[Parvovirus infections in cats in animal shelters]. / Parvovirus-Infektionen bei Katzen in Tierheimen.

Due to widespread vaccination programs against feline panleukopenia virus (FPV), the disease associated with this virus infection, feline panleukopenia, is rarely seen in privately owned cats in Germany. In contrast, the situation in animal shelters differs due to the constant intake of new cats that are often unprotected. In such facilities, panleukopenia outbreaks are common and often accompanied by a high number of fatalities. Due to the high contagiosity of the virus, some shelters do not accept cats with clinical signs suspicious for panleukopenia, since these animals can pose a risk to the shelter population. However, not only cats with panleukopenia shed parvovirus, but also healthy, asymptomatic cats can and thus contribute to risk of infection. Nevertheless, the risk for panleukopenia outbreaks in animal shelters can be reduced by rigorous outbreak management. This includes hygiene measures using correctly applied cleaning and disinfection protocols, quarantine measures, separate isolation units, as well as specific prophylactic measures, such as identification of infected animals and immunization of susceptible groups.

Prevalence of protective feline panleukopenia antibody titers detected by a point-of-care enzyme-linked immunosorbent assay in cats presenting to a university emergency service.

The goal of this study was to determine the prevalence of protective antibody titers against feline panleukopenia (FPL) in cats presenting to an emergency service. Seventy-five cats presenting for care for any injury or illness were eligible for inclusion. Using American Association of Feline Practitioners guidelines, vaccine status - up-to-date, not up-to-date, or unconfirmed - was recorded. Titers against FPL were semi-quantified using a point-of-care test and were classified as protective or non-protective. Of the 75 cats enrolled, 49 had protective titers (65%), whereas 26 (35%) did not. Fifty cats (66.7%) were considered up-to-date, whereas 25 cats (33.3%) were not up-to-date or unconfirmed. Not all up-to-date cats had positive titers and some cats with lapsed vaccines were still considered protected. Of the up-to-date cats, 35/50 (70%) had protective titers, whereas 15 (30%) did not. Of the 25 cats that were not up-to-date, titers were considered protective in 14 (56%) and absent in 11 (44%). This study supports that even in cats considered up-to-date, it is possible that adequate protection against FPL is not present. Care should be taken to appropriately isolate cats affected with illness attributable to FPL from other cats and prevent inadvertent nosocomial transmission.

Le but de cette étude était de déterminer la prévalence des titres d'anticorps protecteurs contre la panleucopénie féline (FPL) chez des chats présentés à un service d'urgence. Soixante-quinze chats présentés pour diverses blessures et maladies étaient éligibles à l'inclusion. L'état de vaccination, à jour ou non à jour/non confirmé selon les directives de l'AAFP a été enregistré. Les titres de FPL ont été semi-quantifiés à l'aide d'un test au chevet du patient et ont été classés comme protecteurs ou non protecteurs. Sur les 75 chats inclus, 49 avaient des titres protecteurs (65 %), tandis que 26 (35 %) n'en avaient pas. Cinquante chats (66,7 %) ont été considérés comme à jour, tandis que 25 chats (33,3 %) étaient non à jour ou non confirmés. Parmi les chats à jour, 35/50 (70 %) avaient des titres protecteurs, tandis que 15 (30 %) n'en avaient pas. Sur les 25 chats qui étaient non à jour, les titres étaient considérés comme protecteurs chez 14 (56 %) et absents chez 11 (44 %). Les chats qui étaient à jour n'avaient pas uniformément des titres positifs, tandis que certains chats dont les vaccins n'étaient pas à jour étaient encore considérés comme protégés. Cette étude soutient que même chez les chats considérés à jour, il est possible qu'une protection adéquate contre la FPL ne soit pas présente. Des précautions doivent être prises pour isoler de manière appropriée les chats atteints de maladies attribuables à la panleucopénie féline des autres chats et éviter une transmission nosocomiale accidentelle.(Traduit par les auteurs).

