Clinicopathological findings of FeLV- positive cats at a secondary referral center in Florida, USA (2008–2019)

Abstract

Objectives The aim of this study was to describe the seroprevalence, presenting complaint, clinicopathological changes, co-morbidities and outcomes of feline leukemia virus positive cats presented to a specialty referral center in Florida, USA. Methods In this retrospective study, medical records of 8050 cats presented to a private referral center from August 2008 to September 2019 were reviewed. Inclusion criteria required was a positive result for feline leukemia virus by point-of-care antigen testing or immunofluorescence assay. Results Forty-one cases met the inclusion criteria. Of 2002 cats that were tested, 41 cats (2%) met the inclusion criteria. One cat had a negative point of care antigen test result and positive bone marrow IFA result. The mean age at diagnosis was 9 years. The main reasons for presentation were abnormal complete blood cell count results (35%), followed by pleural effusion (18%), and anorexia (15%). The most common laboratory abnormalities included anaemia (71%), of which 74% had a nonregenerative anemia, thrombocytopenia (52%), elevated aspartate aminotransferase (50%), hyperbilirubinemia (35%), and hypokalemia (35%). Seven percent of cats (3/41) were also positive for feline immunodeficiency virus. The most common diagnoses were neoplasia (76%) and bone marrow disorders (12%). Cats with neoplasia were significantly younger. Survival to discharge was 88%. Conclusion and relevance Results of this study show that feline leukemia virus is uncommon in secondary referral center, even if this represents a population of unhealthy cats. The most common associated diagnosis was neoplasia, which was more likely to be seen in younger cats (< 4 years of age). The mean age of cats positive for feline leukemia virus was also older than previously published data. These findings support the current guidelines which indicate that cats presented with clinical illness should be tested for FeLV at the time of presentation.

Epidemiological Insights into Feline Leukemia Virus Infections in an Urban Cat (Felis catus) Population from Brazil

“…Despite this, studies have shown that hematological disorders and lymphoma, the main neoplasia associated with FeLV, can also occur in non-productive infections [6,20,31,32]. Anemia is one of the most frequently described hematological disorders and clinical manifestations in FeLV-infected cats, as observed in the present study [6,13,24,33]. In addition, as reported by other studies, cats with anemia were more likely to be FeLV positive [24].…”

Discordant FeLV p27 immunoassay and PCR test results in 21 cats with hematologic disorders

“… 1 Focal infection of the bone marrow may also occur; however, in this situation, the clinicopathologic findings would be reversed, with positive bone marrow PCR and negative p27 testing. 40 In one report of cats with progressive FeLV infection, a higher FeLV RNA copy number was detected by real-time PCR of splenic samples than blood or bone marrow; however, it is not clear if this also applies to proviral DNA. 41 Focal infection could result in antigen positivity with negative blood and bone marrow proviral PCR results.…”

Feline leukemia as a still relevant problem in domestic and wild animals – the current state of knowledge

“…Test immunofluorescencji (IFA). Test immunofluorescencji jest metodą molekularną, która polega na wykrywaniu antygenu p27 wirusa FeLV za pomocą specjalnych przeciwciał fluorescencyjnych, głównie w neutrofilach i płytkach krwi (17,24). Testy te wykazują trwałą wiremię u zakażonych kotów, już po zajęciu szpiku kostnego.…”

“…Reakcja łańcuchowa polimerazy (PCR) to technika molekularna pozwalająca na amplifikację fragmentów DNA lub RNA w warunkach laboratoryjnych. Jest ona szczególnie czuła i pozwala na wykrycie bardzo małych ilości materiału genetycznego, jest w stanie wykryć wirusa we krwi nawet w przypadku braku aktywnej wiremii (17,24). Obecnie badania te stanowią złoty standard w wykazywaniu obecności FeLV.…”