Detection of feline parvovirus in dying pedigree kittens

Epidemiology and molecular characterization of Feline panleukopenia virus from suspected domestic cats in selected Bangladesh regions

Feline panleukopenia (FPL) is a highly contagious cat disease and is endemic in Bangladesh. The study aims to describe the epidemiology and molecular characterization of the Feline panleukopenia virus from the suspected domestic cats in selected Bangladesh regions. Randomly, 161 rectal swabs were collected from the pet hospitals between July 2021 and December 2022. A structured questionnaire was administered through face-to-face interviews with cat owners in order to collect data on potential risk factors for FPL, such as age, sex, sharing litter boxes and every day utensils in multicat households, vaccination history, hospital visits for other diseases, and season. The rectal swabs were tested by PCR targeting the VP2 capsid protein gene, and six PCR-positive samples were further sequenced for molecular characterizations. The risk factors for FPLV were identified using multivariable logistic regression analysis. The overall prevalence of FPL among suspects was 22.9%. The mortality and case fatality were 10.6%, and 45.9%, respectively. However, mortality in kittens was significantly higher (16.4%) than younger cats. The odds of FPL were 8.83 times (95% CI: 3.14-24.85) higher among unvaccinated cats than vaccinated cats. The winter season had almost six times (95% CI: 1.38-24.40) higher odds of FPL than rainy season. In a multicat house, the odds of FPL was about five times (95% CI: 1.93-13.45) higher for cats that shared a litter box and food utensils compared to those that did not engage in such sharing. Visiting hospitals for other reasons nearly triples the odds of FPL (OR: 2.80, 95% CI: 1.04-7.54) compared to cats that do not visit hospitals. Analysis of partial sequence of the VP2 gene revealed genetic variations among the isolates from different regions. Among these isolates, four were identical to FPLV isolates from South Korea and China, while one showed complete homology with FPLV isolates from Thailand. In contrast, the remaining one was 100% identical to Carnivore protoparvovirus-1 isolated from a feline sample in Italy. Our isolates were classified into three distinct clades alongside Feline panleukopenia virus and Carnivore protoparvovirus-1. One in every three suspected cats was infected with Feline panleukopenia. Regular vaccination of the cats, especially those that share common litter box and food utensils and visit hospitals for other purposes, will help reduce the prevalence of FPL in Bangladesh. Besides, it is worth emphasizing the existence of genetic diversity among the circulating Feline panleukopenia viruses in Bangladesh.

Vaccination and Antibody Testing in Cats

Vaccines protect cats from serious diseases by inducing antibodies and cellular immune responses. Primary vaccinations and boosters are given according to vaccination guidelines provided by industry and veterinary organizations, based on minimal duration of immunity (DOI). For certain diseases, particularly feline panleukopenia, antibody titres correlate with protection. For feline calicivirus and feline herpesvirus, a similar correlation is absent, or less clear. In this review, the European Advisory Board on Cat Diseases (ABCD) presents current knowledge and expert opinion on the use of antibody testing in different situations. Antibody testing can be performed either in diagnostic laboratories, or in veterinary practice using point of care (POC) tests, and can be applied for several purposes, such as to provide evidence that a successful immune response was induced following vaccination. In adult cats, antibody test results can inform the appropriate re-vaccination interval. In shelters, antibody testing can support the control of FPV outbreaks by identifying potentially unprotected cats. Antibody testing has also been proposed to support decisions on optimal vaccination schedules for the individual kitten. However, such testing is still expensive and it is considered impractical to monitor the decline of maternally derived antibodies.

Feline infectious peritonitis: answers to frequently asked questions concerning FIP and coronavirus

Feline infectious peritonitis (FIP) is caused by infection with feline coronavirus (FCoV), a highly infectious virus transmitted mostly indirectly, by sharing litter trays with a FCoV excretor, or by fomites. The majority of FCoV-infected cats remain healthy, with up to 12% developing FIP. While any age or breed of cat can develop FIP, FIP disproportionately affects pedigree kittens: most studies found that around 70% of FIP cases occurred in pure-bred cats under 2 years of age. In this paper, some questions about FCoV and FIP that are likely to be asked of, and by, a veterinary nurse will be addressed.

