27 February 2004
EWCP Press release: Rabies Outbreak Update
As you are all aware, we have been implementing an emergency intervention in an attempt to contain the rabies to the wolves in the Web valley alone. The strategic aim was to achieve vaccination coverage of 65-70% in packs adjacent to the disease front and a minimum of 30-50% coverage in packs further away. One 'buffer' pack was left between the reported disease front and the packs to be vaccination to account for the possibility of existing pre-clinical infection in the buffer pack.
The Ethiopian government, represented at a federal level by the Ethiopian Wildlife Conservation Organisation (EWCO) and the Oromiya Rural Land and Natural Resource Administration Authority at a regional level gave us permission to capture and vaccinate 60 wolves as an initial sample. The continuation of the intervention thereafter was dependent on us submitting a report showing 1) the response of the wolves to the vaccine and specifically the antibody titres achieved, and 2) the results of the follow-up monitoring. The report was submitted to EWCO and Oromiya on 26 January 2004 and their decision on the continuation of the intervention is expected this week.
Since the beginning of the intervention on 13 November 2004, we have had a team in the field catching and vaccinating the wolves in two areas - both of which harbour relatively high densities of wolves. These are the two remaining core areas in the Bale Mountains - the Upper Web valley (Morobawa) containing approximately 70 animals in ten packs, and the core area of the Sanetti plateau with an estimated 46 animals in six packs. The first phase of the intervention lasted two months, during which time 59 wolves were trapped and vaccinated - 36 from eight packs in the Upper Web Valley and 23 from six packs in the core Sanetti area. Vaccination coverage per pack ranged from 38% to 83% in frontline packs. A sample of these wolves was recaptured approximately 4 weeks after primary vaccination, to investigate the immune response to the rabies vaccine and to deliver a booster dose.
Eighteen wolves were recaptured and an additional 11 unvaccinated animals were immunised during this phase, resulting in an overall total to date of 70 vaccinated wolves. The serum samples from all wolves, including those recaptured, were tested for rabies virus neutralisation antibodies by the Veterinary Laboratories Agency, UK. All animals were seronegative at first capture. All vaccinated and recaptured wolves had antibody titres well above the threshold conferring protection (geometric mean: 7.41 IU/ml, while 0.5 IU/ml is recommended by the World Health Organization as the minimum protective antibody level). While the impact of the capture effort on the population will be studied through the long-term monitoring carried out by the EWCP, short-term effects appear minimal. All signs of trapping injury in the initial capture (cuts, bruises) had resolved by the time of recapture. One potentially serious injury was incurred when a wolf broke the medial toe of its right forefoot in a trap. The nature of the injury necessitated amputation of the digit at the first interphalangeal joint. The wound was treated and the animal was observed taking weight on the foot after anaesthetic recovery. The wolf has since been resighted and appears to be healthy. Of the total of 73 wolves that have been trapped to date, there have been no known post-trapping problems or mortality. Of all the trapped animals, only two animals have not been recently resighted and efforts are being made to find these animals.
Stuart Williams, Deborah Randall and Darryn Knobel
Ethiopian Wolf Conservation Programme 27 February 2004