Typhoid Fever or Enteric fever is a systemic disease characterised by mainly fever and abdominal pains which is caused by the dissemination of the bacteria called Salmonella Typhi or Paratyphi (type A, B or C). Fever of between 38.8 degrees Celsius and 40.5 degrees Celsius is documented to be present in almost about 75% of all cases that report to the hospital. This fever is typically prolonged and can continue up to 4 weeks if left untreated.
Typhoid fever is an infectious disease that can affect both males and females, adults and children alike. The highest fatality rate are reported to be in children less than 4 years of age. It is an endemic disease in certain areas of the world and there have also been epidemics of the disease in other areas. Typhoid Fever remains a major public health issue in many populations around the world. In 2015 alone, there were 12.5 million new cases of typhoid fever worldwide according to the available statistics.
Some individuals who are infected with the bacteria Salmonella typhi or paratyphi may end up becoming chronic carriers of the bacteria without showing any symptoms of the disease. They become agents of transmission of the bacteria to other individuals. Statistics shows that around 2% to 5% of those who develop typhoid fever become chronic carriers as the bacteria persists in the biliary tract even after symptoms may have resolved.
Mode of Transmission
The bacteria that causes typhoid (Salmonella typhi and paratyphi) is found in the faeces of humans and has been shown to cause disease only in human beings. It can be transmitted from person to person through different forms which may include
- Consumption of contaminated food or water especially when the food has been prepared in or by a poor hygienic process.
- Direct feco-oral transmission (when feaces enters a person’s mouth especially after using the toilet without proper hand washing and eating immediately).
- Consumption of shell-fish taken from sewage polluted areas.
- Consumption of raw fruits and vegetables where human excreta have been used as fertiliser.
- Ingestion of contaminated milk and milk products.
- Flies may cause human infection through transfer of the infectious agent from faeces to food.
- Epidemics of typhoid can occur when the water sources are polluted and a large number of people consume the same contaminated source of drinking water.
There is higher risks of typhoid fever in countries or areas with low standards of hygiene and water supply facilities. The risk for travellers is generally low, except for those who travel to parts of Northern Africa, West Africa, South Asia, parts of Indonesia and Peru.
Signs and Symptoms
The signs and symptoms of typhoid vary from person to person and also in children and adults. The manifestation of some symptoms and signs are dependent on the severity of the disease and complications. Some individuals may also not show any signs or symptoms of the disease even though they are infected.
When symptoms or signs appear, they may include
- Fever (gradual onset or sustained fever)
- Abdominal pains
- Nausea and vomiting
- General malaise (feeling sick)
- Anorexia (poor appetite)
- Constipation (more in adults)
- Diarrhoea (more in children)
- Pink spots on the trunk of light skinned individuals
- Hepatosplenomegaly (enlarged liver and spleen)
- Cough or pneumonia
How Typhoid is Diagnosed
The diagnosis of typhoid involves the history of the clinical features and physical examination which can help rule out other possible causes of the presenting symptoms. The definitive diagnosis of typhoid however, involves laboratory investigations to detect the presence of Salmonella typhi or paratyphi.
Blood or stool culture of the bacteria is the gold standard for diagnosing typhoid. However, other lab tests such as widal test and the typhidot test are available to compliment the blood or stool culture.
The widal test is a quantitative test that demonstrates antibodies against salmonella antigens O titre (somatic) and H titre (flagella). The Typhidot test is more qualitative and consists of a dot ELISA kit that can detect immunoglobulins M and G antibodies against the outer membrane of the Salmonella typhi.
Treatment and Prevention
Typhoid Fever can be treated with antibiotics although the issue of microbial resistance is threatening the efficacy of the drugs used. Fluoroquinolones like ciprofloxacin and third generation cephalosporins like ceftriaxone and cefixime are the first line treatment for typhoid. Surgical intervention is required for individuals with typhoid perforation which is a complication of the disease.
There are available vaccines against typhoid which can prevent the infection in up to 30% to 70% success rate in the first 2 years. The vaccines can remain with potent effects for up to seven years and recommended for those at high risk or those travelling to endemic areas of the disease.
Other preventive measures that can be taken against typhoid fever infection include
- Drinking clean and treated water.
- Eating well cooked and prepared food.
- Better environmental sanitation and personal hygiene.
- Better hand washing especially after using the toilet.
- Infected individuals should not prepare food for others.
- Reporting to the hospital early to treat the disease.
- Infectious Disease Advisor – Infectious Diseases – Enteric Fever
- WHO – Diseases – Typhoid Fever
- Wikipedia – Typhoid Fever
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