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

Chapter 1: Quantitation of Theileria parva sporozoites: Review of literature 29
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parotideus superficialis) and prescapular as they are near the predicted tick feeding sites, standing
coat, lacrimation, anorexia and dyspnoea in acute cases. Diarrhoea may also be present in more
chronic cases. Corneal opacity and nervous signs may be observed in some cases, the latter being
commonly misdiagnosed as cowdriosis.
1.1.6.2. Laboratory
East Coast fever is diagnosed by detection of piroplasms in the blood, schizonts in lymph node
biopsies, antibodies by the Immuno-Fluorescent Antibody Test (IFAT) (Burridge and Kimber,
1972) and PCR techniques (Bishop et al., 1992; Ogden et al., 2003). PCR, though highly
sensitive, is not suitable for routine field use due to high cost. A slide enzyme-linked
immunosorbent assay (SELISA) described by Kung'u and Goodger (1990) for Babesia has been
adapted to use schizont-infected lymphoblasts as antigen for ECF diagnosis.
1.1.6.3. Post-mortem
Most of the pathology observed at post-mortem examination results from effects of tissue
infiltration by proliferating lymphoblasts. The signs include ulceration of the abomasal mucosa,
multifocal necrosis of liver and kidneys, froth in the trachea, enlarged and hemorrhagic lymph
nodes, hemorrhagic enteritis of the caecum (Zebra stripping) and enlarged spleen. Lymphoid
tissues may be atrophic if the animal has passed through a chronic course of the disease.
Field-use positive diagnosis consists of presence of clinical signs and demonstration of schizonts.
In the absence of detectable schizonts, clinical signs with or without detectable piroplasms only
constitute a suspected case (Yeoman, 1966).
1.1.7. Control
The control of ECF is a matter of utmost importance for the livestock industries of the region.
Controlling the disease has evolved from livestock movement control and slaughter, to tick control
with acaricides, to immunisation by the infection and treatment method (Radley, 1981; Norval et
al., 1992e). Effective chemotherapy has also been developed but tick control has been the most
widely implemented strategy (Berkvens, 1991; Pegram et al., 2000). Integrating the various
methods, depending on epidemiological status, among other considerations, is currently the policy
of choice in many affected regions (Uilenberg, 1996). To a large extent, uncontrolled livestock
movement is responsible for spread of both vector and parasite to new areas (Berkvens et al.,1988;
Billiouw et al., 1999). However, limiting the movement of cattle from infected areas is largely
unsuccessful in countries where the informal farming sector is difficult to police, or where