Karoo Paralysis

As you know, Karoo paralysis occurs in certain geographical areas in winter and may lead to serious losses . . .

MSD Animal Health supplies the following dips that can be used against Karoo paralysis tick:

  • Zipdip (Reg. No. G381 Act 36/1947)
  • Wipe-out (Reg No. G1434 Act 36/1947)
  • Delete (Reg. No. G2815 Act 36/1947)
  • Delete-All (Reg. No. G2837 Act 36/1947)

As you know, Karoo paralysis occurs in certain geographical areas in winter and may lead to serious losses.

Causes

This tick paralysis is caused by Karoo paralysis tick (Ixodes rubicundus). The adult tick excretes a toxin that causes paralysis in sheep and goats. The tick is a 3-host tick and the immature stages of the ticks can be found on scrub hares and elephant shrews. The lifecycle of the tick is about 2 years. The ticks can often be found along the lower line of the neck, chest and belly. The active period for adult ticks begins usually late in summer and reaches peak levels in autumn and early winter (April/May) and declines thereafter. By the end of September, a few adults will be found on livestock.

Distribution

The distribution of the tick is associated with the presence of “besembos” (Rhus erosa) and “suurpol” grass. This vegetation tends to harbour these type of ticks and their intermediate hosts.

Symptoms

The paralysis commonly occurs from February and reaches a peak in April and May. Sudden drops in temperature caused by rain, cold winds and cloudy conditions seem to stimulate the activity of the adult ticks. Affected animals become paralysed and some may show signs of inco-ordination and stumbling.

Treatment

Most affected animals recover within 24 to 48 hours once the ticks have been removed or animals have been dipped. Unless ticks are removed, the animal remains paralysed and dies within days. Angora goats are susceptible to paralysis tick and great losses can be incurred if animals are not dipped early enough.

Control

The following prevention guidelines are recommended:

  • If possible, remove susceptible animals from especially mountainous sheep camps that have a southerly aspect.
  • Dip animals strategically around the potential outbreak periods. Dips generally have longer residual effect on wooled sheep as compared to non-wooled sheep. Remember that rainwater can affect the duration of effectively of dips.