The food we eat and the water we drink can cause many diseases: from the delicate to the fatal.
Typhoid fever is one such food-borne infection that is common in the developing world. Presenting a subtle illness during the initial phase, typhoid may be difficult to identify. It can cause fatal complications in 3-4 weeks.
Epidemics of typhoid-like illness have been known to mankind for millennia. Since it closely mimics typhus fever - a serious infective illness caused by microbes called Rickettsiae - it was termed as typhoid [typhus-like] fever. By the 1800s, it was clearly defined as an infection affecting the intestines. It was, thus, called enteric fever.
Now, typhoid is identified as a dreadful infection, especially in the developing world, where poor sanitation and bad hygiene are common dangers. It is estimated that every year about 20 million people suffer from typhoid and nearly 60,000 die of its complications. In recent years, resistance to commonly-used antibacterial drugs has become a cause for concern.
Source of infection
Typhoid is caused by bacteria called Salmonella typhi. These microbes occur exclusively in humans and is, therefore, the only source of infection. The bacteria are shed in the faecal matter by acutely ill patients as well as chronic carriers - those who recover from the illness, but continue to shed the bacteria for months. Food and water handled by infected persons, or contaminated with faecal matter due to poor sanitation or houseflies, can also be a medium of transmission of the bacteria from person to person.
Once in the gut, the bacteria escape the acid in the stomach and soon find their way through the lining of the small intestinal wall. They are captured by the macrophages, the defensive blood cells, and through them the germs enter the blood and reach the liver, bone marrow, and spleen, from where they start multiplying. They are then excreted through the bile juices. Fever and other manifestations of the disease result from the response of the human host to the multiplying microbes.
Untreated typhoid fever runs a course for about four weeks; the late complications that may occur by the third or fourth week may prove fatal.
During the first week, the body temperature in the affected person rises slowly to about 102°F, and there may be headache, malaise, abdominal pain etc., Patients may also have constipation, or diarrhoea. Some patients may have bleeding from the nose. By second week, the fever rises further and the patient feels very weak and may be unable to even get up. In about a third of the patients, there may be a pinkish rash over the abdomen and trunk. They are called rose spots.
Many patients have diarrhoea with greenish, "pea-soup-like" stools; and, some may have constipation. Some may also have confusion and agitation. The abdomen may be distended and there may be pain in the right lower part of the abdomen. The liver and spleen enlarge by this stage, and the physician can feel them easily.
By third week, some patients may develop complications of typhoid fever. Bleeding from the gut and perforation of the ulcers in the small intestine may result in peritonitis and sepsis. They are the most dreaded complications. They may develop even after the patient has shown improvement.
These complications may need urgent medical and/or surgical intervention. Rare complications include encephalitis [brain fever] with confusion or delirium, and they may also affect the heart, pancreas, kidneys, bones etc.
The diagnosis of typhoid fever is not easy. The illness does not offer definite clues. Confirmation of infection is possible only with a culture of blood, or other material. Even these may sometimes prove elusive as only about 50-70 per cent of cultures may show a positive report. Cultures of bone marrow aspirate and gastric or intestinal secretions may provide a higher yield of 90 per cent, but these are difficult to obtain. Serological tests, like the popular Widal Test, are neither sensitive nor specific and are, therefore, not reliable as diagnostic tools for typhoid fever.
Typhoid fever is treated with antibacterial drugs that kill Salmonella typhi. Chloramphenicol, a drug that blocks the multiplication of the bacteria, was widely used for typhoid earlier, but lack of efficacy and cases of serious adverse effects have made them redundant today.
In recent times, Salmonella has also developed resistance to many commonly-used antibacterial drugs. Quinolones like ciprofloxacin are oral antibiotics used for treating typhoid fever, but resistance to these drugs is also emerging. Ceftriaxone injections, or oral azithromycin, are being used more often these days in the treatment of typhoid fever. The treatment is usually given for 10-14 days.
In some patients, symptoms may relapse after a few days and they may need treatment all over again. About 1-4 per cent of cases may become chronic carriers, and they would need antibiotic treatment for about six weeks.
Prevention of typhoid fever essentially involves clean eating habits and maintenance of personal hygiene. Use of boiled water and eating only hot and steaming food would minimise the risk of typhoid infection. Raw foods, and food and beverages from street vendors should be avoided.
Effective vaccination is available against typhoid fever; the protection can last for about 3-4 years after vaccination. This is highly recommended for travellers from the developed world, when they visit endemic areas of typhoid fever. Vaccination should be taken at least a week prior to travel.
Prevent the Spread
Even if your symptoms seem to go away, you may still be carrying S typhi. If so, the illness could return, or you could pass the disease to other people especially if you work at a job where you handle food, or care for small children. If you are being treated for typhoid fever, it is important to do the following:
- Keep taking the prescribed antibiotics for as long as the doctor has asked you to take them
- Wash your hands carefully with soap and water after using the bathroom, and do not prepare or serve food for other people.
Consult your doctor and perform a series of stool cultures to ensure that no bacteria remain in your body.
- Source: Centers for Disease Control and Prevention, US
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