Prevalence of antibodies against feline panleukopenia virus in client-owned cats in Southern Germany

Feline panleukopenia is a frequent and commonly fatal disease of cats. Recent published studies have raised suspicions that some cats fail to develop antibodies after vaccination. The purpose of this study was to assess the prevalence of antibodies against feline panleukopenia virus (FPV) in cats in Southern Germany, and to identify factors that are associated with a lack of antibodies. In total, 350 cats presented to the Clinic of Small Animal Medicine, Ludwig-Maximilians-Universitaet were randomly included in the study. Information regarding signalment, origin, environment, lifestyle, housing conditions, health status, chronic diseases, glucocorticoid therapy, and vaccination status were collected. Antibodies were detected by haemagglutination inhibition test. Asymptomatic chi-squared tests and univariable logistic regression were used to investigate associations between a lack of antibodies and the different variables. Associations determined to be statistically significant at P < 0.1 were verified by a multivariable logistic regression analysis.Of the 350 cats, 103 (29.4%) had no antibodies against FPV. Chronic kidney disease, neoplasia, glucocorticoid therapy, and vaccination status were significantly associated with a lack of antibodies. The cats with no antibodies were likely to have inadequate immunity against panleukopenia and those with chronic diseases or receiving glucocorticoids were less likely to be protected.     

Frequency and significance of feline leukemia virus infection in necropsied cats

Feline leukemia virus (FeLV) infection was diagnosed immunohistologically on paraffin-embedded tissues obtained from 1,095 necropsied cats. Significant association of FeLV infection was demonstrated by chi 2 and Fisher's tests with various conditions and diseases (ie, anemia, tumors of the leukemia/lymphoma complex, feline infectious peritonitis, bacterial infections, emaciation, FeLV-associated enteritis, lymphatic hyperplasia, and hemorrhage). Unexpected findings associated with FeLV infection were icterus, several types of hepatitis, and liver degeneration. A negative association with FeLV infection was found for most parasitic and viral infections, including feline panleukopenia. Neither positive nor negative associations were established for FeLV infection and most forms of nephritis, including severe glomerulonephritis. Feline leukemia virus-infected cats were significantly (Kruskal-Wallis test) older than were FeLV-negative cats with the same nonneoplastic FeLV-associated diseases.     

Prevalence and sequelae of feline leukemia virus infection in laboratory cats

Over a 4-year period, 1,683 pound-source cats received at a research institution were screened for feline leukemia virus (FeLV) infection, using an indirect fluorescent antibody test. Viremia was detected in 83 of the cats, for a prevalence of 4.9%. During this period, FeLV infection was detected in 5 kittens on a research project; lymphoma or anemia developed 6 to 17 months after the infections were detected. It was concluded that apparently healthy cats infected with FeLV may not be appropriate for some biomedical research projects.     

Cyclic hematopoiesis associated with feline leukemia virus infection in two cats

Cyclic oscillations in the numbers of blood elements were detected in 2 cats with FeLV infection. Periodic neutropenia, followed by a return to normal neutrophil numbers, was detected in both cats. The mean cycle duration was 11.8 days, with a range of 8 to 14 days. Just before the return of normal neutrophil numbers, monocytosis developed. In 1 cat, cyclic variations in the number of reticulocytes and platelets also were detected. Bone marrow aspirates obtained during periods of neutropenia had a predominance of progranulocytes in the myeloid cell line. myeloid hyperplasia, with numerous segmented neutrophils, was seen in bone marrow aspirates obtained during periods of normal neutrophil numbers. Oral administration of prednisolone resulted in cessation of the cyclic oscillations of blood elements in 1 cat. Cyclic hematopoiesis appeared to be another non-neoplastic manifestation of FeLV infection.     

