Detection of protective antibody titers against feline panleukopenia virus, feline herpesvirus-1, and feline calicivirus in shelter cats using a point-of-care ELISA

Serum antibody titers are a useful measurement of protection against infection (feline panleukopenia virus [FPV]) or clinical disease (feline herpesvirus-1 [FHV] and feline calicivirus [FCV]), and their determination has been recommended as part of disease outbreak management in animal shelters. The objective of this study was to determine the sensitivity, specificity, and inter-observer and inter-assay agreement of two semi-quantitative point-of-care assays for the detection of protective antibody titers (PAT) against FPV, FHV and FCV in shelter cats. Low sensitivity for FPV antibodies (28%) rendered a canine point-of-care assay inappropriate for use in cats. The feline point-of-care assay also had low sensitivity (49%) and low negative predictive value (74%) for FPV PAT detection, but was highly accurate in the assessment of FHV and FCV PAT. Improvements in accuracy and repeatability of FPV PAT determination could make this tool a valuable component of a disease outbreak response in animal shelters.     

Onset of immunity in kittens after vaccination with a non-adjuvanted vaccine against feline panleucopenia, feline calicivirus and feline herpesvirus

The induction of a quick onset of immunity against feline parvovirus (FPV), feline herpesvirus (FHV) and feline calicivirus (FCV) is critical both in young kittens after the decline of maternal antibodies and in cats at high risk of exposure. The onset of immunity for the core components was evaluated in 8–9 week old specific pathogen free kittens by challenge 1 week after vaccination with a combined modified live (FPV, FHV) and inactivated (FCV) vaccine. The protection obtained 1 week after vaccination was compared to that obtained when the challenge was performed 3–4 weeks after vaccination. The protocol consisted of a single injection for vaccination against FPV and two injections 4 weeks apart for FHV and FCV.At 1 week after vaccination, the kittens showed no FPV-induced clinical signs or leukopenia following challenge, and after FCV and FHV challenges the clinical score was significantly lower in vaccinated animals than in controls. Interestingly, the relative efficacy of the vaccination was comparable whether the animals were challenged 1 week or 3–4 weeks after vaccination, indicating that the onset of protection occurred within 7 days of vaccination. Following the 1-week challenge, excretion of FPV, FHV and FCV was significantly reduced in vaccinated cats compared to control kittens, confirming the onset of immunity within 7 days of vaccination.     

Epidemiologic evaluation of multiple respiratory pathogens in cats in animal shelters

Upper respiratory tract infection (URI) propagates readily within cats in shelters and often results in euthanasia of affected cats. In a case-control evaluation of 573 cats in eight shelters in California in 2001 and 2002, the prevalence of feline calicivirus (FCV) was from 13 to 36%, feline herpesvirus (FHV) was from 3 to 38%, and prevalence of Bordetella bronchiseptica, Chlamydophila felis, and Mycoplasma species was from 2 to 14%. Cats with URI tended to be housed in isolation, dehydrated, and younger than cats without URI, and infected with FHV, Mycoplasma species, FCV, or C felis. Shelters differed in the prevalence of pathogens and many cats appeared positive for infection after about 1 week of sheltering. It is helpful for shelters to understand the risk factors associated with URI in order to evaluate the costs and benefits of treatment and improve their procedures to decrease the incidence of URI within their facilities. Antiherpetics and antimycoplasmal drugs may be beneficial for individual animal care. Results document the utility of comprehensive URI surveillance and herd management for specific pathogens typical in that shelter.     

