Paralysis tick outbreaks reported in the Karoo

Several Angora goats are reported to have died in the past week due to outbreaks of the Karoo paralysis tick (Ixodes rubicundus).

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According to Dr Mackie Hobson, a veterinarian affiliated with the SA Mohair Growers’ Association, outbreaks of the Karoo paralysis tick normally occur in February and peak in April and May.

“It is often associated with a sudden drop in temperature, or cold, damp and overcast weather. An outbreak can lead to considerable losses if not detected early. The ticks normally attach to the Angora goat’s ventral body, neckline and legs above the knees,” he said. The tick transmits a toxin that leads to paralysis in the host animal.

The young adult parasites found on Angora goats are small and brown, but change to orange and rust-brown when they start feeding. When the ticks are fully engorged, they are a shiny, dark brown.

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Usually, several goats in a flock are affected at the same time. Infected animals may exhibit varying levels of paralysis, ranging from slight weakness to unsteadiness of the hindquarter. As the effects of the toxin progress, the goat’s hindquarter can become completely paralysed or the animal may suffer complete paralysis or death.

According to Hobson, most Angora goats respond within 24 hours to 48 hours once the ticks have been removed. It is imperative that infected animals be removed from the camp and treated, particularly within three months of shearing.