FIV Antibody Research Articles

Progressive and regressive infection with feline leukemia virus (FeLV) in cats in southern Brazil: Prevalence, risk factors associated, clinical and hematologic alterations.

Enzyme-linked immunosorbent assay (ELISA) for viral antigen is commonly used for the diagnosis of progressive feline leukemia virus (FeLV) infection but is not able to determine the true prevalence of infection when used as the sole test. Additional testing to detect proviral DNA will identify regressive (antigen negative) FeLV infections as well as progressive infections. Therefore, this study aimed to determine the prevalence of progressive and regressive FeLV infection, outcome-associated factors, and hematologic changes. A cross-sectional study was performed on 384 cats selected from routine hospital care. Blood samples were subjected to complete blood count, ELISA for FeLV antigen and FIV antibody, and nested PCR amplifying the U3- LTR region and gag gene, which are conserved in most exogenous FeLV. The prevalence of FeLV infection was 45.6% (CI95% 40.6-50.6%). The prevalence of progressive infection (FeLV+P) was 34.4% (CI95% 29.6-39.1%), that of regressive infection (FeLV+R) was 10.4% (CI95% 7.4-13.4%), for discordant but positive results 0.8% (CI95% 0.75-0.84%), for FeLV+P coinfected with FIV 2.6% (CI95% 1.2-4.0%), and FeLV+R coinfected with FIV 1.5% (CI95% 0.3-2.7%). Male cats were three times more likely to be in the FeLV+P group. Cats coinfected with FIV were 4.8 times more likely to belong to the FeLV+R group. In the FeLV+P group, the main clinical changes were lymphoma (38.5%), anemia (24.4%), leukemia (17.9%), concomitant infections (15.4%), and feline chronic gingivostomatitis - FCGS (3.8%). In the FeLV+R group, the main clinical signs were anemia (45.4%), leukemia (18.2%), concomitant infections (18.2%), lymphoma (9.1%), and FCGS (9.1%). Cats in the FeLV+P and FeLV+R groups showed mainly thrombocytopenia (56.6% and 38.2%), non-regenerative anemia (32.8% and 23.5%), and lymphopenia (33.6% and 20.6%). Hemoglobin concentration, packed cell volume (PCV), platelet count, lymphocytes, and eosinophils in the FeLV+P and FeLV+R groups had lower medians than the control group (FeLV/FIV-uninfected, healthy). Erythrocyte and eosinophil counts were statistically different among the three groups, with the medians of the FeLV+P and FeLV+R groups being lower than those of the control group. In addition, the median PCV and band neutrophil counts were higher in FeLV+P than in FeLV+R. Our results show a high prevalence of FeLV, different factors associated with the course of infection, and more frequent and severe hematologic changes in progressive infections compared with regressive infections.

Seroepidemiological and Clinicopathological Study of Feline Coronavirus (FCoV) and Feline Infectious Peritonitis (FIP), Could Guide to SARS-CoV-2 (COVID-19) in ‘One Health’ Approach

Feline coronavirus 176 seropositive cats were examined in 2014-2019. Seroepidemiological, serological, clinical, haematological and biochemical data were analysed with IBM-SPSS Statistics. Clinicopathological signs were typical with enteric form in 125 cats (71%) and FIPV in 51 cats (29%). Fever, depression, dullness, weight loss, vomitus, growth retardation, diarrhoea, ocular and neurological symptoms were findings. 40 cats (23%) were died, 17 had pleural effusion, 19 had ascites, and 16 Rivalta tests were positive. Post-mortem FIP confirmation was at 8 cats. Of the FCoV seropositive cats, 22 (12.5%) had FIV antibodies, 7 (3.9%) were positive for FLV antigens, 2 (1.1%) were positive for FCoV, FIV and FLV, and 2 (1.1%) were FmopV RNA positive. FCoV, canine enteric CoV, human CoV-229E and CoV-NL63 belong to Alphacoronavirus, and canine respiratory CoV, Human CoV-OC43, CoV-HKU1, SARS, MERS and COVID-19 belong to Betacoronavirus genus, originated from bat gene pool and is of animal origin cause zoonotic infections. Covid-19 pathogenesis is not fully understood and data‘s focused on case fatality rates. Covid-19 was reported as anthropozoonosis infecting cats, dogs, tigers and lions. The panthropism risk should be investigated. In particular, the clinicopathology and treatment modalities of feline coronavirus and COVID-19 infections are having similarities such as GS-441524 as the main metabolite of remdesivir prodrug and dexamethazone responses, and both can cause resident and persistent infections in many organs, including the eyes and brain, of varying severity. The obtained data have been evaluated in the 'One Health' approach to better understand the aetiology, pathogenesis and clinicopathology of coronavirus infections, and presenting valuable findings to help the control of COVID-19 epidemic. Veterinary medicine will help to multidisciplinary collaboration to develop effective vaccines and drugs with many years of coronavirus experiences.