Isolation of feline calicivirus and feline herpesvirus from domestic cats 1980 to 1989

Isolation rates of feline herpesvirus (FHV) and feline calicivirus (FCV) from oropharyngeal swabs, taken from 6866 cats in 1980 to 1989 were studied retrospectively. FCV was isolated from 1364 (19.9 per cent) and FHV from 285 (4.2 per cent). The ratio of FCV:FHV isolations varied from 1.3:1 to 15:1 in individual years with an overall ratio of 4.8:1. Isolation of both viruses was fairly uniform for each year and there was no breed or sex disposition to either virus. Of 872 cats shedding FCV and 213 cats shedding FHV, of known age, 447 (51.3 per cent) with FCV and 140 (65.7 per cent) with FHV were under one year old, compared to only 35.3 per cent of the whole population sampled. For the years 1985 to 1989, more information was obtained about the cases. Of 4626 cats tested, 1180 (25.5 per cent) had acute upper respiratory tract disease (URTD) of which 348 (29.5 per cent) were shedding FCV and 162 (13.7 per cent) FHV. A further 597 had chronic URTD and of these, 102 (17.1 per cent) were shedding FCV and 18 (3 per cent) FHV. In 120 cases of suspected vaccine reaction/breakdown, FCV was isolated from 34 (28.3 per cent) and FHV from only two (1.7 per cent). FHV was not isolated from any of 412 cases presenting with chronic gingivitis/stomatitis alone; 181 (43.9 per cent) were shedding FCV and when cats with other signs in addition to chronic gingivitis were included, this proportion increased to 70.4 per cent.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term immunity in cats vaccinated with an inactivated trivalent vaccine.

OBJECTIVE: To evaluate duration of immunity in cats vaccinated with an inactivated vaccine of feline panleukopenia virus (FPV), feline herpesvirus (FHV), and feline calicivirus (FCV). ANIMALS: 17 cats. PROCEDURE: Immunity of 9 vaccinated and 8 unvaccinated cats (of an original 15 vaccinated and 17 unvaccinated cats) was challenged 7.5 years after vaccination. Specific-pathogen-free (SPF) cats were vaccinated at 8 and 12 weeks old and housed in isolation facilities. Offspring of vaccinated cats served as unvaccinated contact control cats. Virus neutralization tests were used to determine antibody titers yearly. Clinical responses were recorded, and titers were determined weekly after viral challenge. RESULTS: Control cats remained free of antibodies against FPV, FHV, and FCV and did not have infection before viral challenge. Vaccinated cats had high FPV titers throughout the study and solid protection against virulent FPV 7.5 years after vaccination. Vaccinated cats were seropositive against FHV and FCV for 3 to 4 years after vaccination, with gradually declining titers. Vaccinated cats were protected partially against viral challenge with virulent FHV. Relative efficacy of the vaccine, on the basis of reduction of clinical signs of disease, was 52%. Results were similar after FCV challenge, with relative efficacy of 63%. Vaccination did not prevent local mild infection or shedding of FHV or FCV. CONCLUSIONS: Duration of immunity after vaccination with an inactivated, adjuvanted vaccine was > 7 years. Protection against FPV was better than for FHV and FCV. CLINICAL IMPLICATIONS: Persistence of antibody titers against all 3 viruses for > 3 years supports recommendations that cats may be revaccinated against FPV-FHV-FCV at 3-year intervals.     

Effects of anesthesia and surgery on serologic responses to vaccination in kittens

OBJECTIVE: To determine the effects of anesthesia and surgery on serologic responses to vaccination in kittens. DESIGN: Prospective controlled trial. ANIMALS: 32 specific-pathogen-free kittens. PROCEDURES: Kittens were assigned to 1 of 4 treatment groups: neutering at 7, 8, or 9 weeks of age or no neutering. All kittens were inoculated with modified-live virus vaccines against feline panleukopenia virus (FPV), feline herpesvirus (FHV), and feline calicivirus (FCV) at 8, 11, and 14 weeks of age and inactivated rabies virus (RV) at 14 weeks of age. Serum antibody titers against FPV, FHV, and FCV were determined at 8, 9, 11, 14, and 17 weeks of age; RV titers were determined at 14 and 17 weeks of age. RESULTS: Serologic responses of kittens neutered at the time of first vaccination (8 weeks) were not different from those of kittens neutered 1 week before (7 weeks) or 1 week after (9 weeks) first vaccination or from those of kittens that were not neutered. In total, 31%, 0%, 69%, and 9% of kittens failed to develop adequate titers against FPV, FCV, FHV, and RV, respectively, by 17 weeks of age. CONCLUSIONS AND CLINICAL RELEVANCE: Neutering at or near the time of first vaccination with a modified-live virus vaccine did not impair antibody responses in kittens. Many kittens that were last vaccinated at 14 weeks of age had inadequate antibody titers at 17 weeks of age. Kittens may be vaccinated in the perioperative period when necessary, and the primary vaccination series should be extended through at least 16 weeks of age.     

