Mesenteric ischemia as a cause of early death among mice infected by Schistosoma mansoni

Laboratory maintenance of the Schistosoma mansoni cycle is necessary for developing studies regarding the diagnosis, treatment and control of schistosomiasis. Within this perspective, it is paramount that mice infected by the parasite should present a minimum survival of six months. However, between October 2016 and May 2017, early deaths were observed among infected animals kept in the vivarium of the Schistosomiasis Reference Service of IAMFIOCRUZ. Therefore, the purpose of the present study was to present the results obtained after investigating the main cause of death among these animals. To achieve this, animals that died or that needed to be euthanized due to clinical distress caused by parasite infection were necropsied to investigate the cause of death and clinical condition. Fragments from the intestines, mesenteric vessels and livers were removed and were subjected to histopathological studies. In addition, mouse feces were collected and analyzed using the hydrogen peroxide reaction to detect occult blood. Over an eight-month period, 70 deaths were noted. Forty two animals presented mesenteric ischemia, a vascular insufficiency syndrome that causes a reduction in the nutrient supply to the intestinal viscera. There is, therefore, a need to reduce the infective parasite load in mice to increase their survival, reduce distress caused by the infection and ensure maintenance of the S. mansoni cycle, thus enabling continuity of scientific studies on this parasitosis.

Casos autoctones de esquistossomose mansonica em criancas de Recife, PE / Casos autoctonos de esquistosomiasis mansonica en ninos de Recife, PE, Brasil / Autochthonous cases of schistosomiasis in children in Recife, Northeastern Brazil

OBJETIVO : Investigar criadouros com moluscos hospedeiros e casos humanos autóctones para esquistossomose. MÉTODOS : Entre julho de 2010 e setembro de 2012 foram realizados: (1) levantamento malacológico para busca ativa de criadouros, coleta e identificação de caramujos Biomphalaria positivos para Schistosoma mansoni em Recife, PE; (2) inquérito de prevalência com 2.718 escolares, de sete a 14 anos, para diagnóstico de casos de esquistossomose; (3) exame clínico e ultrassonografia nos casos positivos para S. mansoni. Os casos foram investigados quanto à sua autoctonia e avaliados clinicamente. Os casos e criadouros foram georreferenciados e espacializados. RESULTADOS : Foram identificados 30 criadouros de B. straminea , quatro deles potenciais focos de transmissão, uma vez que os testes moleculares identificaram DNA de S. mansoni nos caramujos coletados. Foram diagnosticadas 14 crianças com esquistossomose; entre elas, cinco foram consideradas casos autóctones da doença. CONCLUSÕES : Ações emergenciais pela vigilância em saúde são necessárias para evitar que a esquistossomose se endemize em Recife, como acontece em localidades litorâneas do estado de Pernambuco. .

OBJETIVO Investigar criaderos con moluscos hospedadores y casos humanos autóctonos para esquistosomiasis. MÉTODOS Se ejecutaron: estudio malacológico para búsqueda activa de criaderos, colecta e identificación de caracoles Biomphalaria positivos para S. mansoni en Recife, PE, entre julio de 2010 y septiembre de 2012, pesquisa de prevalencia con 2.718 escolares, de siete a 14 años, para diagnóstico de casos de esquistosomiasis, examen clínico y de ultrason en los casos positivos para S. mansoni. Los casos fueron investigados con respecto a su autoctonía y evaluados clínicamente. Los casos y criaderos fueron geo-referenciados y espacializados. RESULTADOS Se identificaron 30 criaderos de B. straminea, cuatro de ellos potenciales focos de transmisión, luego que las pruebas moleculares identificaron DNA de S. mansoni en los caracoles colectados. Se diagnosticaron 14 niños con esquistosomiasis, entre ellas cinco fueron considerados casos autóctonos de la enfermedad. CONCLUSIONES Acciones de emergencia para vigilancia de salud son necesarias para evitar que la esquistosomiasis se vuelva endémica en Recife como sucede en localidades del litoral de Pernambuco. .

OBJECTIVE : Investigate breeding sites with host snails and autochthonous human cases of schistosomiasis. METHODS : Between July 2010 and September 2012 were performed: (1) malacological survey searching for breeding sites, collection and identification of Biomphalaria snails positive for Schistosoma mansoni in Recife, PE, Northeastern Brazil; (2) prevalence survey in 2,718 schoolchildren aged from seven to 14 years old to identify cases of schistosomiasis, clinical examination and ultrasound in positive cases of S. mansoni. The autochthony of the cases was investigated and the case were clinically evaluated. The cases and breeding sites were georeferenced and spatially described. RESULTS : The results identified 30 breeding with B. straminea, four of which were potential foci of transmission, as molecular testing identified snails with S. mansoni DNA. There were 14 children diagnosed with schistosomiasis, of which five were considered to be autochthonous cases of the disease. CONCLUSIONS : Urgent measures are required in order to avoid schistosomiasis becoming endemic to Recife, as has happened in other coastal areas of the state of Pernambuco. .