CD4+ and CD8+ T lymphocyte counts and ratio in cats with chronic gingivostomatitis and naturally infected with feline immunodeficiency virus: a preliminary study

This study aimed to evaluate the CD4+ and CD8+ T lymphocytes counts and CD4+: CD8+ ratio in a colony of cats with chronic gingivostomatitis (CGS). We used forty domestic short-haired cats inhabiting the same colony. Ten cats with CGS were immunodeficiency virus-positive (group IV), and ten with CGS were immunodeficiency virus-negative (group III). As a control, twenty cats without CGS were used: ten cats were immunodeficiency virus-positive (group II) and ten cats were immunodeficiency virus-negative (group I). We employed flow cytometry to count CD4+ and CD8+ T lymphocytes. In cats infected with the immunodeficiency virus, the presence of CD4+ lymphocytes were lower both for animals with and without CGS. Conversely, not immunodeficiency virus-infected cats with CGS had a higher amount of CD4+ when compared to seronegative animals without CGS. The counts of CD8+ T lymphocytes showed no significant difference among cats with CGS, whether infected with immunodeficiency virus or not. The CD4+: CD8+ ratio was only different for group III, which was higher than any other group. No difference was observed for total lymphocyte number and CD8+ among groups. By contrast, mean CD4+ levels were different, with cats from groups III and IV showing higher levels than those from groups I and II. The flow cytometry could be a useful tool for the diagnosis and prognosis of cats with CGS infected by the immunodeficiency virus.

Serological survey of Neospora caninum and Toxoplasma gondii in shelter-housed cats infected with feline immunodeficiency virus, Brazil

Felines play a leading role in the epidemiology of Toxoplasma gondii infection, but there is scarce information about the epidemiology of Neospora caninum, particularly in feline immunodeficiency virus (FIV)-infected cats. Cats seropositive to T. gondii do not usually show symptoms unless they are immunosuppressed, such as FIV-infected cats. The same relationship remains poorly known for N. caninum, although it has been associated with neurological disorders in HIV-infected people. Since FIV-infected cats are prone to develop encephalitis of unknown etiology, this study aimed to evaluate the presence of specific antibodies to T. gondii and N. caninum in a shelter for stray cats naturally infected with FIV. A total of 104 serum samples from cats living in a shelter, located in São Paulo city (Brazil), was assessed for T. gondii and N. caninum specific antibody by indirect fluorescent-antibody test (IFAT). Of the 104 cats, 25 (24%) were infected with FIV and, aside from these, 8 (32%) had antibodies against T. gondii (titers from 16 to 128). Only 1 (4%) of the FIV infected cats had antibodies against N. caninum, which was the first record of coinfection. Among the FIV-naïve cats, 11 (14%) were positive for T. gondii (titers from 16 to 256) and only 1 (1.2%) had antibodies against N. caninum. Serologically positive reactions to T. gondii and N. caninum were not correlated with age or sex (p>0.05), and there was no correlation between FIV and the occurrence of anti-T. gondii or anti-N. caninum antibodies (p>0.05). Further studies encompassing larger cat populations from different origins and locations are essential to clarify the prevalence of T. gondii and N. caninum antibodies in FIV-positive cats.

Prevalence of autosomal dominant polycystic kidney disease in Persian and Persian-related cats in Brazil

Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic disease in cats. However, scarce data on its prevalence are available in Brazil. Persian cats and Persian-related breeds were assessed by molecular genotyping for a C to A transversion in exon 29 of PKD1 gene to determine ADPKD prevalence in a Brazilian population. Genomic DNA extracted from peripheral whole blood or oral swabs samples was used to amplify exon 29 of PKD1 gene employing a PCR-RFLP methodology. From a total of 616 animals, 27/537 Persian and 1/17 Himalayan cats showed the single-nucleotide variant (C to A) at position 3284 in exon 29 of feline PKD1. This pathogenic variation has been identified only in heterozygous state. The prevalence of ADPKD in Persian cats and Persian-related breeds was 5.03% and 1.6%, respectively. There was no significant association between feline breed, gender or age with ADPKD prevalence. Of note, the observed ADPKD prevalence in Persian cats and Persian-related breeds in Brazil was lower than the ones reported in other parts of the world. This finding may be related to genetic counseling and consequent selection of ADPKD-free cats for reproduction.

