RESUMO: Os arbovírus são agentes transmitidos por artrópodes que representam considerável ameaça à saúde pública em todo o mundo, causando doenças em humanos e animais. Neste trabalho foi realizada investigação sorológica para detecção de anticorpos totais contra diferentes tipos de arbovírus em quatis (Nasua nasua) de vida livre do Parque Nacional do Iguaçu (PNI) através do teste de Inibição da Hemaglutinação. Amostras de soro foram testadas utilizando-se antígenos de 33 arbovírus pertencentes aos gêneros Alphavirus, Flavivirus, Orthobunyavirus e Phlebovirus. As análises evidenciaram que 23,6% (17/72) dos quatis apresentaram soropositividade para pelo menos um dos antígenos testados, incluindo reações monotípicas e heterotípicas. Foi detectada soropositividade para Alphavirus (5,9%, 1/17; WEEV), Flavivirus (64,7%, 11/17; YFV, ILHV, SLEV, BSQV, ROCV, VNO, DEN1, DEN2, DEN3, DEN4, NJLV), Phlebovirus (88,2%, 15/17; ICOV, BUJV) e Orthobunyavirus (5,9%, 1/17; ORIV). A presença de anticorpos para esses vírus em quatis do PNI indica uma aparente transmissão silenciosa de arbovírus, incluindo N. nasua como um possível amplificador destes arbovírus na área estudada. Os dados encontrados servem de alerta quanto ao possível risco de estabelecimento de um ciclo de transmissão de arbovírus envolvendo insetos vetores e quatis, ou ainda, outros animais silvestres, consequentemente, podendo incluir o homem nessa cadeia de transmissão.

ABSTRACT: Arboviruses are agents transmitted by arthropods and represent a considerable threat to public health worldwide, causing diseases in humans and animals. A serological investigation was carried out to detect total antibodies against different types of arboviruses in free-living coatis (Nasua nasua) from the Iguaçu National Park (INP) through the Hemagglutination Inhibition test. Serum samples were tested using antigens from 33 arboviruses belonging to the genera Alphavirus, Flavivirus, Orthobunyavirus, and Phlebovirus. The data showed that 23.6% (17/72) of coatis were seropositive for at least one of the tested antigens, including monotypic and heterotypic reactions. Seropositivity was detected for Alphavirus (5.9%, 1/17; WEEV), Flavivirus (64.7%, 11/17; YFV, ILHV, SLEV, BSQV, ROCV, WNV, DENV-1, DENV-2, DENV-3, DENV-4, and NJLV), Phlebovirus (88.2%, 15/17; ICOV and BUJV) and Orthobunyavirus (5.9%, 1/17; ORIV). The presence of antibodies to these viruses in coatis from INP indicated an apparent silent circulation of arbovirus, implying N. nasua to be a possible amplifying host of these arboviruses in the studied area. The data reported also serve as a warning about the possible risk of establishing an arbovirus transmission cycle involving vector arthropods and coatis, or even other wild animals, consequently, including humans in this transmission chain.

Abstract We report a case of encephalitis associated with Zika virus infection and reactivation of varicella-zoster virus in the central nervous system of a Brazilian child. This case raises the possibility that reactivation of the latent varicella-zoster virus may be a mechanism of neurological impairment induced by acquired Zika virus infection.

This study showed that laboratory markers of recent infection by dengue, Zika or chikungunya arboviruses were detected in the biological samples of approximately one-third of patients with encephalitis, myelitis, encephalomyelitis or Guillain-Barré syndrome, in a surveillance programme in Piauí state, Brazil, between 2015-2016. Fever and myalgia had been associated with these cases. Since in non-tropical countries most infections or parainfectious diseases associated with the nervous system are attributed to herpesviruses, enteroviruses, and Campylobacter jejuni, the present findings indicate that in tropical countries, arboviruses may now play a more important role and reinforce the need for their surveillance and systematic investigation in the tropics.

