Clinicopathological and Epidemiological Findings in Pet Cats Naturally Infected with Feline Immunodeficiency Virus (FIV) in Australia

Feline immunodeficiency virus (FIV): Prevalence, risk factors, and clinical findings in domestic cats (Felis catus) from southern Brazil

Feline immunodeficiency virus (FIV) is a retrovirus affecting domestic cats worldwide and causing immunosuppression and reduced quality of life. The prevalence of FIV infection varies according to geographic regions / countries and it is associated with domestic cat health managements (vaccination, neutering, basic health care, etc.). This study aimed to evaluate prevalence, risk factors and some clinical information of FIV infection in a domestic cat population in southern Brazil. A total of 366 cats from ten different veterinary facilities and 43 neighborhoods located in the city of Caxias do Sul were sampled for this study. Each animal was examined by a clinical veterinarian and blood was collected for laboratory analysis. Blood samples were tested with a point-of-care (POC) assay to detect FIV antibodies and a real-time polymerase chain reaction (qPCR) to detect and quantify FIV proviral DNA. The results demonstrated an overall prevalence of 7.1 % (n = 26; 95 % CI = 4.9 % - 10.2 %) of FIV infection. FIV-positive cats demonstrated undetectable (n = 6; 23.1 %) and detectable (n = 20; 76.9 %) proviral DNA, with loads varying from less than 10 (101) to 4460,000 (106.6) with a mean of 480,000 (105.7) copies/mL. FIV-positive cats were significantly older (median age of 7 years), also presenting outdoor access (OR: 5.0, p = 0.046), feline leukemia virus (FeLV) coinfection (OR: 7.1, p < 0.001) and other chronic diseases (OR: 4.1, p = 0.34) as main risk factors. FIV-positive animals presented a 9.9- and 7.6-times higher risk for developing lymphoma and anemia in the multivariate analysis. This study contributes to assess some important epidemiological aspects of FIV infection in cats in southern Brazil, highlighting the strong association of FIV and FeLV coinfection.

Investigations into disease associations with feline immunodeficiency virus (FIV) infection in lions (Panthera leo) in Australia: a case-control study

BACKGROUND

Feline immunodeficiency virus (FIV) is a highly mutable retrovirus with numerous species-specific strains, such as those infecting domestic cats (Felis catus, FIVFca) and wild populations of nondomestic cats including lions (Panthera leo, FIVPle). When FIVFca infection manifests as disease in domestic cats, common presentations include lymphadenopathy, lymphoid malignancies, oral cavity disease, immunological dysfunctions and neurological abnormalities. In contrast to domestic cats, there has been little published evidence of direct FIVPle disease associations in lions. The objective of the study, therefore, was to conduct a longitudinal case-control comparison of clinical findings and survival analysis of FIVPle-infected and FIVPle-uninfected captive lions to investigate possible FIVPle disease associations in nondomestic felids in Australia.

METHODS

Between 2005 and 2023, 38 lions were recruited from zoos across Australia. Lions had been FIV tested as part of a routine diagnostic service. The 38 lions included in the study comprised 15 FIV-infected (9 males, 6 females) and 23 FIV-uninfected (9 males, 14 females) animals. Lifetime longitudinal clinical histories and clinicopathological data collected by zoos for these lions were interrogated, including survival data.

RESULTS

FIV-infected lions were more likely to be reported with lower mean corpuscular volume (MCV) (fL) (P = 0.015), monocytes (%) (P = 0.023), chloride (mmol/L) (P = 0.016) and phosphate (mmol/L) (P = 0.029), but with a higher mean corpuscular hemoglobin concentration (MCHC) (g/L) (P = 0.001) and bicarbonate (mmol/L) (P = 0.035), than FIV-uninfected lions. The disease associations usually seen in domestic cats with FIV infection were not observed in lions, and there was no difference in survival between FIV-infected and FIV-uninfected lions. The main limitation of the study was a small sample size dictated by the number of lions able to be recruited from zoos in Australia over an 18-year period.

CONCLUSION

Few differences were found between case and control groups, suggesting that FIV-infected lions did not experience clinicopathological changes that predisposed them to future disease compared with FIV-uninfected lions. Further research will help to determine whether these results are indicative of a general absence of FIV-associated disease in captive lions, or the result of nonpathogenic FIVPle subtype(s) present in Australia.

