BackgroundIn a cat that had ostensibly recovered from feline leukemia virus (FeLV) infection, we observed the reappearance of the virus and the development of fatal lymphoma 8.5 years after the initial experimental exposure to FeLV-A/Glasgow-1. The goals of the present study were to investigate this FeLV reoccurrence and molecularly characterize the progeny viruses.ResultsThe FeLV reoccurrence was detected by the presence of FeLV antigen and RNA in the blood and saliva. The cat was feline immunodeficiency virus positive and showed CD4+ T-cell depletion, severe leukopenia, anemia and a multicentric monoclonal B-cell lymphoma. FeLV-A, but not -B or -C, was detectable. Sequencing of the envelope gene revealed three FeLV variants that were highly divergent from the virus that was originally inoculated (89-91% identity to FeLV-A/Glasgow-1). In the long terminal repeat 31 point mutations, some previously described in cats with lymphomas, were detected. The FeLV variant tissue provirus and viral RNA loads were significantly higher than the FeLV-A/Glasgow-1 loads. Moreover, the variant loads were significantly higher in lymphoma positive compared to lymphoma negative tissues. An increase in the variant provirus blood load was observed at the time of FeLV reoccurrence.ConclusionsOur results demonstrate that ostensibly recovered FeLV provirus-positive cats may act as a source of infection following FeLV reactivation. The virus variants that had largely replaced the inoculation strain had unusually heavily mutated envelopes. The mutations may have led to increased viral fitness and/or changed the mutagenic characteristics of the virus.
The composition of the microbiome plays a significant role in the pathogenesis of inflammatory bowel disease (IBD) in humans and chronic enteropathies (CE) in dogs. The administration of probiotic micro-organisms is one way of modulating the microbiome, but experiments elucidating mechanisms of action of probiotics in the intestine of healthy and CE dogs are lacking. The aim of our study was to investigate the effects of different Toll-like receptor (TLR) ligands and Enterococcus faecium (EF) on ex vivo cultured duodenal samples and whole blood (WB) from dogs with food-responsive chronic enteropathy (FRE) when compared to healthy dogs. Biopsy stimulation was performed in 17 FRE and 11 healthy dogs; WB stimulation was performed in 16 FRE and 16 healthy dogs.
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