Feline parvovirus infection and associated diseases

Feline panleukopenia, caused by the single-stranded DNA virus feline parvovirus (FPV), is a highly contagious and often lethal disease of cats and other Felidae. FPV, but also canine parvovirus (CPV) can be isolated from both healthy and diseased cats. In Germany, CPV was detected in only approximately 10% of feline samples, but in Southeast Asia, reports estimated that up to approximately 80% of diseased cats were infected with CPV. Infection spreads rapidly, especially in cells with high mitotic activity, such as bone marrow, lymphoid tissue and intestinal crypt cells. Anorexia, vomiting, diarrhoea, neutropenia and lymphopenia are common in clinically affected cases. In utero or neonatal infection can result in cerebellar hypoplasia. Depending on the severity of clinical signs, mortality ranges from 25 to 100%. Effective vaccination and thorough disinfection are of the utmost importance in the prevention of disease transmission in multi-cat households and animal shelters. If clinical signs develop, supportive treatment should be commenced. The efficacy of feline recombinant interferon and FPV antibodies has not been clearly demonstrated. Commercially available vaccines should induce protective immunity when administered according to current guidelines. Recent studies suggest that in some kittens, maternally derived antibodies (MDA) can persist for much longer than has been previously recognised. FPV serum antibody tests are available, but protection status needs to be interpreted with caution in kittens with MDA and a negative titre in adult cats does not necessarily denote lack of protection.

Feline panleukopenia virus: its interesting evolution and current problems in immunoprophylaxis against a serious pathogen

Vaccination of cats against feline panleukopenia virus (FPV) has been a routine part of feline medicine for the past 40 or more years, and many of the same vaccines that were first developed in the 1960s are still in routine use today. However, there has been significant evolution of the virus in the last 40 years, in particular the emergence of canine parvovirus (CPV) in dogs in the late 1970s, which was a host range variant of the FPV-like virus, and the world-wide spread of the CPV-derived viruses since 1978. FPV and the various antigenic types of CPV have been isolated from cats, raccoons, and many different wild and captive carnivores. The consequences of these changes in the viral populations have not been investigated, and the effectiveness of the current vaccine protocols have not been reported. Here we review the recent findings about the evolution of the viruses in carnivores including cats, and describe a study that looks at the efficiency of vaccination of kittens using the standard protocols, which shows that many cats are not protected by those approaches.

Fast parallel detection of feline panleukopenia virus DNA by multi-channel microchip electrophoresis with programmed step electric field strength

A multi-channel microchip electrophoresis using a programmed step electric field strength (PSEFS) method was investigated for fast parallel detection of feline panleukopenia virus (FPV) DNA. An expanded laser beam, a 10× objective lens, and a charge-coupled device camera were used to simultaneously detect the separations in three parallel channels using laser-induced fluorescence detection. The parallel separations of a 100-bp DNA ladder were demonstrated on the system using a sieving gel matrix of 0.5% poly(ethylene oxide) (M(r) = 8 000 000) in the individual channels. In addition, the PSEFS method was also applied for faster DNA separation without loss of resolving power. A DNA size marker, FPV DNA sample, and a negative control were simultaneously analyzed with single-run and one-step detection. The FPV DNA was clearly distinguished within 30 s, which was more than 100 times faster than with conventional slab gel electrophoresis. The proposed multi-channel microchip electrophoresis with PSEFS was demonstrated to be a simple and powerful diagnostic method to analyze multiple disease-related DNA fragments in parallel with high speed, throughput, and accuracy.

Vaccination against Feline Panleukopenia: implications from a field study in kittens

BACKGROUND

Feline Panleukopenia (FPL) is a serious disease of cats that can be prevented by vaccination. Kittens are routinely vaccinated repeatedly during their first months of life. By this time maternally derived antibodies (MDA) can interfere with vaccination and inhibit the development of active immunity. The efficacy of primary vaccination under field conditions was questioned by frequent reports to the Paul-Ehrlich-Institut on outbreaks of FPL in vaccinated breeding catteries. We therefore initiated a field study to investigate the development of immunity in kittens during primary vaccination against FPL.64 kittens from 16 litters were vaccinated against FPL at the age of 8, 12 and 16 weeks using three commercial polyvalent vaccines. Blood samples were taken before each vaccination and at the age of 20 weeks. Sera were tested for antibodies against Feline Panleukopenia Virus (FPV) by hemagglutination inhibition test and serum neutralisation assay in two independent diagnostic laboratories.

