Evidence for current circulation of an ancient West Nile virus strain (NY99) in Brazil

Abstract INTRODUCTION: In Brazil, West Nile virus (WNV) was first detected, in 2018, in horses with neurological disease. AIM: We report the first case of WNV infection in a horse from Ceará state and the complete genome sequence of an isolate from Espírito Santo state. Both infections occurred in 2019. METHODS: WNV was isolated from the tissues of a horse with neurological signs in Espírito Santo and sequenced by MiSeq. RESULTS: Phylogenetic analysis revealed that the isolate belongs to lineage 1a, clustering with the NY99 strain, a strain that has not circulated in the USA since 2005. CONCLUSIONS: Our findings reinforce the hypothesis that WNV has been silently circulating in Brazil for many years.

West nile virus infections are here! are we prepared to face another flavivirus epidemic?

Abstract Emerging arthropod-borne viruses (arboviruses), such as chikungunya and Zika viruses, are a major threat to public health in countries like Brazil where biodiversity is high and medical care is sometimes precarious. West Nile fever is a disease caused by the West Nile Virus (WNV), an RNA virus belonging to the Flaviviridae family. It is transmitted by infected mosquitoes to numerous animals like birds, reptiles and mammals, including human and non-human primates. In the last decade, the number of reported cases of WNV infection in humans and animals has increased in the Americas. Circulation of WNV in forests and rural areas in Brazil has been detected based on serological surveys and, in 2014, the first case of West Nile fever was confirmed in a patient from Piauí State. In 2018, the virus was isolated for the first time from a horse from a rural area in the state of Espírito Santo presenting with a neurological disorder; this raises the possibility that other cases of WNV encephalitis may have occurred without clinical recognition and without laboratory diagnosis by specific assays. The imminent WNV outbreak poses a challenge for Brazilian clinicians and researchers. In this review, we summarize the basic biological and ecological characteristics of this virus and the clinical presentation and treatment of febrile illnesses caused by WNV. We also discuss the epidemiological aspects, prophylaxis of WNV infections, and monitoring strategies that could be applied in the possibility of a WNV outbreak in Brazil.

Comparison between tests for tuberculosis diagnosis in slaughtered bovines / Comparação entre testes de diagnóstico para tuberculose em bovinos abatidos

Our goal for this article is to compare several different diagnosis tests for bovine tuberculosis identification. We have performed bacterial isolation, histopathological characterization, acid-fast bacilli (AFB) identification and M. bovis DNA detection. Lesions suggestive of Tuberculosis were sampled from bovine lymph nodes during slaughtering of bovines at an abattoir that operates under federal inspection. The bacterial isolation was performed in solid culture mediums, the histopathological characterization was made by Hematoxylin-eosinstaining, and AFB identification by Ziehl-Neelsen staining. Bacterial DNA detection was performed by Polymerase Chain Reaction (PCR) using DNA from two different sources, directly collected from the tuberculosis-like lesions (PCR followed by nested PCR) and from isolated bacteria. We have concluded that the multi-step approach, including histopathological characterization, bacterial isolation and AFB identification, is strongly recommended to diagnose tuberculosis in bovines. Furthermore, PCR assays using specimens of lesions suggestive of tuberculosis are a faster and more promising way to diagnose the disease. However, it should not be used alone due to the low sensitivity shown in this study.(AU)

O objetivo deste estudo foi a comparação entre diferentes testes de diagnóstico para tuberculose bovina. Foram realizados o isolamento bacteriano, a caracterização histopatológica, a identificação de bacilos álcool-ácido resistentes e a detecção do DNA de M. bovis pela reação em cadeia da polimerase, em bovinos adultos abatidos em matadouros frigoríficos sob o Serviço de Inspeção Federal, valendo-se de amostras de linfonodos com lesões macroscópicas sugestivas de tuberculose, identificadas e coletadas durante o abate. O isolamento bacteriano foi realizado pelo cultivo em meios de cultura sólidos; a caracterização histopatológica, pela coloração com hematoxilina-eosina; e a identificação de bacilos álcool-ácido resistentes foi feita pela coloração de Ziehl-Neelsen. A detecção de DNA foi realizada em amostra extraída das lesões sugestivas de tuberculose pela reação em cadeia da polimerase, seguida da nested reação em cadeia da polimerase e por meio das colônias isoladas para identificação do M. bovis, utilizando-se também da reação em cadeia da polimerase . Os resultados obtidos permitiram concluir que os testes histopatológicos, o isolamento bacteriano e a identificação de bacilos álcool-ácido resistentes são aconselháveis para o diagnóstico da tuberculose bovina. Além disso, ensaios de reação em cadeia da polimerase utilizando amostras de lesões sugestivas de tuberculose são um modo mais rápido e promissor para diagnosticar a enfermidade, no entanto não deve ser utilizado sozinho, em virtude da baixa sensibilidade apresentada neste estudo.(AU)