← Blood forms of T. lewisi Blood forms of T. evansi → Detection of trypanosomes in human blood by microscope Why and How ? 1- Trypanosomes are parasites living in blood, and can infect Human 2- The 2 classical forms of the disease in Human are “sleeping sickness” in Africa, and “Chagas disease” in Latin America 3- But Atypical human infections by animal trypanosomes were observed in Africa and Asia 4- Trypanosomes were observed accidentally in blood of patients complaining of fever, while malaria was suspected 5- The number of these atypical cases is probably underestimated, therefore the laboratory staff should pay attention in observation of trypanosomes in blood when looking for detection of malaria parasites in blood smears Why ?
Transcript
← Blood forms of T. lewisi
Blood forms of T. evansi →
Detection of trypanosomes in human blood by microscope Why and How ?
1- Trypanosomes are parasites living in blood, and can infect Human2- The 2 classical forms of the disease in Human are “sleeping sickness” in Africa, and “Chagasdisease” in Latin America3- But Atypical human infections by animal trypanosomes were observed in Africa and Asia4- Trypanosomes were observed accidentally in blood of patients complaining of fever, whilemalaria was suspected5- The number of these atypical cases is probably underestimated, therefore the laboratory staffshould pay attention in observation of trypanosomes in blood when looking for detection of malariaparasites in blood smears
Why ?
• Trypanosomes can be observed in Giemsa stained blood smears at magnification X 400 orpreferably X 1,000
• Trypanosome is an extra-cellular parasite, unicellular, and its morphology is characteristicincluding a plasma membrane, a nucleus, a kinetoplast and a flagellum
- K = kinetoplast
- N = nucléus
- M = membrane
- F = free flagellum (in most of the cases)KMN
F
Trypanosoma evansi in camel’s blood (X1,000)
How ?
Other forms canbe observed, but
K, N and M arealways visible
Trypanosoma lewisi in rat’s blood ( X1,000)Trypanosoma lewisi in an infant’s blood(X1,000)
(from Sarataphan et al 2007)
Persons at risk to be infected by animaltrypanosomes
Trypanosoma evansi- Cattle farmers, veterinary technicians and persons living or working in contact with animals
(slaughter houses, butcheries etc.) and biting insects are at risk in T. evansi endemicareas.
- T. evansi endemic areas are Latin America, North Africa, Middle East and Asia
Trypanosoma lewisi- People exposed to rats and flea bites, sewage workers, farmers, and people living in poor conditions
in urban areas, especially children and babies (< 3 months) but also adults.
- T. lewisi is endemic worldwide
If you detect trypanosomes in blood, please:
- Inform the Medical Doctor (Contact:…………………………………)- Collect all information from the patient or relative and his environment (location, work, insect bites, etc)- Keep the slides in safe place
Even if malaria is diagnosed as well, wait for the decision of a MD as more clinical examinationsand blood/serum collection will be performed before starting the cure against malaria.
