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.     

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)     

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.     

Prevalence of Feline Chlamydia psittaci and Feline Herpesvirus 1 in Cats with Upper Respiratory Tract Disease

The epidemiology of feline chlamydiosis and feline herpesvirus 1 (FHV1) infection in cats was determined using a duplex polymerase chain reaction assay. In cats with upper respiratory tract disease (URTD), prevalences of 66 (14.3%) of 462 cats and 98 (21.2%) of 462 cats were found for Chlamydia psittaci and FHV1, respectively. In cats without URTD, prevalences were 1/87 (1.1%) for both pathogens. Younger cats, cats sampled in summer, and cats with conjunctivitis were more likely to be positive for C psittaci than were cats sampled in other seasons and cats without conjunctivitis. Cats with recent contact with cats outside the household, cats with acute disease, and sneezing cats were more likely to be positive for FHV1 than were cats that had not had recent contact with cats outside the household, cats with chronic disease, and cats that were not sneezing. Purebred cats were less likely to be positive for FHV1 than were mixed breed cats and prevalence varied with year of sampling. Coinfection with both pathogens was lower than would be expected from their respective prevalences. Vaccinated cats were equally likely to be positive for FHV1 as unvaccinated cats. In sneezing cats FHV1 was more likely to be detected than C psittaci, particularly in acute cases, and when sneezing was not accompanied by conjunctivitis. Cats with reproductive disease concurrent with URTD were more likely to be infected with FHV1 than with C psittaci. Thus, the factors that should be considered in clinical diagnoses of C psittaci infections are the presence of conjunctivitis, age, and season, whereas contact with other cats, acute disease, and sneezing should be considered in diagnoses of FHV1 infection.     

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.     

Feline calicivirus: a neglected cause of feline ocular surface infections?

Objective To investigate the prevalence of feline calicivirus (FCV) infection in relation to ocular surface lesions in cats with upper respiratory tract diseases (URTD). Animals studied Ninety‐nine cats with ocular surface infection and symptoms or recent history of URTD were examined at various rescue shelters and hospitals. Procedure A complete general and ophthalmic examination was performed including Schirmer tear test, slit‐lamp biomicroscopy, fluorescein and lissamine green staining. Clinical and ocular symptoms were scored and recorded. Conjunctival samples were collected using a cytobrush, and nucleic acid extraction using RT‐PCR was carried out to analyze for the presence of various infectious agents. Results RT‐PCR detected either FCV, feline herpes virus type 1 (FHV‐1), Chlamydophila felis or Mycoplasma spp. in 63/99 samples. 30/63 samples were positive for FCV, 23/63 for C. felis, 21/63 for Mycoplasma spp., and 16/63 for FHV‐1. Out of the 30 FCV‐positive samples, 11 were positive only for FCV and in 19 samples FCV was seen in combination with other agents. FCV infection was highest in animals examined at the rescue centers and in the age group of 0–2 months. Erosive conjunctivitis was an important ocular finding. Oral ulcers were detected in all FCV‐infected cats. Conclusion Results indicate that FCV is highly prevalent in cats with URTD either as a sole infectious agent or in combination with other pathogens and therefore is a potential cause for ocular surface lesions during the URTD.     

Recent epidemiological status of feline upper respiratory infections in Japan

Epidemiology of upper respiratory infections of cats was studied. Nasal, ocular, and oral swabs collected from 111 cats presented at animal hospitals during the past 2.5 years were examined. Twenty-four (21.6%) and 4 (3.6%) cats were diagnosed as feline calicivirus (FCV) infection and feline viral rhinotracheitis, respectively, indicating FCV is more prevalent than feline herpesvirus-1, which revealed a considerable shift from data obtained in 1970s. Cat sera immunized by using vaccines containing either FCV F9 or 255 strains neutralized 42.9% and 66.7% of the FCV isolates, respectively. Chlamydia psittaci, examined by a PCR assay amplifying the ompA gene, was found in 26.9% of 26 diseased cats that typically showed conjunctivitis and rhinitis.     

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.     

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.     

An etiological investigation of domestic cats with conjunctivitis and upper respiratory tract disease in Japan

Chlamydophila felis (C. felis), feline herpesvirus-1 (FHV-1) and feline calicivirus (FCV) were detected in 39 (59.1%), 11 (16.7%) and 14 (21.2%) cats respectively, from 66 domestic cats presented with conjunctivitis and upper respiratory tract disease (URTD) in 9 prefectures of Japan. Dual and multiple infections were found in 7 (10.6%) cats with both C. felis and FHV-1, 10 (15.2%) cats with both C. felis and FCV, and 1 (1.5%) cat with all three agents. C. felis was isolated from 11 (28.2%) of 39 PCR positive cats. Antigenic difference was found in a 96 kDa protein of our isolates and Fe/145 strain isolated in USA. In conclusion, C. felis is the most common agent of feline conjunctivitis and URTD, and the coinfection with C. felis, FHV-1 and FCV are also common in cats in Japan.     

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.     

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.     

