Protozology (proto = primitive) Study of protozoa. Blood flagellates ( Haemoflagellates ) 1. African Trypanosomiasis (Sleeping sickness) 2. American Trypanosomiasis ( Chagas disease) 3. Leishmaniasis. Blood sorozoans : Malaria (Plasmodium) Toxoplasmosis.
(proto = primitive)
Study of protozoa
Are hemoflagellates protozoan belonging to Zoomastigophorai.e. Move by flagella and divide by longitudinal fission
1. Trypanosoma gambiense & Trypanosoma rhodesiense:
2. Trypanosoma cruzi:
American trypanosomiasis (Chagas disease).
3. Leishmania donovani:
Visceral leishmaniasis (kala-azar)
4. Leishmania tropica:
Cutaneous leishmaniasis (oriental sore)
5. Leishmania braziliensis:
Mucocutaneous leishmaniasis (Espundia)
American trypanosomiasis (Chagas disease).African Trypanosomiasis (Sleeping sickness)
Caused by Trypanosoma cruzi
by bugs e.g. Triatoma infestans.
The bug releases trypomastigotes in its feces near the wound, which enter the host throughthe wound or through intact mucosal membranesHabitat
The infection by Tse tse fly.
The metacyclic trypanosomal forms in the saliva of the insect are inoculated to human during the bite.
Trypanosoma appear in the peripheral blood 5 to 21 days after the infecting bite.
Trypanosomacruzi in blood sample, Giemsa stained
Trypanosoma, 18-30 µm in length, in peripheral blood. Giemsa stain
1-Trypanosomal primary lesion (chancre) develops at the site of bite (the parasite multiply).
2-Hemolymphatic early stage where the parasite reach and multiply in blood with fever, sweating, headache, anemia, increased pulse rate, joint and muscle pain and enlarged regional lymph nodes (lymphadenopathy).
3-Cerebral late stage where the parasite reach the C.N.S. causing chronic inflammation with ischaemia and hemorrhage leading to meningoencephalitis, with sever headache, mental dullness and excessive sleeping, finally coma and death.
Suramin or Pentamidine for hemolymphatic stage and melarsoprol for late cerebral stage.
Laboratory diagnosis Microscopic examination - ELISA.
American trypanosomiasis (Chagas disease)Clinical findings
The symptomatic chronic stage may not occur for years. Its manifestations include cardiomyopathy (the most serious manifestation); pathologies of the digestive tract (megacolon) and weight loss.
Chronic Chagas disease and its complications can be fatal.
Leishmania donovani : Visceral Leishmaniasis (Kala-azar)
Leishmania tropica : Cutaneous Leishmaniasis (Tropical sore)
Leishmania braziliensis: MucocutaneousLeishmaniasis (Espundia)
Leishmaniasis is found in parts of about 88 countries. Approximately 350 million people live in these areas.
Cutaneous leishmaniasis is found in Egypt Leishmania tropica
Transmision by sand flies
Mode of infection: inject the infective stage (promastigotes) during blood meals, which are phagocyted by macrophages and transform into amastigotes, which multiply in infected cells and affect the internal organs (visceral leishmaniasis),
Disease: Skin (cutaneous leishmaniasis), or mucocutaneous tissue and skin (mucocutaneous leishmaniasis).
Leishamnia amastigotes, bone marrow aspirate, Giemsa stain
Leishamnia promastigotes having a single flagellum, Giemsa stain
Pentavalent antimony compounds or sodium stibogluconate (under investigation).
Note:Wuchereria bancrofti vector is Anopheles mosquito also
1- Malarial classical symptoms release of merozoites and their toxin from ruptured RBCS in the end of each erythrocytic cycle which complete every 72 hours in Plasmodium malariaeand every 24 hours in other species: it consists of
a- Cold stage or rigor stage (10 min to one hour)
b- Hot or fever stage (1-4 hours), due to release of most merozoites.
c- Sweating stage (1-4 hours), due to rapid drop of temp and is accompanied by reinfection of RBCs.
2-Anemiadue to destruction of RBCs, splenomegaly and hepatomegaly due to engulfed pigment by R.E.S.
3- Adhesion and clumping of infected RBCs in capillaries cause their occlusion (thrombocytopenia) , headache, myalgia, convulsions, coma, diarrhea or dysentery and dehydration.
The sexual part of the life cycle takes place only in cats, which makes cats the parasite's primary host. The second asexual phase, can take place in other warm-blooded animals, including cats, mice, humans, and birds. The hosts in which asexual reproduction takes place is the intermediate host.
2. Congenital toxoplasmosis which makes cats the parasite's : Cause severe, often fatal cerebral damage to a fetus and who recover often show mental defects. In early pregnancy it cause abortion or still birth and in late pregnancy symptoms occur in the infant 2-3 months after birth.
1. Microscopic examination of aspirates and fluids.
3. Animal inoculation (e.g. lymph node biopsy material in mice).