Prevalence of feline leukemia virus infection and serum antibodies against feline immunodeficiency virus in unowned free-roaming cats

OBJECTIVE: To determine prevalence of FeLV infection and serum antibodies against feline immunodeficiency virus (FIV) in unowned free-roaming cats. DESIGN: Cross-sectional serologic survey. ANIMALS: 733 unowned free-roaming cats in Raleigh, NC, and 1,143 unowned free-roaming cats in Gainesville, Fla. RESULTS: In Raleigh, overall prevalence of FeLV infection was 5.3%, and overall seroprevalence for FIV was 2.3%. In Gainesville, overall prevalence of FeLV infection was 3.7%, and overall seroprevalence for FIV was 4.3%. Overall, FeLV prevalence was 4.3%, and seroprevalence for FIV was 3.5%. Prevalence of FeLV infection was not significantly different between males (4.9%) and females (3.8%), although seroprevalence for FIV was significantly higher in male cats (6.3%) than in female cats (1.5%). CONCLUSIONS AND CLINICAL RELEVANCE: Prevalence of FeLV infection and seroprevalence for FIV in unowned free-roaming cats in Raleigh and Gainesville are similar to prevalence rates reported for owned cats in the United States. Male cats are at increased risk for exposure to FIV, compared with female cats.     

Prevalence of feline leukemia virus infection in domestic cats in Rio de Janeiro

Peripheral blood smears of 1094 domestic cats were collected and tested by indirect immunofluorescence antibody assay for p27 antigen in cells to study the prevalence and risk factors for feline leukemia virus (FeLV) in the state of Rio de Janeiro. Sex, age, breed, outdoor access, neutering status, type of habitation (household, shelter, veterinary clinics and other places), number of household cats and clinical signs were registered on a form. Among the tested samples, 11.52% were positive. Risk factors for FeLV infection included outdoor access, age range between 1 and 5 years old, and cohabitation with numerous cats.     

Diseases associated with spontaneous feline leukemia virus (FeLV) infection in cats

More than 2000 cats sent for necropsy in order to provide a diagnosis were investigated immunohistologically using paraffin sections for the presence of a persistent infection with feline leukemia virus (FeLV). The spectrum of neoplastic and non-neoplastic diseases associated significantly with FeLV infection was determined statistically. Three-quarters of the cats with persistent FeLV infections died of non-neoplastic diseases and about 23% died of tumors, nearly exclusively those of the leukemia/lymphoma disease complex. A strong association with liver degeneration, icterus and a FeLV-associated enteritis was found in addition to the known association with non-neoplastic diseases and conditions such as anemia, bacterial secondary infections and respiratory tract inflammations due to the immunosuppressive effect of FeLV, hemorrhages and feline infectious peritonitis. Surprisingly, diseases and conditions like feline infectious panleukopenia, enteritis (of other types than FeLV-associated enteritis and feline infectious panleukopenia), glomerulonephritis, uremia and hemorrhagic cystitis were not associated with persistent FeLV infection. Another unexpected finding was that most pathogenic infectious agents demonstrated in the cats were not FeLV-associated either. Thus, immunosuppression due to FeLV infection seems to make the animals susceptible to certain pathogenic infectious agents, but not to the majority.     

Immunologic profiles of cats with persistent, naturally acquired feline leukemia virus infection

Several immunologic responses were measured in 13 healthy cats with naturally acquired, persistent feline leukemia virus (FeLV) viremia from 4 multiple-cat households and were compared with responses from 28 of their healthy, non-FeLV-viremic housemates. Significant differences (P = less than 0.05) were not observed between results of FeLV-viremic and nonviremic cats for peripheral blood leukocyte or lymphocyte count, percentage of peripheral blood mononuclear cells able to form rosettes with guinea pig RBC or with antibody- and complement-coated sheep RBC, lymphocyte proliferative response to concanavalin A or pokeweed mitogen, or serum immunoglobulin G concentration. Seemingly, persistent FeLV viremia, when naturally acquired, may exist for some time without lymphopenia or a marked loss of mitogen-induced lymphocyte proliferation.     

Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in North America and risk factors for seropositivity

OBJECTIVE: To determine seroprevalence of FeLV and FIV infection among cats in North America and risk factors for seropositivity. DESIGN: Prospective cross-sectional survey. ANIMALS: 18,038 cats tested at 345 veterinary clinics (n=9,970) and 145 animal shelters (8,068) between August and November 2004. PROCEDURE: Cats were tested with a point-of-care ELISA for FeLV antigen and FIV antibody. A multivariable random effects logistic regression model was used to identify risk factors significantly associated with seropositivity while accounting for clinic-to-clinic (or shelter) variability. RESULTS: 409 (2.3%) cats were seropositive for FeLV antigen, and 446 (2.5%) cats were seropositive for FIV antibody; 58 (0.3%) cats were seropositive for infection with both viruses. Multivariable analysis indicated that age, sex, health status, and cat lifestyle and source were significantly associated with risk of seropositivity, with adults more likely to be seropositive than juveniles (adjusted odds ratios [ORs], 2.5 and 2.05 for FeLV and FIV seropositivity, respectively), sexually intact adult males more likely to be seropositive than sexually intact adult females (adjusted ORs, 2.4 and 4.66), and outdoor cats that were sick at the time of testing more likely to be seropositive than healthy indoor cats (adjusted ORs, 8.89 and 11.3). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that certain characteristics, such as age, sex, health status, and lifestyle, are associated with risk of FeLV and FIV seropositivity among cats in North America. However, cats in all categories were found to be at risk for infection, and current guidelines to test all cats at the time of acquisition and again during illness should be followed.     

A review of feline leukemia virus and feline immunodeficiency virus seroprevalence in cats in Canada

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are common and important infectious diseases of cats in Canada. Prevalence data are necessary to define prophylactic, management, and therapeutic measures for stray, feral and owned cats. Recently, comprehensive data on the seroprevalence of retrovirus infections of cats in Canada have become available and are reviewed. Further investigation into geographic variations in retrovirus seroprevalence within Canada is warranted, and may provide information to improve recommendations for testing and prevention. As well, more information is needed on FIV subtypes in Canada to improve diagnostics and vaccines, as well as to provide information on disease outcomes.     

Development of the immunofluorescent antibody test for detection of feline leukemia virus infection in cats.

Studies of the immunodetection of various microorganisms by various assay systems indicated that the most specific and sensitive assays are immunofluorescence, radioimmunoassay, and immunoblot analysis (western blot), followed by sensitive but less specific ELISA and agglutination assays and, finally, by even less sensitive but very specific virus isolation and double immunodiffusion techniques. The first test for the clinical detection of FeLV infection in pet cats was the immunofluorescent antibody (IFA) test, which was introduced in 1972. The FeLV test is used for detection for FeLV infection and not as a test for leukemia or any other feline disease. The IFA test was compared with an immunodiffusion (ID) test and with tissue culture isolation (TCI) of the virus in 26 cats to establish a standard for FeLV tests. Excellent correlation was observed between the IFA and the ID tests (100%).     

Prevalence of feline leukemia virus and antibodies to feline immunodeficiency virus in cats in Norway.

Serum samples from 224 Norwegian cats were analyzed for the presence of feline leukemia virus (FeLV) p27 common core antigen, and for antibodies to feline immunodeficiency virus (FIV). Ninety specimens originated from the serum bank at the central referral clinic at the Norwegian College of Veterinary Medicine, which had been collected during the years 1983-1989; 67 sera were submitted from veterinarian practitioners; while 67 sera originated from cats presented for euthanasia. The cats were classified into one "healthy" and one "sick" group. Only 2.2% of sick cats and 1.2% of healthy cats showed FeLV antigenemia, a finding which is lower than which has been reported from many other countries. The prevalence of FIV antibodies was 10.1% in sick cats and 5.9% in healthy cats. Antibodies to FIV was most prevalent in male cats (14.7%) than in female cats (2.1%), and more prevalent among domestic cats (12.0%) compared to pedigree cats (2.4%). Antibodies to FIV in the cats demonstrated increasing prevalence with increasing age. It may be concluded that FeLV causes minor problems in Norwegian cats, while FIV is present in a similar prevalence to what is reported from other countries.     

Husbandry practices for cats infected with feline leukemia virus or feline immunodeficiency virus.

