Domestic cat hepadnavirus (DCH) is an emerging virus related to the hepatitis B virus (HBV). The pathogenic potential of DCH in cats remains to be established. The molecular prevalence of DCH varies ...widely in the regions investigated so far. The aim of this study was to determine the prevalence, load, and risk factors for DCH detection among cats in Hong Kong, and to generate molecular and epidemiological data on the DCH strains circulating in cats in Hong Kong. DCH DNA was detected using DCH-specific qPCR in 57/513 (11.1%) residual diagnostic blood samples from owned cats. The median viral load was 8.85 × 10
copies/mL of whole blood (range for the 5th to the 95th percentile, 3.33 × 10
to 2.2 × 10
copies per mL). Two outliers had higher viral loads of 1.88 × 10
copies/mL and 4.90 × 10
copies/mL. DCH was detected in cats from 3 months to 19 years of age. Sex, age, neuter status, breed, or elevated serum alanine aminotransferase were not statistically associated with DCH DNA detection. On phylogenetic analysis based on 12 complete genome sequences, the Hong Kong DCH viruses clustered in Genotype A with viruses from Australia and Asia (clade A1), distinct from viruses from Europe (clade A2). Sequence analysis found that DCH has similar epsilon and direct repeat regions to human HBV, suggesting a conserved method of replication. Based on our findings, the DCH strains circulating in Hong Kong are a continuum of the Asiatic strains.
The global problem of unowned domestic cats, driven by their phenomenal reproductive success, carries significant economic, animal welfare and biodiversity costs. Desexing owned cats prior to puberty ...prevents unwanted litters that contribute to unowned cat populations. The prevalence and predictors of desexing, and the age at which surgery was carried out were investigated using anonymized electronic patient records in the VetCompass Australia database of cats presented to veterinary practices. Of 52,941 cats born between 2010 and 2017, 83.6% were desexed. Among 7463 desexed females, 21.5% had been desexed by 4 months of age, 59.8% by 6 months and 85.4% by 1 year. Sex, breed, location and socioeconomic indices significantly influenced desexing status and age at surgery. Cats born between 2010 and 2017 had greater odds of being desexed than cats born between 1995and 2009 at each age cut-off (≤ 4 months OR 1.76, CI
1.58-1.97, ≤ 6 months OR 1.50, CI
1.38-1.62 and ≤ 1 year OR 2.33, CI
2.11-2.57 p < 0.001). Most cats presented to veterinarians in Australia are desexed. Compared with cats born before 2010, cats born later are significantly younger at desexing but, even so, many cats would have reached sexual maturity before surgery. These findings will inform the design of front-line strategies promoting prepubertal desexing and they demonstrate, for the first time, a shift towards desexing younger cats.
Viral diseases play a very important role in feline medicine, and research on feline viruses and viral diseases is a well-established field that helps to safeguard the health of domestic cats and ...non-domestic felids, many of which are endangered ...
Brachycephalic obstructive airway syndrome (BOAS) is a chronic, lifelong, debilitating, primarily obstructive airway disease which adversely affects the quality of life of many popular dog breeds. ...Respiratory restriction in bulldog breeds, pugs and Boston terriers frequently co-exist with pathologies of the gastrointestinal tract. In addition, many brachycephalic dogs that appear clinically normal are, in fact suffering from chronic hypoxia and its systemic consequences. Concurrent gastroesophageal reflux-associated conditions, sleep disorders and systemic hypertension further impact the welfare of affected dogs. Acceptance of BOAS and associated clinical signs as being 'normal for the breed' is common amongst owners. While surgical correction of the upper airway is the mainstay of treatment, the provision of subsequent, frequently lifelong medical management is equally important for the maintenance of an acceptable quality of life, at least for some affected patients. Here we review the current knowledge concerning brachycephaly, combine it with shared clinical experience in the management of this debilitating condition, and discuss ethical considerations and the responsibility of veterinarians to contribute public education and to support appropriate breed standards for animals under our care.