RESULTS

There was a good correlation between the results obtained in different laboratories and with different methods. Despite triple vaccination 36.7% of the kittens did not seroconvert. Even very low titres of MDA apparently inhibited the development of active immunity. The majority of kittens displayed significant titres of MDA at 8 and 12 weeks of age; in some animals MDA were still detected at 20 weeks of age. Interestingly, the vaccines tested differed significantly in their ability to overcome low levels of maternal immunity.

CONCLUSIONS

In the given situation it is recommended to quantify antibodies against FPV in the serum of the queen or kittens before primary vaccination of kittens. The beginning of primary vaccination should be delayed until MDA titres have declined. Unprotected kittens that have been identified serologically should be revaccinated.

Prognostic factors in cats with feline panleukopenia

BACKGROUND

Feline panleukopenia is a highly contagious and often lethal disease.

OBJECTIVE

The purpose of the study was to identify prognostic factors for survival of cats with panleukopenia.

ANIMALS

Between 1990 and 2007, 244 cats were diagnosed with panleukopenia in the Clinic of Small Animal Medicine, LMU University of Munich, Germany. Diagnosis was established by electron microscopy, polymerase chain reaction of feces or blood, antigen ELISA of feces, pathognomonic histopathological lesions at necropsy, or some combination of these procedures.

METHODS

Medical records of each cat were evaluated retrospectively.

RESULTS

Survival rate was 51.1%. No significant correlation was found between outcome and living conditions, age, vaccination status (unvaccinated versus one or more vaccines administered), or severity of clinical signs. However, of the vaccinated cats, none had received a vaccine later than 12 weeks of age as a kitten. Nonsurvivors had significantly lower leukocyte and thrombocyte counts at presentation compared with survivors. The relative risk of death for patients with <1,000/μL leukocytes was 1.77 times as high as in patients with a leukocyte count of 1,000-2,500/μL (P=.038), and 1.85 times as high as in patients with >2,500/μL leukocytes (P=.001). The likelihood of a fatal outcome was higher when serum albumin concentration was <30 g/L or serum potassium concentration <4 mmol/L.

CONCLUSIONS AND CLINICAL IMPORTANCE

Vaccination strategies that do not include vaccination of kittens beyond 12 weeks of age may not be adequate to prevent panleukopenia. Leukopenia, thrombocytopenia, hypoalbuminemia, and hypokalemia are negative prognostic factors in cats with panleukopenia.

Panleucopénie féline aiguë : à propos d’un cas traité avec succès par l’interféron-ω

La panleucopénie féline est une infection virale (due à un petit parvovirus FPV). Ce virus est très stable et capable de survivre une année à température ambiante dans les matières organiques sur un support solide. Quasiment tous les chats sensibles sont exposés et infectés au cours de leur première année de vie. La forme aiguë de la maladie est fréquente, avec hyperthermie, anorexie et léthargie, précédant de trois ou quatre jours les premiers signes cliniques. Dans la plupart des cas, la mortalité peut être évitée par un traitement symptomatique et des soins appropriés. Cependant, la maladie, dans sa forme aiguë, est souvent associée à une bactériémie chez les jeunes chats non vaccinés, pouvant se révéler mortelle. Lorsqu’un traitement symptomatique n’est pas suffisamment efficace, le recours à une thérapie antivirale pourrait être une alternative. L’interféron recombinant félin oméga a été utilisé avec succès selon un protocole d’administration décrit, le statut médical du chat étant suivi avant, pendant et après le traitement mis en place.

Feline panleukopenia. ABCD guidelines on prevention and management

OVERVIEW

Feline panleukopenia virus (FPV) infects all felids as well as raccoons, mink and foxes. This pathogen may survive in the environment for several months and is highly resistant to some disinfectants.

