BioEd Online

What problems face the Ethiopian wolf population?

There are only some 500 Ethiopian wolves (Canis simensis), living in seven scattered high-altitude pockets of the Bale Mountains of Ethiopia and the population is plagued by rabies. They faced large outbreaks in 1992 and 2003, and there is a risk of future outbreaks wiping them out entirely.

How does rabies enter the Ethiopian wolf population?

Rabies runs rampant in the Ethiopian domestic dog population. As humans increasingly settle in areas of the mountains more widely inhabited by wildlife, their dogs mingle with and sometimes bite the wolves. The Ethiopian wolf, resembling a European fox with its red fur and long snout, is a playful animal: so licking and grooming within packs can spread the disease. Wolf fights between competing territorial groups can then spread the problem further.

Do they face other challenges?

The other main threat is habitat destruction, as humans increasingly expand their livestock grazing areas to higher elevations. Such encroachment is the usual way that animal populations are driven to small numbers. But, says Dan Haydon of the University of Glasgow, UK: "Disease is often the final nail in the coffin." The wolves also are at risk of canine distemper and parvovirus, both of which can be fatal.

What can be done?

There are oral vaccines for rabies that can be dropped by aircraft into wild populations. But there are difficulties in using this strategy in Ethiopia, including a lack of funds, expertise and infrastructure. There are also concerns amongst African authorities about the nature of this vaccine, which is a genetically modified product.

"I would like to see a more open-mined attitude in Ethiopia about the use of oral vaccines," says Haydon, who is studying strategies for the wolves' survival.

Given these limitations, Haydon thinks that a more targeted strategy with injected vaccines, given to trapped and sedated wolves, could do the trick. In this week's Nature, he and his colleagues report that vaccinating animals found in connecting corridors between subpopulations is effective at confining the disease to individual groups and stopping its spread.¹

Is that feasible?

Haydon thinks so. His team has already done a small project, during the 2003 outbreak (see ' Rabies threatens world's rarest dog'), in which they vaccinated more than 80 wolves for £30,000 (US$55,000). The result? Their model shows that the chance of infection passing through a corridor plummeted from about 25% to 8%.

"With the existing experience, we can probably manage a similar intervention (in the future) for as little as £20,000," says Claudio Sillero, of Oxford University's Wildlife Conservation Research Unit and a co-author of the paper. That's much, much cheaper than a total elimination programme vaccinating all the domestic dogs in Ethiopia would cost "several million pounds" Sillero estimates.

Is it worth the effort?

Some wildlife advocates have concerns that this type of vaccination might harm individual wolves through the process of capture, sedation and handling. But Haydon argues there is no evidence of any harm, and hopes work will continue to save them. "The Ethiopian wolf is a unique animal. They are extremely beautiful," he says. "It is very important to Ethiopia."

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