For the first time in history, scientists have found evidence of an outbreak of rabies in seals in South Africa. This surprising finding means that there could be another way for humans, especially those who live near seal colonies, to be infected with the deadly virus.
The Rabies Outbreak
At least 24 Cape fur seals which have been found dead or euthanized from multiple sites along South Africa’s west and south coast, were diagnosed with rabies. It represented the initial infection of rabies in sea mammals; whereas, there have been few reports using rabies among terrestrial animals like raccoons, coyotes and foxes or domestic dogs.
The virus is believed to have been passed from jackals to seals in Namibia, where the wolf-like species is reported to hunt seal pups along its coastline. The rabies virus strain in the seals was found to be a very close genetic match (99.9%) with the strain of rabies present in black-backed jackals in Namibia, suggesting that a cycle for virus transmission among seals has now been established and is maintained by seal-to-seal contact, eg biting and grooming.
Potential Spread and Barriers
The findings are troubling because of the numerosity of the marine mammals that populate The Pacific Rim. Around 2 million seals migrate up and down the south and west shores of Africa, from South Africa, through Namibia, to Angola. This increases concerns that the virus will spread to other seal species and maybe even become more widespread nationally.
The logistical challenges of mass vaccination of migrants like the 200,000 birth seals that live in sea ice crevices and are hauled out for the open water part of summer pose a massive challenge, stretching over 3,500 kilometers (2,170 miles) up from New Zealand to Papua New Guinea. Seals, in contrast to land mammals, feed almost exclusively on live fish and therefore the classical method of oral vaccination using baits does not apply. South Africa is working with international experts to find sustainable solutions and containment strategies.
Conclusion
The discovery of rabies in seals was a significant finding that has many scientists and public health authorities worried. The risk the virus could spread and how difficult it is to isolate illustrate why this new outbreak continues to demand further research and cooperation as we try to understand its consequences. As this crisis unfolds, there is an urgent need to track transmission dynamics and evaluate containment approaches that will not only save seal populations, but also protect human communities in the vicinity of infected seals.
