Clinical signs
After the infective bite, the parasites localise and multiply in lymph nodes. About one or two weeks after the bite, the lymph nodes become enlarged. Because the ticks usually attach to the ear, the parotid lymph node just below the ear often becomes enlarged first. A few days later, fever develops and other superficial lymph nodes get enlarged. Over the next week or so, other clinical signs start to show. These include a soft cough due to fluid in lungs, difficulty in breathing, diarrhoea sometimes blood tinged, muscle wasting and white discolouration of the eyes and gums. The parasites then invade red blood cells at which point the animal is infective to ticks. Sometimes, the parasites can invade the central nervous system resulting in so-called "turning sickness" and paralysis. If not treated, the affected animals can collapse and die within three or four weeks of the infective tick bite.
Treatment:
East Coast fever can be treated by injecting parvaquone and buparvaquone. It can also be treated by halofuginone, an anticoccidiosis drug administered by mouth. The treatment is more effective if administered early in the disease.
Control measures:
Tick control, vaccination and chemotherapy are the three main methods
in the control of East Coast fever. Frequent dipping cattle in acaricide
supported by movement control can prevent cattle and wild animals from
straying into the control area and introducing infected ticks. However,
this method is costly and requires a high standard of organisation. It
is only feasible in well-managed closed herds. Vaccination against East
Coast fever is effective but animals may react to the vaccine and cause
clinical disease. In cattle herded extensively by pastoralists, East Coast
fever occurs most commonly in young animals and the treatment of clinical
cases as they appear is probably the best approach. In practice, these
methods should be combined to bring out the most effective control results.
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