Canine parvovirus in asymptomatic feline carriers

Canine parvovirus (CPV) and feline panleukopaenia virus (FPLV) are two closely related viruses, which are known to cause severe disease in younger unvaccinated animals. As well as causing disease in their respective hosts, CPV has recently acquired the feline host range, allowing it to infect both cats and dogs. As well as causing disease in dogs, there is evidence that under some circumstances CPV may also cause disease in cats. This study has investigated the prevalence of parvoviruses in the faeces of clinically healthy cats and dogs in two rescue shelters. Canine parvovirus was demonstrated in 32.5% (13/50) of faecal samples in a cross sectional study of 50 cats from a feline only shelter, and 33.9% (61/180) of faecal samples in a longitudinal study of 74 cats at a mixed canine and feline shelter. Virus was isolated in cell cultures of both canine and feline origin from all PCR-positive samples suggesting they contained viable, infectious virus. In contrast to the high CPV prevalence in cats, no FPLV was found, and none of 122 faecal samples from dogs, or 160 samples collected from the kennel environment, tested positive for parvovirus by PCR. Sequence analysis of major capsid VP2 gene from all positive samples, as well as the non-structural gene from 18 randomly selected positive samples, showed that all positive cats were shedding CPV2a or 2b, rather than FPLV. Longitudinally sampling in one shelter showed that all cats appeared to shed the same virus sequence type at each date they were positive (up to six weeks), despite a lack of clinical signs. Fifty percent of the sequences obtained here were shown to be similar to those recently obtained in a study of sick dogs in the UK (Clegg et al., 2011). These results suggest that in some circumstances, clinically normal cats may be able to shed CPV for prolonged periods of time, and raises the possibility that such cats may be important reservoirs for the maintenance of infection in both the cat and the dog population.     

Polymerase chain reaction (PCR) amplification of parvoviral DNA from the brains of dogs and cats with cerebellar hypoplasia

Cerebellar hypoplasia in cats is caused most commonly by an in utero or perinatal infection with feline panleukopenia virus (parvovirus). Cerebellar hypoplasia has been reported infrequently in dogs, but no viral etiology has been identified to date. DNA was extracted from archival, paraffin-embedded, cerebellar tissue from 8 cats and from 2 canine littermates with cerebellar hypoplasia, 2 canine littermates with cerebellar cortical abiotrophy, 6 dogs with congenital cerebellar vermal defects, 1 dog with congenital hydranencephaly, and 15 dogs and cats with various encephalitdes. The DNA extracted from each cerebellum was subject to polymerase chain reaction (PCR) amplification by 3 primer pairs specific for parvovirus DNA. Sequence analysis of PCR products from each of the 8 cats and 2 dogs with cerebellar hypoplasia confirmed their identity with parvoviral DNA. The 6 dogs with cerebellar vermal defects, 2 dogs with cortical abiotrophy, 1 dog with congenital hydranencephaly, and all control samples were PCR negative for parvovirus. Parvoviral structural proteins were not identified by immunohistochemistry in either dog with cerebellar hypoplasia. This study shows that parvoviral DNA can be amplified from feline and canine archival brain tissue and that cerebellar hypoplasia in dogs might be associated with in utero parvovirus infection.     

Seroprevalence of Canine Herpesvirus‐1 in the Belgian Dog Population in 2000

Canine herpesvirus‐1 (CHV‐1) is known to be associated with fertility and fecundity disorders as well as neonatal mortality in puppies of less than 3 weeks of age. The virus is presumed to be enzootic in dogs all over the world and recent studies in several European countries suggest a high seroprevalence among the dog population. In the year 2000, a total of 647 Belgian canine sera from 102 privately owned patients and 545 breeding dogs were analysed with an enzyme‐linked immunosorbent assay (ELISA). Furthermore 77 of the samples were submitted to two serum neutralization (SN) tests for comparison. An overall CHV‐1 seroprevalence of 45.75% was observed in the Belgian dog population. No significant differences could be observed based on breeding status, reason for consultation or sex. The correlation between the ELISA and both SN tests appeared to be moderate with a significantly greater sensitivity of the ELISA. This study also demonstrated that the CHV‐1 seroprevalence in the Belgian dog population is similar to that in other recently investigated European countries and that the incidence in breeding units is not necessarily higher than in non‐breeding dogs.     