Pathogenesis of feline enteric coronavirus infection

Fifty-one specific pathogen-free (SPF) cats 10 weeks to 13 years of age were infected with a cat-to-cat fecal-oral passed strain of feline enteric coronavirus (FECV). Clinical signs ranged from unapparent to a mild and self-limiting diarrhea. Twenty-nine of these cats were FECV na?ve before infection and followed sequentially for fecal virus shedding and antibody responses over a period of 8-48 months. Fecal shedding, as determined by real-time polymerase chain reaction (RT-PCR) from rectal swabs, appeared within a week and was significantly higher in kittens than older cats. FECV shedding remained at high levels for 2-10 months before eventually evolving into one of three excretion patterns. Eleven cats shed the virus persistently at varying levels over an observation period of 9-24 months. Eleven cats appeared to have periods of virus shedding interlaced with periods of non-shedding (intermittent or recurrent shedders), and seven cats ceased shedding after 5-19 months (average 12 months). There was no change in the patterns of virus shedding among cats that were excreting FECV at the time of a secondary challenge exposure. Four cats, which had ceased shedding, re-manifested a primary type infection when secondarily infected. Cats with higher feline coronavirus (FCoV) antibody titers were significantly more likely to shed virus, while cats with lower titers were significantly less likely to be shedding. Twenty-two kittens born to experimentally infected project queens began shedding virus spontaneously, but never before 9-10 weeks of age. Natural kittenhood infections appeared to be low grade and abortive. However, a characteristic primary type infection occurred following experimental infection with FECV at 12-15 weeks of age. Pregnancy, parturition and lactation had no influence on fecal shedding by queens. Methylprednisolone acetate treatment did not induce non-shedders to shed and shedders to increase shedding.     

Factors associated with upper respiratory tract disease caused by feline herpesvirus, feline calicivirus, Chlamydophila felis and Bordetella bronchiseptica in cats: experience from 218 European catteries

A full history of the management practices and the prevalence of upper respiratory tract disease (URTD) at 218 rescue shelters, breeding establishments and private households with five or more cats was recorded. Oropharyngeal and conjunctival swabs and blood samples were taken from 1748 cats. The prevalences of feline herpesvirus (FHV), feline calicivirus (FCV), Chlamydophila felis and Bordetella bronchiseptica were determined by PCR on swab samples. An ELISA was applied to determine the prevalence of antibodies to B. bronchiseptica. The rates of detection by PCR of each pathogen in the cats in catteries with and without ongoing URTD were, respectively, FHV 16 per cent and 8 per cent; FCV 47 per cent and 29 per cent; C. felis 10 per cent and 3 per cent; and B. bronchiseptica 5 per cent and 1.3 per cent; the seroprevalences of B. bronchiseptica were 61 per cent and 41 per cent, respectively. There was evidence that FHV, FCV and B. bronchiseptica played a role in URTD. The risk factors associated with the disease were less than excellent hygiene, contact with dogs with URTD, and larger numbers of cats in the cattery or household.     

A study of feline upper respiratory tract disease with reference to prevalence and risk factors for infection with feline calicivirus and feline herpesvirus.