Seroepidemiological and Clinicopathological Study of Feline Coronavirus (FCoV) and Feline Infectious Peritonitis (FIP), Could Guide to COVID-19 in ‘One Health’ Approach.

Feline coronavirus 176 seropositive cats were examined in 2014-2019. Seroepidemiological, serological, clinical, haematological and biochemical data’s were analysed with IBM-SPSS Statistics. Clinicopathological signs were typical with enteric form in 125 cats (71%) and FIPV in 51 cats (29%). Fever, depression, dullness, weight loss, vomitus, growth retardation, diarrhoea, ocular and neurological symptoms were findings. 40 cats (23%) were died, 17 had pleural effusion, 19 had ascites, and 16 Rivalta tests were positive. Post-mortem FIP confirmation was at 8 cats. Amongst FCoV seropositive cats, 22 (12.5%) had FIV antibodies, 7 (3.9%) FLV antigens, 2 (1.1%) positive for FCoV, FIV and FLV and 2 (1.1%) were FmopV RNA positive. FCoV, canine enteric CoV, human CoV-229E and CoV-NL63 belong to Alphacoronavirus, and canine respiratory CoV, Human CoV-OC43, CoV-HKU1, SARS, MERS and COVID-19 belong to Betacoronavirus genus, originated from bat gene pool and cause zoonotic infections. Covid-19 pathogenesis is not fully understood and data’s focused on case fatality rates. Covid-19 was reported as anthropozoonosis infecting cats, dogs, tigers and lions. The panthropism risk should be investigated. In particular, feline coronavirus and COVID-19 pathogenesis is resemblance and both may cause multiple organ-located and persistent infections, including eyes and brain, of varying severity. The obtained data have been evaluated in the 'One Health' approach to better understand the etiology, pathogenesis and clinicopathology of coronavirus infections, and presenting valuable findings to help the control of COVID-19 epidemic. Veterinary medicine will help to multidisciplinary collaboration to develop effective vaccines and drugs with many years of coronavirus experiences.

Occurrence of feline immunodeficiency virus and feline leukaemia virus in Maputo city and province, Mozambique: a pilot study.

ObjectivesFeline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) are immunosuppressive viruses in cats that increase their susceptibility to zoonotic pathogens. This study aimed to determine the occurrence of one or both viruses, the risk factors associated with infection, and to develop further recommendations.MethodsThis was a cross-sectional study conducted at the Veterinary Faculty of Eduardo Mondlane University, Mozambique, between March and December 2017, in 145 cats. From each of 145 cats, we took 1.5 ml of blood by jugular puncture for detection of antibodies to FIV and FeLV antigens in whole blood using a commercial test kit, DFV Test FeLV/FIV.ResultsWe found an overall prevalence of 11.0% and 14.5% for FIV antibodies and FeLV antigens, respectively, with four (2.8%) cats coinfected by both pathogens. Male cats were more likely to be infected with FIV (odds ratio [OR] 1.1, 95% confidence interval [CI] 0.3–4.0) compared with female cats. Clinically ill cats were more likely to have a positive result for FeLV antigen infection (OR 18.8, 95% CI 5.2–68.3). Moreover, cats living in suburban areas have a greater chance of a positive result for FeLV infection (OR 3.7, 95% CI 1.4–9.6) compared with cats living in urban areas.Conclusions and relevanceFIV and FeLV occur in cats from Maputo and possibly all over the country. Further studies should be conducted in Mozambique and other African countries to define the burden of both pathogens in cats, coinfection with other zoonotic pathogens and the possible role played by the cats on the transmission of zoonotic and opportunistic diseases to humans.

