Molecular diagnosis of Hepatozoon canis in symptomatic dogs in the city of Goiania, Goiás, Brazil

ABSTRACT More than 300 species have been described in the genus Hepatozoon, occurring in different vertebrates. Among these, only Hepatozoon canis and Hepatozoon americanum are seen in dogs. Different methods may be used for laboratory diagnosis. The most common of these is direct parasitological examination of parasite stages in blood smears. The aim of this investigation was to conduct a phylogenetic study on Hepatozoon isolates from symptomatic dogs in the city of Goiânia, Goiás, Brazil. Blood samples were obtained from 40 symptomatic dogs that had been referred to the Veterinary Hospital of the Federal University of Goiás. Among these, only two samples were positive for Hepatozoon spp. using the direct parasitological method. These samples were then subjected to a DNA extraction process and amplification of a fragment of the 18S rRNA by means of PCR. Subsequently, the PCR products from each sample were purified and sequenced. The sequences obtained were then analyzed using the BLASTn algorithm, which identified both sequences of this study as Hepatozoon canis. By applying the Mega4 software, it was confirmed that these isolates of H. canis from dogs in Goiânia are similar to other reference isolates of the same species from other regions of Brazil and worldwide

Aspectos clínicos, epidemiológicos e patológicos da infecção natural em bovinos por Trypanosoma vivax na Paraíba Clinical, epidemiological and pathological signs of natural infection in cattle by Trypanosoma vivax in Paraíba, Brazil

Descrevem-se dois surtos de tripanossomíase por Trypanosoma vivax em bovinos, ocorridos em dois estabelecimentos do alto sertão da Paraíba. Os sinais clínicos, a patologia e a epidemiologia da doença foram estudados no período de maio de 2005 a novembro de 2006.T. vivax foi identificado em esfregaços da capa leucocitária e mediante a reação em cadeia da polimerase (PCR). Os animais afetados apresentaram anorexia, depressão, febre, anemia, perda de peso, redução da produção leiteira, cegueira transitória, aborto e sinais nervosos caracterizados por incoordenação motora, salivação, opistótono, nistagno, tetania e bruxismo. Todos os animais que apresentaram sintomatologia nervosa morreram. As alterações macroscópicas observadas em um bovino submetido à necropsia foram aumento de volume dos linfonodos, atrofia serosa dos depósitos de gordura, aumento de volume do baço com evidência da polpa branca, hidropericárdio, além de petéquias e equimoses no epicárdio. Histologicamente havia meningoencefalite. O controle da doença na propriedade com tratamento específico dos casos clínicos com aceturato de diminazene foi eficiente, pois após o tratamento não se verificou mais a presença do parasita em esfregaços sanguíneos nem evidência clínica da enfermidade em até 2 meses após o início do surto. Os fatores epidemiológicos favoráveis à ocorrência dos surtos foram a abundância de vetores mecânicos, como tabanídeos e Stomozys spp., e a entrada, no rebanho, de animais oriundos de propriedades onde ocorreu a doença em questão. Sugere-se que o semi-árido do Nordeste, devido a períodos prolongados de secas e altas temperaturas, é região de instabilidade enzoótica para a tripanossomíase, em conseqüência, provavelmente, ao ambiente desfavorável para o desenvolvimento de vetores durante a maior parte do ano.<br>Two outbreaks of trypanosomiasis by Trypanosoma vivax, reported in cattle, occurred on two farms located in the state of Paraíba, northeastern Brazil. The epidemiology, clinical signs and pathology of the disease were studied from May 2005 to November 2006. T. vivax was identified morphologically and by polymerase chain reaction test (PCR). The affected cattle presented anorexia, depression, fever, anemia, weight loss, reduction in milk production, transitory blindness, abortion and some nervous signs as nystagmus, tetany and bruxism. All cattle that presented nervous signs died. Necropsy findings were enlarged lymph and spleen, serous atrophy of the fat depots, proeminence of the splenic white pulp, hydropericardium and pericardial petechiae and ecchymoses on the epicardium. Histologically there was meningoencephalitis. The treatment of the clinical cases with diminazena aceturate was efficient with clearance of the parasite from the blood or disappearance of clinical signs in up to 2 months after the beginning of the outbreak on the two farms studied. The epidemiologic factors favoring the occurrence of the outbreak were the abundance of mechanical vectors, as tabanids and Stomoxys sp., and the introduction into the herd of cattle from farms where the disease occurred. It is suggested that the semiarid of the Brazilian Northeast is an enzootic instability region for trypanosomiasis due to its prolonged periods of drought and high temperatures, constituting during most part of the year an unfavorable environment for the development of vectors