areas of poor sanitation.

Symptoms usually start within one or two weeks after ingestion of the bacteria. If the condition is identified and treated promptly, the symptoms may begin to ease within three to five days of beginning a course of antibiotics. If left untreated, typhoid fever can rapidly worsen over a period of weeks and become life threatening.

Some of the common symptoms of typhoid include:

• Typhoid is notorious for causing a fever that can reach temperatures as high as 39-40°C (103-104°F).
• Profuse sweating
• Children and young adults aged between 5 and 19 years are most commonly affected
• Headache and muscle pain
• Abdominal bloating and discomfort
• Nausea and vomiting
• Loss of appetite
• Diarrhea or constipation. While children are more likely to get diarrhea, adults may get constipated.
• Fatigue
• Small pink rash of flat spots across the body, especially the torso

High fever may lead to delirium and confusion
The progression of untreated typhoid fever is generally marked by four stages, with each lasting around a week. Typhoid that is correctly treated usually resolves within a week and these stages are avoided.

During the first week, fever slowly intensifies and the sufferer may be weak and unwell, with a cough, headache and slow heart rate. Nose bleeds and abdominal pain may also manifest. If the Widal test is performed during this time, it is likely to give a false negative result due to the test's lack of sensitivity and specificity.

In the second week, the fever temperature is high and the heart rate low, and the sufferer may be confused and agitated. The rose spot rash may appear across the chest and abdomen. The abdomen may also be bloated and painful and there may be greenish diarrhea or constipation. The Widal reaction should be positive in the case of infection when performed during this week.

In the third week, serious complications such as intestinal bleeding arise. Another life-threatening condition is perforation of the intestine at the distal ileum, which leads to peritonitis and septicemia. Other organs such as the brain may be affected, a condition termed encephalitis. In addition, the gall bladder may become inflamed, there may be involvement of the heart and bone tissue and abscesses may manifest.

The fever slowly resolves during the fourth and final week.