- A recently published study has found that wild felines are exposed to viruses common to domestic cats, such as feline coronavirus.
- Certain species that frequent oil palm plantations in Malaysian Borneo, such as the leopard cat and Malay civet, may act as carriers of viruses back into forest areas.
- These findings are of concern, conservationists say, due to the potential impact on threatened small cat species, such as the endangered flat-headed cat and the vulnerable Sunda clouded leopard.
- Integration of animal welfare into conservation action and oil palm management plans are potential solutions to mitigate the risks of transmission, the study authors say.
Antibody tests conducted on domestic cats and wild cats in Malaysian Borneo indicate that oil palm plantations may act as transmission sites for viruses, according to a new study.
The study, carried out by researchers working with the Health at the Edge Project, which investigates wildlife parasite transmission in forest-agricultural landscapes in Borneo, and published in the journal Transboundary and Emerging Diseases, found that threatened species of wild cat, such as the flat-headed cat (Prionailurus planiceps) and the Sunda clouded leopard (Neofelis diardi), share viruses common to domestic animals in and around the Lower Kinabatangan Wildlife Reserve in the Malaysian state of Sabah.
Domestic cats (Felis catus) are fairly common on some oil palm plantations and act as a form of pest control for oil palm workers, preying on rats. They are often free-ranging and wander close to or into nearby forests. Meanwhile, forest-dwelling wild cats, such as the leopard cat (Prionailurus bengalensis), sometimes enter nearby oil palm plantations to hunt prey. Flat-headed cats are considered wetland specialists, but there is growing evidence indicating they also visit plantations in search of frogs and rodents.
As they conducted their study, the researchers netted five leopard cats and two flat-headed cats on or close to the edges of oil palm plantations. They also trapped 11 Malay civets (Viverra tangalunga) and two Sunda clouded leopards using cages inside the nearby forest.
Some of the domestic cats included in the study and trapped wild animals tested positive for feline coronavirus, feline panleukopenia virus, and feline calicivirus antibodies. Only domestic cats tested positive for feline herpesvirus antibodies. Based on these findings, the researchers conclude that circulation of viruses within oil palm plantations between domestic and wild carnivores is a possibility, though it’s unclear at this stage in which direction they’re being transmitted. Two leopard cats and one flat-headed cat tested positive for feline coronavirus antibodies. The same flat-headed cat was also positive for feline calicivirus antibodies.
“I think overall the case study is evidence that in some way they are sharing the same place and the same areas,” said study co-author Sergio Guerrero-Sánchez, a postdoctoral fellow at the Centre for Applied One Health Research and Policy Advice at the City University of Hong Kong. “They can get in very close contact, not necessarily interacting directly, but using the same spot in a matter of hours or enough for one cat to transmit the disease to another.”
A viral pathway
Certain species adapt better to monoculture oil palm plantations than others, increasing interactions with domestic animals. Leopard cats and Malay civets, for example, are known to frequent these areas. The researchers suggest that in doing so, these species may act as viral carriers as they move back into the forest.
“Most importantly, our findings highlight an underestimated effect of oil palm plantations on the native community of carnivores, through the risk of infectious disease transmission from domestic animals due to increased inter-species interactions and habitat overlap,” the authors write. These viruses could be moving in both directions, said co-author Liesbeth Frias, a postdoctoral fellow at the Asian School of the Environment at Nanyang Technological University in Singapore. But the overall concern, she said, is over the potential impact on endangered species.
Of the viruses found, feline coronavirus and feline panleukopenia virus are noted as being of particular concern. The former can develop into feline infectious peritonitis, which can be fatal. Alongside the flat-headed cat and two leopard cats, two domestic cats tested positive for feline coronavirus antibodies. Feline panleukopenia virus, meanwhile, can be particularly harmful to kittens and young cats: Two clouded leopards, two Malay civets and 12 domestic cats had antibodies for FPLV.
“In the physical inspection, [the domestic and wild cats] didn’t show any signs of disease, which is also very tricky, especially in wildlife, because they don’t show the sickness until they are very, very sick,” Guerrero-Sánchez said. “We don’t know if some diseases might be affecting more kittens than adults. We don’t know what’s happening there.”
Based on records of viruses passing to other species, he said that “we need to assume that there is a risk for the population.” Other studies have noted evidence of viral transmission between domestic and feral cats with captive and free-ranging populations of snow leopards, tigers, bobcats and pumas, among others. Free-ranging dogs also pose a risk, as they can spread canine distemper virus: an outbreak in the Serengeti in Tanzania in the 1990s decimated lion populations.
Susan Cheyne, a teaching fellow in biological anthropology at Oxford Brookes University, who was not involved in the study, shared these concerns. “This paper has highlighted a clear threat, but there are many unanswered questions e.g., how wild carnivores react to disease/virus infection,” she wrote in an email, noting that reactions can differ between hosts. “However, the precautionary principle should always take precedence: these animals are endangered and already highly threatened thus we should take every effort to minimize the disease risk.”
The authors stressed that these findings are based on a small sample size; 27 domestic cats and d wild carnivores were tested in total. That said, Frias said it’s a vital first look into this issue. “Southeast Asia is a hotspot of biodiversity and of pathogens, and outbreaks are bound to happen. But there’s not so much information about wildlife disease,” she said. “I think having this paper out, even though it’s a short communication … gives that baseline data that we were needing and that many other agencies probably also need to some extent.”
Wai-Ming Wong, small cats program director for Panthera, the global wild cat conservation organization, said the study should act as a launch pad for further research. Panthera was among the funders of the study. “I think the threat is potentially significant,” he said. “But there’s a lot more about disease transmission that we need to understand to properly evaluate and answer the questions … the findings definitely warrant further investigation.”
Among those questions are the prevalence of disease within populations and whether these viruses are affecting Borneo’s other small cat, the enigmatic bay cat (Catopuma badia). “[T]he flat-headed cat and bay cat are arguably two of the world’s rarest cat species and they could disappear with a blink of an eye if we don’t address these threats, or even find out more about these threats, the extent of them and how they’re impacting populations,” Wong said.
From baseline to solutions?
While Guerrero-Sánchez and Frias said their findings are concerning for these threatened species, they could also lead to opportunities to tackle the problem head-on. Working together with plantation managers and other agencies to develop vaccination and sterilization campaigns for domestic and free-roaming cats could be one approach.
“One thing that I find important is that wildlife disease[s] are not often included in conservation strategies,” Frias said. “So having this baseline data, even if it’s very basic, could really help with conservation efforts, and maybe guide some conservation actions, for example, through wildlife disease risk assessments.”
Integrating surveys of this kind and broader animal welfare into conservation action and oil palm plantation protocols would, the researchers said, be a positive step to mitigate the threat.
“This study shows that disease transmission does occur in this kind of agricultural human dominated landscapes,” Wong said. “It’s really important, I think, anyway, for agricultural companies who are responsible for this habitat modification to include animal health monitoring in their management plans, much like they’re including high conservation value areas into their plantations that allow animals to move between landscapes.”
Cheyne said that due to the need for both qualified vets and laboratory facilities, such programs would be a considerable challenge to implement. But given the risks of zoonotic disease transmission, it’s nonetheless a “critical aspect to manage and to integrate into plantation management protocols,” she said.
This article was originally published at Mongabay.com.
Banner: Two Sunda clouded leopards tested positive for the highly contagious feline panleukopenia virus. Listed as vulnerable by the IUCN, there are thought to be around 4,500 of this species left in the wild. Image by Cloudtail the Snow Leopard via Flickr (CC BY-NC-ND 2.0).