In vitro comparison of RNA preparation methods for detection of feline calicivirus in urine of cats by use of a reverse transcriptase-polymerase chain reaction assay

Update on feline calicivirus: viral evolution, pathogenesis, epidemiology, prevention and control

Feline calicivirus (FCV) is a prevalent and impactful viral pathogen affecting domestic cats. As an RNA virus, FCV exhibits high mutability and genetic plasticity, enabling its persistence within cat populations. Viral genetic diversity is associated with a broad spectrum of clinical manifestations, ranging from asymptomatic infections and mild oral and upper respiratory tract diseases to the potential development of virulent systemic, and even fatal conditions. This diversity poses distinctive challenges in diagnosis, treatment, and prevention of diseases caused by FCV. Over the past four decades, research has significantly deepened understanding of this pathogen, with an emphasis on molecular biology, evolutionary dynamics, vaccine development, and disease management strategies. This review discusses various facets of FCV, including its genomic structure, evolution, innate immunity, pathogenesis, epidemiology, and approaches to disease management. FCV remains a complex and evolving concern in feline health, requiring continuous research to enhance understanding of its genetic diversity, to improve vaccine efficacy, and to explore novel treatment options.

Prevalence of viral infections in Norwegian cats with and without feline lower urinary tract disease

The prevalence of various viral infections was examined in primary accession cases of feline lower urinary tract disease (FLUTD) and healthy control cats in Norway. Urine samples from 102 cats with clinical signs of FLUTD and 73 healthy control cats were tested for the presence of feline calicivirus (FCV), feline coronavirus (FCoV) and feline herpesvirus-1 (FHV-1) by polymerase chain reaction. All urinary samples were negative for FCV and FCoV. One (1%) of the FLUTD cats was found to be positive for FHV-1. The results did not indicate an association between the viral infections examined and signs of FLUTD in the study sample.

Nested case-control study of feline calicivirus viruria, oral carriage, and serum neutralizing antibodies in cats with idiopathic cystitis

BACKGROUND

The epidemiology of feline calicivirus (FCV) infection in cats with idiopathic cystitis (FIC) has not been investigated by contemporary molecular biologic methods.

OBJECTIVES

To determine the prevalence of and evaluate risk factors for FCV viruria, oral carriage, and virus neutralizing (VN) antibodies in cats with and without FIC.

ANIMALS

Cats with nonobstructive FIC (n = 47), obstructive FIC (n = 22), and FCV upper respiratory tract infection (URI; n = 25), and healthy client-owned (n = 18) and colony-housed (n = 24) cats.

METHODS

Oropharyngeal secretions and urine were evaluated with a FCV p30 gene-based real-time reverse-transcriptase polymerase chain reaction (RT-PCR) assay. Serum VN antibody titers were determined by a modified microtiter assay. Associations of risk factors with log-transformed antibody titers were determined by multivariable generalized linear regression.

RESULTS

FCV viruria was detected in 4 (6%) and 3 (12%) cats with FIC and URI, respectively. In 3 FIC cats, viruria was unassociated with detectable oral virus carriage. Oral FCV carriage was detected in 7 (10%) FIC cats. Median antibody titers were significantly higher in cats with obstructive FIC (1 :256), nonobstructive FIC (1:128), and URI (1:512) compared with healthy client-owned (1:16) and colony-housed (1:4) cats (P < .001). Other than disease, multivariate analysis did not identify any other explanatory variables for increased titers in cats with FIC or URI.

CONCLUSIONS AND CLINICAL IMPORTANCE

FCV viruria was detected in cats with FIC and URI, however, its etiologic significance is uncertain. Serologic results suggest increased FCV exposure in FIC cats compared with controls. Further investigations are needed to clarify the potential role of FCV in FIC.

Inactivation of Norovirus by ozone gas in conditions relevant to healthcare

We evaluated the ability of ozone gas to inactivate Norovirus and its animal surrogate feline calicivirus (FCV) in dried samples placed at various locations within a hotel room, a cruise liner cabin and an office. Norovirus was measured by quantitative reverse transcriptase real-time polymerase chain reaction (QRT-PCR) assay, and FCV by a combination of QRT-PCR and virus infectivity assays. We were able to reduce the concentration of infectious FCV by a factor of more than 10(3), and in some cases beyond detection, under optimal conditions of ozone exposure with less than an hour of total operation. QRT-PCR assays indicated similar decreases in both viral RNAs. Virus-containing samples dried onto hard surfaces (plastic, steel and glass), and soft surfaces such as fabric, cotton and carpet, were equally vulnerable to the treatment. Our results show that Norovirus can be inactivated by exposure to ozone gas from a portable commercial generator in settings such as hotel rooms, cruise ship cabins and healthcare facilities.

Real-time PCR for mumps diagnosis on clinical specimens--comparison with results of conventional methods of virus detection and nested PCR

BACKGROUND

Since November 2003, the UK has seen a dramatic rise in the number of mumps cases, resulting in increasing demands on virology laboratories to confirm mumps infection in a timely and efficient manner. Traditional mumps virus detection methods are often insensitive, lengthy, and cumbersome. Some laboratories in the UK now use molecular methods that are based on nested polymerase chain reaction (PCR). Early serological diagnosis often relies on detection of anti-mumps IgM, which may be absent in the first 10 days of illness.

OBJECTIVES

We compared a one-step real-time RT-PCR with an established nested PCR (SH-PCR) and virus detection by culture and antigen detection, and assessed the clinical usefulness of mumps real-time PCR for diagnosis from CSF.

STUDY DESIGN

In total, 280 clinical samples were investigated by real-time PCR, nested PCR and a combination of traditional virus detection methods (antigen detection on oral samples, cell culture on all samples). Furthermore, 88 CSF samples submitted for diagnosis of possible viral meningitis were analysed by real-time PCR.

RESULTS

The real-time PCR detected the highest number of positive oral samples (119/180) compared to SH-PCR (92/180) and combined virus culture and antigen detection procedures (90/180). Sensitivity of mumps virus detection in urine was poor for all three methods: 34.0% (traditional detection), 29.8% (real-time PCR) and 2.1% (SH-PCR), respectively. Real-time PCR on 88 CSF samples identified five patients with mumps meningitis, significantly increasing viral diagnosis in this cohort.

CONCLUSION

Real-time PCR on oral samples is the investigation of choice for mumps infection. Mumps virus detection in urine by any of the PCRs used was clearly less successful. Real-time PCR on CSF samples seems a promising adjunct for diagnosis of mumps meningitis, especially in an age group with high incidence of mumps.