Lack of contact with feline immunodeficiency virus in the Iberian lynx

The feline immunodeficiency virus is a lentivirus that infects felids worldwide. It may induce a profound immunodysfunction in domestic cats, while wild felids seem less prone to disease. During routine health check monitoring of the endangered Iberian lynx populations, 465 samples from 311 individuals were tested between 2004 and 2017. All of them tested negative for molecular detection of provirus. Similarly, only one adult male tested positive for FIV antibodies by means of both ELISA and immunoblot. This lack of contact contrasts with the seropositivity detected in other wild felid species, mainly in Africa and the Americas, and confirms that the Iberian Peninsula is not an FIV-endemic area. To prevent a potential disease spreading, the seropositive individual was kept captive for 22 months and remained FIV antibody-positive and antigen-negative during this period. After evaluating potential risks, it was re-introduced to nature. Among other possibilities, this Iberian lynx could have cleared an FIV infection. Moreover, we found 0% qPCR prevalence in 84 feral cats sampled in the area between 2012 and 2016.

Seroprevalence of heartworm infection, risk factors for seropositivity, and frequency of prescribing heartworm preventives for cats in the United States and Canada.

OBJECTIVE To determine the seroprevalence of heartworm infection, risk factors for seropositivity, and frequency of prescribing heartworm preventives for cats. DESIGN Prospective cross-sectional study. ANIMALS 34,975 cats from 1,353 veterinary clinics (n = 26,707) and 125 animal shelters (8,268) in the United States and Canada. PROCEDURES Blood samples were collected from all cats and tested with a point-of-care ELISA for Dirofilaria immitis antigen, FeLV antigen, and FIV antibody. Results were compared among geographic regions and various cat groupings. RESULTS Seropositivity for heartworm antigen in cats was identified in 35 states but not in Canada; overall seroprevalence in the United States was 0.4%. Seroprevalence of heartworm infection was highest in the southern United States. A 3-fold increase in the proportion of seropositive cats was identified for those with (vs without) outdoor access, and a 2.5-fold increase was identified for cats that were unhealthy (vs healthy) when tested. Seroprevalence was 0.3% in healthy cats, 0.7% in cats with oral disease, 0.9% in cats with abscesses or bite wounds, and 1.0% in cats with respiratory disease. Coinfection with a retrovirus increased the risk of heartworm infection. Heartworm preventives were prescribed for only 12.6% of cats at testing, and prescribing was more common in regions with a higher seroprevalence. CONCLUSIONS AND CLINICAL RELEVANCE At an estimated prevalence of 0.4%, hundreds of thousands of cats in the United States are likely infected with heartworms. Given the difficulty in diagnosing infection at all clinically relevant parasite stages and lack of curative treatment options, efforts should be increased to ensure all cats receive heartworm preventives.

Phylogenetic characterisation of feline immunodeficiency virus in naturally infected cats in Croatia indicates additional heterogeneity of subtype B in Europe.

This study was performed on 29 domestic cats with a variety of clinical signs, possibly related to FIV infection. Blood samples were tested by a rapid immunochromatographic (ICA) procedure for detection of FIV antibodies. Subsequently, polymerase chain reaction (PCR) was performed to amplify a portion of the proviral gag gene. All 11 positive PCR products were sequenced and compared with previously reported FIV sequences. Croatian proviral isolates that could be amplified were clustered within subtype B, and additional heterogeneity was confirmed by the formation of three separate clusters. Phylogenetic analysis of circulating strains in Croatia and in southeast Europe is necessary to improve diagnostic methods and selection of the appropriate vaccinal strains.