BACKGROUND In this study, we evaluated the role of free-living domestic pigeons (Columba livia) as a reservoir of arboviruses in the city of Belém, state of Pará, Brazil. We investigated the presence of antibodies against the most prevalent arboviruses. OBJECTIVES This study was aimed at evaluating some clinical and physical parameters of domestic pigeons, including the presence of antibodies to Amazon-endemic arboviruses. METHODS Eighty-five healthy pigeons were captured in Mangal das Garças Park, in Belém, and were bled. Upon capture, the birds were subjected to a clinical examination in search of alterations that could indicate the presence of arboviruses. Blood samples were converted to serum and tested using the haemagglutination inhibition (HI) technique with a panel of 19 antigens of arboviruses circulating in the Amazon. The confirmation assay for the positive reactions to the viral species tested by HI was a neutralisation test in new-born Swiss albino mice (Mus musculus) [mouse neutralisation test (MNT)]. FINDINGS A total of 10 (11.8%) serum samples tested positive for antiflavivirus antibodies by HI. All the samples positive for the HI test were subjected to MNT for detection of viruses and yielded negative results (logarithmic neutralisation index < 1.7). MAIN CONCLUSION The results represent the first serological detection of antiarbovirus antibodies in domestic pigeons as potential hosts of arboviruses in Brazil. The detection of haemagglutination-inhibiting antibodies against genus Flavivirus indicated that there was recent contact between the analysed domestic pigeons and these arboviruses. Further studies are needed to evaluate the role of free-living pigeons in the maintenance cycle and spread of arboviruses in the Amazon.

<title>Resumo</title><p>O Estado do Pará corresponde a 26% da Amazônica brasileira, onde uma grande quantidade de Arbovírus tem sido descrito. O presente trabalho teve como objetivo determinar a prevalência de anticorpos detectados pela técnica de inibição de hemaglutinação contra nove tipos diferentes de arbovírus da família <italic>Bunyaviridae,</italic> sendo oito do gênero <italic>Orthobunyavirus: vírus Guaroa, vírus Maguari, vírus Tacaiuma, vírus Utinga, vírus Belem, vírus Caraparu, vírus Oropouche</italic> e <italic>vírus Catu</italic>e um do gênero <italic>Phlebovirus: vírus Icoaraci,</italic> em soros de búfalos de água no Estado do Pará, Brasil. Para todos os Arbovírus investigados houve presença de anticorpos, com exceção do <italic>vírus Belém.</italic>Anticorpos para o <italic>vírus Maguari</italic> foram mais prevalentes (7,33%). O rebanho bubalino do presente estudo mostrou variáveis níveis de anticorpos em reações heterotípicas e monotípicas podendo indicar que há circulação da maioria dos bunyavírus estudados em búfalos domésticos no estado do Pará, e que o vírus Maguari é o de maior circulação. Por isso, são necessários outros estudos para investigar o papel dos búfalos de água na manutenção e dispersão de arbovírus, assim como se esses vírus podem causar enfermidades na referida espécie, principalmente, em casos de defeitos congênitos e abortamentos.</p>

<title>Abstract</title><p>The State of Pará comprises 26% of Brazilian Amazon region where a large diversity of arboviruses has been described. This study sought to assess the prevalence and distribution of haemagglutination-inhibition antibodies against antigens of nine different types of arbovirus of the <italic>Bunyaviridae</italic> family, where eight were <italic>Orthobunyavirus: Guaroa virus, Maguari virus, Tacaiuma virus, Utinga virus, Belem virus, Caraparu virus, Oropouche virus</italic> and <italic>Catu virus,</italic> and one <italic>Phlebovirus: Icoaraci virus</italic> in sera samples of water buffaloes in Pará State, Brazil. For all Arboviruses investigated there were antibodies, with the exception of <italic>Belem virus.</italic> Antibodies to <italic>Maguari virus</italic>were more prevalent (7.33%). The water buffaloes of the present study showed variable levels of antibodies in monotypic and heterotypic reactions that may indicate there are movements from most bunyavirus studied in domestic buffaloes in the state of Pará, and the <italic>Maguari virus</italic> presents the largest circulation. Therefore, further studies are needed to investigate the role of water buffalo in the maintenance and dispersal of arboviruses, as well as whether these viruses can cause disease in that species, especially in cases of birth defects and abortions.</p>