A cross-sectional survey of a convenience sample of cats was carried out to determine the prevalence of and risk factors for respiratory tract disease, feline calicivirus (FCV) infection and feline herpesvirus (FHV) infection. Seven hundred and forty cats were studied; samples for isolation of FCV and FHV were obtained from 622 (84%). Data on individual cat and household variables were obtained by questionnaire for each cat and analysed using univariable and logistic regression analysis. Thirty-eight percent (282/740) of cats surveyed had respiratory tract disease. Eighteen of 24 predictor variables were found to be significantly (P<0.05) associated with the presence of respiratory tract disease in a cat on univariable analysis. Following logistic regression, several factors retained significance including isolation of FCV and FHV, younger cats (4-11 months of age) and multiple cat households. A negative association was found with breeding catteries and other types of household in comparison with rescue catteries. Overall, feline calicivirus was isolated from 162/622 (26%) of cats sampled; 33% of the cats with respiratory tract disease were FCV positive compared to 21% of healthy cats. Variables significantly associated with FCV isolation on logistic regression were the presence of respiratory tract disease and contact with dogs with and without respiratory tract disease. Feline herpesvirus was isolated from 30/622 (5%) of all cats sampled; 11% of cats with respiratory tract disease were FHV positive compared to 1% of healthy cats. Variables significantly associated with FHV isolation on univariable analysis included age, gender, and the presence of respiratory tract disease. Vaccination showed a negative association. Logistic regression analysis of the data for FHV was limited by the sample size and the low prevalence of FHV.     

Chronic oral infections of cats and their relationship to persistent oral carriage of feline calici-, immunodeficiency, or leukemia viruses.

Two hundred and twenty-six cats from the Veterinary Medical Teaching Hospital (VMTH), a cat shelter, and a purebred cattery were tested for chronic feline calicivirus (FCV), feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) infections. Chronic oral carriage of FCV was present in about one-fifth of the cats in each of the groups. FIV infection was not present in the purebred cattery, was moderately prevalent (8%) in the pet population of cats examined at the VMTH for various complaints and was rampant in the cat shelter (21%). Unexpectedly high FeLV infection rates were found in the hospital cat population (28%) and in the purebred cattery (36%), but not in the cat shelter (1.4%). FCV and FeLV infections tended to occur early in life, whereas FIV infections tended to occur in older animals. From 43 to 100% of the cats in these environments had oral cavity disease ranging from mild gingivitis (23-46%), proliferative gingivitis (18-20%), periodontitis (3-32%) and periodontitis with involvement of extra-gingival tissues (7-27%). Cats infected solely with FCV did not have a greater likelihood of oral lesions, or more severe oral disease, than cats that were totally virus free. This was also true for cats infected solely with FeLV, or for cats dually infected with FeLV and FCV. Cats infected solely with FIV appeared to have a greater prevalence of oral cavity infections and their oral cavity disease tended to be more severe than cats without FIV infection. FIV-infected cats that were coinfected with either FCV, or with FCV and FeLV, had the highest prevalence of oral cavity infections and the most severe oral lesions.     

Effects of maternally-derived antibodies on serologic responses to vaccination in kittens

The optimal vaccination protocol to induce immunity in kittens with maternal antibodies is unknown. The objective of this study was to determine the effects of maternally-derived antibody (MDA) on serologic responses to vaccination in kittens. Vaccination with a modified live virus (MLV) product was more effective than an inactivated (IA) product at inducing protective antibody titers (PAT) against feline panleukopenia virus (FPV). IA vaccination against feline herpesvirus-1 (FHV) and feline calicivirus (FCV) was more effective in the presence of low MDA than high MDA. Among kittens with low MDA, MLV vaccination against FCV was more effective than IA vaccination. A total of 15%, 44% and 4% of kittens had insufficient titers against FPV, FHV and FCV, respectively, at 17 weeks of age. Serologic response to vaccination of kittens varies based on vaccination type and MDA level. In most situations, MLV vaccination should be utilized and protocols continued beyond 14 weeks of age to optimize response by all kittens.     