Increased Serum Alkaline Phosphatase in a FeLV-Positive Cat

Background: Feline Leukemia Virus (FeLV) is an oncogenic virus that usually invades bone marrow causing non-regenerative anemia and thrombocytopenia. In FeLV positive cats, the myeloid leukemia is characterized by intense proliferation of blast cells in a bone marrow with myeloid precursor predominance and several malignancies degree. The leukocyte alkaline phosphatase is found secondary granules of mature neutrophils of humans, horses and cows but not in dogs and cats,which demonstrate the enzyme activity in myeloblast and promyeloblasts cells. In this case is describing a FeLV-positive case with leukemic disorder accompanied by extremely high levels of serum alkaline phosphatase.Case: A 8-year-old castrated male Domestic Short Hair cat with a 3-month history of convulsions, pica, vomits, lethargy, hypodipsia and anorexia was examined and showed mild dehydration, severe jaundice and hyperpnoea. Laboratory results evidenced severe normocytic hypochromic non-regenerative anemia, moderated leukocytosis with severe degenerativeneutrophil left shift, moderated lymphocytosis and severe thrombocytopenia. Serum biochemical profle showed mild hyperalbuminemia, moderated increment in alanine transaminase and severe increment in alkaline phosphatese. The cat waspositive for ELISA point of care FeLV antigen and negative for FIV antibodies. Urinalysis revealed moderated bilirubinuria and proteinuria. The bone marrow cytology showed high cellularity, increased of M:E ratio, rare megakaryocyte lineage, erythroid hypoplasia, myeloid hyperplasia with blast excess and dysgranulopoiesis.Discussion: FeLV is a virus that usually causes cytopenias and in this case this was well evidenced through a severe non regenerative anemia and thrombocytopenia. Generally, anemia is a non-neoplastic complication of FeLV mainly related to suppressive effects hematopoietic and stromal cells of the bone marrow. Nevertheless, in this case, the anemia also maybe attributable to the observed acute myeloid leukemia. Neutrophilia is an uncommon fnding in FeLV-infected cats, even more with the severe degenerative left shift as in the present case. This fnding could be associated to a myeloid hyperplasia. Some biochemical alterations, as hyperalbuminemia and increment in values of serum ALT could be explained by clinical observations like dehydration and some degree of hepatic enlargement, respectively. However, the excessive value forserum alkaline phosphatase activity is an unpublished fnding in cats. In humans high levels of ALP has been associated with neutrophilia and it is quite likely that a great amount of degenerative neutrophils may contribute for high leakage of ALP than in other circumstances of neutrophilia. This is the frst report of a FeLV-positive cat exhibiting extremely high serum values of the enzyme ALP, possibly attributable to acute myeloid leukemia.Keywords: neutrophilia, cytopenia, non-regenerative anemia, acute leukemia.

Animal Behavior Case of the Month

The patient was a 2.5-year-old 5-kg (11-lb) castrated male domestic shorthair cat. History The patient was housed exclusively indoors. The family included 2 parents and their 2 daughters (ages, 7 and 12), and there were no other animals in the house. The cat had been obtained from a local animal shelter when it was 10 weeks old; the history of the cat before adoption was unknown. The patient had been neutered when it was 6 months old. The cat had negative results of FIV antibody and FeLV antigen tests, which had been performed when it was 6 months old. A short time after the adoption, the family noticed that the cat seemed to be timid and easily frightened by loud noises (eg, sneezing or laughter) and sudden movements (eg, standing up from a chair) of people. The cat ran from the front door when it was opened or from a room when a person entered it. Two and a half years after adoption, the cat was intolerant of holding or petting by family members for periods longer than a few seconds. When the patient was frightened and nervous, it had its ears back and pupils dilated and ran to hide under furniture. When the cat could not escape from a room, it paced and seemed to look for a door. The cat had always slept on the oldest daughter’s bed during each night. The cat tended to stay in that daughter’s room more often than it stayed in other rooms; however, the cat typically remained > 3 feet from her, at which distance the cat was calm and relaxed. The cat never had aggressive behavior or inappropriate elimination when it was frightened, such as at a veterinary clinic. Members of the family always used quiet voices and slow movements near the cat. A pheromone diffuser a was used to reduce the fearful attitude of the cat. These interventions did not have an effect on the cat’s behavior. Approximately 1 year before the behavioral evaluation, the primary care veterinarian had prescribed an anxiolytic medication (alprazolam [0.1 mg/ kg {0.045 mg/lb}, PO, q 12 h]) for the cat because of an owners’ request. After the cat received the first dose of