Virological Survey in free-ranging wildcats (Felis silvestris) and feral domestic cats in Portugal

To determine the presence of viral pathogens in natural areas a survey was conducted on an opportunistic sample of fifty eight wild (Felis silvestris silvestris) and feral cats (F. s. catus). The biological materials included serum, lung tissue extract and stool. Feline leukemia virus p27 antigen was detected in 13/50 serum/lung tissue extract samples (26%), canine distemper virus antibodies were detected in 2/26 serum/lung tissue extract samples (7.7%), feline coronavirus RNA was present in 6/29 stool samples (20.7%) and feline parvovirus DNA in 2/29 stool samples (6.9%). Canine distemper virus RNA was not detected. Feline immunodeficiency virus and feline coronavirus antibodies were not detected. Evidence of exposure to feline leukemia virus, canine distemper virus, feline coronavirus and feline parvovirus was found in wild and feral cats raising the importance of performing a comprehensive survey to correctly evaluate the potential threat of infectious diseases to endangered species, namely to the wildcat and to the Iberian lynx, which is meant to be reintroduced after 2012 in Portugal.     

Evaluation of tongue as a complementary sample for the diagnosis of parvoviral infection in dogs and cats.

Diagnosis of canine parvovirus type 2 and feline panleukopenia virus infection in dogs and cats may be hampered by the severity of enteric lesions, secondary bacterial overgrowth, and rapid onset of autolysis. In contrast to small intestine, tongue epithelium is less sensitive to postmortem changes. Sections of tongue and small intestine from 11 dogs and 11 cats with a clinical history and gross and microscopic lesions compatible with canine and feline parvoviral infection were examined for parvoviral infection using real-time polymerase chain reaction (PCR), immunohistochemistry (IHC), and direct fluorescent antibody testing (FA). Parvoviral DNA was detected by PCR in both small intestine and tongue of all but 1 dog. Nineteen of 22 animals (86%) with suspect or positive FA staining in the small intestine also had positive FA and IHC staining in the tongue. Three of 3 dogs (100%) whose carcasses had been frozen and thawed prior to necropsy had more consistently positive staining in tongue than in small intestine by FA and IHC. These data confirm tongue as an excellent complementary sample for parvoviral testing in dogs and cats, especially in cases in which postmortem autolysis has occurred.     

Principles of treatment for feline lymphoma

Lymphoma is the most commonly diagnosed neoplasm in cats. As feline leukemia virus antigenemia has decreased over the past 15 years, there has been a profound shift in the presence, signalment, and frequency of sites of feline lymphoma in North America. There is variation in anatomic classification systems, but most studies have divided lymphoma into four groups: alimentary, mediastinal, multicentric, or extranodal. Clinical signs and common differential diagnoses for each of the forms are described. Staging allows for evaluation of the extent of disease. As in the dog, lymphoma is a systemic disease in the cat, and chemotherapy is the treatment of choice for most forms. Exceptions are described. In contrast to canine lymphoma, feline lymphoma is generally more challenging and frustrating to treat than canine lymphoma. Response rates are lower, and remission duration is shorter. Fortunately, cats treated with chemotherapy tend to have less toxicity than dogs. Positive prognostic factors are feline leukemia virus-negative, clinically well at time of diagnosis, and response to therapy. Achieving a complete remission is prognostic for survival. Unfortunately, response cannot be predicted before treatment.     

Inhibition of canine and feline alcohol dehydrogenase activity by fomepizole

OBJECTIVE: To determine and compare substrate specificity and kinetic rate constants of feline and canine alcohol dehydrogenase (ADH) with ethanol (EtOH) and ethylene glycol (EG) as substrates in vitro, with and without fomepizole. SAMPLE POPULATION: Livers from 3 dogs and 3 cats. PROCEDURE: Canine and feline ADH activity, in cytosolic fractions of homogenized liver, was determined by use of various concentrations of nicotinamide adenine dinucleotide (NAD), EtOH, or EG as substrates. Initial reaction velocities were calculated, and kinetic inhibition rate constants (Ki) for fomepizole were determined. RESULTS: Substrate specificity of canine and feline ADH for EtOH or EG was not significantly different. A 2-fold difference was detected in the maximal velocity of canine, compared with feline, ADH, using either substrate. Fomepizole Ki in feline hepatic homogenates was significantly greater than Ki in canine hepatic homogenates when either EtOH or EG was used as substrate (10- and 30-fold, respectively). A 6-fold increase in the concentration of fomepizole was required to achieve ADH inhibition, with feline homogenates equivalent to those of canine homogenates. CONCLUSIONS AND CLINICAL RELEVANCE: Feline ADH has lower enzymatic capacity for turnover or is less concentrated in liver than canine ADH with regard to EtOH and EG catalysis. Canine ADH was more effectively inhibited by fomepizole than feline ADH. Results suggest that higher dosages of fomepizole may be more effective to treat cats with EG intoxication than dosages reported to treat dogs.     

