Frequency of histopathological changes in Howler monkeys ( Alouatta sp. ) naturally infected with yellow fever virus in Brazil

Abstract: INTRODUCTION: Due to the importance that Howler monkeys have on the yellow fever (YF) epidemiological sylvatic cycle in Brazil, more accurate morphological diagnostic criteria needs to be established, especially considering the differences that may exist between the genera of Brazilian non-human primates (NHPs) involved in yellow fever virus (YFV) epizootics. METHODS: Records of YF epizootics in NHPs in Brazil between 2007 and 2009 were obtained from the Brazilian Ministry of Health database to select YF positive (n=98) Howler monkeys (Alouatta sp.) for this study. The changes described in the histopathological reports were categorized by organ and their frequencies calculated. RESULTS: The most frequent lesions observed in the animals with YF were hepatocyte apoptosis (Councilman body formation), midzonal hepatocyte necrosis, steatosis, liver hemorrhage, inflammatory mononuclear cell infiltration of the liver, renal acute tubular necrosis and interstitial nephritis. Midzonal hepatocyte necrosis, steatosis and hemorrhage presented positive correlations with apoptosis of hepatocytes, suggesting strong YFV pathogenic effect association; they were also the main histopathological changes in the Alouatta sp. A pronounced negative correlation between apoptosis of hepatocytes and hepatic mononuclear cell infiltration pointed to significant histopathological differences between YFV infection in Howler monkeys and humans. CONCLUSIONS: The results warn that NHPs may exhibit different response patterns following YFV infection and require a more careful diagnosis. Presumptive diagnosis based on primate histopathological lesions may contribute to public health service control.

Epizootias em primatas não humanos durante reemergência do vírus da febre amarela no Brasil, 2007 a 2009 / Epizootics in nonhuman primates during reemergence of yellow fever virus in Brazil, 2007 to 2009

Objetivo: descrever e analisar a mudança do perfil epidemiológico da febre amarela silvestre no Brasil – que passa a ocorrer fora da Amazônia – a partir de 1999, quando a detecção do vírus em primatas permitiu a aplicação oportuna de novas medidas de vigilância. Metodologia: este estudo faz uma análise descritiva das epizootias em primatas notificadas ao Ministério da Saúde (MS) entre 2007 e 2009; para captação dos dados, foram utilizadas a Ficha de Notificação de Epizootia do Sistema de Informação de Agravos de Notificação (Sinan) e planilha de notificação diária. Resultados: No período, foram notificadas 1.971 epizootias em primatas, sendo 73 no ano de 2007, 1.050 em 2008 e 848 em 2009; essas epizootias ocorreram em 520 municípios de 19 estados; do total de epizootias notificadas, 209 (10,6 por cento) foram confirmadas para febre amarela. Conclusão: as informações aqui discutidas são fundamentais para o aperfeiçoamento da vigilância e a consolidação da notificação de epizootias em primatas, como instrumento de prevenção de casos humanos da doença.

Objective: to describe and analyze the change in the epidemiological profile of sylvatic yellow fever – whose cases began to occur outside the Amazon region, in Brazil – from 1999, when the detection of the virus in primates has led to the timely implementation of new surveillance measures. Methodology: this study is a descriptive analysis of epizootics in primates notified to the Ministry of Health between 2007 and 2009; data were captured using the Epizootic Notification Form of the Brazilian Information System for Notifiable Diseases (Sinan) and daily reporting spreadsheet. Results: from 1,971 epizootics reported during the period, 73 occurred in 2007, 1,050 in 2008, and 848 in 2009; and 209 (10.6 per cent) were confirmed for yellow fever; these epizootics have been registered in 520 municipalities of 19 states. Conclusion: the information discussed herein is fundamental for improving the surveillance and consolidating the notification of epizootics in primates, as a tool for preventing human cases of the disease.