What is Typhoid fever?
Typhoid fever is an infection of the intestinal tract with the organism Salmonella typhi. It thrives in conditions of poor sanitation, overcrowding and social chaos. It is a potentially fatal acute illness that affects different systems of the body and is very common in developing countries whereas, fewer than 400 cases are reported in the United States each year.
The genera family of Salmonella has another implicating serotype called Salmonella paratyphi A,B,C which causes a milder form of illness like typhoid fever hence the name, paratyphoid fever, and these organisms both dwell solely within a human reservoir.
The term Enteric Fever is generally used to describe both Typhoid and Paratyphoid Fevers.
How is Typhoid Fever gotten?
The infection is transmitted by the feaco-oral route thus;
- By hand-to-mouth transmission after using a contaminated toilet and neglecting hand washing,
- It can be contracted by ingestion of food or drink served by an infected food handler with poor hygiene (i.e. a chronic shedder of salmonella typhi), or by
- Oral transmission through sewage contaminated water or an infected shellfish.
Related: How Safe is your FOOD?
How Typhoid fever is spread in the body (Pathogenesis)
Upon ingestion, Salmonella typhi enters the walls of the intestine where they adhere to clusters of lymphoid tissue. The bacterium uses it for its own reproduction and breaks out into the blood stream to invade other parts of the body especially the liver and spleen. From the liver, it gets into the bile of the gall bladder from where the bacteria can either re-enter the gastrointestinal tract through the bile for a heavy re-infection of the host or it is shed in stool to possibly infect other people. It is the gall bladder that houses the organism in chronic carriers. The bacteria can survive for weeks in water or dried sewage.
Typically, most people come down with an unexplained high fever with a headache and generalized body aches (sounding a lot like Malaria, right?). In addition, there could be associated abdominal pain, constipation/diarrhoea. The person may also complain of pain in the upper right side of the abdomen depicting an enlargement of the liver, and could also affect the spleen too. In severe cases, complications may arise leading to bleeding within the bowels and even perforation, the patient could become delirious while some may lapse into a coma or even death.
After a typical acute illness, a few people can become carriers of salmonella typhi and continue to release the bacteria in their stools for years.
On the other hand, some others only suffer a very mild illness that goes unrecognized and can become long term carriers of the bacteria.
There are different types of blood tests that can be done such as a blood culture which can specifically yield the growth of the organism even in first week of illness but depending on the lab, may take as long as 3- 7 days for results so this is less routinely done. Besides a generic full blood count that would show an elevated count of the white blood cells as proof of an on-going infection, the more commonly used (seldom reliable) test is the widal test which detects antibodies to salmonella typhi. From a basic understanding of our body’s immune system the presence of antibodies usually indicates a previous form of infection and does not necessarily serve as proof of a current infection.
Therefore, for a widal test to be diagnostic the ideal practice is to do a paired test comparison 3 days apart and a serial rise in the titre value could serve as proof on an on-going typhoid infection.
Other possible tests are the stool or even urine culture which may be present only at various points of the illness and again cultures take too long to produce results. ELISA and fluorescent antibody study is a highly specialized test to look for substances specific to salmonella typhi, so is really expensive- and not done around here.
Treating Typhoid Fever
The fluoroquinolones remain the drug of choice. Chronic carriers should be treated for up to 4 weeks and cholecystectomy (gall bladder surgery) may be necessary in some cases.
An important highlight is the fact that Typhoid Fever is a Preventable Disease.
An important highlight is the fact that Typhoid Fever like many other infections prevalent in Sub-Saharan Africa, like in other developing countries is a preventable disease. Obviously improved sanitation, use of clean/safe water, careful hand washing, better toilet habits and careful choice of food service vendors are the key ways to prevent a typhoid infection.
Practical tips for Prevention of Typhoid fever infection
i. Water treatment
ii. Proper waste disposal
iii. Protecting food supply from contamination
iv. Carriers must not be allowed to work as food handlers
v. It is safer for travelers to drink only boiled or bottled water
vi. Immunization with vaccines against typhoid fever is available and they require booster doses because their effects wane with time.