Zika puzzle in Brazil: peculiar conditions of viral introduction and dissemination: a review

This article discusses the peculiar conditions that favoured the unexpected introduction of Zika virus into the poorest northeastern region of Brazil in 2015, its speed of transmission to other Brazilian states, other Latin American countries and other regions, and the severity of related neurological disorders in newborns and adults. Contrasting with evidence that Zika had so far caused only mild cases in humans in the last six decades, the epidemiological scenario of this outbreak in Brazil indicates dramatic health effects: in 2015, an increase of 20-fold in notified cases of microcephaly and/or central nervous system (CNS) alterations suggestive of Zika congenital infection, followed by an exponential increase in 2016, with 2366 cumulative cases confirmed in the country by the end of December 2016. A significant increase in Guillain-Barré syndrome in adults has also been reported. Factors involved in viral dissemination, neural pathogenesis and routes of transmission in Brazil are examined, such as the role of social and environmental factors and the controversies involved in the hypothesis of antibody-dependent enhancement, to explain the incidence of congenital Zika syndrome in Brazil. Responses to the Zika outbreak and the development of new products are also discussed.

Zika puzzle in Brazil: peculiar conditions of viral introduction and dissemination - A Review.

This article discusses the peculiar conditions that favoured the unexpected introduction of Zika virus into the poorest northeastern region of Brazil in 2015, its speed of transmission to other Brazilian states, other Latin American countries and other regions, and the severity of related neurological disorders in newborns and adults. Contrasting with evidence that Zika had so far caused only mild cases in humans in the last six decades, the epidemiological scenario of this outbreak in Brazil indicates dramatic health effects: in 2015, an increase of 20-fold in notified cases of microcephaly and/or central nervous system (CNS) alterations suggestive of Zika congenital infection, followed by an exponential increase in 2016, with 2366 cumulative cases confirmed in the country by the end of December 2016. A significant increase in Guillain-Barré syndrome in adults has also been reported. Factors involved in viral dissemination, neural pathogenesis and routes of transmission in Brazil are examined, such as the role of social and environmental factors and the controversies involved in the hypothesis of antibody-dependent enhancement, to explain the incidence of congenital Zika syndrome in Brazil. Responses to the Zika outbreak and the development of new products are also discussed.

Estudo histopatologico do sistema nervoso periferico na doenca de Chagas experimental

Com a finalidade de estudar o comprometimento do sistema nervoso periferico na doenca de Chagas experimental, foram inoculados grupos de camundongos machos adultos com 10 elevado quinta tripomastigotas sanguineos da cepa Colombiana e uma cepa de Trypanosoma cruzi provinientes de triatomineos do Municipio de Sao Raimundo nonato, Piaui - Brasil, por via intraperitoneal. A necropsia destes animais ocorreu entre o vigesimo primeiro dia e oitavo dia do mes de infeccao, quando foram retirados o nervo ciatico, musculo esqueletico da coxa e coracao. Em seguida, os fragmentos foram fixados em formol a 10 por cento para exame histopatologico de rotina e imuno-histoquimico. Alem destes tecidos, examinamos o coracao para confirmacao da infeccao. O exame microscopico do nervo ciatico corado pela hematoxilina-eosina de todos os animais apresentou infiltrado inflamatorio formado de linfocitos e plasmocitos localizados no endoneuro, e com maior prevalencia no perineuro dos nervos ciaticos, originando um processo de neurite intersticial ou perineurite na fase aguda e cronica de ambas as cepas. Constatou-se, tambem, um intenso processo de vascularite no vervo ciatico e musculo esqueletico da coxa na fase cronica e, ocasionalmente, necrose das paredes vasculares com a cepa Colombiana. Alguns camundongos cronicos, infectados com a cepa Colombiana, exibiram sinais de paresia ou paralisia dos membros posteriores e a presenca de amastigotas nos nervos dos animais paraliticos. Nestes animais, encontramos lesoes do nervo ciatico associado ao comprometimento do musculo esqueletico da coxa onde e evidente a miosite, surgindo, esporadicamente, a miosite calcificante em alguns camundongos cronicos. Os camundongos apresentam miocardite, pericardite e endocardite. No entanto, a presenca de amastigotas foram observadas frequentemente na fase aguda. Os resultados da imunoperoxidase apresentaram amastigotas ou antigenos parasitarios nos cortes histologicos do coracao, nervo ciatico e musculo esqueletico da coxa, os quais foram semelhantes ao observado pelos tecidos corados pela HE.