Detection and molecular characterization of caliciviruses (vesivirus and norovirus) in an outbreak of acute diarrhea in kittens from Brazil

Prevalence and Molecular Evolution of Parvovirus in Cats in Eastern Shandong, China, between 2021 and 2022

Feline panleukopenia (FPL) is a highly contagious infectious disease caused by infection with feline parvovirus (FPV) and canine parvovirus type 2 (CPV-2). In recent years, the number of cats with FPL has increased with the expansion of pet cat population in China. The feces of 51 cats with diarrhea symptoms collected from 2021 to 2022 in Eastern Shandong, China, were detected by polymerase chain reaction for parvovirus and other viruses related to feline diarrhea to investigate the prevalence and gene variation of parvovirus in cats. In all the 51 samples, 45.1% (23/51) were positive for at least one viral pathogen, and the positivity of parvovirus was 41.2% (21/51), showing a high prevalence. Multiple-pathogen testing indicated high-coinfection rates of 42.9% (9/21) with other common viruses in parvovirus-positive cats. Most of the coinfections are feline coronavirus (FCoV), followed by feline astrovirus (FAstV) and feline bocavirus (FBoV). The complete VP2 sequences of 21 parvoviruses were obtained. Among them, 20 sequences were identified as FPV, and only one was CPV-2c of Asian origin, which was first detected from cats in Eastern Shandong, China. A phylogenetic tree of the 20 FPVs was constructed together with 698 FPVs (cat/dog host) worldwide on the basis of complete VP2. The 18 FPVs displayed high-sequence identity to one another (99.8%-100%), and they were clustered into FPV-G1 group, whereas the other two were clustered into FPV-G3 group. The FPV-G1 group increased dramatically to become predominant after 2019 in China, contributing to the prevalence of A91S mutation due to 96.07% FPV-G1 with A91S mutation as well as 100% of FPV-G2 and 99.12% of FPV-G3 with 91A in the statistical analysis. This study enriched the understanding of the prevalence, molecular evolution, and cross-species transmission of parvovirus in cats and provided a basis for responding to challenges in the diagnosis and treatment of FPL.

Exploring the Enteric Virome of Cats with Acute Gastroenteritis

Viruses are a major cause of acute gastroenteritis (AGE) in cats, chiefly in younger animals. Enteric specimens collected from 29 cats with acute enteritis and 33 non-diarrhoeic cats were screened in PCRs and reverse transcription (RT) PCR for a large panel of enteric viruses, including also orphan viruses of recent identification. At least one viral species, including feline panleukopenia virus (FPV), feline enteric coronavirus (FCoV), feline chaphamaparvovirus, calicivirus (vesivirus and novovirus), feline kobuvirus, feline sakobuvirus A and Lyon IARC polyomaviruses, was detected in 66.1% of the samples.. Co-infections were mainly accounted for by FPV and FCoV and were detected in 24.2% of the samples. The virome composition was further assessed in eight diarrhoeic samples, through the construction of sequencing libraries using a sequence-independent single-primer amplification (SISPA) protocol. The libraries were sequenced on Oxford Nanopore Technologies sequencing platform. A total of 41 contigs (>100 nt) were detected from seven viral families infecting mammals, included Parvoviridae, Caliciviridae, Picornaviridae, Polyomaviridae, Anelloviridae, Papillomaviridae and Paramyxoviridae, revealing a broad variety in the composition of the feline enteric virome.

