Do postvaccinal sarcomas occur in Australian cats ?

SUMMARY: A soft tissue sarcoma occurred in the interscapular area of a cat, 1 to 7 months after vaccination at that site. The vaccine contained inactivated feline panleucopaenia virus combined with modified live feline herpesvirus and calicrvirus. The tumour showed histological features of both fibrosarcoma and malignant fibrous histiocytoma. The tumour was observed to evolve from the site of a presumed postvaccinal granuloma. Local recurrence 6 weeks post excision necessitated more radical resection. Euthanasia was performed 2 years later when pleural effusion developed. The cause of effusion was not determined. There was no palpable evidence of local tumour regrowth at the time of euthanasia. A causal relationship between vaccination and sarcoma formation is considered based on the temporal association between the two events, the anatomical location of the tumour and histopathology consistent with postvaccinal sarcomas reported overseas. Six other vaccine site fibrosarcomas, potentially vaccine associated using the above criteria, are summarised.     

Feline viral respiratory disease: a review with particular reference to its epizootiology and control

The two major causes of feline viral respiratory disease are feline viral rhinotracheitis virus and feline calicivirus. This paper reviews the present state of knowledge concerning these viral agents, the clinical syndromes they produce, their maintenance in the cat population including recent developments in the understanding of their carrier states, and finally the methods by which they spread. The second part of the paper attempts to correlate this information in a section which deals with the practical problems of prevention and control; management factors pertinent to the control of respiratory disease and problems of vaccine development and vaccine use are discussed. A short section on treatment is included.     

Multiple crusted cutaneous plaques in a cat

A 12-year-old castrated male, domestic shorthaired cat was presented with multiple skin lesions. The cat lived mainly indoors and was regularly vaccinated against feline herpes-, calici- and parvo-viruses. It had also been vaccinated against feline leukaemia virus 18 months previously and the owner claimed that the skin lesions had developed after that vaccination.     

Vaccination of the young kitten

This paper draws together those diseases of the cat where vaccination is either being practised in the UK or overseas, or is currently being considered. In the UK, vaccination is routinely carried out for feline panleucopenia, feline viral rhino-tracheitis (FVR), and feline calicivirus infection, and in quarantine, cats are also vaccinated against rabies. In the USA and some other countries, vaccination is also carried out against feline leukaemia virus infection, feline Chlamydia psit-taci infection and routinely against rabies. Attempts are also being made to develop vaccines for feline infectious peritonitis (FIP), although there are a number of problems associated with the development of a successful FIP vaccine which will be referred to later. Factors important in prevention and control of the three diseases feline panleucopenia, FVR, and feline calicivirus infection for which vaccination in the UK is commonly practised will be discussed. For each disease, some background information on the virus and the epizootiology of the disease is given, which it is hoped will lead to greater understanding of the principles involved in prevention and control. A few points will then be made about vaccination in some of those diseases where vaccines are being developed or where it is carried out in other countries.     

JAUNDICE IN A SIAMESE CAT WITH IN UTERO FELINE CALICIVIRUS INFECTION

SUMMARY: A one-year-old pregnant female Siamese cat in a febrile toxaemic state was presented aborting. The cat was intensely jaundiced. Virological examination revealed a high virus titre of feline calicivirus in both foetuses and foetal fluids. The cat had a high serum neutralising antibody titre to feline calicivirus.     

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.     

Feline panleukopenia virus, feline herpesvirus-1, and feline calicivirus antibody responses in seronegative specific pathogen-free cats after a single administration of two different modified live FVRCP vaccines

Two groups of feline panleukopenia virus (FPV), feline calicivirus (FCV), and feline herpesvirus-1 (FHV-1) seronegative cats (five cats per group) were administered one of two modified live feline viral rhinotracheitis, calicivirus, and panleukopenia virus (FVRCP) vaccines and the serological responses to each agent were followed over 28 days. While all cats developed detectable FPV and FCV antibody titers; only two cats developed detectable FHV-1 antibody titers using the criteria described by the testing laboratory. For FPV and FHV-1, there were no differences in seroconversion rates between the cats that were administered the intranasal (IN) FVRCP vaccine and the cats that were administered the parenteral FVRCP vaccine on any day post-inoculation. For FCV, the cats that were administered the IN FVRCP vaccine were more likely to seroconvert on days 10 and 14 when compared to cats that were administered the parenteral FVRCP vaccine.     

Neutralisation patterns among recent British and North American feline calicivirus isolates from different clinical origins

The neutralisation patterns of 103 recent isolates of feline calicivirus from cats with chronic stomatitis or acute feline calicivirus disease, and from cats with neither oral nor respiratory disease were compared. There were no statistically significant differences between the proportions of isolates from each clinical source neutralised by individual feline calicivirus cat antisera. Different antisera showed widely differing degrees of cross reactivity; antisera to the most widely used vaccine strain F9 being the most cross reactive, neutralising 54 per cent of all the field isolates, and antisera to a field isolate LS015 the next most cross reactive, neutralising 29 per cent of the field isolates. However, the cross reactivity of antisera to early British isolates (A4, 68/40 and 69/1112) was much reduced (overall less than 10 per cent) whereas in the early 1970s 65 per cent of 117 field isolates from clinically normal cats were neutralised by A4 antiserum, and 40 per cent by each of 68/40 and 69/1112 antisera. This suggests a change in the spectrum of antigenicity among feline calicivirus isolates over the past 15 years. However, the cross reactivity of F9 antisera appeared to be similar to that in earlier studies. The relevance of these findings to vaccination is discussed.     