Prevalence of infectious diseases in cats and dogs rescued following Hurricane Katrina

To determine the prevalence of infectious diseases of animal and zoonotic importance in cats and dogs rescued and transferred from the Gulf Coast region following Hurricane Katrina. Cross-sectional study. 414 dogs and 56 cats rescued and transferred from the Gulf Coast region within 4 months after the hurricane. EDTA-anticoagulated blood and serum samples were tested via PCR and serologic assays for infectious diseases. In dogs, prevalence was highest for anti-West Nile virus (WNV) antibodies (218/390 [55.9%]), Dirofilaria immitis antigen (195/400 [48.8%]), anti-Toxoplasma gondii antibodies (92/366 [25.1%]), and hemotropic mycoplasma DNA (40/345 [11.9%]). The DNA of Bartonella spp, Ehrlichia spp, or Babesia spp or anti-canine influenza virus antibodies were identified in < 2% of dogs. In cats, prevalence was highest for antibodies against Bartonella spp and DNA of Bartonella spp combined (49/55 [89.1 %]), anti-T gondii antibodies (13/55 [23.6%]), hemotropic mycoplasma DNA (5/47 [10.6%]), anti-WNV antibodies (5/48 [10.4%]), D immitis antigen (4/50 [8.0%]), and anti-FIV antibodies (4/56 [7.1%]). A total of 308 (74.4%) dogs and 52 (92.9%) cats had evidence of previous or current vector-borne infections. Cats and dogs rescued from the disaster region had evidence of multiple infectious diseases. The dispersal of potentially infectious animals to other regions of North America where some infections were not typically found could have contributed to new geographic ranges for these organisms or to underdiagnosis in affected animals because of a low index of suspicion in regions with low disease prevalence.

Leishmania chagasi infection in cats with dermatologic lesions from an endemic area of visceral leishmaniosis in Brazil

Although dogs are considered the main domestic reservoirs for Visceral Leishmaniosis (VL), which is caused in the Americas by Leishmania chagasi, infected cats have also been recently found in endemic areas of several countries and became a public health concern. Accordingly, the purpose of this study was to evaluate cats with dermatologic lesions from an endemic area of VL and the natural infection of L. chagasi. A total of 55 cats were selected between April 2008 and November 2009 from two major animal shelters of Araçatuba, Southeastern Brazil. All cats underwent general and dermatologic examinations, followed by direct parasitological examination of lymphoid organs, immunosorbent assay (ELISA) and indirect immunofluorescence (IFAT). In addition, detection of amastigotes was performed by immunohistochemistry (IHC) in skin lesions of all cats. VL was diagnosed in 27/55 (49.1%) cats with dermatological problems. Amastigotes were found in lymphoid organs of 10/27 (37.0%) cats; serology of 14/27 (51.9%), 6/27 (22.2%) and 5/27 (18.5%) cats was positive for ELISA, IFAT and both, respectively. The IHC identified 9/27 (33.3%) cats; 5/27 (18.5%) were positive only for IHC and therefore increased the overall sensitivity. Specific FIV antibodies were found in 6/55 (10.9%) cats, of which 5/6 (83.3%) had leishmaniosis. Real time PCR followed by amplicon sequencing successfully confirmed L. chagasi infection. In conclusion, dermatological lesions in cats from endemic areas was highly associated to visceral leishmaniosis, and therefore skin IHC and differential diagnosis of LV should be always conducted in dermatological patients in such areas.