Hepadnaviruses are partially double-stranded DNA viruses that infect a variety of species. The prototypical virus in this family is the human hepatitis B virus, which chronically infects ...approximately 400 million people worldwide and is a risk factor for progressive liver disease and liver cancer. The first hepadnavirus isolated from carnivores was a domestic cat hepadnavirus (DCH), initially identified in Australia and subsequently detected in cats in Europe and Asia. As with all characterized hepadnaviruses so far, DCH infection has been associated with hepatic disease in its host. Prevalence of this infection in the United States has not been explored broadly. Thus, we utilized conventional and quantitative PCR to screen several populations of domestic cats to estimate DCH prevalence in the United States. We detected DCH DNA in 1 out of 496 animals (0.2%) in the U.S. cohort. In contrast, we detected circulating DCH DNA in 7 positive animals from a cohort of 67 domestic cats from Australia (10.4%), consistent with previous studies. The complete consensus genome of the U.S. DCH isolate was sequenced by Sanger sequencing with overlapping PCR products. An in-frame deletion of 157 bp was identified in the N-terminus of the core open reading frame. The deletion begins at the direct repeat 1 sequence (i.e., the 5′ end of the expected double-stranded linear DNA form), consistent with covalently closed circular DNA resultant from illegitimate recombination described in other hepadnaviruses. Comparative genome sequence analysis indicated that the closest described relatives of the U.S. DCH isolate are those previously isolated in Italy. Motif analysis supports DCH using NTCP as an entry receptor, similar to human HBV. Our work indicates that chronic DCH prevalence in the U.S. is likely low compared to other countries.
In 2015, over 850,000 people died from chronic hepatitis and hepatocellular carcinoma (HCC) caused by hepatitis B virus (HBV). A novel hepatitis B-like virus has recently been identified in domestic ...cats. The pathogenic potential of domestic cat hepadnavirus (DCH), for which 6.5% to 10.8% of pet cats are viremic, is unknown. We evaluated stored formalin-fixed, paraffin-embedded biopsies of diseased and normal feline liver for the presence of DCH using PCR and in situ hybridization (ISH). DCH was detected in 43% (6/14) of chronic hepatitis cases and 28% (8/29) of HCCs, whereas cholangitis (n = 6), biliary carcinoma (n = 18) and normal liver (n = 15) all tested negative for DCH. Furthermore, in DCH-associated cases, the histologic features of inflammation and neoplasia, and the viral distribution on ISH were strikingly similar to those seen with HBV-associated disease. Several histological features common in human HBV-associated hepatitis, including piecemeal necrosis and apoptotic bodies, were identified in DCH-positive cases of chronic hepatitis. In two cases of HCC examined, the proliferation index in regions that were ISH-positive was higher than in ISH-negative regions. The intracellular distribution of virus in both hepatitis and HCC demonstrated that viral nucleic acid is present in both nuclear and cytoplasmic forms. Collectively, these findings demonstrate a compelling association between DCH and some cases of chronic hepatitis and hepatocellular carcinoma in the cat that mirrors features of HBV-associated hepatopathies. Future investigations of viral epidemiology and natural history are needed to establish the impact of DCH on feline health.
