All about typhoid fever

Dr. Samuel Adebayo

Typhoid fever, also known as ‘enteric fever’ or ‘intestinal fever,’ is a potential serious illness that affects many system of the body. It is caused by a group of bacteria called salmonella typhi.

Worldwide, estimated 21 million cases of typhoid fever and about 200,000 deaths are recorded yearly, mostly in developing countries.

The common mode of infection is by ingestion of an infecting dose of the organism, usually through contaminated water or food. So, when an individual is infected, he becomes a reservoir for the bacteria and a source of infection to others. Within one week of infection, the bacteria is present in the blood; after one week, the victim begins to shed the bacteria through stool, and  after the second week, he begins to shed it through both the stool and the urine.

The circle of infection is such that oral transmission comes through food, beverages, fruit, water, etc., handled by an individual who sheds the bacteria through stool or urine. It also comes through hand-to-mouth transmission after using a contaminated toilet and negleting hand hygiene.

In community settings like villages, schools, hostels, churches, etc., poor hygiene and sewage contamination of water supply are the most important means of transmission.

Advances in public health and hygiene have led to the virtual disappearance of typhoid fever in the developed world, while the disease remains endemic in many developing countries like Nigeria.

Presentation of typhoid fever varies, depending on the stage of the disease and the severity.  First week, onset of the illness usually starts with fever, rises gradually within the first few days to high grade. The fever may fluctuate and get worse by the day, settling around 39-400C. There could be rash and skin pigmentation, all of which usually disappears within two or five days.

By the second week, if not treated, the signs and symptoms progress. There could be abdominal distension and pain, constipations, or  diarrhoea ; the spleen and the liver could get enlarged, heart beat may drop. There may be associated cough.

By the third week if not treated, high grade fever will persist. Individuals now are more toxic, with no appetite, weight loss, and severe abdominal distension. There could also be diarrhoea. At this level, the illness may be complicated with bowel perforation.

If by the fourth week the individual is still alive, then there will be high grade fever and mental derangement. So many complications can occur,

If an individual survives with poor or no treatment, such an individual becomes a source of infection to others.

Most cases of typhoid fever may not follow the above classical presentations, though. Typhoid fever patient may even present to the psychiatry emmergency as a case of mental illness. When this happens, it is called ‘typhoid psychosis.’

So, in making the diagnosis of typhoid fever, the clinician must critically assess the patient, carry out necessary laboratory investigations which must be correctly interpreted along with detailed history of the illness from the onset, since many disease conditions can mimic typhoid fever .

The diagnosis of typhoid fever is usually a big challenge to physicians because there are many other febrile illnesses like malaria, pneumonia, gastro enteritis and urinary tract infection that can present as typhoid fever.

One of the major problems with typhoid fever is accurate diagnosis. Most studies in Sub-Saharan Africa show that more than 70 per cent cases of diagnosed typhoid fever are actually malaria wrongly diagnosed on a single widal  titre test.

A single widal test is of little clinical relevance due to the number of cross reactions including malaria.

The gold standard for the diagnosis is to be able to culture the bacteria. It can be cultured from the blood from the first week when, in most cases, the widal titre may not even show any reaction if there is no cross reaction from other febrile illness.

The stool culture can be done as from the second week, while urine culture can be added from the third week. So, for better diagnosis of typhoid in our environment, most studies suggest the combination of full blood count, widal titre, malaria test and stool culture.

If accurately interpreted with the clinical condition of the patient, it will give a more accurate diagnosis rather than the wrong  tradition  single widal titre. Unfortunately, this is the practice in most hospitals and clinics.

In developed countries, they use more advanced diagnostic techniques which include polymerase chain reaction, bone marrow culture, stool culture, urine culture, etc. to acheive accurate diagnosis.

After diagnosis, treatment of typhoid fever may be first, medical; or with surgical intervention if there is associated intestinal  perforation. The major challenge of the treatment of typhoid is self medication and drug abuse, especially antibiotics; coupled with high level of fake drugs the country.

All this has led to high rate of drug resistance to most drugs of choice for the treatment of this ailment. However, newer drugs are replacing the old ones. Early diagnosis and treatment give rise to good outcome in most cases.

Typhoid fever can be prevented by breaking the transmission of the bacteria, avoiding street food, contaminated water, salad, etc.

Meanwhile, you must wash fruits and vegetables adequately before eating; wash hands thoroughly after using the toilet; avoid contaminated satchet waters.

Typhoid vaccines are also available and the protection is 60-80 per cent.

-- Punch