Isolation of Dermatophytes from the Hair Coat of Healthy Persian Cats without Skin Lesions from Commercial Catteries Located in São Paulo Metropolitan Area, Brazil

Background: The study of the epidemiological chain of dermatophytosis, particularly those related to zoophilic fungi, is extremely important because of its frequent occurrence, the high infectivity of the agent, and its anthropozoonotic character. In all latitudes, asymptomatic cats are considered the main reservoirs and sources of dermatophyte infection. The study aimed to characterize the frequency of dermatophyte infection and the potential risk of microsporic infection to the owners and to possible buyers of apparently healthy Persian cats from commercial catteries of São Paulo, Brazil.Materials, Methods & Results: Fur samples were obtained from 61 clinically healthy Persian cats, which were devoid of typical cutaneous lesions and had negative results in Wood’s lamp examination. The average age of the cats was 37.7 months; 18 (29.5%) of them were males and 43 (70.5%) were females. The cats were from commercial catteries located in the metropolitan region of São Paulo state capital. Samples were obtained using the technique of Mariat & Adam using a square (25 cm2) of sterile carpet rubbed across the surface of the hair-coat and skin. People who had close contact with the animals were asked whether they had had typical ringworm lesions in the recent past or at the time of sample collection. The material collected was pressed onto Petri dishes containing agar supplemented with chloramphenicol and cycloheximide. The Petri dishes were handled under sterile conditions and incubated at 25°C for up to 21 days. There was evident fungal growth in 83.6% of the samples, and the only dermatophyte isolated was Microsporum canis. The results were analyzed using the chi-square test in order to verify possible associations between variables (sex and age range) and the frequency of dermatophyte infection in dermatologically healthy animals. However, there was no statistical difference regarding sexual predisposition (P value = 0.139) and age (P value = 0.224) regarding the asymptomatic dermatophyte carriers. Of the 18 people who had close contact with infected cats, eight (44.4%) claimed to have presented with typical tinea corporis lesions in the past and three (16.7%) said that they had such skin lesions at the time of harvest of the cat fur. There were no people who claimed to have been in contact with other species.Discussion: In Brazil, fungal infections represent up to 8.7% of skin diseases in children, and tinea capitis caused by Microsporum canis is the most common superficial mycosis in this age group. Its interspecies transmission has been reported for decades. Approximately 50% of individuals exposed to symptomatic or asymptomatic cats acquire the disease. In up to 70% of families with infected cats, at least one family member may develop the disease. Among domestic cats, the Persian breed is most often cited as prone to spreading dermatophytes. In the study, there was fungal growth in 83.6% of the samples, and only M. canis was isolated. Among the people who had contact with the cats, 44.4% and 16.7% had typical tinea corporis lesions in the past and at the time of the interview, respectively. However, it is speculated that the rate of infection may have been higher in the humans in contact with these cats, since there may have been some hesitation and fear by the people interviewed in reporting the occurrence of characteristic skin lesions, either as a way of preserving the cattery reputation, or to spare the embarrassment in declaring oneself as infected, which is sometimes viewed negatively. The results demonstrate the potential infectivity, pathogenicity, and risk of microsporic infection in buyers of apparently healthy cats from commercial catteries located in the metropolitan region of São Paulo.

Congenital hepatic fibrosis and polycystic kidney disease not linked to C >A mutation in exon 29 of PKD1 in a Persian cat

CASE SUMMARY

We describe the case of a 1-year-old male Persian cat diagnosed with congenital hepatic fibrosis (CHF) associated with renal polycystic disease and, for the first time, we have shown that there was no C >A mutation in exon 29 of PKD1 (polycystic kidney disease 1). The cat presented with a history of chronic weight loss, anorexia, vomiting, depression and lethargy, with profuse salivation and ascites on clinical examination. A mild elevation in liver-associated plasma enzymes suggested a hepatic disease. Owing to the cat's deteriorating condition, it was euthanized. During necropsy, the liver was found to be enlarged, firm and reddish, and the kidney had multiple small cortical cysts. Immunohistochemistry revealed that bile duct cells and epithelial cells of renal cysts showed positive immunoreactivity to keratin 19. Collagen fibers surrounding bile ducts within portal areas demonstrated reactivity to type IV collagen antibody, confirming the congenital nature of the process. A diagnosis of ductal plate malformation consistent with CHF associated with polycystic kidney in a young Persian cat was made. Interestingly, genetic testing revealed a wild-type sequence at position 3284 in exon 29 of PKD1.

RELEVANCE AND NOVEL INFORMATION

The absence of the classic genetic mutation associated with the particular clinical presentation supports the hypothesis of a distinct etiopathogenesis among fibropolycystic diseases in domestic cats. Moreover, congenital hepatic fibrosis is a rare but important differential diagnosis for young Persian cats and their crosses with clinical signs of chronic end-stage liver disease.