Feline panleukopenia virus DNA shedding following modified live virus vaccination in a shelter setting.

This study assessed the frequency and timing of feline panleukopenia virus (FPV) shedding in feces following administration of a modified live FPV vaccine. Feces were collected from 37 shelter cats that did not meet clinical criteria for panleukopenia on the day of vaccination or on days 3, 7, 14, and 21 post-vaccination (NCL group). A commercial quantitative PCR (qPCR) fecal pathogen panel and a canine parvovirus point-of-care antigen test were performed. FPV DNA copy numbers from a concurrent study of 39 cats with panleukopenia (CL group) were compared with the NCL group. Of the 165 samples from the NCL group, one had a weak positive antigen test result on day 7, while nine samples (5.5%) from eight cats (21.6%) produced positive FPV qPCR test results, one on day 3 and eight on day 7. There were no day 21-positive qPCR results in the 11 cats that were revaccinated on day 14. There was no association between the number of additional fecal pathogens identified and a positive FPV qPCR result. Of the cats with positive results, FPV DNA copy numbers differed between NCL group and CL group (median 1.13 × 107 and 5.01 × 108 copies/g feces, respectively; P < 0.001). The FPV qPCR cannot differentiate subclinical infection from vaccine virus shedding. To avoid unnecessary isolation and euthanasia, shelters should therefore limit FPV PCR testing to cats with a high index of suspicion of panleukopenia. The timing of recent vaccination should also be considered when interpreting test results.

Prevalence of autoantibodies that bind to kidney tissues in cats and association risk with antibodies to feline viral rhinotracheitis, calicivirus, and panleukopenia.

BACKGROUND: The feline viral rhinotracheitis, calicivirus, and panleukopenia (FVRCP) vaccine, prepared from viruses grown in the Crandell-Rees feline kidney cell line, can induce antibodies to cross-react with feline kidney tissues. OBJECTIVES: This study surveyed the prevalence of autoantibodies to feline kidney tissues and their association with the frequency of FVRCP vaccination. METHODS: Serum samples and kidneys were collected from 156 live and 26 cadaveric cats. Antibodies that bind to kidney tissues and antibodies to the FVRCP antigen were determined by enzyme-linked immunosorbent assay (ELISA), and kidney-bound antibody patterns were investigated by examining immunofluorescence. Proteins recognized by antibodies were identified by Western blot analysis. RESULTS: The prevalences of autoantibodies that bind to kidney tissues in cats were 41% and 13% by ELISA and immunofluorescence, respectively. Kidney-bound antibodies were observed at interstitial cells, apical border, and cytoplasm of proximal and distal tubules; the antibodies were bound to proteins with molecular weights of 40, 47, 38, and 20 kDa. There was no direct link between vaccination and anti-kidney antibodies, but positive antibodies to kidney tissues were significantly associated with the anti-FVRCP antibody. The odds ratio or association in finding the autoantibody in cats with the antibody to FVRCP was 2.8 times higher than that in cats without the antibody to FVRCP. CONCLUSIONS: These preliminary results demonstrate an association between anti-FVRCP and anti-cat kidney tissues. However, an increase in the risk of inducing kidney-bound antibodies by repeat vaccinations could not be shown directly. It will be interesting to expand the sample size and follow-up on whether these autoantibodies can lead to kidney function impairment.

Feline Parvovirus Seroprevalence Is High in Domestic Cats from Disease Outbreak and Non-Outbreak Regions in Australia.

