Naturally acquired feline bocavirus type 1 and 3 infections in cats with neurologic deficits

Abstract

Feline bocaviruses (FBoVs) have been recognized as novel feline pathogens associated with gastrointestinal diseases. Although bocavirus infections in humans and animals present a broad range of clinical symptoms including neurologic diseases, the neuropathology caused by FBoV infection in cats is unknown. This study aims to investigate the presence of bocavirus in the brain samples of 78 cats showing neurologic deficits and 41 healthy cats using polymerase chain reaction (PCR) and to present the pathological findings of FBoV infection in brain tissues. Only five (6.41%, five out of 78) cats with neurological deficit were FBoV positive on PCR screening and were characterized as FBoV-1 (four out of five) and FBoV-3 (one out of five) by sequencing. Among FBoV-positive cases, viral DNA were detected by PCR in the cerebrum and brain stem of all FBoV-positive cases and rarely detected in the cerebellum of some cases.Histologically, all FBoV-positive cases revealed a variety of inflammatory responses. Among these, 80% (four out of five cases) showed multifocal neuronal vacuolation, mainly found in the cerebrum and brain stem. Eosinophilic inclusion-like materials were found within the nuclei of glial cells in the FBoV-3-positive case. In situ hybridization revealed FBoV DNA in oligodendroglia and vacuolated neurons detected using dual labelling with Olig-2 and NeuN immunohistochemistry, respectively. Transmission electron microscopy confirmed the presence of FBoV-3 virions in the nuclei of glial cells. Apart from localization in brain tissues, the FBoV DNA were also detected in multiple lymph nodes (five out of five) and some intestines (two out of five) of such positive cases, suggesting both parenteral and enteral infections. Complete genome sequence analysis revealed genetic diversity of detected FBoV-1, which were closely related to the strains found in China and Hong Kong, while the detected FBoV-3 presented distant monophyletic clade to previously detected FBoV-3 sequences. The FBoVs, together, should be considered a neurotropic virus and a possible cause for neuronal vacuolation in cats with neurologic deficits.

Canine bufavirus (Carnivore protoparvovirus-3) infection in dogs with respiratory disease

“…Parvovirus localization in the central nervous system, where it was associated with minimal to no inflammation, has been reported in many infected cases, but the pathogenesis of this phenomenon is still questioned. 31,40,41,45,54 According to genomic analysis, these detected CBuV Thai strains were genetically close to the CBuV strains found in Hungary. 25 A previous study speculated that there are 2 amino acid differences between the CBuV strains obtained from respiratory and enteric origins; however, we did not find such amino acid changes in our sequences.…”

“…Parvovirus localization in the central nervous system, where it was associated with minimal to no inflammation, has been reported in many infected cases, but the pathogenesis of this phenomenon is still questioned. 31,40,41,45,54…”

“…The ISH procedures were performed following previously described protocols with slight modifications. 41 After deparaffinization and dehydration, 4-µm thick sections were treated with citrate buffer (pH 6) at 95°C for 20 minutes. The sections were then permeabilized using 10 ng/ml of proteinase K solution at 37°C for 10 minutes and immediately postfixed with 0.4% cold formaldehyde for 5 minutes.…”

Domestic cat hepadnavirus detection in blood and tissue samples of cats with lymphoma

“… 2022 ; Piewbang et al. 2022b ). IHC targeting CD79 was sequentially performed following ISH targeting DCH DNA.…”

Molecular detection and genetic characterization of porcine circovirus 4 (PCV4) in Thailand during 2019–2020

“…The FFPE tissues were stained with hematoxylin and eosin (HE) for histopathology study. To identify PCV4 tissue localization, in situ hybridization (ISH) was performed according to a previously described protocol with some modifications 23 . Briefly, PCV4-specific probe targeting 110 bp of the Cap gene of PCV4 was constructed using a PCR DIG Probe Synthesis Kit (Roche Diagnostics, Basel, Switzerland) following the manufacturer's instructions.…”