Veterinary session

Feline Leukemia Virus (FeLV) is a member of the family Retroviridae, subfamily Oncornavirinae. This gamma-retrovirus infects feline species. It occurs worldwide and was the main cause of death of domestic cats formerly. Nowdays, due to the proper screening and vaccination protocols, this number has decreased. The prevalence of the virus is almost the same in every countries (1–8%) unlike prevalence of Feline Immunodeficiency Virus (FIV). FeLV is an exogen pathogen that replicates in many types of tissues, and causes both proliferative and degenerative changes. It contains a protein core with positive-sense single-stranded RNA (+ssRNA), protected by an envelope. If FeLV spreads to the bone marrow and infects hematopoietic precursor cells, the elimination of the virus become impossible for the immune system. FeLV has several subtypes, that are mainly defined by host cell spectrum. The three most important subtypes are FeLV-A, FeLV-B and FeLV-C, all immunologically closely related. Only FeLV-A is passed horizontally. Vertical infection can occur transplacentally or when the queen licks and nurses the kittens.

The purpose of our research was to assess FeLV-infected cat population in Hungary and to examine the utility of diagnostic tests used in clinics. We collected 184 EDTA-anticoagulated blood samples from cats in different parts of the country. Above this, we examined if there was any singificant correlation between the positivity of tests and some variables (eg. holding, gender, age).

Regarding to our results, 24 specimens were positive to FeLV with ELISA in-clinic test (Witness FIV-FeLV, Zoetis®), 24 specimens were positive with classic end-point polimerase chain reaction (PCR). Statistic analysis has been carried out with R software. The true prevalence of FeLV was 9,0% with Witnesss test and 8,2% with PCR. Correspondence between positivity and some variables was analyzed with logistic regression (p<0,05): a higher tendency of infection can be seen in case of male cats and cats with more than 3 years of age, but the results are not significant.

Our results emphasise the importance of screening and monitoring retroviral infections, also the need of keeping the appropriate vaccination guidelines.