Hemoplasmas em gatos domésticos: prevalência e sua associação à infecção natural pelos vírus das imunodeficiência e/ou leucemia felinas

Abstract

Infectious diseases present high morbidity among domestic cats and a delayed or misdiagnosis may result in patient death. The association between feline immunodeficiency (FIV) and/or feline leukemia (FeLV) viruses infections with hemoplasmas has great importance in veterinary practice, since agents may act synergically increasing risks for infected animals. To date, there are no studies in Brazil critically examining whether or not hemoplasma infections are associated with retroviral infection in cat. Thus, the aim of this study was to determine the prevalence and risk factors for Mycoplasma haemofelis (Mhf) and Candidatus Mycoplasma haemominutum (Mhm) infections in domestic cats tested for FIV and FeLV with a commercial ELISA kit. Based on serologic testing, cats were grouped as i) FIV-positive (n=25); ii) FeLV-positive (n=39); iii) FIV/FeLV-positive (n=8); and iv) FIV/FeLV-negative (n=77), or base-comparison group. CBCs were followed by DNA extraction, species-specific PCR (16S rRNA gene) for Mhf and Mhm and Southern blotting for all animals. Among all animals tested for retroviral infection (n=149), 16,8%, 26,2% and 5,4% were seropositive for FIV, FeLV and both retroviruses respectively. Associated factors to retroviral infections included an increased mean age (FIV, p<0,001), neutered status and history of fights/bites (FIV, p=0,033 and <0,001 respectively); presence of fleas (FeLV, p=0,018); history of blood transfusions and roaming outdoors (FIV/FeLV, p=0,028 and 0,033 respectively). Among evaluated clinical signs, anorexia and pale mucous (FIV, p=0,004 and 0,034 respectively); lethargy/depression, jaundice and tachycardia (FeLV, p=0,033, 0,036 and 0,003 respectively) were identified. Among CBC findings, anemia was related to FIV (p=0,012) and FeLV (p<0,001) infections, whereas thrombocytopenia was only related to FIV infection (p=0,015). Animals with FIV or double FIV and FeLV infections had a reduced WBC count (p=0,021 and 0,012 respectively). Mhf DNA was found in 4.0%, 2.6%, 12.5% and 7.8% of the cats from groups i, ii, iii and iv respectively, while 32.0%, 5.1%, 50.0% and 5.2% of these animals had a Mhm infection. Host factors that were associates to the presence of hemoplasma DNA included the retroviral status (p=0,001), history of fights/bites (p=0,003), roaming outdoors (p=0,001), living with other cats (p=0,008) and pale mucous (p=0,033). The logistic regression model used herein showed that cats with FIV (OR=4,25; p=0,009) and both FIV and FeLV (OR=7,56; p=0,014) were at greater risk of being hemoplasma infected than retroviral negative cats, mainly due to Mhm infection (OR=8,59, p=0,001 and OR=18,25, p=0,001 respectively). Among pure-breed cats, FIV-positive status was associated with hemoplasma infection (OR 45,0; p=0,001).