The City of Cape Town, South Africa, shared the results of an expert scientific workshop convened in partnership with the Department of Forestry, Fisheries, and the Environment (DFFE), the Two Oceans Aquarium Foundation, and Sea Search. The workshop focused on a perceptible increase in “unusual and unprovoked” Cape Fur Seal bites and aggression in the Western Cape, which is “directly linked” to the confirmed presence of the rabies virus in some of these seals.
Aggression in seals linked to rabies
Although “some levels” of aggression in seals is regarded as “normal” and result from factors such as “territorial behaviour, maternal protectiveness, pain or distress” and poor health, the statement notes “excessive aggression associated with unusual behaviour”. This change in behaviour is being attributed to the presence of rabies in the seal population. Rabies is reportedly “well-established in the Cape Fur Seal population” and “unlikely to be eradicable”. Therefore, it is now considered endemic, requiring “ongoing and long-term management”.
It is suggested that rabies was transmitted to these seals from another wildlife population, rather than local domestic dogs. While other animals can experience a “slow burn” of “flares and declines”, there are concerns that seals are different to these populations as they are “highly gregarious animals living in very large colonies”.
“Given that this is the first documented rabies infection in a marine mammal population there are many unknowns.”
The response
Coastal authorities are working with the State Vet, veterinary experts, researchers, marine mammal experts, and animal welfare organisations to implement “ongoing proactive measures” to manage the outbreak. Measures include:
- Reporting
- Ongoing surveillance
- Possible euthanasia
- Research partnerships
- Vaccination
- Testing
Vaccination concerns
There are “over 2 million” Cape Fur Seals across Southern Angola and the Eastern Cape, so vaccination of the wild population is “not considered viable or possible”. However, a vaccination strategy could be useful. A vaccination trial focusing on animals that come into regular contact with humans was “strongly recommended”; the Two Oceans Aquarium is to develop a standard procedure for vaccinating seals. Visiting elephant seals and Sub-Antarctic fur seals will also be vaccinated as a precautionary measure. Vaccinated seals will be tagged where possible.
Public health
The public health advisory remains that rabies vaccines are “not recommended for the general public at this time”. However, anyone who is bitten or scratched by a seal resulting in an open wound must seek medical attention immediately and receive post-exposure prophylaxis. Domestic dogs should have up to date vaccines and owners must ensure that their dogs avoid contact with seals.
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