Risk factors for time to diagnosis of feline upper respiratory tract disease in UK animal adoption shelters

Feline upper respiratory tract disease (URTD), mainly caused by feline calicivirus (FCV) and feline herpesvirus, is a major cause of disease outbreaks in feline accommodation such as animal shelters, catteries and multi-cat households. We conducted a longitudinal, yearlong study in five UK feline animal shelters to identify risk factors for the time to diagnosis of URTD. We were especially interested in risk factors that could be identified at the time the cat entered the shelter. Shelter staff recorded data for 1434 cats during 2002–2003. Most of the cats were domestic shorthair cats and were from private households, or were stray or abandoned. Sixty cats without clinical signs of URTD at entry had URTD diagnosed (typically within the first month at the centre). We used two multivariable models: one was a Cox proportional-hazards model, and the other a regression analyses with complementary log–log model.The hazard varied substantially between shelters and was considerably lower for the shelter that had a purpose-built admissions unit with its own isolation facilities. The hazard was greater for purebred cats (HR 4.3–5.0) and for neutered cats (HR 2.0). The hazard was also typically greater if the centre had a greater proportion of cats present with URTD. The analyses suggested that the centre-level risk factors were more important in determining hazard than cat-level risk factors.     

Comparison of prevalence of feline herpesvirus type 1, calicivirus and parvovirus infections in domestic and leopard cats in Vietnam

A serosurvey of feline herpesvirus type 1 (FHV-1), feline calicivirus (FCV), and feline parvovirus (FPV) in cats from Ho Chi Minh City area in southern Vietnam was conducted in December 1998, and we compared the results with our previous results in northern Vietnam (Hanoi area). The positive rate of FHV and FCV in domestic cats were 44% and 74%, respectively. They were rather higher than those in Hanoi area, while the seropositivity of FPV (44%) was similar to that in Hanoi area. In leopard cats, the positive rate of FPV was high (3/4) and it indicated that FPV was prevailing in leopard cats in Vietnam.     

Relevance of feline calicivirus, feline immunodeficiency virus, feline leukemia virus, feline herpesvirus and Bartonella henselae in cats with chronic gingivostomatitis

Despite its common occurrence, the aetiology of chronic gingivostomatitis in cats remains uncertain. Aetiology is likely multifactorial, and several infectious agents may be associated with chronic gingivostomatitis. The purpose of this study was to investigate the prevalence of feline calicivirus (FCV), feline immunodeficiency virus (FIV), feline leukemia virus (FeLV), feline herpesvirus (FHV), and Bartonella henselae (B. henselae) in cats with chronic gingivostomatitis and in an age-matched control group. In addition, other factors, e. g., environmental conditions were investigated. In 52 cats with chronic gingivostomatitis and 50 healthy age-matched control cats, the presence of FCV ribonucleic acid (RNA), and FHV deoxyribonucleic acid (DNA) (polymerase chain reaction [PCR] from oropharyngeal swabs), and B. henselae DNA (PCR from oropharyngeal swabs and blood), as well as FeLV antigen (serum), and antibodies against FCV, B. henselae, and FIV (serum) were examined. FCV RNA was significantly more common in cats with chronic gingivostomatitis (53.8%, p < 0.001) than in controls (14.0%); a significant difference was also found in the prevalence of antibodies to FCV between the cats with chronic gingivostomatitis (78.8%, p = 0.023) and controls (58.0%). Of the other infectious agents investigated, there was no significant difference in the prevalence between the cats with chronic gingivostomatitis and the controls. The results of this study allow the conclusion that FCV, but no other infectious agents, is commonly associated with chronic gingivostomatitis in cats.     

Feline calicivirus infection in kittens borne by cats persistently infected with the virus

On the basis of repeated isolation of feline calicivirus (FCV) from oropharyngeal swabs four to eight months after exposure to FCV strain 255, four carrier queen cats were identified. These cats gave birth to 16 kittens. Litters were individually housed with their mothers until nine weeks of age and were monitored virologically and serologically from birth until 15 weeks old. All kittens became infected between three and nine weeks old and shed FCV consistently for periods of three to 11 weeks. Clinical signs of FCV were observed in 11 kittens but none developed severe respiratory disease. At the time of initial infection maternal antibody titres in the kittens ranged from 1:4 to 1:24. Within one to three weeks of infection titres began to rise. The results indicated that kittens of queen cats persistently infected with FCV frequently experience mild or subclinical immunising infections.     

