BLOOD PARASITES: Collect blood sample into a plain tube to get serum, place the strip on a flat surface, and apply the serum. Add a buffer solution, and allow staying for 10mins then observing two pink lines, one for control (below) and one for test (above) indicating a positive result.
In hematology laboratory, leishmaniasis is diagnosed by;
(1) Direct visualization of the amastigotes (often referred to as leishman-donovan bodies) in a thin or thick smear stained with leishman or giemsa stain. Amastigotes are seen within monocytes or, less commonly in neutrophils in peripheral blood and in macrophages in bone marrow aspirates. They are small, round bodies 2-4mm in diameter with indistinct cytoplasm, a nucleus, and a small rod-shaped kmetoplast. Occasionally, amastigotes may be seen lying free between cells.
Filarial worms causes filariasis. Filariasis involving the lymphatics is the cause of elephantiasis and it is caused b the filarial worms, Brugia malayi, Wuchereria bancrofti and Brugia timori whereas filarial infections of the subcutaneous tissues are caused by Loa loa. The larvae of these worms, called microfilariae are transmitted by mosquitoes to humans, where they show periodicity with fluctuating levels at different times of the day, thus it is very important to know the type of periodicity exhibited by the filarial worms in order to know the correct time for blood collection.
Capillary blood is normally used because they contain high concentration of microfilaria than venous blood. However, even when blood has been collected at the appropriate time, micrfilarial can be scanty, so that serological or rapid immunochromatographic tests and concentration techniques may be requires.
Blood smears as indicated for malaria parasite the microfilaria of each of the filarial worms has its own structural feature such as; sheathed and unsheathed, extension of nuclei to tip or not.
Filtration method: this is the most sensitive concentration method of microfilariae, but samples must be handles gently to preserve the organisms.
- 10ml of sodium citrate anticoagulated blood is mixed with 10ml of methylene or azure B saline solution in a tube.
- Pour the mixture through a transparent polycarbonate membrane filter of 3mm porosity. The filter traps the microfilaria and it is placed face upwards on a side, a drop of saline is added, and a cover slip is placed on top.
- The entire membrane is examined microscopically for motile microfilariae using a x10 objective with condenser iris partially closed.
Quantitative buffy coat and microhaematocrit method:
Microfilariae can be detected using the same methods as for detection of trypomastigotes
LYSED CAPILLARY BLOOD
- Mix 1ml of blood with 9ml of 2% formalin in a tube
- Centrifuge at 100g for 5 minutes
- Discard the supernatant and place all the deposit on a slide
- Add 1 drop of field’s stain A or 1% methylene blue to facilitate species identification.
- View motile microfilariae using x10 objective lens
Babesia is a thick-borne intraerythrocyctic protozoan which causes a disease called babesiosis. Humans are infected by chance in the natural cycle of transmission between the tick and its domestic or wild animal host.
It is mostly prevalent in sub tropical and tropical countries.
Signs and Symptoms: the infections results in high fever accompanied by jaundice and severe hemolytic anaemia with hemoglobinuria, there is a leycocytosis with neutrophilia.
The parasite can be seen in the erythrocytes in geimsa stained blood films. Morphologically they are variable round or oval bodies that may be mistaken for the ring form of plasmodium. However, in babesiosis the dividing cells characteristically consist of two daughter cells held together by a thin strand of cytoplasm, also no pigment occurs in erythrocytes infected with older stages of babesia.
TRYPANOSOME SPECIE: The trypanosome specie cause the disease called trypanosomiasis. Trypanosome brucci gambiense causes African chronis trypanosomiasis (sleeping sickness) which is mostly common in West Africa and West central Africa. Trypanosome brucei rhodesiense is common in east, central and southern African and causes acute trypanosomiasis.
Mode of transmission: African trypanosomiasis is tranmitted by a small number of species of tse tse flies belonging to the genus glossina. (Glossina morristan for T.b. rhodesiense and glossina palpalis for T.b. gambiense). However, trypanosomiasis can also be gotten from blood transfusion in BLOOD PARASITES.