The enteric virome of cats with feline panleukopenia differs in abundance and diversity from healthy cats

Feline panleukopenia (FPL) is a severe, often fatal disease caused by feline panleukopenia virus (FPV). How infection with FPV might impact the composition of the entire eukaryotic enteric virome in cats has not been characterized. We used meta-transcriptomic and viral particle enrichment metagenomic approaches to characterize the enteric viromes of 23 cats naturally infected with FPV (FPV-cases) and 36 age-matched healthy shelter cats (healthy controls). Sequencing reads from mammalian infecting viral families largely belonged to the Coronaviridae, Parvoviridae and Astroviridae. The most abundant viruses among the healthy control cats were feline coronavirus, Mamastrovirus 2 and Carnivore bocaparvovirus 3 (feline bocavirus), with frequent coinfections of all three. Feline chaphamaparvovirus was only detected in healthy controls (6 out of 36, 16.7%). Among the FPV-cases, in addition to FPV, the most abundant viruses were Mamastrovirus 2, feline coronavirus and C. bocaparvovirus 4 (feline bocaparvovirus 2). The latter and feline bocaparvovirus 3 were detected significantly more frequently in FPV-cases than in healthy controls. Feline calicivirus was present in a higher proportion of FPV-cases (11 out of 23, 47.8%) compared to healthy controls (5 out of 36, 13.9%, p = 0.0067). Feline kobuvirus infections were also common among FPV-cases (9 out of 23, 39.1%) and were not detected in any healthy controls (p < .0001). While abundant in both groups, astroviruses were more frequently present in FPV-cases (19 out of 23, 82.6%) than in healthy controls (18 out of 36, p = .0142). The differences in eukaryotic virome composition revealed here indicate that further investigations are warranted to determine associations between enteric viral co-infections on clinical disease severity in cats with FPL.

Neutralizing antibodies for SARS-CoV-2 in stray animals from Rio de Janeiro, Brazil

The epidemic of coronavirus disease 2019 (COVID-19), caused by a novel Betacoronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became a public health emergency worldwide. Few reports indicate that owned pets from households with at least one human resident that was diagnosed with COVID-19 can be infected by SARS-CoV-2. However, the exposure to SARS-CoV-2 of pets from households with no COVID-19 cases or stray animals remains less assessed. Using real-time reverse transcriptase polymerase chain reaction (RT-PCR) and plaque reduction neutralization test (PRNT90), we investigated the infection and previous exposure of dogs and cats to SARS-CoV-2 during the ongoing COVID-19 epidemic in Rio de Janeiro, Brazil. From June to August 2020, 96 animals were sampled, including 49 cats (40 owned and 9 stray) and 47 dogs (42 owned and 5 stray). Regarding owned pets, 75.6% (62/82) belonged to households with no COVID-19 cases. Samples included serum, and rectal and oropharyngeal swabs. All swabs were negative for SARS-CoV-2 RNA, but serum samples of a stray cat and a stray dog presented neutralizing antibodies for SARS-CoV-2, with PRNT90 titer of 80 and 40, respectively. Serological data presented here suggest that not only owned pets from households with COVID19 cases, but also stray animals are being exposed to SARS-CoV-2 during the COVID-19 pandemic.

Feline Virome-A Review of Novel Enteric Viruses Detected in Cats

Recent advances in the diagnostic and metagenomic investigations of the feline enteric environment have allowed the identification of several novel viruses that have been associated with gastroenteritis in cats. In the last few years, noroviruses, kobuviruses, and novel parvoviruses have been repetitively detected in diarrheic cats as alone or in mixed infections with other pathogens, raising a number of questions, with particular regards to their pathogenic attitude and clinical impact. In the present article, the current available literature on novel potential feline enteric viruses is reviewed, providing a meaningful update on the etiology, epidemiologic, pathogenetic, clinical, and diagnostic aspects of the infections caused by these pathogens.

Animals as Reservoir for Human Norovirus

Norovirus is the most common cause of non-bacterial gastroenteritis and is a burden worldwide. The increasing norovirus diversity is currently categorized into at least 10 genogroups which are further classified into more than 40 genotypes. In addition to humans, norovirus can infect a broad range of hosts including livestock, pets, and wild animals, e.g., marine mammals and bats. Little is known about norovirus infections in most non-human hosts, but the close genetic relatedness between some animal and human noroviruses coupled with lack of understanding where newly appearing human norovirus genotypes and variants are emerging from has led to the hypothesis that norovirus may not be host restricted and might be able to jump the species barrier. We have systematically reviewed the literature to describe the diversity, prevalence, and geographic distribution of noroviruses found in animals, and the pathology associated with infection. We further discuss the evidence that exists for or against interspecies transmission including surveillance data and data from in vitro and in vivo experiments.

