PH walks into the consultation room. She complains of fever, headache, and shivering. Before the doctor could ask her questions, she demands for a typhoid test in addition to malaria test. She says, ‘my diseases are usually malarial fever and typhoid fever.’
Typhoid fever is an infectious disease caused by the bacterium, Salmonella typhi majorly. Salmonella paratyphi causes a few infections too. This bacterium is transmitted via contaminated water and food. Infected persons transfer the bacterium to others when they contaminate water or food with their feces which contains the bacterium. Unlike malarial fever which is contracted following an infected bite of a female Anopheles mosquito, typhoid fever is contracted via oral intake of infected water, food, or both.
Risk factors: The following increase the risk of an individual getting infected with typhoid fever.
- Eating in unhygienic canteens or restaurants
- Consumption of unwashed fruits
- Living in houses with poor sanitary disposal methods
- Drinking from rivers or streams. If infected stools are disposed off into streams and an individual drinks from it, typhoid infection may result.
Conversely, individuals with healthy eating and drinking lifestyles are very unlikely to have typhoid infections. Such individuals probably eat home prepared foods or eat in restaurants where the cooks pass the food handlers’ test.
What clinical features are suggestive of typhoid fever? Broadly speaking, most symptoms found in individuals with typhoid fever are found in other infectious diseases. However, a combination of the following features would increase a clinical suspicion of typhoid fever.
- Continuous high grade fever (Remittent fever). There is no period of the day that the individual does not have fever. In malarial infection, the fever is intermittent (off and on).
- Abdominal pain may be more intense.
- Constipation and or diarrhea may be present.
- On clinical evaluation, the heart rate is not as elevated as is expected of the high degree of fever seen in typhoid infection. Usually with fever, heart rate increases. In typhoid fever, the heart rate does not increase accordingly.
Laboratory test for typhoid infection: When individuals request for typhoid test in developing countries especially, they usually mean Widal test. Widal test is majorly of historical importance. It is important to note that the results of Widal test are not unique to typhoid fever. Also, the test has to be done repeatedly, days apart, to confirm if it is positive or not. This delay is unnecessary. Recommended tests include
- A gram stain of the stool from the infected individual. If the result is suggestive of the presence of Salmonella typhi, it helps to support clinical diagnosis of typhoid fever. Treatment would therefore commence immediately.
- A culture of stool or blood which shows the growth of the typhoid bacterium. This takes a few days.
- Blood test for the level of the white blood cells usually reveals a low count in typhoid fever.
Implications of assumption of typhoid fever: Individuals who assume that they are infected with typhoid fever would most likely use medications, antibiotics, to treat the disease. This habit increases the risk of medication resistance. This means that the medications have been abused and no more work to eradicate the typhoid bacterium. This leads to a dangerous situation in which an individual with clinical and/or laboratory diagnosis of typhoid fever is prescribed the ideal antibiotic but does not get better.
Key notes: Typhoid infection is very rare among persons with good food and water hygiene. Clinical evaluation by health personnel is important to prevent wrong self diagnosis.
Dr Ademola Orolu is a Consultant Family Physician. He holds the Fellowship of The West African College of Physicians. He is also an Associate Fellow of The National Postgraduate Medical College of Nigeria. He is in active clinical practice. He is a writer, a patient advocate, and has a passion for health education. He is the chief editor of The Family Doctors. He can be contacted via firstname.lastname@example.org