Measures aimed at reducing the length of stay (LOS) of cats in shelters can promote animal welfare and more efficient use of resources. The extent to which variables shown to impact LOS are broadly ...applicable is unclear. The aim of this study was to describe a population of cats adopted from an urban shelter, and to analyze the association between potential predictor variables and LOS. A study cohort was identified retrospectively from shelter records (
= 2584), 48.8% of which were < 12 weeks old at admission, and 80.7% were stray. Among 445 cats relinquished by owners, reasons for surrender were primarily owner-related (87.2%). Overall, reason for surrender and coat color were significantly associated with LOS. Hazard ratios showed that all reasons for surrender for owner-relinquished cats were associated with a shorter LOS than stray cats and this association was significant (
< 0.05) for all except cat behavioral or medical reasons. In contrast to previous reports, white cats had a significantly (
< 0.05) longer LOS than black cats. This study highlights an important role for shelter-specific baseline data to inform and measure the effect of interventional studies aimed at improving animal welfare by reducing LOS in shelter-housed cats.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions of people worldwide since its emergence in 2019. Knowing the potential capacity of the virus to adapt to other ...species, the serological surveillance of SARS-CoV-2 infection in susceptible animals is important. Hong Kong and Seoul are two of Asia's most densely populated urban cities, where companion animals often live in close contact with humans. Sera collected from 1040 cats and 855 dogs during the early phase of the pandemic in Hong Kong and Seoul were tested for SARS-CoV-2 antibodies using an ELISA that detects antibodies against the receptor binding domain of the viral spike protein. Positive sera were also tested for virus neutralizing antibodies using a surrogate virus neutralization (sVNT) and plaque reduction neutralization test (PRNT). Among feline sera, 4.51% and 2.54% of the samples from Korea and Hong Kong, respectively, tested ELISA positive. However, only 1.64% of the samples from Korea and 0.18% from Hong Kong tested positive by sVNT, while only 0.41% of samples from Korea tested positive by PRNT. Among canine samples, 4.94% and 6.46% from Korea and Hong Kong, respectively, tested positive by ELISA, while only 0.29% of sera from Korea were positive on sVNT and no canine sera tested positive by PRNT. These results confirm a low seroprevalence of SARS-CoV-2 exposure in companion animals in Korea and Hong Kong. The discordance between the RBD-ELISA and neutralization tests may indicate possible ELISA cross-reactivity with other coronaviruses, especially in canine sera.
A 2‐year‐old male desexed Ragdoll cat with a 1‐year history of sneezing and nasal discharge presented with a large subcutaneous cervical mass, identified as the right medial retropharyngeal lymph ...node on computed tomography (CT). A right orbital mass, destructive sino‐nasal cavity disease and multiple pulmonary nodules were also identified. Aspergillus felis was cultured from the lymph node. After treatment with posaconazole and liposomal amphotericin B the lymph node enlargement and orbital mass resolved but left frontal sinus involvement and pulmonary lesions persisted despite additional caspofungin therapy. The cat was euthanized 14 months after diagnosis with dysphagia and chronic progressive exophthalmos. A meningeal granuloma with intravascular fungal hyphae was identified at post‐mortem and A felis was cultured from the left frontal sinus and a right retrobulbar fungal granuloma. This case demonstrates that disseminated disease is a possible sequel to invasive fungal rhinosinusitis caused by A felis in cats.
Practical relevance:
Prior to 1990 papillomaviruses (PVs) were not recognised to infect or cause disease in domestic cats. Since this time, the use of histology, immunohistochemistry and, more ...recently, molecular techniques has revealed that PVs almost certainly cause feline viral plaques and Bowenoid in situ carcinomas, oral papillomas and feline sarcoids. In addition, there is increasing evidence that PVs play a significant role in the development of feline cutaneous squamous cell carcinomas, one of the most common skin cancers of cats. Recent studies have also revealed that most cats are asymptomatically infected with PVs. This raises a critical question that is currently unanswered: why do only a small proportion of infected cats develop disease? In the future it may be possible to prevent PV-induced diseases by using a vaccine to prevent PV infection. Alternatively, novel therapies may be developed that prevent PVs from causing clinical disease by stimulating the host immune response.
Clinical challenges:
A recognition of the skin diseases caused by PVs is important to more accurately predict disease progression. Unfortunately, there are currently no non-surgical treatments that have been proven to be beneficial in cats and clinical management of PV-induced skin disease in cats can be challenging.
Global importance:
PVs have a worldwide distribution and negatively impact feline health and welfare globally.
Audience:
This review is aimed at clinicians, especially those who regularly treat cats with skin disease. The review will also be useful to oncologists and researchers who have an interest in how cancer develops in cats.
Evidence base:
In producing this update the authors have drawn on recently published peer-reviewed literature.
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