Fatores de risco associados à prevalência de anticorpos anti-Sarcocystis neurona, Neospora spp. e Toxoplasma gondii em equinos de Roraima, Amazônia / Risk factors associated to the prevalence of anti-Sarcocystis neurona, Neospora spp. and Toxoplasma gondii antibodies in horses from Roraima, Brazilian Amazon

Amostras de sangue de 303 equinos provenientes de 56 propriedades do município de Rorainópolis, Roraima, foram avaliadas por Reação de Imunofluorescência Indireta (RIF) para pesquisa de anticorpos contra Sarcocystis neurona, Toxoplasma gondii e Neospora spp. Algumas amostras de soros positivos para Sarcocystis spp. foram avaliadas pelo Western Blotting (WB) utilizando antígenos crus de S. neurona. A partir dos resultados sorológicos, possíveis fatores de risco foram avaliados frente a variáveis individuais e de propriedade. A prevalência de anticorpos anti-Sarcocystis spp. foi estimada em 43,2% (37,6-49,0%), anti-Neospora sp. em 26,7% (21,9-32,2%) e anti-T. gondii de 18,5% (14,3-23,4%). Quatorze amostras (14/15) testadas por WB resultaram positivas para antígenos de S. neurona. Das propriedades, 76,8% (43/56) apresentaram pelo menos um equino positivo para Sarcocystis spp.; 69,6% (39/56) para Neospora spp. e 55,4% (31/56) para T. gondii. Dos equinos, 13 (4,3%) apresentarem anticorpos para os três agentes, 50 (16,5%) para Sarcocystis spp. e Neospora spp., 10 (3,3%) para Neospora spp. e T. gondii, e oito (2,6%) para Sarcocystis spp. e T. gondii. As variáveis associadas (P≤0,05) à presença de anticorpos foram: para Neospora spp. não pastejar em áreas alugadas, ausência de assistência veterinária na propriedade, sexo masculino, não estabular animais e plantel equino acima de 5 animais; enquanto para T. gondii foram o contato com felinos, animais da raça lavradeiro, animal estabulado, criação de bovinos na propriedade e plantel equino acima de 5 animais. Não houveram variáveis associadas a presença de anticorpos contra S. neurona. Relata-se no presente estudo a primeira detecção de anticorpos anti-S. neurona, Neospora spp. e T. gondii em equinos do estado de Roraima, localizado na Amazônia Setentrional Brasileira, ressaltando para a elevada frequência de fazendas com equinos soropositivos.

Samples of 303 horses from 56 ranches of Rorainópolis municipality, state of Roraima, were evaluated by means of the Indirect Immunofluorescence Test (IFAT) to detect antibodies against Sarcocystis spp., Toxoplasma gondii and Neospora spp. A subset of positive sample (n=15) against Sarcocystis spp. was evaluated by Western Blotting (WB) with crude antigen of S. neurona. From the serological result, possible risk factors were evaluated against individual or farming variables. The prevalence of anti-Sarcocystis spp. antibodies was estimated to be 43.2% (37.6-49.0%), anti-Neospora sp. was 26.7% (21.9-32.2%), and anti-T. gondii was 18.5% (14.3-23.4%). Fourteen samples (14/15) evaluated by WB were positive for S. neurona antigens. From the ranches, 76.8% (43/56) presented at least one positive horse for Sarcocystis spp., 69.6% (39/56) for Neospora spp., and 55.4% (31/56) for T. gondii. Thirteen (14.3%) horses had antibodies against all agents, 50 (16.5%) had antibodies against Sarcocystis spp. and Neospora spp., 10 (3.3%) for Neospora spp. and T. gondii, and eight (2.6%) for Sarcocystis spp. and T. gondii. Associated variables (P≤0.05) for antibodies against Neospora spp. were not found in horses fed on rented pastures, not in horses without veterinary assistance and stables, and not in herds up to 5 horses; while they were associated for T. gondii by contact with cats, in the Lavradeiro breed with use of stables, in horses raise with cattle, and in herds up to 5 horses. There were no variables associated with the presence of antibodies against S. neurona. Antibodies against S. neurona, Neospora spp. and T. gondii were reported in horses from the state of Roraima, Northern Brazilian Amazon, highlighting to the elevate prevalence on ranches.(AU)

Seroprevalence of Rickettsia spp. in Equids and Molecular Detection of 'Candidatus Rickettsia amblyommii' in Amblyomma cajennense Sensu Lato Ticks From the Pantanal Region of Mato Grosso, Brazil.

The aim of the study was to evaluate exposure of equids to rickettsial agents (Rickettsia rickettsii, Rickettsia parkeri, 'Candidatus Rickettsia amblyommii', Rickettsia rhipicephali, and Rickettsia bellii) and rickettsial infection in ticks of a Pantanal region of Brazil. Sera of 547 equids (500 horses and 47 donkeys) were evaluated by indirect immunofluorescence assay. In total, 665 adults and 106 nymphal pools of Amblyomma cajennense F. sensu lato, 10 Dermacentor nitens Neumann ticks, and 88 larval pools of Amblyomma sp. were tested by polymerase chain reaction (PCR). Overall, 337 (61.6%) equids were reactive (titer ≥64) to at least one antigen of Rickettsia spp. The prevalence values for Rickettsia were 66%, and the highest endpoint titers were observed for 'Ca. R. amblyommii'. By PCR 3 (0.45%) A. cajennense s.l. females were positive for 'Ca. R. amblyommii'. Minimum infection rates of 0.75% for nymphs and 0.34% for larvae were calculated. Positive samples of ticks have had a fragment of the 16S mitochondrial rRNA gene sequenced and sequences showed 99% identity to Amblyomma sculptum Berlese. This study reports a wide exposure of equids to Rickettsia agents, and PCR evidence of infection with 'Ca. R. amblyommii', for the first time, in A. sculptum.

Prevalence and risk factors for Equine Infectious Anemia in Poconé municipality, northern Brazilian Pantanal.

Serum samples collected from 547 equids in the Pantanal region of Brazil were evaluated for antibodies to Equine Infectious Anemia Virus (EIAV) by the agar gel immunodiffusion test. Risk factors associated with EIAV seropositivity were evaluated and spatial dependence investigated using a Spatial Lag Model. EIAV prevalence on farms in the Pantanal was 52.0% (13/25) with adjusted prevalence between equids of 31.5% (17.4-48.8% 95% CI). Intra-herd prevalence ranged from 5.0 to 77.0%. Statistical analysis demonstrated that farms and animals in regularly flooded areas had respectively 60 and 146 fold higher chance to be sero-positive than farms and animals located in non-flooded areas. Spatial Lag Model results were generally consistent with this conclusion although there was a negative spatial correlation between farms located within in regularly inundated regions, suggesting that other factors, such as management practices, probably play a significant role in transmission of EIAV. Equids with clinical signs were 3.74-fold more likely to be sero-positive than those without clinical signs. The results of this work reveal a high prevalence of EIAV in the Pantanal area of Brazil demonstrating that equids reared in this region are at great risk of infection.