In vitro quantitation of Theileria parva sporozoites for use - TropMed ...

22 Chapter 1: Quantitation of Theileria parva sporozoites: Review of literature
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Table 1: Some stocks of Theileria parva used for immunizing cattle against ECF.
Stock Origin Country Reference
Katete Katete Zambia (Geysen et al., 1999)
Chitongo Namwala Zambia (Geysen et al., 1999)
Muguga Kikuyu Kenya (Brocklesby et al., 1961)
Marikebuni Coast Province Kenya (Irvin et al., 1983)
Buffalo 7014 Laikipia Kenya (Morzaria et al., 1990)
Kiambu Kiambu Kenya (Radley et al., 1975b)
Kasoba Karonga Malawi (Musisi et al., 1996a)
Serengeti Serengeti Tanzania (Radley et al., 1975b)
Boleni Boleni Zimbabwe (Lawrence and Mackenzie, 1980)
Uganda Kigungu Uganda (Minami et al., 1983)
Nyakizu Nyakizu Rwanda (Paling and Geysen, 1981)
1.1.2.3. Cycle of Theileria parva in the tick host
Tick instars feeding on an infected bovine ingest erythrocytes infected with piroplasms. The
piroplasms differentiate into micro and macro-gametes in the gut lumen subsequently fusing to
produce zygotes that invade the epithelial cells (Watt and Walker, 2000). This is the sexual
reproductive stage of the parasite. Motile kinetes are formed from zygotes and migrate through the
haemolymph to the salivary glands about the same time as the tick undergoes moulting (Mehlhorn
et al., 1978). They invade the "e" cells of the type III acini and develop into multinucleated
sporoblasts (Fawcett et al., 1982a). Type III acini are responsible for fluid transport as the tick
concentrates blood meals (Bowman and Sauer, 2004) and Binnington (1978) described the role of
"e" cells as one of secreting granules that may be used in cementing the tick to the host upon
attachment. When the tick starts feeding, the sporoblast syncytium undergoes cytoplasmic fission
resulting in mature uni-nucleated sporozoites (Fawcett et al., 1982a), which are the infective stage
for cattle. Although experimental induction of sporogony by exposing the ticks to a temperature of
37°C has been described (Young et al., 1979), in nature it is generally assumed that the tick needs