Oral supplementation with L-lysine did not prevent upper respiratory infection in a shelter population of cats

Cats in animal shelters are highly susceptible to infection by feline herpesvirus (FHV) by virtue of their stress and close proximity to other cats. Animal shelters take several different approaches to prevent FHV-related upper respiratory infections (URIs), including empirically treating all cats with L-lysine, a supplement believed to prevent the replication of FHV and, therefore, manifestations of herpesvirus infections. In this study we tested oral supplementation of L-lysine as a means to prevent URIs. One hundred and forty-four cats were treated with L-lysine in a small amount of canned food once daily. A 'no treatment' group of 147 cats received no lysine during the course of the study. The development of conjunctivitis or URI was tracked between the two groups. In all measures, there was no effect between the two groups, suggesting that lysine was not able to prevent URI or conjunctivitis in our shelter situation. Cats entering shelters encounter stressors that may make them more susceptible to FHV reactivation or infection. Infection control and control of fomite transmission are also key to keeping cats healthy in a group housing situation. The finding that lysine did not prevent URI in this animal shelter suggests that shelters may better use their resources by finding ways to decrease stress among their feline population, focusing on proper infection control measures, and limiting fomite transmission of disease.     

Response of feral cats to vaccination at the time of neutering

OBJECTIVE: To determine whether administration of inactivated virus or modified-live virus (MLV) vaccines to feral cats at the time of neutering induces protective serum antiviral antibody titers. DESIGN: Prospective study. ANIMALS: 61 feral cats included in a trap-neuter-return program in Florida. PROCEDURES: Each cat received vaccines against feline panleukopenia virus (FPV), feline herpes virus (FHV), feline calicivirus (FCV), FeLV, and rabies virus (RV). Immediately on completion of surgery, vaccines that contained inactivated RV and FeLV antigens and either MLV or inactivated FPV, FHV, and FCV antigens were administered. Titers of antiviral antibodies (except those against FeLV) were assessed in serum samples obtained immediately prior to surgery and approximately 10 weeks later. RESULTS: Prior to vaccination, some of the cats had protective serum antibody titers against FPV (33%), FHV (21%), FCV (64%), and RV (3%). Following vaccination, the overall proportion of cats with protective serum antiviral antibody titers increased (FPV [90%], FHV [56%], FCV [93%], and RV [98%]). With the exception of the FHV vaccine, there were no differences in the proportions of cats protected with inactivated virus versus MLV vaccines. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that exposure to FPV, FHV, and FCV is common among feral cats and that a high proportion of cats are susceptible to RV infection. Feral cats appeared to have an excellent immune response following vaccination at the time of neutering. Incorporation of vaccination into trap-neuter-return programs is likely to protect the health of individual cats and possibly reduce the disease burden in the community.     

Isolation of feline herpesvirus-1 and feline calicivirus from healthy cats in Swedish breeding catteries

Feline calicivirus (FCV) could be isolated from four cats (2.6%) and feline herpesvirus-1 (FHV) from none of 152 clinically healthy cats from 22 Swedish breeding catteries. These cats had all previously shown signs of respiratory tract disease or conjunctivitis, although several years ago. The results suggest that carriers of FCV and FHV were uncommon in Swedish breeding catteries studied. Prevalence rates in other European countries and North America are usually higher, especially of FCV. The lower prevalence rates in our study might be explained by test group selection, differences in factors such as management, environment, or genetic constitution of the cats, or by sample handling. It was concluded that the presence of an FCV shedder in the cattery does not mean that all cats in the group are infected, but special measures are recommended to avoid infection of susceptible cats.