Antibody responses to feline leukaemia vaccination: exploring the effect of sex, boosting schedule, site of administration and vaccine type.

ObjectivesHistorically, vaccines have been administered in the dorsal interscapular region of cats (the 'scruff' of the neck) owing to easy access to the subcutaneous space. In response to concerns about sarcomas developing at injection sites (feline injection site sarcomas [FISSs]), and a possible association between feline leukaemia virus (FeLV) vaccination and the development of FISS, alternative FeLV vaccination sites such as the distal left hindlimb and tail have been proposed by influential vaccination bodies and various key opinion leaders. There is a dearth of evidence, however, to demonstrate the development of a comparable immune response after FeLV vaccination in these sites.

Antibody Responses in Cats Following Primary and Annual Vaccination against Feline Immunodeficiency Virus (FIV) with an Inactivated Whole-Virus Vaccine (Fel-O-Vax FIV).

Although the antibody response induced by primary vaccination with Fel-O-Vax FIV (three doses, 2-4 weeks apart) is well described, the antibody response induced by annual vaccination with Fel-O-Vax FIV (single dose every 12 months after primary vaccination) and how it compares to the primary antibody response has not been studied. Residual blood samples from a primary FIV vaccination study ( = 11), and blood samples from cats given an annual FIV vaccination ( = 10), were utilized. Samples from all 21 cats were tested with a commercially available PCR assay (FIV RealPCR), an anti-p24 microsphere immunoassay (MIA), an anti-FIV transmembrane (TM; gp40) peptide ELISA, and a range of commercially available point-of-care (PoC) FIV antibody kits.

Measuring the Humoral Immune Response in Cats Exposed to Feline Leukaemia Virus.

Retroviruses belong to an important and diverse family of RNA viruses capable of causing neoplastic disease in their hosts. Feline leukaemia virus (FeLV) is a gammaretrovirus that infects domestic and wild cats, causing immunodeficiency, cytopenia and neoplasia in progressively infected cats. The outcome of FeLV infection is influenced by the host immune response; progressively infected cats demonstrate weaker immune responses compared to regressively infected cats.

Anti-SU Antibody Responses in Client-Owned Cats Following Vaccination against Feline Leukaemia Virus with Two Inactivated Whole-Virus Vaccines (Fel-O-Vax Lv-K and Fel-O-Vax 5).

A field study undertaken in Australia compared the antibody responses induced in client-owned cats that had been vaccinated using two inactivated whole feline leukaemia virus (FeLV) vaccines, the monovalent vaccine Fel-O-Vax Lv-K and the polyvalent vaccine Fel-O-Vax 5. Serum samples from 428 FeLV-uninfected cats (118 FeLV-vaccinated and 310 FeLV-unvaccinated) were tested for anti-FeLV neutralising antibodies (NAb) using a live virus neutralisation assay to identify 378 FeLV-unexposed (NAb-negative) and 50 FeLV-exposed (NAb-positive; abortive infections) cats, following by anti-surface unit (SU) FeLV-A and FeLV-B antibody ELISA testing. An additional 42 FeLV-infected cats (28 presumptively regressively infected, 14 presumptively progressively infected) were also tested for anti-SU antibodies.

Genomic epidemiology reveals multiple introductions of SARS-CoV-2 from mainland Europe into Scotland.

Coronavirus disease 2019 (COVID-19) was first diagnosed in Scotland on 1 March 2020. During the first month of the outbreak, 2,641 cases of COVID-19 led to 1,832 hospital admissions, 207 intensive care admissions and 126 deaths. We aimed to identify the source and number of introductions of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) into Scotland using a combined phylogenetic and epidemiological approach.

Absence of adaptive evolution is the main barrier against influenza emergence in horses in Asia despite frequent virus interspecies transmission from wild birds.

Virus ecology and evolution play a central role in disease emergence. However, their relative roles will vary depending on the viruses and ecosystems involved. We combined field studies, phylogenetics and experimental infections to document with unprecedented detail the stages that precede initial outbreaks during viral emergence in nature.