Derivation of feline vaccine-associated fibrosarcoma cell line and its growth on chick embryo chorioallantoic membrane – a new in vivo model for veterinary oncological studies

Feline vaccine associated fibrosarcomas are the second most common skin tumor in cats. Methods of treatment are: surgery, chemotherapy and radiotherapy. Nevertheless, the usage of cytostatics in feline vaccine associated sarcoma therapy is limited due to their adverse side effects, high toxicity and low biodistribution after i.v. injection. Therefore, much research on new therapeutic drugs is being conducted. In human medicine, the chick embryo chorioallantoic membrane (CAM) model is used as a cheap and easy to perform assay to assess new drug effectiveness in cancer treatment. Various human cell lines have different tumors growth on CAM. In veterinary medicine such model has not been described yet. In the present article derivation of feline vaccine associated fibrosarcoma cell line and its growth on CAM is described. The cell line and the tumor grown were confirmed by histopathological and immunohistochemical examination. As far as we believe, this is the first attempt to create such model, which may be used for further in vivo studies in veterinary oncology.     

Interaction of a combined feline viral rhinotracheitis-feline calicivirus vaccine and the FVR carrier state.

The effect of field feline viral rhinotracheitis (FVR) virus challenge on cats previously vaccinated with a combined FVR/feline calicivirus intramuscular vaccine was studied in relation to the development of an FVR carrier state. There was no virus shedding of either of the two vaccine viruses following vaccination. Treatment with corticosteroid 60 days after vaccination and before challenge with FVR virus did not induce virus re-excretion in vaccinates or controls; neither did similar treatment induce shedding 63 days after challenge of both vaccinates and controls with virulent field virus. After a further 55 days however, FVR virus shedding was elicited in one of four previously vaccinated and challenged cats compared with two of four unvaccinated and challenged controls. Two sentinel cats remained virologically and serologically free of FVR throughout. The vaccine was shown to be effective in controlling the disease; 12 weeks after initial vaccination no clinical signs were seen in three of four cats following intranasal challenge with 10(5)CCID50 of virulent field FVR virus, and a mild transient unilateral ocular and nasal discharge was seen in the remaining cat for one day only. Severe clinical signs of approximately 10 days' duration were seen in all four unvaccinated challenged controls. The virological and serological responses of the cats were also recorded.     

Cessation of feline calicivirus shedding coincident with resolution of chronic gingivostomatitis in a cat

Feline calicivirus (FCV) shedding and oral bacterial flora were monitored over a period of 22 months in a case of feline gingivostomatitis (FGS). The cat was treated daily with 50 mg thalidomide capsules by mouth, and 200 mg lactoferrin powder was applied directly to the lesions. Clinical signs began to resolve after 11 months when, in addition to treatment, the diet had been changed to an additive-free cat food supplemented with antioxidant vitamins A, D3 and E. Resolution of clinical signs of FGS coincided with the cessation of FCV shedding, and this is the first report documenting such an association. Which part of the treatment, if any, contributed to the cure requires further investigation.     

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.     

Interstitial nephritis in cats inoculated with Crandell Rees feline kidney cell lysates

Parenteral administration of Crandell Rees feline kidney (CRFK) cell lysates or feline herpesvirus 1, calicivirus, and panleukopenia virus-containing vaccines (FVRCP) grown on CRFK cells induces antibodies against CRFK cells. These antibodies also react with feline renal cell extracts. The purpose of this study was to determine whether interstitial nephritis would be detected in cats that were immunologically sensitized with CRFK lysates, boosted with CRFK lysates, and then biopsied 2 weeks after the booster. Cats (2 per group) were immunologically sensitized against CRFK lysates by administering 10 microg, 50 microg, or 50 microg plus alum 13 times (12 times in the first 50 weeks) over 2 years. Two cats were inoculated three times, 4 weeks apart with an FVRCP vaccine for intranasal administration as kittens, boosted 50 and 102 weeks later, and then renal biopsies taken 2 weeks after the last booster. Neither of the cats vaccinated with the FVRCP for intranasal administration had detectable renal inflammation. One cat in each of the three CRFK lysate sensitization groups had lymphocytic-plasmacytic interstitial nephritis.     

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.     

