The Felidae family includes species of significant ecological importance, as they play essential roles in the entire trophic chain. However, just like domestic cats, wild felids also face a number of health challenges, including viral diseases. For this family, two viral diseases stand out: Feline Viral Immunodeficiency (Fiv) and Feline Viral Leukemia (FeVL). Both are particularly worrying for the conservation of these species, the knowledge and clinical management of which is of great relevance to animal health professionals.
Fiv and FeLV are relatively common in domestic cats. However, we are still investigating the impact of these viruses on wild felids. Both are caused by viruses from the Retroviridae and affect felids in general, weakening their immune systems and making them more susceptible to secondary infections. Feline immunodeficiency virus (FIV) acts slowly by compromising the immune system of the infected animal, while feline leukemia (FeLV) also causes immunosuppression and can potentially develop anemia and lymphoma. Transmission can occur vertically, from mother to kitten, or horizontally, through bites or scratches by contaminated felids. It is believed that there may be an transmission between domestic and feral cats, but to date, there are few studies on this subject.
Whether it's Fiv or FeLV, both have a poor prognosis. However, Fiv allows the animal to live a healthier and longer life, if treated correctly. Felv, on the other hand, is characterized by neoplastic and hematological formations, leading to a more severity of presentation and therefore more difficult to treat.
Currently, cases have been recorded in several species, such as lions (Panthera leo), pumas (Puma concolor), tigers (Panthera ilves), leopards (Panthera pardus), jaguars (Panthera onca), cheetahs (Acinonix jubatus), lynxes (Lynx rufus), ocelots (Leopardus pardalis), haycats (Leopardus colocolo) cats (Leopardus colocolo), maracajás cats (Leopardus wedii), and bush cats (Leopardus tigrinus). However, reports to date indicate that the virus is not highly pathogenicity in wild animals, meaning that they can carry the virus without necessarily developing clinical signs or immunosuppression.
The European wildcat (Felis ilvestres ilvestres) is the species in which FeLV is most frequently reported in free-living populations, suggesting a high prevalence and indicating that the virus is kept circulating within a natural sylvatic cycle in these populations (HOFMANN-LEHMANN, personal communication; DANIELS et al., 1999; FROMONT et al., 2000; LEUTENEGGER et al., 1999a).
A recent recorded case involved a puma in the Environmental Preservation Area (APA) Macaé de Cima (Cidade-ES). After being rescued by the environmental police and veterinarians, the animal underwent a check-up and was tested for Fiv and Felv, with a positive result, even though it was asymptomatic. The puma's condition raised questions about the possibility, biosecurity and feasibility of its release, or referral to a suitable institution or, unfortunately, the need for euthanasia, due to the lack of adequate conditions to keep it and the possibility of conditions to keep it and the possibility of transmission to other felines under human care¹.
There is a lack of in situ studies in the area for a better understanding of the pathology and how it affects wild felids. The increase in the number of seropositive animals may be of worrying due to the high dissemination of the disease and may be associated with ecological changes in the natural habitat, the host or the pathogen. Currently, based on current studies present, the pathology does not have the character of an epidemic outbreak, but it is worth emphasizing that it is important to deepen our knowledge of these diseases in order to improve the management and conservation of these important animals in the wild.
¹There have been no further updates on the case
References:
O Globo (2023, May 11). Puma with feline AIDS may be put down if it doesn't get adopted.https://oglobo.globo.com/um-so-planeta/noticia/2023/05/prisao-perpetua-ou-morte-conhecera-historia-da-onca-pardaa-que-vive-drama-causadopela-acao-humana.ghtml.
Paulo, S. (n.d.). Exposure of wild felids to selected infectious agents. Usp.Br. Retrieved September 8, 2023, from https://www.teses.usp.br/teses/disponiveis/10/10133/tde-26012007-171939/publico/ClaudiaFiloni.pdf
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