ABSTRACT
Abstract Due to anthropic environmental changes, vector-borne diseases are emerging worldwide. Ticks are known vectors of several pathogens of concern among humans and animals. In recent decades, several examples of tick-borne emerging viral diseases have been reported (Crimean Congo hemorrhagic fever virus, Powassan virus, encephalitis virus, heartland virus, severe fever with thrombocytopenia syndrome virus). Unfortunately, few studies addressing the presence of viruses in wild ticks have been carried out in South America. With the aim of detecting flaviviruses and orthobunyaviruses in ticks, we carried out molecular detection in wild ticks collected in the state of Minas Gerais, Brazil. No Flavivirus-positive ticks were detected; however, we detected activity of Orthobunyavirus in 8 Amblyomma tick specimens. One of those individuals was positive for Bunyamwera orthobunyavirus, which represents the first report of this virus among ticks in South America. Further studies related to the ecology of zoonotic diseases are needed to increase knowledge of this topic, including attempts at viral isolation, full genome sequencing and biological characterization. In this way, we will obtain a better picture of the real risk of ticks as a vector for viral diseases for humans and animals on our continent, where no tick-borne viral disease is known to occur.
Resumo Alterações ambientais causadas pelo homem têm levado à emergência de doenças transmitidas por vetores no mundo. Carrapatos são vetores conhecidos de vários patógenos de importância médica e veterinária, tendo sido reportado nas últimas décadas um grande número de enfermidades virais emergentes transmitidas por eles (vírus da Febre Hemorrágica da Crimeia-Congo, vírus Powassan, vírus da Encefalite, vírus Heartland e vírus da Síndrome da Febre Trombocitopênica Severa). Infelizmente, poucos estudos envolvendo a pesquisa de vírus em carrapatos foram conduzidos na América do Sul até o momento, e nas últimas décadas um elevado número de enfermidades virais emergentes transmitidas por estes artrópodes foi relatado. Com o objetivo de investigar a presença de flavivírus e orthobunyavírus em carrapatos, foi conduzida uma análise molecular em espécimes coletados no estado de Minas Gerais, Brasil. Em nenhum carrapato foi detectada a presença de Flavivirus, no entanto, em 8 espécimes do gênero Amblyomma, foi detectada a presença de Orthobunyavirus, dos quais um espécime foi positivo para Bunyamwera orthobunyavirus. Novos estudos relacionados à ecologia de doenças zoonóticas, incluindo tentativas de isolamento viral, sequenciamento completo do genoma e caracterização biológica, são necessários. Desta forma, será possível ter uma base sobre os riscos da transmissão de vírus patogênicos por carrapatos em nosso continente, uma vez que até agora isso é desconhecido.
Subject(s)
Animals , Male , Female , Ticks/virology , Orthobunyavirus/genetics , Flavivirus/genetics , Phylogeny , Surveys and Questionnaires , Orthobunyavirus/isolation & purification , Orthobunyavirus/classification , Flavivirus/isolation & purification , Flavivirus/classificationABSTRACT
ABSTRACT We describe a sensitive method for simultaneous detection of Oropouche and Oropouche-like viruses carrying the Oropouche S segment, as well as the Mayaro virus, using a multiplexed one-step reverse transcription real-time polymerase chain reaction (RT-qPCR). A chimeric plasmid containing both Mayaro and Oropouche targets was designed and evaluated for the in vitro production of transcribed RNA, which could be easily used as a non-infectious external control. To track false-negative results due to PCR inhibition or equipment malfunction, the MS2 bacteriophage was also included in the multiplex assay as an internal positive control. The specificity of the multiplex assay was evaluated by Primer-Blast analysis against the entire GenBank database, and further against a panel of 17 RNA arboviruses. The results indicated an accurate and highly sensitive assay with amplification efficiency greater than 98% for both targets, and a limit of detection between two and 20 copies per reaction. We believe that the assay described here will provide a tool for Mayaro and Oropouche virus detection, especially in areas where differential diagnosis of Dengue, Zika and Chikungunya viruses should be performed.
Subject(s)
Humans , Orthobunyavirus/classification , Orthobunyavirus/genetics , Bunyaviridae Infections/diagnosis , Bunyaviridae Infections/virology , Alphavirus Infections/diagnosis , Alphavirus Infections/virology , Alphavirus/classification , Alphavirus/genetics , Reverse Transcriptase Polymerase Chain Reaction , Multiplex Polymerase Chain ReactionABSTRACT
This study aimed to investigate the circulation of Orthobunyavirus species in the state of Mato Grosso (MT) Brazil. During a dengue outbreak in 2011/2012, 529 serum samples were collected from patients with acute febrile illness with symptoms for up to five days and 387 pools of female Culex quinquefasciatuscaptured in 2013 were subjected to nested-reverse transcription-polymerase chain reaction for segment S of the Simbu serogroup followed by nucleotide sequencing and virus isolation in Vero cells. Patients (5/529; 0.9%) from Cuiabá (n = 3), Várzea Grande (n = 1) and Nova Mutum (n = 1) municipalities were positive for the S segment of Oropouche virus (OROV). Additionally, eight/387 Cx. quinquefasciatuspools were positive for the segment, with a minimum infection rate of 2.3. Phylogenetic analysis indicated that all the samples belong to the subgenotype Ia, presenting high homology with OROV strains obtained from humans and animals in the Brazilian Amazon. The present paper reports the first detection of an Orthobunyavirus, possibly OROV, in patients and in Cx. quinquefasciatus mosquitoes in MT. This finding reinforces the notion that arboviruses frequently reported in the Amazon Region circulate sporadically in MT during dengue outbreaks.