جستجوی آنتی بادی ویروس نقص سیستم ایمنی در گربه های ولگرد شهرستان اهواز، جنوب غرب ایران

The present study was performed to determine the prevalence of FIV in stray cat's population of Ahvaz different area. Serum samples were collected from 90 cats from 2005 to 2007. The studied cats were divided into two age groups ( 3 years) and based on clinical signs (such as lymphadenopathy, periodontal diseases, gingivitis, abscess and cashecsi) into two groups also. The results were analyzed using Fischer's exact test and Chi-square analysis. Prevalence to FIV antibodies in these cats was 15.55% (14 of 90) by means of ELISA Test Kit, indicating that this virus is present in the ecosystem. The infection had more prevalence in cats above 3 years (78.6%; 11 of 14) compared with cats less than 3 years (21.4%; 3 of 14). Statistical analysis showed significant difference between different age groups (P 0.05). Three out of 12 cases (25%) which had clinical signs and 11 out of 78 cases (14.1%) which hadn’t clinical signs were seropositive. There was no significant difference between the two groups also (P>0.05). This study showed that FIV exist among cat's population of Ahvaz area and separation of companion and stray cats is very important for prevention of disease transmission to companion cats.

Efficacy of HIV-1 and FIV subunit vaccines against FIV (132.3)

Abstract Defining the minimum essential vaccine components required for protective immunity to HIV and FIV remains a major challenge. A recent study reported that recombinant HIV-1 capsid p24 vaccines conferred cross-protection against FIV in cats. Current studies were performed to confirm this protection and identify other protective HIV/FIV proteins. Pathogen-free cats were immunized 3X with HIV p24 (CA), HIV p66 (reverse transcriptase RT), FIV p24, FIV p66, FIV p15 (matrix MA), or combination in adjuvant (plus LPS/IL-12), and were challenged 3 wk later with FIV. Infection was monitored by immunoblot for FIV antibodies, and by FIV RT and PCR tests of lymphoid cells. Cellular immunity was monitored by virus-specific IFN-γ ELISPOT and CFSE-based proliferation of T cells. Protection rates were 2/8 cats for HIV p24, 2/8 HIV p24+p66, 3/7 HIV p66, 1/8 FIV p24, 0/3 FIV p15, 2/7 FIV p24+p66, 5/7 FIV p66, 2/4 HIV p24+FIV p66, and 0/8 adjuvant or PBS. Vaccinated cats had strong IFN-γ and CD4/CD8-CFSE responses to HIV or FIV peptides, but developed no virus neutralizing antibodies. Combined protection rates for current and previous studies are 40/64 cats for HIV p24, 4/25 FIV p24, 5/7 FIV p66, 3/7 HIV p66, 0/3 FIV p15, 0/22 adjuvant, and 0/37 PBS. Thus, cross-protective immunity between HIV-1 and FIV is achievable, and selection of vaccine proteins and epitopes based on structural homology that risk viral fitness is an effective strategy.

Seroprevalences of feline leukemia virus and feline immunodeficiency virus in cats with abscesses or bite wounds and rate of veterinarian compliance with current guidelines for retrovirus testing

To determine the seroprevalences of and seroconversion rates for FeLV and FIV infection in cats treated for bite wounds and cutaneous abscesses and to evaluate compliance with recommendations to determine the retrovirus infection status of cats at acquisition and 60 days after a high-risk event. Prospective study. 967 cats from 134 veterinary practices in 30 states. Cats with bite wounds or abscesses were evaluated by use of a point-of-care immunoassay for blood-borne FeLV antigen and FIV antibody. Veterinarians were asked to retest cats approximately 60 days later to determine whether seronegative cats had seroconverted after injury. The combined FeLV-FIV status of only 96 (9.9%) cats was known prior to wound treatment. At the time of treatment, 187 (19.3%) cats were seropositive for 1 or both viruses. Age (adult), sex (male), history of cutaneous wounds, and outdoor access were significantly associated with seropositivity. At 73 of 134 (54.5%) veterinary practices, retesting of cats for retrovirus infection status was recommended to owners of 478 cats. Only 64 (13.4%) cats were retested; of these, 3 of 58 (5.2%) cats that were initially seronegative for FIV antibody seroconverted. A high proportion of cats with abscesses or bite wounds were seropositive for FeLV antigen or FIV antibody. Compliance with recommendations to test cats for retrovirus infection status at acquisition or after treatment for injury was low. The FeLV-FIV infection status of cats with potential fight wounds should be determined at time of treatment and again 60 days later.

