N-ras mutation in a canine lymphoma: short communication

Lymphomas of dogs were investigated by molecular genetic methods. Regions of exon 1 and 2 of the N-ras gene, which harbours the mutation hot spots (codons 12, 13 and 61) were screened. A GGT [symbol: see text] GAT (glycine [symbol: see text] aspartic acid) mutation in codon 13 was present in a multicentric-type lymphoma of a 1-year-old male dog.     

Clinical trial of a feline pheromone analogue for feline urine marking

Thirty-six cases of feline urine marking problem were collected through the cooperation of veterinary practitioners in the Kanto, Chubu, and Kansai areas in Japan, for an assessment of the clinical effect of treatment with a synthetic analogue of a feline cheek gland pheromone-like product. The mean frequency of urine marking was 14.2 times/week (median, 10; range, 1-77) at pre-treatment week (preW), and decreased significantly from the first week of treatment, dropping to 4.2 times/week (median, 2; range, 0-44) at the fourth week of treatment. This effect continued until the fourth week after cessation of treatment. These 36 cases were divided into 3 groups based on the effectiveness of treatment as demonstrated in the fourth week of treatment; 37% was categorized as the totally eliminated group (urine marking was not seen), 40% as the reduced group (the frequency of urine marking was equal to or less than 50% that of the preW), and 23% as the unchanged group (the frequency of urine marking was more than 50% that of the preW). Effectiveness of treatment in these groups was 38%, 24%, and 38% at the fourth week after the cessation of treatment, respectively. The decreasing rate of urine marking was compared between cats with and without intercat aggression, and it was revealed that the frequency of marking was sustained at high level in cats with intercat aggression. These results suggest that this pheromone treatment is as effective in Japan as has been reported in other countries for solving feline urine marking problems.     

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.     

Experimental transmission of a feline mycobacterial skin disease (feline leprosy)

Non-culturable acid-fast bacteria from two spontaneous cases of so-called feline leprosy were transmitted to rats and cats and further passaged in rats or cats. Two to six months after infection, cats developed cutaneous lesions that were indistinguishable from spontaneous cases, including the occurrence of nasal granulomata in one cat. When injected into rats, the mycobacteria caused a generalized mycobacteriosis and the granulomatous reaction was composed chiefly of macrophages without polymorphonuclear granulocytes. Infection of cats with Mycobacterium lepraemurium did not produce any lesions. The feline disease may be a suitable model for the study of human leprosy (Hansen's Disease).     

Prevalence of feline immunodeficiency virus in submissions of feline serum to a diagnostic laboratory in Atlantic Canada

The purpose of this project was to identify the prevalence of feline immunodeficiency virus (FIV) in the Atlantic region of Canada, and to determine possible associations between FIV serological status and breed, sex, and age. Feline serum samples (671) submitted to the Prince Edward Island Diagnostic Services — Atlantic Veterinary College laboratory between January 1, 1988 and July 30, 1989 were considered eligible for this study. The majority of samples originated from Prince Edward Island (607). Testing was performed in duplicate using commercial 96-well enzyme-linked immunosorbent assay test kits for FIV antibody. Results included a seropositive rate of 7.6% for all submissions. Mean age of FIV-seropositive cats was eight years. There was an increasing risk of FIV-seropositive status associated with age. Prevalence of FIV among intact males was significantly higher (odds ratio = 2.59) than other gender categories. The principal conclusion of this study was that FIV is present in cats of the Atlantic provinces, and that its associations and prevalence are consistent with those found in other North American epidemiological studies.     

Prevalence of feline leukaemia provirus DNA in feline lymphomas

A significant drop in the prevalence of feline leukaemia virus (FeLV) antigenaemic cats and antigen-associated lymphomas has been observed after the introduction of FeLV vaccination and antigen-testing with removal of persistently antigenaemic cats. However, recent reports have indicated that regressively infected cats may contain FeLV provirus DNA and that lymphoma development may be associated with the presence of provirus alone. In the present study, we investigated the presence of FeLV antigen and provirus DNA in 50 lymphomas by immunohistochemistry and semi-nested polymerase chain reaction, respectively. Interestingly, almost 80% of T-cell lymphomas and 60% of B-cell lymphomas contained provirus DNA while only 21% of T-cell lymphomas and 11% of B-cell lymphomas expressed FeLV antigen. In conclusion, our results support previous hypotheses that vaccination and removal of persistently antigenaemic cats have led to a drop in FeLV antigen-expressing lymphomas. However, FeLV provirus DNA is still present in a high percentage of feline lymphomas.     

Cryptosporidiosis in a feline leukemia virus-positive cat

A 4-year-old FeLV-positive cat with a 1-year history of intermittent diarrhea and subsequent anorexia, depression, and weight loss had enteric cryptosporidiosis at necropsy. Cryptosporidium sp is an important cause of gastroenteritis and diarrhea in various species, including human beings with acquired immunodeficiency syndrome. A major determinant of the severity of the disease caused by Cryptosporidium sp is the immunologic status of the affected animal. Cryptosporidiosis should be included in the differential diagnosis of protracted diarrhea in FeLV-positive cats. Because cryptosporidiosis now is recognized as a zoonosis, cats with this disease should be considered a potential source of human infection.     

Chromosomal hyperdiploidy in a feline sarcoma.

An eight-year-old male cat developed a sarcoma. The cytogenetic evaluation of the tumour cells showed the presence of hyperdiploidy (range 40 to 46 chromosomes). This hyperdiploidy was encountered in all the cells examined. Extra-chromosomes numbers C1, C2, B4, D4 and E3 were mainly responsible for the hyperdiploid chromosomal complements. There was a high incidence of monosomy E3.     