Fibrosarcomas at presumed sites of injection in dogs: characteristics and comparison with non-vaccination site fibrosarcomas and feline post-vaccinal fibrosarcomas

Fifteen fibrosarcomas, surgically excised from presumed sites of injection in dogs, and 10 canine fibrosarcomas excised from sites not used for injection were histologically and immunohistochemically compared with 20 feline post-vaccinal fibrosarcomas. Canine fibrosarcomas from presumed injection sites were of grade I (3), of grade II (4) and grade III (8). Two fibrosarcomas from non-injection sites were of grade I, four of grade II and four of grade III. Feline samples were classified as grade I (2), grade II (4) and grade III (14). All fibrosarcomas from presumed injection sites of both species showed lymphocytic inflammatory infiltration located at the tumour periphery, while two canine fibrosarcomas from non-injection sites showed perivascular inflammatory infiltration within the neoplasm. All samples were immunohistochemically examined for vimentin, smooth muscle actin, muscle specific actin and desmin expression. All tumours were positive for vimentin. Ten canine fibrosarcomas from presumed injection sites and all feline samples contained cells consistent with a myofibroblastic immunophenotype. Aluminium deposits were detected in eight canine fibrosarcomas from presumed injection sites and 11 feline post-vaccinal fibrosarcomas by the aurintricarboxylic acid method. The present study identifies distinct similarities between canine fibrosarcomas from presumed injection sites and feline post-vaccinal fibrosarcomas, suggesting the possibility of the development of post-injection sarcomas not only in cats, but also in dogs.     

Polymerase chain reaction analysis for viruses in paraffin-embedded myocardium from dogs with dilated cardiomyopathy or myocarditis

OBJECTIVE: To perform polymerase chain reaction (PCR) analysis on paraffin-embedded myocardium from dogs with dilated cardiomyopathy (DCM) and dogs with myocarditis to screen for canine parvovirus, adenovirus types 1 and 2, and herpesvirus. SAMPLE POPULATION: Myocardial specimens from 18 dogs with an antemortem diagnosis of DCM and 9 dogs with a histopathologic diagnosis of myocarditis were evaluated. PROCEDURE: Paraffin-embedded myocardial specimens were screened for viral genome by PCR analysis. Positive-control specimens were developed from cell cultures as well as paraffin-embedded tissue specimens from dogs with clinical and histopathologic diagnoses of viral infection with canine parvovirus, adenovirus types 1 and 2, and herpesvirus. The histologic characteristics of all myocardial specimens were classified regarding extent, location, and type of inflammation and fibrosis. RESULTS: Canine adenovirus type 1 was amplified from 1 specimen from a dog with DCM. Canine parvovirus, adenovirus type 2, and herpesvirus were not amplified from any myocardial specimens. Histologic analysis of specimens from dogs with DCM revealed variable amounts of fibrosis; myocardial inflammation was observed in 1 affected dog. Histopathologic analysis of specimens from dogs with myocarditis disclosed variable degrees of inflammation and fibrosis. CONCLUSIONS AND CLINICAL RELEVANCE: Viral agents canine parvovirus, adenovirus types 1 and 2, and herpesvirus are not commonly associated with DCM or active myocarditis in dogs. Additional studies evaluating for nucleic acid from viruses that less commonly affect dogs or different types of infectious agents may be warranted to gain insight into the cause of DCM and myocarditis in dogs.     