Introduction Saint Louis encephalitis virus (SLEV) primarily occurs in the Americas and produces disease predominantly in humans. This study investigated the serological presence of SLEV in nonhuman primates and horses from southern Brazil. Methods From June 2004 to December 2005, sera from 133 monkeys (Alouatta caraya, n=43; Sapajus nigritus, n=64; Sapajus cay, n=26) trap-captured at the Paraná River basin region and 23 blood samples from farm horses were obtained and used for the serological detection of a panel of 19 arboviruses. All samples were analyzed in a hemagglutination inhibition (HI) assay; positive monkey samples were confirmed in a mouse neutralization test (MNT). Additionally, all blood samples were inoculated into C6/36 cell culture for viral isolation. Results Positive seroreactivity was only observed for SLEV. A prevalence of SLEV antibodies in sera was detected in Alouatta caraya (11.6%; 5/43), Sapajus nigritus (12.5%; 8/64), and S. cay (30.8%; 8/26) monkeys with the HI assay. Of the monkeys, 2.3% (1/42) of A. caraya, 6.3% 94/64) of S. nigritus, and 15.4% (4/26) of S. cay were positive for SLEV in the MNT. Additionally, SLEV antibodies were detected by HI in 39.1% (9/23) of the horses evaluated in this study. Arboviruses were not isolated from any blood sample. Conclusions These results confirmed the presence of SLEV in nonhuman primates and horses from southern Brazil. These findings most likely represent the first detection of this virus in nonhuman primates beyond the Amazon region. The detection of SLEV in animals within a geographical region distant from the Amazon basin suggests that there may be widespread and undiagnosed dissemination of this disease in Brazil.

Rocio virus (ROCV) is an encephalitic flavivirus endemic to Brazil. Experimental flavivirus infections have previously demonstrated a persistent infection and, in this study, we investigated the persistence of ROCV infection in golden hamsters (Mesocricetus auratus). The hamsters were infected intraperitoneally with 9.8 LD50/0.02 mL of ROCV and later anaesthetised and sacrificed at various time points over a 120-day period to collect of blood, urine and organ samples. The viral titres were quantified by real-time-polymerase chain reaction (qRT-PCR). The specimens were used to infect Vero cells and ROCV antigens in the cells were detected by immunefluorescence assay. The levels of antibodies were determined by the haemagglutination inhibition technique. A histopathological examination was performed on the tissues by staining with haematoxylin-eosin and detecting viral antigens by immunohistochemistry (IHC). ROCV induced a strong immune response and was pathogenic in hamsters through neuroinvasion. ROCV was recovered from Vero cells exposed to samples from the viscera, brain, blood, serum and urine and was detected by qRT-PCR in the brain, liver and blood for three months after infection. ROCV induced histopathological changes and the expression of viral antigens, which were detected by IHC in the liver, kidney, lung and brain up to four months after infection. These findings show that ROCV is pathogenic to golden hamsters and has the capacity to cause persistent infection in animals after intraperitoneal infection.

O objetivo foi avaliar a prevalência de anticorpos para arbovírus na área de influência do Projeto Juruti antes da exploração mineral local. Foram examinados 1.597 soros humanos e 85 de animais silvestres. A pesquisa de anticorpos foi realizada pelo teste de inibição da hemaglutinação contra antígenos dos arbovírus mais prevalentes na Amazônia brasileira e IgM-ELISA para dengue e febre amarela. Soros humanos inibidores da hemaglutinação positivos para Mayaro e Oropouche foram também testados por IgM-ELISA. Anticorpos inibidores da hemaglutinação para alfavírus, orthobunyavirus e/ou flavivírus foram detectados, sendo 28,7% reações monotípicas. Infecções recentes para Oropouche (n = 23), Mayaro (n = 5), e dengue (n = 20) foram confirmadas por IgM-ELISA. A prevalência de anticorpos inibidores da hemaglutinação em soros de animais silvestres foi de 8,2% para flavivírus. Os resultados obtidos mostram que houve circulação ativa dos vírus Mayaro, Oropouche e dengue no período do estudo em humanos em Juruti, Pará, Brasil, e de diversos arbovírus em animais silvestres, indicando presença desses vírus em áreas do Município de Juruti.

