Specialty infectious disease ICD-9-CM 086.5-086 | ICD-10 B56-B57 MeSH D014352 | |
 | ||
Trypanosomiasis or trypanosomosis is the name of several diseases in vertebrates caused by parasitic protozoan trypanosomes of the genus Trypanosoma.In humans this includes African trypanosomiasis and Chagas disease. A number of other diseases occur in other animals.
Contents
Approximately 30,000 people in 36 countries of sub-Saharan Africa have African trypanosomiasis, which is caused by either Trypanosoma brucei gambiense or Trypanosoma brucei rhodesiense. Chagas disease causes 21,000 deaths per year mainly in Latin America.
Signs and symptoms
The tsetse fly bite erupts into a red chancre sore and within a few weeks, the person can experience fever, swollen lymph glands, blood in urine, aching muscles and joints, headaches and irritability. In the first phase, the patient has only intermittent bouts of fever with lymphadenopathy together with other non-specific signs and symptoms. The second stage of the disease is marked by involvement of the central nervous system with extensive neurological effects like changes in personality, alteration of the biological clock (the circadian rhythm), confusion, slurred speech, seizures and difficulty in walking and talking. These problems can develop over many years and if not treated, the person dies. It is common to the African continent.
Diagnosis
Cattle may show enlarged lymph nodes and internal organs. Haemolytic anaemia is a characteristic sign. Systemic disease and reproductie are common, and cattle appear to waste away.
Horses with dourine show signs of ventral and genital edema and urticaria.
Infected dogs and cats may show severe systemic signs.
Diagnosis relies on recognition of the flagellate on a blood smear. Motile organisms may be visible in the buffy coat when a blood sample is spun down. Serological testing is also common.
Prevention
Diminazene, homidium, isometadium, suramin, and melarsomine can all be used to treat infections. Resistance is increasing in endemic areas and recurrent treatments may be necessary.
The use of trypanotolerant breeds for livestock farming should be considered if the disease is widespread.
Fly control is another option but is difficult to implement.
The main approaches to controlling African trypanosomiasis are to reduce the reservoirs of infection and the presence of the tsetse fly. Screening of people at risk helps identify patients at an early stage. Diagnosis should be made as early as possible and before the advanced stage to avoid complicated, difficult and risky treatment procedures.
Treatment
Diagnosis is often missed in the first phase of the disease due to non-specific nature of symptoms. Pentamidine and Suramin are used for treatment in the first phase. Melarsoprol, nifurtimox and eflornithine are drugs used in second phase of the disease. However none of the therapies available are optimal in terms of adverse events and ease of administration.
Other animals
Some species of cattle such as the African buffalo, N'dama, and Keteku appear trypanotolerant and do not develop symptoms. Calves are more resistant than adults.