Cutaneous metastases of a bronchial adenocarcinoma in a cat

This case report describes a cat with metastasis of a bronchial adenocarcinoma to the abdominal skin. The cat had been treated with antibiotics and corticosteroids for several episodes of coughing when it acutely developed erythema, pustules and plaques on the abdominal skin. Diagnosis was based on cytological examination of fine-needle aspirates of cutaneous pustules, X-ray examination of the thorax and histological examination of skin biopsy samples. As the prognosis was poor, the cat was euthanased. Necropsy findings confirmed the diagnosis. Cutaneous metastases of lung carcinoma are rare in cats but have been reported in the digits with underlying bone involvement. To the authors' knowledge, this is the first report of metastasis of a feline bronchial carcinoma to the ventral skin.     

PATHOGENICITY OF A STRAIN OF FELINE CALICIVIRUS FOR DOMESTIC KITTENS

A strain of feline calicivirus, isolated from a cheetah exhibiting ulcerative glossitis and conjunctivitis, was administered by aerosol to 4 domestic cats and by contact to a fifth cat. Despite the limited number of animals available for the experiment, the pathogenicity of the virus strain for domestic cats was established. In aerosol-infected animals, clinical signs were referable to infection of both upper and lower respiratory tracts. The virus produced an interstitial pneumonia which, early in infection, was uncomplicated by secondary bronchopneumonia. The in-contact cat exhibited clinical signs referable to infection of the oral cavity only and no lesions were noted in the lower respiratory tract at autopsy. Ulcerative glossitis was a feature of the disease in aerosol-infected and in-contact cats. The virus was isolated from the pharynx of all cats for up to 21 days after infection and from the tonsils at autopsy. The tonsils were considered to be a probable site of multiplication of virus in "carrier" cats.     

Three-year duration of immunity in cats following vaccination against feline rhinotracheitis virus, feline calicivirus, and feline panleukopenia virus

Forty-two seronegative cats received an initial vaccination at 8 weeks of age and a booster vaccination at 12 weeks. All cats were kept in strict isolation for 3 years after the second vaccination and then were challenged with feline calicivirus (FCV) or sequentially challenged with feline rhinotracheitis virus (FRV) followed by feline panleukopenia virus (FPV). For each viral challenge, a separate group of 10 age-matched, nonvaccinated control cats was also challenged. Vaccinated cats showed a statistically significant reduction in virulent FRV-associated clinical signs (P = .015), 100% protection against oral ulcerations associated with FCV infection (P < .001), and 100% protection against disease associated with virulent FPV challenge (P < .005). These results demonstrated that the vaccine provided protection against virulent FRV, FCV, and FPV challenge in cats 8 weeks of age or older for a minimum of 3 years following second vaccination.     

Intranasal vaccination against upper respiratory tract disease (U.R.D.) in the cat—I. Virological and serological observations in cats suffering from U.R.D.

A number of cat colonies in The Netherlands, in which upper respiratory tract disease (U.R.D.) was endemic, were examined for the presence of feline herpes virus (H) and feline calici virus (C) infections. In total 108 cats were examined. In 59% of the cases feline calici virus was isolated and feline herpes virus in 39% of the cases. Mixed infections were found in 26% of the cats. The virus isolates were all neutralised by anti-sera against attenuated strains of feline herpes virus and feline calici virus which are incorporated in a newly developed combined C-H vaccine against U.R.D. in cats. Intranasal application of this vaccine induced a distinct increase in resistance against experimental challenge with virulent C and H, as soon as 24 hours after vaccination.     

Nasal swelling due to plasma cell infiltrate in a cat without plasma cell pododermatitis

A cat with an upper respiratory infection was presented for examination. Close examination of the face revealed a firm, haired rounded swelling on the bridge of the nose. Serum protein electrophoresis demonstrated a mild hypergammaglobulinaemia. The cat tested negative for feline immunodeficiency virus. Skin biopsy of the nasal lesion revealed nodular angiocentric infiltrates in the deep dermis and subcutis. The mixed infiltrate had numerous plasma cells. Presence of calicivirus antigen could not be demonstrated within the skin lesion by immunohistochemical staining. The cat was treated for upper respiratory infection and 1 month later the nasal lesion had resolved. A firm and rounded swelling over the bridge of the nose may be a feline cutaneous plasmacytic reaction pattern.     

Pustular calicivirus dermatitis on the abdomen of two cats following routine ovariectomy

An unusual form of calicivirus dermatitis is described in two cats. Two fully vaccinated cats were re-admitted for anorexia and depression following routine ovariectomy. Signs of upper respiratory disease were not present. One cat subsequently showed painful necrosis of the incision wound, the other one developed dyspnoea with pleural effusion and discrete tongue ulcers. Intact pustular lesions confined to the surgically prepared abdomen appeared in both cats, respectively, on days 11 and 9. The histopathological diagnosis was panepidermal pustulosis and necrotizing dermatitis. Positive immunohistochemical staining consistent with feline calicivirus antigen was detected in epithelial cells within pustular lesions. The cats were treated with antibiotics and ketoprofen. The cat with progressive dyspnoea was euthanized. The clinical signs in the other cat rapidly and completely resolved following glucocorticoid therapy. It is hypothesized that the reported cases may represent a distinct calicivirus-induced pustular dermatitis following ovariectomy.