Induction of feline immunodeficiency virus from a chronically infected feline T-lymphocyte cell line

The infection of the feline T-lymphocyte cell line FeT-J with the feline immunodeficiency virus (FIV) Petaluma strain led to the establishment of nonvirus-producing cells. One clone (C15) obtained by limiting dilution was found to express FIV in response to chemical inducers of retroviruses. The chemical treatment of C15 cells led to not only FIV protein synthesis but also an augmentation of viral production. Examination of the C15 cell derivatives obtained by recloning revealed that 10-40% of treated cells constitutively expressed FIV antigens, whereas 100% with expressed FIV antigen in response to the inducer. Chemical induction resulted in more than a 100-fold increase in infectious viral production. The results suggest that a majority of FeT-J cells that are infected with FIV exist in a non-productive state. Establishing a cell line that can be non-productively infected by FIV may help determine the mechanisms of FIV latency.     

Treatment of a case of refractory feline chronic gingivostomatitis with feline recombinant interferon omega

Chronic gingivostomatitis is a common debilitating disease in cats, which is often refractory to medical and surgical treatment. An eight-year-old, neutered female domestic shorthair cat with a history of gingivitis was presented with chronic gingivostomatitis. Initial treatment by extraction of all premolars and molars was unsuccessful. However, the condition resolved within six weeks of treatment with feline recombinant interferon omega (Virbagen; Virbac).     

Activation of AKT in feline mammary carcinoma: a new prognostic factor for feline mammary tumours

The PI3K/AKT/PTEN pathway is involved in the pathogenesis of several human cancers. This study investigated the biological and prognostic value of PI3K/AKT/PTEN pathway dysregulation in feline mammary tumours. Expression of p-AKT, HER2, PTEN and steroid receptors was assessed by immunohistochemistry (IHC) in 27 malignant and 12 benign mammary tumours from 39 female cats followed up over a 24-month period. Feline mammary carcinoma (FMC) cell lines were analyzed by Western blot and the feline AKT gene sequence was characterized. p-AKT expression statistically correlated with tumour malignancy, histological dedifferentiation and clinical recurrence. The animals with tumours expressing p-AKT had a shorter disease-free period than those with p-AKT-negative tumours. AKT activation was associated with HER2 expression and PTEN down-regulation, as occurs in human breast cancer, and feline AKT sequencing showed high homology with the human AKT gene. No AKT activation was observed in relation to either oestrogen receptor α (ERα) or progesterone receptor expression. Taken together, these data offer an explanation for AKT signalling and its role in FMC pathogenesis and prognosis, shedding new light on similarities between feline mammary tumours and hormone-independent breast cancer.     

Deletions in the 7a ORF of feline coronavirus associated with an epidemic of feline infectious peritonitis

A population of Persian cats experienced an epidemic of feline infectious peritonitis (FIP) over 2 years. Twelve cases of FIP occurred in litters born during this period. Cats contracting FIP were all genetically related through the sire. Feline coronavirus (FCoV) genomic RNA was detected consistently in this study in biologic samples from adult cats, kittens suffering from FIP, and their siblings. Analysis of viral 7a/7b open reading frame (ORFs) were analyzed and revealed two distinct virus variants circulating in the population, one with an intact 7a ORF and one with two major deletions in the 7a ORF. The 7b ORFs were intact and similar among all virus isolates, although point mutations resulting in amino acid changes were present. The sire was determined to be infected with both variants, and was persistently virus-infected. We speculate the deletion variant arose from the non-deletion variant during viral replication in this population, possibly in the sire.     

Comparison of feline parvovirus subspecific strains using monoclonal antibodies against a feline panleukopenia virus

Four monoclonal antibodies (mAb) against a feline panleukopenia virus (FPLV) TU 1 strain, one of the host range variants of feline parvovirus (FPV), were produced and applied for antigenic analysis of FPLV, canine parvovirus (CPV) and mink enteritis virus (MEV). All mAbs were considered to be directed at epitopes on the virus capsid surface because they neutralized the infectivity and inhibited the hemagglutination (HA) of the homologous virus as well as other FPV strains. They were of the mouse IgG1 type. High antigenic homogeneity among FPLV strains was confirmed by HA-inhibition (HI) test with the mAbs and polyclonal immune sera against FPLV or CPV. But the TU 11 strain of FPLV was antigenically distinguished from the remaining 14 FPLV strains by both the HI test and the micro-neutralization test with one of the mAbs produced. MEV Abashiri strain was found to be antigenically indistinguishable from FPLV. Most of the CPV strains isolated after 1981 were considered to be antigenically different from earlier CPV isolates when some mAbs were applied in the serological tests, confirming the replacement of CPV by an antigenic variant in Japan. However, antigenically different CPVs were detected at the end of 1984 from unrelated epizootics occurred a month apart in the same area.     

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.     

Studies of enteric coronaviruses in a feline cell line

Development is reported of a feline cell line which can support the growth of coronaviruses from canine (CCV), feline (FIPV) and porcine (TGEV) species. The cell culture has been serially transferred over 100 times and has retained its initial growth requirements, proliferative capacity and morphologic features. Each virus had specific growth characteristics in this cell culture although all produced a similar CPE and plaques under agar. Cross neutralization studies demonstrated a two-way relationship between TGEV and CCV and between TGEV and FIPV, whereas a one-way relationship was demonstrated between CCV and FIPV.