Prevalence of enteropathogens in cats with and without diarrhea in four different management models for unowned cats in the southeast United States

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Most cats in shelters, sanctuaries, foster homes, and trap-neuter-return programs carried at least one enteropathogen.

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Tritrichomonas foetus and coronavirus were more common in cats with diarrhea.

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Other bacterial, viral, protozoal, and helminth enteropathogens were present in cats with normal feces and diarrhea.

The objective of this study was to determine the prevalence of enteropathogens in cats with and without diarrhea in four different models for managing unowned cats: short-term animal shelter, long-term sanctuary, home-based foster care, and trap-neuter-return. Fecal samples from 482 cats, approximately half of the cats with normal fecal consistency and half with diarrhea, were tested by zinc sulfate centrifugation and by real-time PCR for a panel of enteropathogens.

At least one enteropathogen of feline or zoonotic importance was detected in a majority of cats, regardless of management model. For most enteropathogens, the presence or absence of diarrhea was not significantly associated with infection, the exceptions being Tritrichomonas foetus in sanctuary cats with diarrhea (26%) and normal fecal consistency (10%), respectively (P ≤ 0.04), and feline coronavirus in foster cats (80% and 58%) (P ≤ 0.001). The types of enteropathogens detected were related to the type of management model, e.g., viral and protozoal infections were most common in shelters, sanctuaries, and foster homes (confinement systems), whereas helminth infections were most common in trap-neuter-return programs (free-roaming cats).

These results suggest that management practices for unowned cats are inadequate for control of enteropathogens and that the presence of diarrhea is a poor indicator of enteropathogen carriage. Risk-management strategies to reduce transmission to people and other animals should focus on sanitation, housing, compliance with preventive care guidelines, periodic surveillance, response to specific enteropathogens, humane population management of free-roaming community cats, public health education, and minimizing the duration and number of cats in mass confinement.

Serological and molecular investigation of 2117-like vesiviruses in cats

Vesivirus 2117 was first discovered as a contaminant in Chinese hamster ovary (CHO) cell cultures used for human drug production. Similar vesiviruses (VeVs) have been detected recently in dogs. In order to address the hypothesis that cats may also be exposed to 2117-like VeVs, in this study, we screened 236 feline sera using an enzyme-linked immunosorbent assay (ELISA) based on a recombinant VP1 protein from the canine VeV Bari/212/07/ITA. IgG antibodies against the 2117-like VeV were detected in 37.3% of the sera tested. Also, by screening cat faecal specimens, the RNA of a 2117-like VeV was detected in a clinically healthy cat.

Molecular characterization of a feline calicivirus isolated from tiger and its pathogenesis in cats

Feline calicivirus (FCV) is a virus that causes respiratory disease in cats. In this study, the FCV TIG-1 was isolated from Siberian tiger feces collected in 2014 in Heilongjiang Province, China. Phylogenetic analysis among TIG-1 and other FCVs showed that TIG-1 does not share the same lineage with other FCV isolates from Heilongjiang or other regions in China but is located in the same cluster with the FCV strain Urbana, which was isolated from the United States. The growth kinetics in vitro and the pathogenicity in cats between TIG-1 and the domestic cat-origin FCV strain F9 (vaccine strain) and strain 2280 were compared. We found that the growth kinetics of strains TIG-1 and 2280 were faster than that of strain F9 from 12h to 36h post-infection, indicating that strains TIG-1 and 2280 produce infectious virions and reach peak yields earlier. Challenge experiments in cats showed that TIG-1 grew faster than the other two strains in the lungs of cats and that TIG-1 is a virulent FCV with 100% morbidity and lethality. In addition, the histopathological results showed that the virulent TIG-1 strain directly led to severe lung tissue damage and indirectly led to intestinal damage. The results presented here show that a tiger-origin FCV exhibits high virulence in cats.