Embedding research and enquiry in Australian DVM curriculum

Research and enquiry (R&E) is an integral part of veterinary training. It is a foundation of evidence-based practice. In the University of Sydney Doctor of Veterinary Medicine degree R&E culminates in a cap-stone experience in Year 3: a 'professionally focused project', a student-driven and academic supported individual research project. The project provides an authentic experience within a veterinary discipline. Students work with an academic advisor who provides guidance for developing and achieving meaningful educational and professional goals. Successful advising depends upon a shared understanding of, and commitment to, the advising process by students, advisors and the university. The R&E mission can be broadly defined as - veterinarians recognise that evidence-based approach to practice, which is based on the scientific method, leads to the generation of new knowledge that underpins the veterinary medical profession.

Characterization of platelet rich plasma in feline immunodeficiency virus-infected cats: Cell, and PDGF-BB and TGF-ß1 growth factor analysis

Autologous platelet-rich plasma (PRP) contains growth factors (GFs) that modulate the expression of inflammatory cells; thus, these products could be considered a good strategy to favor tissue regeneration in feline immunodeficiency (FIV) positive cats. However, there is no scientific documentation on obtaining PRP in FIV-positive cats. Authors hypothesized that PRP can be obtained in FIV cats following the PRGF®-Endoret® methodology. The objectives of this study were to compare the platelet, erythrocyte, and leukocyte concentration between whole blood (WB) and the PRP; and determine the concentration of platelet-derived growth factor BB (PDGF-BB) and transforming growth factor β1 (TGF-β1) in FIV-positive cats. Sixteen adults FIV-positive asymptomatic cats were included in the study. WB samples were drawn and the PRP was obtained by centrifugation at 265g for 10 min. Erythrocyte and leukocyte, platelets, and mean platelet volume (MPV) were determined both in WB and in PRP. PDGF-BB and TGF-β1 concentrations were additionally determined in PRP. Platelet concentration increased 1.1 times in PRP fraction compared to WB, but no significant differences were reported. MPV was statistically higher in WB than in PRP (p = 0.001). Erythrocytes and leukocytes counts were decreased by 99% and 92%, respectively in the PRP fraction (p < 0.001). Regarding TGF-ß1, a higher concentration was shown in the PRP (p < 0.02). Although the product obtained could not be classified as PRP according to the PRGF®-Endoret® methodology, based on the drastic reduction of RBC and WBC, the PLT concentrate is of high purity.

The Late Asymptomatic and Terminal Immunodeficiency Phases in Experimentally FIV-Infected Cats-A Long-Term Study

Feline immunodeficiency virus (FIV) is a lentivirus in the family Retroviridae that infects domestic cats resulting in an immunodeficiency disease featuring a progressive and profound decline in multiple sets of peripheral lymphocytes. Despite compelling evidence of FIV-associated immunopathology, there are conflicting data concerning the clinical effects of FIV infection on host morbidity and mortality. To explore FIV-associated immunopathogenesis and clinical disease, we experimentally inoculated a cohort of four specific pathogen-free kittens with a biological isolate of FIV clade C and continuously monitored these animals along with two uninfected control animals for more than thirteen years from the time of inoculation to the humane euthanasia endpoint. Here, we report the results obtained during the late asymptomatic and terminal phases of FIV infection in this group of experimentally FIV-infected cats.

A Retrospective Comparative Evaluation of Selected Blood Cell Ratios, Acute Phase Proteins, and Leukocyte Changes Suggestive of Inflammation in Cats

Neutrophil-to-lymphocyte (NLR), monocyte-to-lymphocyte (MLR), and platelet-to-lymphocyte (PLR) ratios have been proposed as diagnostic and prognostic markers for neoplastic and inflammatory diseases in dogs and cats. The aim of this retrospective preliminary study was to evaluate the relationship between these ratios and markers of inflammation routinely measured in cats. A total of 275 cats were enrolled. Complete blood count, serum amyloid A (SAA), albumin, globulin, and albumin-to-globulin ratio (AGR) data were analyzed, as well as the presence of leukocyte alterations considered suggestive of inflammation (LAI: neutrophils left shift, toxic neutrophils, and reactive lymphocytes) evaluated in blood smears. The NLR and MLR correlated positively with SAA and globulins and negatively with albumin and AGR. Higher NLR and MLR were found in cats with increased SAA and globulins and decreased albumin and AGR. The PLR correlated negatively with albumin and AGR. A higher PLR was found in cats with hypoalbuminemia. Cats with LAI had higher NLR, MLR, and PLR. In cats with no changes in parameters indicative of inflammation, 11.25, 0.42, and 528.3 were identified as upper limits for NLR, MLR, and PLR, respectively. In conclusion, the NLR, MLR, and PLR act as good inflammatory markers easily evaluated by routine hematology.