Multiple, epizootic outbreaks of feline panleukopenia (FPL) caused by feline parvovirus(FPV) occurred in eastern Australia between 2014 and 2018. Most affected cats were unvaccinated.We hypothesised that low population immunity was a major driver of re-emergent FPL. The aim ofthis study was to (i) determine the prevalence and predictors of seroprotective titres to FPV amongshelter-housed and owned cats, and (ii) compare the prevalence of seroprotection between a regionaffected and unaffected by FPL outbreaks. FPV antibodies were detected by haemagglutinationinhibition assay on sera from 523 cats and titres ≥1:40 were considered protective. Socioeconomicindices based on postcode and census data were included in the risk factor analysis. The prevalenceof protective FPV antibody titres was high overall (94.3%), even though only 42% of cats wereknown to be vaccinated, and was not significantly different between outbreak and non-outbreakregions. On multivariable logistic regression analysis vaccinated cats were 29.94 times more likelyto have protective FPV titres than cats not known to be vaccinated. Cats from postcodes of relativelyless socioeconomic disadvantage were 5.93 times more likely to have protective FPV titres. Thepredictors identified for FPV seroprotective titres indicate targeted vaccination strategies in regionsof socioeconomic disadvantage would be beneficial to increase population immunity. The criticallevel of vaccine coverage required to halt FPV transmission and prevent FPL outbreaks should bedetermined.

Faecal shedding of parvovirus deoxyribonucleic acid following modified live feline panleucopenia virus vaccination in healthy cats.

Positive canine parvovirus (CPV) faecal test results have been reported in dogs after modified live virus (MLV) vaccination. Thus, the aim was to investigate feline panleucopenia virus (FPV) shedding in recently vaccinated, adult, clinically healthy cats and to assess related factors. Forty cats were vaccinated with an FPV MLV vaccine. Faeces of cats were tested for presence of parvovirus DNA on days 7, 14, 21 and 28 by quantitative real-time PCR; DNA-positive samples were subjected to partial VP2 gene sequencing. Virus isolation was performed whenever sufficient amounts of faeces were available. Serum antibody titres were measured by haemagglutination inhibition on days 0, 7 and 28. Overall, 30.0 per cent (12/40; 95% CI 18.0 to 45.6) of cats shed parvovirus DNA. Sequencing revealed FPV vaccine virus DNA in three cats, FPV field virus DNA in four cats and CPV field virus DNA in one cat. Shedding was significantly associated with lack of prevaccination antibody titres (40) (P=0.016; OR: 6.44; 95% CI 1.44 to 28.89) and with postvaccination titre increases (fourfold) (P=0.029; OR: 5.00; 95% CI 1.17 to 21.39). Shedding of field or vaccine virus DNA seems to be common in healthy cats which can be a concern in shelters and catteries. Diagnostic tools should be developed to facilitate differentiation of vaccine and field virus shedding.

Antibody response to feline panleukopenia virus vaccination in cats with asymptomatic retrovirus infections: a pilot study.

OBJECTIVES: Currently, there are only a few studies on how immunocompromised cats, such as cats infected with feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV), respond to vaccination. Therefore, this study measured feline panleukopenia virus (FPV) antibodies in retrovirus-infected cats within a period of 28 days after FPV vaccination, and compared the immune response to that of non-infected cats. METHODS: Eight asymptomatic retrovirus-infected cats (four FeLV, four FIV), and non-infected age-matched control cats (n = 67) were vaccinated with a commercial FPV modified live virus (MLV). Pre- and post-vaccination antibody titres were measured by haemagglutination inhibition (HI) on days 0, 7 and 28. An HI titre ⩾1:40 was defined as protective. An adequate response to vaccination was defined as a four-fold titre increase or higher. Comparison of the immune response of retrovirus-infected and non-infected cats was performed. RESULTS: Pre-vaccination FPV antibody titres ⩾1:40 were present in 100% (n = 8/8; 95% confidence interval [CI] 62.8-100) of retrovirus-infected and in 77.6% (n = 52/67; 95% CI 66.2-86.0) of non-infected cats. An adequate response to vaccination (titre increase ⩾four-fold) was seen in 1/8 retrovirus-infected cats (12.5%; 95% CI 0.1-49.2) compared with 22/67 non-infected cats (32.8%; 95% CI 22.8-44.8). In cats with high pre-vaccination titres (⩾1:160), a four-fold titre increase or higher was observed in 1/8 retrovirus infected cats (12.5%; 95% CI 0.1-49.2) compared with 4/42 non-infected cats (9.5%; 95% CI 3.2-22.6). None of the eight retrovirus-infected cats developed illness or vaccination side effects after vaccination with MLV against FPV within the 28 days. There were no significant differences between groups: for pre-vaccination titres; for at least four-fold titre increases following vaccination in either all cats or the cats with high pre-vaccination titres; and concerning adverse effects. CONCLUSIONS AND RELEVANCE: All retrovirus-infected asymptomatic cats had pre-vaccination FPV antibodies indicating protection against panleukopenia. Response of retrovirus-infected cats to vaccination was similar to the response of non-infected cats.