Cats that are persistently infected with FeLV or feline immunodeficiency virus but are not manifesting clinical signs of disease are at risk for developing a wide variety of immunosuppressive, degenerative, or neoplastic diseases. Infected cats should be isolated to prevent transmission of virus to healthy cats, and to protect infected cats from exposure to pathogens that can cause life-threatening secondary infections. Iatrogenic transmission of virus from infected cats in isolation to healthy cats may be reduced by strict adherence to handling, sanitation, and disinfection procedures. Husbandry practices that may delay the complications of infection include regular vaccination, provision of high-quality diets, reduction of stress, control of endoparasites and ectoparasites, and early and aggressive treatment of clinical signs of disease.     

Two outbreaks of virulent systemic feline calicivirus infection in cats in Germany

Over the last years, several outbreaks of virulent systemic feline calicivirus (VS-FCV) infection have been described in the USA and several European countries. The paper describes two outbreaks of VS-FCV infection in cats in Germany. Data concerning clinical, laboratory, and histopathological features ofVS-FCV infection were collected from two outbreaks affecting 55 and 4 cats, respectively. Presence of feline calicivirus was confirmed by PCR followed by sequencing of the PCR-products. Clinical signs were variable, including severe upper respiratory tract infection, dyspnoea, oral and footpad ulceration, facial oedema, enteritis, pneumonia, bleeding disorder, high fever, and icterus. Both outbreaks were characterized by a high mortality rate.The present report describes the first documented outbreaks of VS-FCV infection in cats in Germany. Clinical and histopathological features are comparable to outbreaks described in the USA and Europe. However, phylogenetic analysis of the virus genome suggests that virus strains involved in these outbreaks were different from each other and from virulent strains isolated before, confirming the known genetic variability of FCV.     

Clinical aspects of feline immunodeficiency and feline leukemia virus infection

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are retroviruses with a global impact on the health of domestic cats. The two viruses differ in their potential to cause disease. FIV can cause an acquired immunodeficiency syndrome that increases the risk of developing opportunistic infections, neurological diseases, and tumors. In most naturally infected cats, however, FIV itself does not cause severe clinical signs, and FIV-infected cats may live many years without any health problems. FeLV is more pathogenic, and was long considered to be responsible for more clinical syndromes than any other agent in cats. FeLV can cause tumors (mainly lymphoma), bone marrow suppression syndromes (mainly anemia) and lead to secondary infectious diseases caused by suppressive effects of the virus on bone marrow and the immune system. Today, FeLV is less important as a deadly infectious agent as in the last 20 years prevalence has been decreasing in most countries.     

Biological effects of staphylococcal protein A immunotherapy in cats with induced feline leukemia virus infection.

Biological effects of staphylococcal protein A (SPA) immunotherapy were studied in 5 viremic and 6 nonviremic cats with induced FeLV infection and in 6 control cats. The SPA therapy neither reversed FeLV viremia nor resulted in consistent improvement in humoral immune responses to FeLV antigens. However, SPA immunotherapy induced a proliferative response in bone marrow granulocytic lineage, possibly resulting in expression of FeLV-free mature neutrophils in the blood. Seemingly, viral burden and chemiluminescent responses were reversed in viremic cats during SPA immunotherapy.     

Epizootiologic association between feline immunodeficiency virus infection and feline leukemia virus seropositivity

Five hundred twenty-one feline serum samples submitted to the Texas Veterinary Medical Diagnostic Laboratory between Nov 1, 1988, and Jan 31, 1989 were tested for antibody to feline immunodeficiency virus (FIV) by use of an ELISA. The prevalence of FIV infection in this population was 11.3% (95% confidence interval: 8.6 to 14.0%). Serologic test results for FeLV were available for 156 of the 521 cats. A significant (P = 0.008) association between FIV infection and FeLV seropositivity was observed; FeLV-positive cats were nearly 4 times more likely to be seropositive for FIV than were FeLV-negative cats. The association remained statistically significant (P = 0.021) after adjusting for age and gender, using multiple-logistic regression analysis.