Evaluation of a monoclonal antibody based ELISA for detection of feline Chlamydia psittaci

A commercially available ELISA designed for the detection of C trachomatis in human urogenital specimens was compared with cell culture for the detection of Chlamydia psittaci in cat conjunctival swabs and in twofold dilutions of a cell culture pool of a feline strain of C psittaci. Cell culture was more sensitive than the ELISA test for detection of C psittaci.     

Common virus infections in cats, before and after being placed in shelters, with emphasis on feline enteric coronavirus

The purpose of this study was to determine the origin and subsequent spread of feline calicivirus (FCV), feline herpesvirus (FHV), and feline enteric coronavirus (FECV) in cats relinquished to shelters. FCV was isolated from the oral fauces of 11% of healthy cats upon entry, and isolation rates were highest for kittens (33%). FHV shedding was very low (4%) at the time of entry and occurred mainly in juveniles. FECV shedding was also common among newly relinquished cats (33%), especially older kittens and juveniles (90%). The subsequent spread of all three viruses was rapid and efficient in the shelter environment. Fifteen percent of cats were shedding FCV, 52% FHV, and 60% FECV after 1 week. More detailed studies were done with FECV shedding, which could be accurately quantitated. The amounts of FECV shed by infected cats ranged from 10(2)to 10(16)particles/swab of feces. FECV shedding was several logs higher in young kittens with primary infection than adult cats with primary infections. The mean levels of FECV shedding among adults were the same for primary and chronic infections. Although shelters were not the primary source of these viruses for many relinquished cats, factors intrinsic to the shelter environment were critical in amplifying shedding and spread to susceptible individuals. Extrinsic factors were especially important for the spread of FHV and FECV. FHV shedding rates increased from 4% to 50% in 1 week's time. The speed and magnitude of the increase in FHV shedding suggested that there was reactivation of latent infections as well as acquisition of new infections. FECV shedding increased 10 to 1,000,000 fold in 1 week among cats that were already infected at entry, and more than one-half of initially negative cats were shedding FECV a week later. Feline calicivirus infection was the least likely to spread in the shelter. The infection rate only increased from 11 to 15% in 1 week.     

Evaluation of cytologic findings in feline conjunctivitis

Background

Cytologic examination of smears prepared from ocular swabs of conjunctiva from cats with conjunctivitis permits identification of the type of inflammation and possibly specific microorganisms. Results of studies of the diagnostic utility of cytology for detection of infectious causes of feline conjunctivitis have been inconsistent.

Objectives

The objectives of this study were to describe cytologic findings in cats with conjunctivitis and to compare those findings with results of PCR analysis for feline herpesvirus (FHV‐1), Chlamydophila felis (C felis), and Mycoplasma felis (M felis).

Methods

Conjunctival smears from 88 cats with conjunctivitis and 10 healthy control cats were stained with a Romanowsky stain and evaluated for the type of inflammation and evidence of an infectious agent. PCR analysis for FHV‐1, C felis, and M felis was performed.

Results

Infectious agents identified by PCR analysis were FHV‐1 in 9 cats (10%), C felis in 8 cats (9%), and M felis in 6 cats (7%). Inclusions interpreted as chlamydial inclusions were found in all cytologic smears from cats positive for C felis by PCR analysis and in 3 PCR‐negative cats. Inclusions interpreted as Mycoplasma organisms were found in 3 of 6 cats that were PCR‐positive for M felis and in 1 PCR‐negative cat. FHV‐1 inclusion bodies were not detected on cytologic examination.

Conclusions

Cytologic examination can be diagnostic for C felis infection when many typical inclusions are present. Cytologic examination was unreliable in diagnosing M felis infection, and viral inclusions of FHV‐1 were not found in specimens stained with Romanowsky stains.     

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.     

Comparison of the Polymerase Chain Reaction and Culture for the Detection of Feline Chlamydia psittaci in Untreated and Doxycycline-Treated Experimentally Infected Cats

The diagnostic sensitivity of the polymerase chain reaction (PCR) was compared with that of culture on conjunctival swabs over the course of infection in 4 doxycycline-treated and 4 untreated cats that were experimentally infected with feline Chlamydia psittaci. Treated cats were given 25 mg (5 mg/kg) of doxycycline orally twice daily for 3 weeks from day 6 after challenge. Clinical signs improved within 3 days of institution of treatment. Culture remained positive for 1 day and PCR remained positive for up to 5 days after treatment was commenced. No recurrence of clinical signs occurred and the organism could not be detected by either PCR or culture for 2 weeks after cessation of therapy. In the 4 untreated cats, conjunctival swabs were taken daily to day 14 and every 2nd weekday to day 64 after challenge. PCR was significantly more sensitive than culture in untreated cats overall (PCR 85.7%, culture 72.9%, P approximately 0) and for cats with clinical signs (PCR 89.2%, culture 79.2%, P = .008). PCR and culture had equivalent sensitivity (100%) for cats showing clinical signs in the 1st month of infection, whereas PCR was considerably more sensitive than culture for cats showing clinical signs in the 2nd month (PCR 72.9%, culture 47.9%, P = .028). Organisms were not detected by PCR in blood or any tissue collected from treated or untreated cats at postmortem. Thus, effective treatment of chlamydiosis in cats is possible with much shorter treatment regimens than currently recommended, and PCR is the more sensitive diagnostic method in chronically infected cats.     

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.