Serological and molecular evidence of exposure to arthropod-borne organisms in cats from northeastern Spain

One hundred sixty-eight cat sera from Spain were tested for IgG antibodies to Rickettsia conorii ( Rc), Ehrlichia canis ( Ec), Anaplasma phagocytophilum ( Ap) and Bartonella henselae ( Bh) antigens using IFA and for FeLV antigen and FIV antibody by ELISA. For 47 whole blood samples, PCR testing was performed for Rickettsia, Ehrlichia and Bartonella. Seroprevalences were: Bh (71.4%), Rc (44%), Ec (11.3%), FeLV (8.5%), FIV (7.4%) and Ap (1.8%). Bh antibodies were associated with seroreactivity to both Ec and Rc antigens. FIV antibodies were associated with illness and cats older than 2 years. Bartonella henselae and B. clarridgeiae ( Bcl) DNA was amplified from seven and one sample, respectively.

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

To determine seroprevalence of FeLV and FIV infection among cats in North America and risk factors for seropositivity. Prospective cross-sectional survey. 18,038 cats tested at 345 veterinary clinics (n=9,970) and 145 animal shelters (8,068) between August and November 2004. 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. 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). 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.

Feline immunodeficiency virus vaccine: A rational paradigm for clinical decision-making

A veterinarian must take into consideration his/her responsibility to prevent disease when assessing the needs of a client's cat that is risk for FIV infection based on its established lifestyle. Cats infected with FIV have debilitated immune functions and exhibit a high level of chronic morbidity impacting on the animal's welfare and the owner's economic abilities to maintain the pet. Attempts to reduce the prevalence of FIV solely by advising clients to maintain their cats indoors has resulted in poor compliance and not impacted on a change in infection rates with outdoor cats. Therapeutics have not impacted on outcomes in infected animals. There has a need for a vaccine for high-risk cats. Options for vaccines that do not confound the current FIV antibody test have not been efficacious against a broad spectrum of isolates. Fel-O-Vax FIV, a conventional non-marker whole virus, has shown good efficacy against heterologous challenges. The intervention should be discussed with cat owners since the vaccine has a reasonable expectation of preventing FIV infection in cats at risk without undue safety issues. Veterinarians who do not initiate this dialogue with owners who have outdoor cats in an environment where 2.5% of cats in the USA are infected may be remiss in their professional responsibilities.

Disseminated Mycobacterium avium infection in young cats: overrepresentation of Abyssinian cats

Disseminated Mycobacterium avium-intracellulare complex (MAC) infection was diagnosed in 10 young cats (1-5 years of age) from Australia or North America between 1995 and 2004. A further two cats with disseminated mycobacteriosis (precise agent not identified) were recognised during this period. Of the 12, 10 were Abyssinian cats, one was a Somali cat and one was a domestic shorthair cat. None of the cats tested positive for either FeLV antigen or FIV antibody. The clinical course of these infections was indolent, with cats typically presenting for weight loss, initially in the face of polyphagia, with a chronicity of up to several months. Additional clinical features included lower respiratory tract signs and peripheral lymphadenomegaly. A marked diffuse interstitial pattern was evident in thoracic radiographs, even in cats without overt respiratory involvement. Hair clipped to perform diagnostic procedures tended to regrow slowly, if at all. Diagnosis was generally made by obtaining representative tissue specimens from mesenteric lymph nodes, liver or kidney at laparotomy, or from a popliteal lymph node. The primary antecedent event was most likely colonisation of either the alimentary or respiratory tract, followed by local invasion and eventual lymphatic and haematogenous dissemination. Nine cases were treated using combination therapy with agents effective for MAC infection in human patients. Two cats are still undergoing initial therapy and have responded. Of the remaining seven, all responded during long courses (5-14 months) of clarithromycin combined with either clofazimine or rifampicin, and a fluoroquinolone or doxycycline. Of these, three cats remain well (with durations between 2 months and 2 years following therapy); two developed recurrent disease (at 3 months and 2 years, respectively, following therapy) and have restarted therapy. The remaining two cats improved 1 year and 5 months, respectively, after diagnosis but ultimately succumbed. The two cats in which therapy was restarted have improved dramatically. Certain lines of Abyssinian and Somali cats likely suffer from a familial immunodeficiency that predisposes them to infection with slow-growing mycobacteria such as MAC.