INFECTION

Transmission occurs via the faecal-oral route. Indirect contact is the most common route of infection, and FPV may be carried by fomites (shoes, clothing), which means indoor cats are also at risk. Intrauterine virus transmission and infection of neonates can occur.

DISEASE SIGNS

Cats of all ages may be affected by FPV, but kittens are most susceptible. Mortality rates are high - over 90% in kittens. Signs of disease include diarrhoea, lymphopenia and neutropenia, followed by thrombocytopenia and anaemia, immunosuppression (transient in adult cats), cerebellar ataxia (in kittens only) and abortion.

DIAGNOSIS

Feline panleukopenia virus antigen is detected in faeces using commercially available test kits. Specialised laboratories carry out PCR testing on whole blood or faeces. Serological tests are not recommended, as they do not distinguish between infection and vaccination.

DISEASE MANAGEMENT

Supportive therapy and good nursing significantly decrease mortality rates. In cases of enteritis, parenteral administration of a broad-spectrum antibiotic is recommended. Disinfectants containing sodium hypochlorite (bleach), peracetic acid, formaldehyde or sodium hydroxide are effective.

VACCINATION RECOMMENDATIONS

All cats - including indoor cats - should be vaccinated. Two injections, at 8-9 weeks of age and 3-4 weeks later, are recommended, and a first booster 1 year later. A third vaccination at 16-20 weeks of age is recommended for kittens from environments with a high infection pressure (cat shelters) or from queens with high vaccine-induced antibody levels (breeding catteries). Subsequent booster vaccinations should be administered at intervals of 3 years or more. Modified-live virus vaccines should not be used in pregnant queens or in kittens less than 4 weeks of age.

The Swedish breeding cat: population description, infectious diseases and reproductive performance evaluated by a questionnaire

The questionnaire based study gives a combined description of management, infectious diseases and reproductive performance in breeding catteries during 1 year. The mean number of cats per cattery was 6.1, and 25% of the breeders let some of their cats have free access to outdoors. Breeders reported that infection with feline panleukopenia virus, feline immunodeficiency virus or feline leukaemia virus was uncommon, but 8% of the breeders had sold or had themselves owned a cat that died of feline infectious peritonitis. Presence of conjunctivitis was reported by 33.3% of the breeders. Mean litter size was 3.7 ± 1.5, with 9.7% stillbirths and 8.3% kitten mortality week 1–12. The percentage of stillborn kittens increased with the age of the queen and litter size, and also differed among breeds. Kitten mortality differed among breeds, but did not increase with age of the queen. Seven percent of the litters were delivered by caesarean section, significantly more during winter and positively associated with presence of stillborn kittens.

Effect of vaccination on parvovirus antigen testing in kittens

OBJECTIVE

To determine the frequency and duration of feline panleukopenia virus (FPV) vaccine-induced interference with fecal parvovirus diagnostic testing in cats.

DESIGN

Prospective controlled study.

ANIMALS

Sixty-four 8- to 10-week-old specific-pathogen-free kittens.

PROCEDURES

Kittens were inoculated once with 1 of 8 commercial multivalent vaccines containing modified-live virus (MLV) or inactivated FPV by the SC or intranasal routes. Feces were tested for parvovirus antigen immediately prior to vaccination, then daily for 14 days with 3 tests designed for detection of canine parvovirus. Serum anti-FPV antibody titers were determined by use of hemagglutination inhibition prior to vaccination and 14 days later.

RESULTS

All fecal parvovirus test results were negative prior to vaccination. After vaccination, 1 kitten had positive test results with test 1, 4 kittens had positive results with test 2, and 13 kittens had positive results with test 3. Only 1 kitten had positive results with all 3 tests, and only 2 of those tests were subjectively considered to have strongly positive results. At 14 days after vaccination, 31% of kittens receiving inactivated vaccines had protective FPV titers, whereas 85% of kittens receiving MLV vaccines had protective titers.

CONCLUSIONS AND CLINICAL RELEVANCE

Animal shelter veterinarians should select fecal tests for parvovirus detection that have high sensitivity for FPV and low frequency of vaccine-related test interference. Positive parvovirus test results should be interpreted in light of clinical signs, vaccination history, and results of confirmatory testing. Despite the possibility of test interference, the benefit provided by universal MLV FPV vaccination of cats in high-risk environments such as shelters outweighs the impact on diagnostic test accuracy.

