Clinical manifestation of experimental trypanosoma evansi infection in the dromedary camel and the effect of treatment on haematological, biochemical and serological values
Abstract
With the growing awareness of the unique role the camel plays in
agriculture and environmental preservation, increasing attention is being
focused on improving its productivity and health status, so as to
improve and diversify the production capacity of the marginal lands.
Information on individual parameters of the camel's haematological and
biochemical values is largely inadequate. Because the haematological and
biochemical profiles can be useful aids in diagnosis of certain diseases,
the norm for these parameters need to be established. Trypanosoma
evatisi (T. evnnsi) is one of the most economically important diseases of
the camel and there is need to study this disease in detail. This study
was carried out with the aim of elucidating some of the haematological
and biochemical parameters in normal and T.evansi infected camels.
Haematologicaland biochemical values in healthy dromedary camels
were determined in eleven camels for a period of 4 weeks. These values
correlated well with those established in other countries.
Nine camels were artificially infected with T. evensi isolated from a
naturally infected camel and passaged through mice. Two camels were
used as non-infected controls. Four camels (Group A) were allowed to
run with disease throughout the study period, while 5 camels (Group B)
were treated with Cymelarsan at the recommended therapeutic dose of
O.25mg/kg body weight by deep intramuscular injection at the onset of
the clinical disease. Three out of 4 camels in group A died of the
disease, while all camels in group B survived to the end of the
experiment. The clinical signs manifested by the infected camels
included inappetance, dullness, enlarged superficial lymph nodes,
excessive bilateral lacrimation, ventral oedema, poor hair coat and
emaciation. Pyrexia coincided or closely followed parasitaemia crises.
Post mortem examination revealed excessive peritoneal and pericardial
fluids, haemorrhages in the gastrointestinal tract (especially in the
abomasum and small intestines), froth in trachea and lungs, congested
meninges and kidneys and oedematous brain.
Following infection PCY,RBCand HBlevels dropped rapidly in the
first 3 weeks in all the infected animals. In group A camels, PCY, RBC
and Hb levels continued to decline until they died or the study was
terminated, while in the treated camels these parameters levelled off 4
weeks after treatment and started recovering. There was an increase in
some enzyme activity notably AP, AST, CKand LDHafter infection even
though there was no statistical significant difference in some of the
enzyme changes when compared to the non-infected controls.
Parasites disappeared f'rom peripheral circulation within 24 hours
after treatment and were no longer detectable to the end of the study.
Circulating antigens which were detected 2 weeks after infection were
cleared within 10 weeks following treatment. In the 4 non-treated
camels, antigens remained detectable throughout the study period.
Thus, in this study baseline data of some haematological and
biochemical values of the Kenya dromedary has been established. A
comprehensive clinical picture of T. evansi infection in the dromedary
camel has been recorded. The study has further demonstrated that
T.evansi infection in camels is fatal, especially when no therapeutic
intervention occurs and that the disease can manifest itself as an acute
syndrome with camels dying within the first few weeks of infection.
The disease causes changes in haematological and biochemical values.
Cymelarsan, as used in this study, elicits complete cure in camels
infected with T. evensi. Antigen-detection ELISA (Ag-ELISA) has been
shown to be a more efficient assay in assessing the patent state of
infection in infected camels and in evaluating the success of therapeutic
intervention than the antibody-detection (Ab-ELISA)test.
Citation
Master of Science in Clinical StudiesPublisher
University of Nairobi Department of Clinical Studies