Rabies-infected seal carcasses are washing up along the Cape coast, prompting the government to issue a warning for marine researchers and members of the public to treat them as “biohazards” and stay away.
At least one in five of hundreds of Cape fur seal carcasses collected in the past year have tested positive for the deadly virus. Seven seals euthanised by the City of Cape Town have also tested positive for rabies, adding to concern the disease is widespread in the local seal population.
Tests on seal brain samples show 29 confirmed rabies cases in the Western Cape, and 15 in the Northern Cape, the department of agriculture, land reform & rural development (DALRRD) confirmed.
Research groups and government entities involved with seals have been instructed to observe strict biohazard protocols when dealing with potentially infected seals. The warning is contained in a DALRRD directive sent last week to affected entities.
“Due to the high prevalence of rabies detected in beached Cape fur seal carcasses, all Cape fur seal carcasses must be dealt with as biohazardous material,” according to the directive, issued by DALRRD animal health director Mpho Maja.
“If anyone comes across a carcass of a Cape fur seal, it must be reported to the local municipality for disposal.”
The directive comes amid an unprecedented upsurge in reports of aggressive seals, forcing the closure of seal-diving operations in Cape Town. Multiple bite victims have been treated, and authorities have urged beachgoers and water sports enthusiasts to avoid seals.
Several marine scientists are concerned about the potential effect infected seals might have on other marine species that feed on them, such as killer whales. Up until now, rabies has been undetected in the marine environment, and the potential effect on the marine ecosystem is unknown.
DALRRD’s directive drew criticism from some marine stakeholders, who say the government was slow to respond to concerns about the seal population — first flagged four years ago due to unprecedented seal mortality.
Initial seal carcass brain samples confirmed fears of disease, possibly linked to environmental stresses. At the time, researchers received reports of some seals behaving aggressively. The cause was unclear.
But when a dog tested positive for rabies in Cape Town after reportedly being bitten by a seal, researchers and state vets made the link.
Scientists now believe seals could be suffering from a range of diseases, including rabies — most likely passed on to seals by an infected jackal in Namibia.
The Cape of Good Hope SPCA — one of the organisations that raised the alarm over seal deaths — said the government could have done more to assist initial research efforts.
“Unfortunately, our findings and subsequent surveillance efforts faced significant hurdles,” said SPCA chief inspector Jaco Pieterse.
“Despite our proactive approach to managing and monitoring this issue, the state veterinary service has not only been slow to assist but has also restricted our ability to publish vital data and continue with essential surveillance activities.
“This includes denials of necessary permits, which directly impede ongoing monitoring and assessment efforts by Sea Search and other organisations,” he said.
DALRRD’s biohazardous directive restricts research on seal carcasses to state vets or permitted organisations — despite the rationale for the restriction being based on research gathered by the now-restricted organisations.
By restricting work on seal carcasses, the state might be preventing additional research, sources said.
“I think it’s just overwhelming for NGOs involved to have so much red tape imposed in a way that makes it impossible to work,” said one researcher.
We are a long way off understanding all the characteristics of rabies in the Cape fur seals
— Dr Tess Gridley, Sea Search co-founder
DALRRD said tightening restrictions was linked to public safety: “This legislative requirement serves to prevent the transmission of this highly fatal disease.”
The department said the permitting requirement for research was specifically designed to enhance safety: “This is a legal requirement for any research involving animals or pathogens to ensure that such research does not unduly endanger the animal and public health status of the national herd and country.
“The detection of the fatal disease rabies in Cape fur seals serves to underline the need for such risk mitigation, including to the researchers themselves.”
Sea Search co-founder Dr Tess Gridley — credited with first raising the alarm about diseased seals — said more research was essential in light of the potential effect on humans and other marine species.
“We are a long way off understanding all the characteristics of rabies in the Cape fur seals,” she said.
Sea Search data submitted to the state showed 19% of recovered Cape fur seal carcasses tested rabies-positive.
“What that shows is if you do come across a seal carcass along the coastline you do have to be cautious — there is a significant risk that animal may have died from rabies,” Gridley said.
Sea Search researchers were vaccinated against rabies and the same precautions should be extended to those officially mandated to handle carcasses, she added.
“We are 110% committed to being compliant ... meeting these stringent requirements will result in delays in essential work being undertaken in the coming months.”
City of Cape Town deputy mayor Eddie Andrews, who is also MMC for spatial planning & environment, said seal carcasses were disposed of at a landfill site.
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