An update on aspects of viral gastrointestinal diseases of dogs and cats

Viruses commonly cause gastrointestinal illnesses in dogs and cats that range in severity from mild diarrhoea to malignant neoplasia. Perpetual evolution of viruses is reflected in changing disease patterns, so that familiar viruses are sometimes discovered to cause new or unexpected diseases. For example, canine parvovirus (CPV) has regained the ability to infect felids and cause a panleucopenia-like illness. Feline panleucopenia virus (FPV) has been shown to cause fading in young kittens and has recently been implicated as a possible cause of feline idiopathic cardiomyopathy. Molecular scrutiny of viral diseases sometimes permits deeper understanding of pathogenesis and epizootiology. Feline gastrointestinal lymphomas have not, in the past, been strongly associated with retroviral infections, yet some of these tumours harbour retroviral proviruses. Feline leukaemia virus (FeLV) may play a role in lymphomagenesis, even in cats diagnosed as uninfected using conventional criteria. There is strong evidence that feline immunodeficiency virus (FIV) can also be oncogenic. The variant feline coronaviruses that cause invariably-fatal feline infectious peritonitis (FIP) arise by sporadic mutation of an ubiquitous and only mildly pathogenic feline enteric coronavirus (FECV); a finding that has substantial management implications for cat breeders and veterinarians. Conversely, canine enteric coronavirus (CECV) shows considerable genetic and antigenic diversity but causes only mild, self-limiting diarrhoea in puppies. Routine vaccination against this virus is not recommended. Although parvoviruses, coronaviruses and retroviruses are the most important known viral causes of canine and feline gastrointestinal disease, other viruses play a role. Feline and canine rotaviruses have combined with human rotaviruses to produce new, reassortant, zoonotic viruses. Some companion animal rotaviruses can infect humans directly. Undoubtedly, further viral causes of canine and feline gastrointestinal disease await discovery.

Kitten mortality in the United Kingdom: a retrospective analysis of 274 histopathological examinations (1986 to 2000)

The postmortem findings in 274 kittens were reviewed. The kittens were grouped by age at death: perinatal (< one day), neonatal (one to 14 days), preweaning (15 to 34 days) and postweaning (35 to 112 days); 203 (74 per cent) of the kittens were postweaning and 38 (14 per cent) were preweaning. Infectious disease was identified in 55 per cent of the kittens, and 71 per cent of the infectious disease was viral and detected significantly more frequently in rescue shelter kittens than in kittens from private homes. Twenty-five per cent of all kitten mortality was due to feline parvovirus (FPV). During the neonatal and preweaning periods, the main viral infections were feline herpesvirus and calicivirus. Feline infectious peritonitis caused the death of 17 kittens in the postweaning period. The rescue shelter kittens were significantly younger than the kittens from private homes (median survival 49 and 56 days) and were more likely to have FPV. The non-pedigree kittens were significantly younger than the pedigree kittens (42 v 56 days), and the pedigree kittens were significantly less likely to originate from rescue shelters. There was no significant difference between the age distribution of the male and female kittens. No diagnosis could be found in 33 per cent of the kittens, and this failure was correlated significantly with the submission of tissue samples as opposed to the whole carcase.

A field trial to assess the effect of vaccination against feline herpesvirus, feline calicivirus and feline panleucopenia virus in 6-week-old kittens

A trivalent (feline panleucopenia, feline herpesvirus, feline calicivirus), modified live, commercially available cat vaccine was used at either 6, 9 and 12 weeks of age (early schedule) or 9 and 12 weeks of age (conventional schedule), and the serological response to vaccination was assessed. The level of maternally derived antibody present at 6 weeks of age was also established. The use of early vaccination at 6 weeks of age induced an antibody response to each virus by 9 weeks of age in a significant proportion of kittens compared with unvaccinated littermates. There was no difference between the conventionally and early-vaccinated groups in terms of antibody response to any antigen by 12 and 15 weeks of age.