[Feline panleukopenia - the important role of antibodies]. / Feline Panleukopenie ­ die wichtige Rolle von Antikörpern.

Feline panleukopenia is an important infectious disease. Despite vaccination, panleukopenia remains common, particularly in young kittens. Development of active immunity after primary vaccination is essential for protection. Therefore, vaccination against panleukopenia is a core vaccine. Efficacy of primary vaccination can be reduced by maternally derived antibodies that can persist up to 20 weeks and interfere with the vaccination. In adult cats, antibody development after vaccination can be reduced during chronic disease or immunosuppression. Approximately 30% of adult cats lack antibodies. Evaluation of antibody titres in kittens enables calculation of the ideal time point to initiate primary vaccinations with the goal to establish effective immunity. In adult cats, evaluation of antibody titres is a useful alternative to avoid unnecessary vaccinations and to create an individual vaccination schedule. Only cats lacking antibodies should be vaccinated. Evaluation of antibodies in private practice can be performed using a rapid in-house test.

Antibody response to feline panleukopenia virus vaccination in healthy adult cats.

OBJECTIVES: According to prior studies, between 25.0% and 92.8% of adult cats have antibodies against feline panleukopenia virus (FPV) and thus are likely protected against FPV infection. It is, however, unknown how healthy adult cats with different antibody titres react to FPV vaccination in the field. Therefore, the aim of the study was to measure antibody titres in healthy adult cats within a period of 28 days after vaccination against FPV and to evaluate factors that are associated with a lack of adequate response to vaccination. METHODS: One hundred and twelve healthy adult cats were vaccinated with a vaccine against FPV, feline herpesvirus and feline calicivirus. Antibodies against FPV were determined before vaccination (day 0), on day 7 and day 28 after vaccination by haemagglutination inhibition (HI). A HI titre ⩾1:40 was defined as protective. An adequate response to vaccination was defined as a four-fold titre increase. Uni- and multivariate statistical analysis was used to determine factors associated with an adequate response. RESULTS: Pre-vaccination antibody titres of ⩾1:40 were present in 64.3% (72/112; 95% confidence interval [CI] 55.1-72.6). Only 47.3% (53/112; 95% CI 37.8-57.0) of cats had an adequate response to vaccination. Factors associated with an adequate response to vaccination were lack of previous vaccination (odds ratio [OR] 15.58; 95% CI 1.4-179.1; P = 0.035), lack of antibodies (⩾1:40) prior to vaccination (OR 23.10; 95% CI 5.4-98.8; P <0.001) and breed (domestic shorthair cats; OR 7.40; 95% CI 1.4-38.4; P = 0.017). CONCLUSIONS AND RELEVANCE: As none of the cats with high pre-vaccination antibody titres (⩾1:160) had an at least four-fold increase in FPV antibody titres, measurement of antibodies rather than regular revaccinations should be performed. Thus, evaluation of FPV antibody titre in cats with previous vaccinations against FPV are recommended prior to revaccination.