Effect of vaccination against feline immunodeficiency virus on results of serologic testing in cats

To determine the effect of vaccination against FIV on results of serologic assays for FIV infection. Prospective clinical trial. 26 specific-pathogen-free cats, 102 laboratory-reared cats (42 unvaccinated and uninfected, 41 vaccinated and uninfected, and 19 infected with FIV), and 22 client-owned cats infected with FIV. To determine the onset and duration of anti-FIV antibody production in cats following vaccination with a whole-virus vaccine, serum was obtained from the 26 specific-pathogen-free cats prior to vaccination and weekly for 10 weeks, then monthly for 52 weeks, after vaccination; serum was tested for anti-FIV antibodies with lateral flow and microwell plate ELISAs. To determine the diagnostic performance of serologic assays for FIV infection, plasma from uninfected, unvaccinated cats; uninfected, vaccinated cats; and FIV-infected cats was tested for FIV antibodies with the 2 ELISAs, a western blot assay, and an immunofluorescence antibody assay and for FIV antigen with an ELISA. Anti-FIV antibodies were detected in all 26 vaccinated cats 1 year after vaccination. Sensitivity of the antibody assays for FIV infection was high (98% to 100%). Specificity was high in unvaccinated cats (90% to 100%) but poor in vaccinated cats (0% to 54%). None of the vaccinated or infected cats had detectable FIV antigen in plasma. Results suggest that vaccination against FIV causes false-positive results for at least 1 year with currently available serologic assays for FIV infection. Negative FIV antibody assay results are highly reliable for detection of uninfected cats, but positive results should be interpreted with caution.

Feline immunodeficiency virus status of Australian cats with lymphosarcoma.

To determine the FIV status of Australian cats with lymphosarcoma and relate this to patient characteristics, tumour characteristics (tissue involvement, histological grade and immunophenotype), haematological and serum biochemical values and FeLV status of affected cats. Prospective study of 101 client-owned cats with naturally-occurring lymphosarcoma. Western blot analysis, ELISA and immunochromatography were used to detect FIV antibodies in serum from cats with lymphosarcoma. On the basis of Western blot analysis (which was considered the most accurate method for determining FIV status), 50/101 (50%) of cats with naturally-occurring lymphosarcoma were positive for FIV antibodies. Of these 50 cats, 35 had tumours of B-cell phenotype, 13 had T-cell tumours and 2 had tumours classified as non-B/non-T. Tumours from eight of these FIV-positive cats contained FeLV gene sequences, including a 9-month-old cat with FeLV antigenaemia. Compared with FlV-negative cats with lymphosarcoma, FIV-positive cats were more likely to be domestic crossbreds (P = 0.004), male (P = 0.048) and have atypical (especially nasal) forms of lymphosarcoma (P = 0.09). Only 39 of 107 (36%) blood or sera tested using ELISA were positive for FIV antibodies (including 5 false-positives). The prevalence of FIV infection was considerably higher in our cohort of cats compared with series of lymphosarcoma cases from the Northern hemisphere. A positive FIV status was strongly associated with lymphosarcoma in Australian cats and it is possible that this infection may predispose to the development of lymphoid neoplasia. The presence of FIV infection would have been underestimated if commercial kits alone had been used for serology.