Background: Feline Leukemia Virus (FeLV) is a major viral pathogen that affects domestic cats worldwide, leading to immunosuppression, anemia, and increased susceptibility to secondary infections and cancers. Stray cat populations, which have limited access to veterinary care, are at higher risk of FeLV infection. This study aims to assess the prevalence and genetic diversity of FeLV in stray cat populations in Portugal.

Methods: A total of 150 stray cats were sampled across various regions of Portugal. Blood samples were collected and tested for FeLV using enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Positive samples were further analyzed for the genetic characterization of the virus through sequencing of the gag gene and env gene.

Results: The overall prevalence of FeLV infection in stray cats was found to be 10.7%. Genetic analysis revealed two distinct viral subtypes, with subtype A being the predominant strain. Phylogenetic analysis indicated a diverse genetic profile of FeLV circulating among Portuguese stray cats, with some genetic variations consistent with regional strains found in neighboring countries.

Conclusion: The study highlights a moderate prevalence of FeLV in Portuguese stray cats and provides valuable insights into the genetic diversity of the virus. These findings suggest the need for improved public health strategies and veterinary interventions to manage FeLV transmission, especially in stray and feral cat populations.

Feline Leukemia Virus (FeLV), prevalence, genetic characterization

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