A case report: encephalitis in lions. Pathological and virological findings

An acute outbreak of encephalomyelitis in lions from a safari-park was investigated. Three moribund lions were euthanatized and a post mortem examination was performed. A disseminated non-suppurative polioencephalomyelitis with demyelination in the spinal cord was the only pathological finding. From tonsil material of one lion feline herpesvirus type 1 was isolated. Canine distemper virus, pseudorabies virus, feline infectious peritonitis virus and rabies were excluded as cause of the disease. The possible role of FHV-1 in etiology of the disease is discussed.     

Review of thymic pathology in 30 cats and 36 dogs

Data are presented from 30 cats and 36 dogs in which thymic disease was recognised clinically or on postmortem examination. The diagnoses included thymic lymphoma (19 cats, l 2 dogs), thymoma (five cats, 18 dogs), thymic branchial cyst formation or cystic change (one cat, four dogs), thymic hyperplasia (two cats), congenital hypoplasia (one cat, one dog), thymic haemorrhage (one cat, one dog) and thymic amyloidosis (one cat). Thymic lymphoma occurred in younger dogs and cats, and was recorded equally among domestic shorthaired and purebred (especially Siamese) cats. Eight cats with thymic lymphoma were tested for feline leukaemia virus and four were positive. Thymoma occurred more frequently in older cats and dogs, and in Labradors and German shepherd dogs. Thymic tumours were associated with paraneoplastic hypercalcaemia (six dogs), megaoesophagus (two dogs) or interface dermatitis with basement membrane immune complex deposition (one cat). Non-neoplastic thymic diseases were associated with myasthenia gravis (one cat), pemphigus foliaceus (one cat) and superficial necrolytic dermatitis (one cat).     

Aldose reductase activity and glucose-related opacities in incubated lenses from dogs and cats

OBJECTIVE: To determine responses of canine and feline lenses to incubation in a medium with a high glucose concentration. SAMPLE POPULATION: Lenses from 35 dogs and 26 cats. PROCEDURE: Glucose concentrations were measured in paired lenses from 25 dogs and 17 cats after incubation for 14 days in high-glucose (30 mmol of glucose/L) or control (6 mmol of glucose/L) medium. Aldose reductase activity was measured spectrophotometrically in the incubated lenses and in freshly frozen lenses from 10 dogs and 9 cats. Two lenses of each group were studied histologically. RESULTS: Canine and feline lenses in high-glucose medium developed glucose-specific opacities of variable localization and extent. Canine lenses developed equatorial vacuoles, but severity of the lesions was not associated with the age of the dog. Lenses from young cats (< or = 4 years old) developed extensive posterior cortical opacities, whereas those from older cats (> 4 years old) did not. Glucose concentrations were similar in all lenses incubated in high-glucose medium; however aldose reductase activity was significantly lower in lenses from older cats, compared with lenses from young cats and from dogs. CONCLUSIONS AND CLINICAL RELEVANCE: High aldose reductase activity and glucose-related opacities suggest a central role for this enzyme in the pathogenesis of diabetic cataracts in dogs and cats. Because onset of diabetes mellitus usually occurs in cats > 7 years of age, low activity of aldose reductase in lenses of older cats may explain why diabetic cataracts are rare in this species despite hyperglycemia.     

Isolation of oral spirochetes from dogs and cats and provisional identification using polymerase chain reaction (PCR) analysis specific for human plaque Treponema spp

Identification of plaque spirochetes from dogs is rare and no studies to date report cultivation of canine or feline plaque spirochetes. Plaque samples obtained from canine and feline patients were cultured in broth media. Spirochetes cultured were subjected to microscopic evaluation and were cloned on a solid medium. The clones were provisionally identified using species-specific PCR for treponema isolated from human plaque. Canine spirochete clones included Treponema denticola, T. socranskii ssp., T. vincentii, T. maltophilum, T. medium, and T. pectinovorum. Feline clones included T. maltophilum and T. socranskii. Non-amplified clones may represent novel treponemes. Future studies will be aimed at comparison of the spirochetes present in dogs and cats with or without periodontal disease.     

The seroprevalence of canine parvovirus-2 in a selected sample of the canine population in ontario

Canine sera, collected from dogs presented to the Ontario Veterinary College between 1976 and 1980, were assessed for canine parvovirus-2 antibody using a microtitre hemagglutination-inhibition test. Special emphasis was made on the period from September 1979 to October 1980 (2892 samples). No antibody was detected in samples collected in 1976 or 1977. The first positive sera were obtained in January 1978. By the end of 1978 antibodies to canine parvovirus-2 were widespread in Ontario dogs and in 1980, 683 of 2191 dogs (31.2%) had antibody. This was before widespread vaccination was being practised and indicates canine parvovirus-2 infection occurred frequently. Evaluation of clinical records of these dogs suggested that most infections had been subclinical.     

