Typhoid Fever
Typhoid fever is more common in the tropics. It tends to occur in places where the sanitation standards are poor. Typhoid fever is caused by a bacterial organism called salmonella typhi . Salmonella paratyphi can also cause fever and abdominal symptoms. The disease caused by both these entities is called enteric fever. The disease presents with a typical, continuous fever for about three to four weeks, relative bradycardia with abdominal pain (due to enlargement of lymph nodes in the abdomen), and constipation.
Salmonella Typhi Bacteria Salmonella Typhi Bacteria
Geographical distribution
Worldwide, typhoid fever affects about six million people with more than 6,00,000 deaths a year. Almost 80% of cases and deaths occur in Asia, and most others in Africa and Latin America. Among Asian countries, India probably has a large number of these cases.
Indian statistics
Typhoid fever is endemic in India. Health surveys conducted by the Central Ministry of Health in the community development areas indicated a morbidity rate varying from 102 to 2219 per 1,00,000 population in different parts of the country. A limited study in an urban slum showed 1% of children up to 17 years of age suffer from typhoid fever every year.
Carriers of typhoid fever
Typhoid infection is mainly acquired from persons who are carriers of the disease. Carriers are people who continue to excrete salmonella through their urine and feces a year after an attack of typhoid. A chronic carrier state develops in about 2 to 5% of the cases. The organisms in such cases make the gall bladder their habitat.
Expert Advice On Typhoid Fever
Clinical Features & Treatment of Typhoid Fever
Clinical Features
The classical sign of typhoid is fever. Fever is continuous and increases as the disease progresses.
A few patients may show abdominal discomfort associated with diarrhea.
Non–specific symptoms: Chills, sweating, headache, loss of appetite, weakness, sore throat, dry cough, constipation and muscle pains are often present.
Patients may lose interest in their surroundings.
Physical examination
Abdomen: On examination, the abdomen shows tenderness associated with enlarged spleen and liver.
Rosy spots may appear on the lower chest and upper abdomen. These may appear in the second week.
The pulse rate is generally slow (relative bradycardia).
Treatment and Prevention of Typhoid Fever
The carrier should be given an intensive course of ampicillin (4–6g a day) together with probenecid for about six weeks.
Control of sanitation
Protection and purification of drinking water supplies, improvement of basic sanitation, and promotion of food hygiene are essential measures to interrupt transmission of typhoid fever. When sanitation is combined with health education, the effects tend to be cumulative, resulting in a steady reduction of typhoid morbidity.
Immunization
Immunization against typhoid does not provide 100% protection, but it definitely lowers both the incidence and seriousness of the infection. it can be given at any age upwards of one year. It is recommended for:
Those living in endemic areas.
Household contact.
Groups at a risk of infection such as school children and hospital staff.
Travelers proceeding to endemic areas.
Those attending melas and arts.
Anti typhoid vaccine
The anti–typhoid vaccines currently available in India are the infectable ones:
Monovalent anti–typhoid vaccine.
Bivalent anti–typhoid vaccine.
TAB vaccine.
Dosage and mode of administration
Primary immunization should consist of two doses (each of 0.5ml) of the vaccine, given subcutaneously, at an interval of about four to six weeks. Children between one and 10 years are to be given smaller doses (i.e. 0.25ml).
Reactions
The typhoid vaccine generally causes local reactions (pain, swelling and tenderness), and also very frequently, constitutional symptoms such as malaise, headache, and pyrexia, which however, usually subside within 36 hours. To reduce the severity of reactions, it has been advised that the vaccine be administered late in the afternoon or evening. Aspirin or other anti–pyretic drugs may be administered to mitigate the unpleasant reactions. Women should not be injected during late pregnancy.
Storage
Anti–typhoid vaccines should be stored in a refrigerator at 20 to 40°C. They should not be frozen.
Causative Factors of Typhoid Fever
The primary sources of infection are feces and urine of cases or carriers, the organisms then make their way into a new patient by way of contaminated food and water.
The secondary sources are contaminated water, food, fingers and flies. There is no evidence that typhoid bacilli are excreted in sputum or milk. Typhoid fever may occur at any age. The highest incidence of this disease occurs in the five to 19 years age group.
Environmental and social factors
The peak incidence is reported during July–September. This period coincides with the rainy season and an increase in the fly population. Typhoid bacilli do not multiply in water, many of them perish within 48 hours. Food being a bad conductor of heat, provides shelter to the bacilli which may multiply and survive for sometime in food. Typhoid bacilli grow rapidly in milk without altering its taste or appearance in any way. Vegetables grown in sewage farms or washed in contaminated water are a health hazard.
Mode of transmission
Typhoid fever is transmitted via the fecal–oral route or urine–oral routes. This may take place directly through soiled hands contaminated with feces or urine of cases or carriers, or indirectly by the ingestion of contaminated water, milk and/or food, or through flies.
Carriers
Since carriers are the ultimate source of typhoid fever, their identification and treatment is one of the most radical ways of controlling typhoid fever.
Carriers of Typhoid Fever
Typhoid infection is mainly acquired from persons who are carriers of the disease. Carriers are people who continue to excrete salmonella through their urine and feces a year after an attack of typhoid. A chronic carrier state develops in 2 to 5% of the cases. The organisms in such cases make the gall bladder their habitat.
Incubation period of Typhoid Fever
Usually about 10 to 14 days.
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