Evaluation of an in-house dot enzyme-linked immunosorbent assay to detect antibodies against feline panleukopenia virus.

Measuring antibody titres to determine a cat's immunity to core diseases instead of just administering annual vaccinations has not been established in Germany so far. An in-house test kit for the detection of antibodies against feline panleukopenia virus (FPV), feline herpesvirus-1 and feline calicivirus-- the ImmunoComb Feline VacciCheck--is now available in several European countries. The aim of this study was to assess the quality of the ImmunoComb Feline VacciCheck to determine antibodies by comparing it to a gold standard. The test is aimed for use in practice to assist decision-making when performing an individual health assessment to see whether a cat is potentially unprotected against FPV and requires FPV vaccination. Sera from 347 cats were included in the study. For antibody detection, haemagglutination inhibition (HI) was performed as gold standard. Sensitivity, specificity and positive and negative predictive values of the ImmunoComb Feline VacciCheck were determined for three different HI titre cut-off points (1:20, 1:40, 1:80). In comparison to the HI, the ImmunoComb Feline VacciCheck showed a sensitivity of 79%, 83% and 87%, and a specificity of 89%, 86% and 81%, respectively. Specificity of the ImmunoComb Feline VacciCheck, which was considered the most important parameter, was acceptable in comparison to HI. Especially when considering an antibody titre of 1:20 sufficient for protection (eg, in an adult animal), the ImmunoComb Feline VacciCheck can be recommended for use in veterinary practice.

Tail vaccination in cats: a pilot study.

Feline injection site sarcomas affect 1-10 cats per every 10,000 vaccinated and are associated with high mortality. Radical resection may be curative, but is often associated with prolonged recovery, disfigurement and loss of function when tumors occur at currently recommended injection sites. The objective of this study was to assess alternatives to currently recommended vaccination sites in terms of preference by oncology practitioners, ease of injection and serological responses. Surgical, radiation and medical oncology practitioners were surveyed regarding their preference for vaccination sites based on the ease of tumor resection. A six-point Likert scale was used to measure each cat's behavioral reaction to vaccination when injected subcutaneously in the distal hind limb or the distal tail. Serum collected before and 1-2 months after vaccination was tested for antibody titers against feline panleukopenia virus (FPV) and rabies virus (RV). The preferred sites for vaccination by 94 oncology practitioners were below the stifle (41%) and the tail (30%). There were no significant differences in the cats' behavioral reaction to vaccination below the stifle (n = 31) and in the distal tail (n = 29). Of the cats seronegative for FPV at the time of vaccination, 100% developed protective antibody titers (≥40) against FPV 1-2 months following vaccination. For cats seronegative for RV, all but one cat (tail vaccine) developed acceptable antibody titers (≥0.5 IU/ml) against RV. Tail vaccination was well tolerated and elicited similar serological responses to vaccination in the distal limbs.

Case series of feline panleukopenia virus in an animal shelter.

The aim of this study was to describe a series of confirmed and suspected cases of feline panleukopenia virus (FPV) and in-contact cats in an adoption-guarantee shelter in an FPV-endemic area by reviewing shelter records over a 10-month period (January-October 2010). Cats were divided into three groups: in-contact group - asymptomatic cats that were housed with a FPV fecal antigen (Ag)-positive cat/kitten as part of a litter group (n = 66); FPV-survivors group (FPV-infected survivors) - tested FPV fecal Ag-positive and showed clinical signs of FPV, but survived (n = 27); FPV-non-survivors group (FPV-infected non-survivors) - showed clinical signs of FPV and either tested FPV fecal Ag-positive or were housed with an Ag-positive family member, but did not survive (n = 52). Ages ranged from 3 weeks to 3 years, but most were <6 months old (in-contact group: 79%; FPV-survivors group: 70%; FPV-non-survivors group: 85%). A seasonal peak occurred over summer, but cases occurred year-round. Anorexia, dehydration, fever and diarrhea predominated in the FPV-survivors group, and death was preceded by clinical signs of circulatory shock in the FPV-non-survivors group. Housing litters of kittens with their mother was not associated with improved outcome, perhaps because in this population clinical FPV infection was relatively common in queens arriving at the shelter with susceptible litters.