Detection of antibodies to Borna disease virus in Turkish cats by using recombinant p40.

Recombinant p40 produced by baculovirus was used in an ELISA to screen samples of serum taken from 80 cats in Istanbul. The sera were also analysed for feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV). Antibodies to Borna disease virus- (BDV) p40 were detected in 34 (42-5 per cent) of the 80 cats. Seventy-three per cent of the sera which were positive for FIV and 26 per cent of the sera which were negative for FIV had antibodies to BDV. There was no difference in the percentage of sera which were positive for BDV between the cats that were positive or negative for FeLV. Three of the cats had neurological disease and two of these had antibodies to BDV. Six sera with low, medium or high optical densities (ODS) by ELISA were analysed by Western blotting. Only the sera with medium and high ODS reacted specifically with p40 at a dilution of 1 in 1,000.     

A comparative study of a new rapid and one-step test for the detection of parvovirus in faeces from dogs, cats and mink

A one-step immunochromatographic test, based on the use of monoclonal antibodies, was developed for the detection of canine parvovirus (CPV) in dog faeces. In addition to canine parvovirus the test can also be used for the diagnosis of infections with viruses causing parvovirus enteritis in cats (feline panleukopenia virus) and mink (mink enteritis virus). Four hundred and forty-three faecal samples were evaluated by comparative testing between this one-step test and three different enzyme-linked immunosorbent assays (ELISA) in Sweden, Denmark and The Netherlands. The result of the evaluation showed an overall relative sensitivity and specificity of 95.8 and 99.7%, respectively. Furthermore, the comparative testing of 83 dog samples in Germany between the one-step test and an immune electron microscopy (IEM) agreed to 85.5%. The sensitivity and specificity were 83.9 and 88.9%, respectively. These results show that the one-step test is a rapid, simple, reproducible and sensitive diagnostic test for the detection of parvovirus in faecal samples of dogs, cats and mink.     

Serologic survey of domestic felids in the Petén region of Guatemala.

Blood samples were analyzed from 30 domestic cats (Felis domesticus) from the Petén region of Guatemala to determine the seroprevalence of common pathogens that may pose a potential risk to native wild felids. Eight of the cats had been vaccinated previously; however, owners were unable to fully describe the type of vaccine and date of administration. In addition, blood samples were obtained from two captive margays (Leopardus wiedii). Samples were tested for antibodies to feline immunodeficiency virus, Dirofilaria immitis, feline panleukopenia virus, feline herpesvirus, feline coronavirus, canine distemper virus, and Toxoplasma gondii and for feline leukemia virus (FeLV) antigen. Fifty percent or more of the cats sampled were seropositive for feline herpesvirus (22 of 30), feline panleukopenia (15 of 30), and T. gondii (16 of 30). Five cats were positive for FeLV antigen. Both margays were seropositive for feline coronavirus and one was strongly seropositive to T. gondii. All animals were seronegative for D. immitis. This survey provides preliminary information about feline diseases endemic to the Petén region.     

Epizootiological investigations of canine distemper virus in free-ranging carnivores from Germany

Canine distemper virus (CDV) infects a broad range of carnivores. To assess whether wild carnivores may play a role in the epidemiology of CDV in domestic dogs in Germany, the seroprevalence of CDV was determined. In sera from red foxes (30 of 591 (5%)) and stone martens (2 of 10 (20%)) antiviral antibodies were detected using a neutralization assay, whereas sera of raccoons, two mink, one pine marten and one raccoon dog were negative. In foxes, there was a significantly higher prevalence in urban and suburban compared to rural regions. When testing lung and spleen tissue samples (fox, badger, stone marten, polecat, raccoon dog) 13 of 253 (5.1%) foxes, 2 of 13 (15.4%) stone martens and 2 of 6 (33%) badgers were virus positive using RT-PCR. Phylogenetic analysis based on partial sequences of the F gene revealed a distinct relatedness to canine CDV isolates. Together, the data support the concept of transmission of CDV between domestic dogs and wild carnivores.