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Trypanosoma Causes Trypanosomiasis West African Trypanosomiasis T.brucei gambiense Sleeping sickness East African Trypanosomiasis T.brucei rhodesiense American Trypanosomiasis T.cruzi Chagas disease Transmitted by Glossina (tsetse fly) Transmitted by Triatoma (reduviid bug)
The name is derived from the Greek trypaô (boring) and soma (body) because of their corkscrew-like motion. Trypanosoma brucei is parasitic protist species that causes several disease for human and animals. Approximately 16-18 million people are currently infected, 50,000 of which die each year.
Epidemiology
Morphology Trypanosomes are minute actively motile fusiform protozoa.large oval nucleus located centeraly near the posterior end there is a kinetoplast. A flagellum arise from the kinetoplast pass along the margin of the undulating membrane projecting from the anterior end as a free flagellum
Trypanosoma parasite
Trypanosoma life stages are: - Epimastigote - Basal body(kinetoplast) anterior of nucleus, with a long flagellum attached along the cell body. - Trypomastigote - Basal body posterior of nucleus, with a long flagellum attached along the cell body. Infective stage for vertebrate is metacyclic trypomastigote. Infective stage for the invertebrate is trypomastigote
Life Cycle of Trypanosoma brucei
Reservoirs For T.b. gambiense, the main reservoir of infection is humans, although both wild and domestic animals have also been seen to harbor the infection. For T.b. rhodesiense, the main reservoir for infection is cattle. However, other domestic animals (dogs, pigs, and sheep) and many game animals also carry the infection.
Reservoirs T.b. gambiense T.b. rhodesiense
Tsetse flies belong to the genus Glossina
Mechanism of disease transmission by Glossina Bite of Glossina Salivar y gland ull of short tumpy metacyclic rypomastigote Infective stage Biological transmission Trypomastigotes (polymorphic trypanosomes) 3 weeks Diagnostic stage 12-42µ Epimastigot e
Pathogenesis and Clinical Picture Incubation period (2 weeks) Trypanosoma chancre (at the site of bite) Via lymphatics: enlarged lymph nodes especially posterior cervical region. (Winterbottom s sign) Via blood stream: headache, fever(fluctuating), muscle & joint pain, irregular erythematous rash. Invasion of bone marrow (hypoplastic anaemia) Enlarged liver & spleen, generalized weakness. Invasion of CNS: severe headache, mental apathy, slow speech, deep sleep, coma & death In East African Trypanosomiasis: Disease runs more rapid & fatal course
Pathogenesis and Clinical Picture Trypanosoma chancre Winterbottom sign Emaciation على عظم Coma before death جلد
Diagnosis 1- Clinical picture 2- Demonstration of trypanosomes: - Microscopic examination of unstained or stained blood films Polymorphic Trypanosomes - Culture on suitable medium (N.N.N OR Weinmann s media to detect Epimastigote) - Animal inoculation * in case of T.brucei rhodesiense injected in lab Animal produce a new form Posterior Nucleus Shift
Diagnosis C.S.F
3- Serological test: Diagnosis Increased total IgM level in serum due to antigenic variation of the surface coat of the parasite. Trypanosome posses genes that code for about 1000 variant forms of their surface glycoproteins (SVG). Switch to a different variant produces a new generation not susceptible to attack by immune factors specific to the previous generation.
Treatment In early stage of the disease: Pentamidine OR Suramin For CNS involvement : Melarsoprol (i.v)
Control Treatment of patients Control of vectors (Glossina) Pentamidine as prophylactic drug
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