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.

Antibody response to vaccines for rhinotracheitis, caliciviral disease, panleukopenia, feline leukemia, and rabies in tigers (Panthera tigris) and lions (Panthera leo).

This article presents the results of a study of captive tigers (Panthera tigris) and lions (Panthera leo) vaccinated with a recombinant vaccine against feline leukemia virus; an inactivated adjuvanted vaccine against rabies virus; and a multivalent modified live vaccine against feline herpesvirus, calicivirus, and panleukopenia virus. The aim of the study was to assess the immune response and safety of the vaccines and to compare the effects of the administration of single (1 ml) and double (2 ml) doses. The animals were separated into two groups and received either single or double doses of vaccines, followed by blood collection for serologic response for 400 days. No serious adverse event was observed, with the exception of abortion in one lioness, potentially caused by the incorrect use of the feline panleukopenia virus modified live vaccine. There was no significant difference between single and double doses for all vaccines. The recombinant vaccine against feline leukemia virus did not induce any serologic response. The vaccines against rabies and feline herpesvirus induced a significant immune response in the tigers and lions. The vaccine against calicivirus did not induce a significant increase in antibody titers in either tigers or lions. The vaccine against feline panleukopenia virus induced a significant immune response in tigers but not in lions. This report demonstrates the value of antibody titer determination after vaccination of nondomestic felids.

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.

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.

Feline panleukopenia virus, feline herpesvirus-1 and feline calicivirus antibody responses in seronegative specific pathogen-free kittens after parenteral administration of an inactivated FVRCP vaccine or a modified live FVRCP vaccine.

Two groups of feline panleukopenia (FPV), feline calicivirus (FCV) and feline herpesvirus 1 (FHV-1) seronegative kittens (six cats per group) were administered one of two feline viral rhinotracheitis, calcivirus and panleukopenia (FVRCP) vaccines subcutaneously (one inactivated and one modified live) and the serological responses to each agent were followed over 49 days (days 0, 2, 5, 7, 10, 14, 21, 28, 35, 42, 49). While the kittens administered the modified live FPV vaccine were more likely to seroconvert on day 7 after the first inoculation than kittens administered the inactivated vaccine, all kittens had seroconverted by day 14. In contrast, FHV-1 serological responses were more rapid following administration of the inactivated FVRCP vaccine when compared with the modified live FVRCP vaccine. There were no statistical differences between the serological response rates between the two FVRCP vaccines in regard to FCV.

Results of molecular diagnostic assays targeting feline herpesvirus-1 and feline calicivirus in adult cats administered modified live vaccines.

In this pilot study, 12 adult, gang-housed cats that were known to be previously exposed (n=12) to feline herpesvirus-1 (FHV-1) and/or vaccinated against (n=2) feline calicivirus (FCV) and FHV-1 were randomly assigned to one of two groups of six cats each. Nasal and pharyngeal samples were collected from each cat on days -7, -3, and 0 prior to vaccination and on days 3, 7, 10, 14, 17, 21, and 28 after vaccination with an FHV-1, FCV, and panleukopenia (FVRCP) vaccine developed for intranasal (six cats) or parenteral (six cats) use. FHV-1 DNA was amplified from 1/12 cats (1/69 samples; 1.4%) prior to vaccination and 2/12 cats after vaccination (2/154 samples; 1.3%). FCV RNA was amplified from 2/12 cats (2/69 samples; 2.9%) prior to vaccination and 7/12 cats (12/154 samples; 7.8%) after vaccination. Positive molecular diagnostic assay results for FHV-1 and FCV were uncommon prior to or after vaccination in these cats.