This study aimed to measure the prevalence of antibodies to arboviruses in the area affected by the Juruti Project before local mining operations. A total of 1,597 human and 85 wild animal sera were examined, using the hemagglutination inhibition test against 19 antigens from the most prevalent arboviruses in the Brazilian Amazon and IgM-ELISA for dengue and yellow fever. Positive sera for Mayaro and Oropouche viruses were also tested by IgM-ELISA. Prevalence of hemagglutination inhibition antibodies to alphaviruses, flaviviruses, and orthobunyaviruses in humans was 28.7%, while for wild animals it was 8.2% for flaviviruses. Recent infections based on presence of IgM was confirmed for Mayaro (n = 5), Oropouche (n = 23), and dengue (n = 20). The results showed active circulation of the dengue, Mayaro, and Oropouche viruses in Juruti, as well as flaviviruses in wild animals, suggesting the circulation of these viruses in the Municipality of Juruti.

O objetivo foi avaliar a prevalência de anticorpos para arbovírus na área de influência do Projeto Juruti antes da exploração mineral local. Foram examinados 1.597 soros humanos e 85 de animais silvestres. A pesquisa de anticorpos foi realizada pelo teste de inibição da hemaglutinação contra antígenos dos arbovírus mais prevalentes na Amazônia brasileira e IgM-ELISA para dengue e febre amarela. Soros humanos inibidores da hemaglutinação positivos para Mayaro e Oropouche foram também testados por IgM-ELISA. Anticorpos inibidores da hemaglutinação para alfavírus, orthobunyavirus e/ou flavivírus foram detectados, sendo 28,7% reações monotípicas. Infecções recentes para Oropouche (n = 23), Mayaro (n = 5), e dengue (n = 20) foram confirmadas por IgM-ELISA. A prevalência de anticorpos inibidores da hemaglutinação em soros de animais silvestres foi de 8,2% para flavivírus. Os resultados obtidos mostram que houve circulação ativa dos vírus Mayaro, Oropouche e dengue no período do estudo em humanos em Juruti, Pará, Brasil, e de diversos arbovírus em animais silvestres, indicando presença desses vírus em áreas do Município de Juruti.

This study aimed to measure the prevalence of antibodies to arboviruses in the area affected by the Juruti Project before local mining operations. A total of 1,597 human and 85 wild animal sera were examined, using the hemagglutination inhibition test against 19 antigens from the most prevalent arboviruses in the Brazilian Amazon and IgM-ELISA for dengue and yellow fever. Positive sera for Mayaro and Oropouche viruses were also tested by IgM-ELISA. Prevalence of hemagglutination inhibition antibodies to alphaviruses, flaviviruses, and orthobunyaviruses in humans was 28.7%, while for wild animals it was 8.2% for flaviviruses. Recent infections based on presence of IgM was confirmed for Mayaro (n = 5), Oropouche (n = 23), and dengue (n = 20). The results showed active circulation of the dengue, Mayaro, and Oropouche viruses in Juruti, as well as flaviviruses in wild animals, suggesting the circulation of these viruses in the Municipality of Juruti.

Descrevem-se aqui dados de prevalência de malária e soroprevalência de arboviroses na linha de base de um estudo de coorte, envolvendo 467 indivíduos, atualmente em curso na Amazônia rural. A maioria (72,2%) dos indivíduos relatou um ou mais episódios maláricos prévios, tendo 15,6% deles tido pelo menos uma internação hospitalar motivada pela malária, mas somente 3,6% dos indivíduos com idade igual ou superior a cinco anos tinham plasmódios (Plasmodium vivax em dez e P. falciparum em quatro) diagnosticados por microscopia. Detectaram-se anticorpos contra Alphavirus, Orthobunyavirus e Flavivirus, pelo teste de inibição de hemaglutinação, em 42,6% dos indivíduos com idade igual ou superior a cinco anos, com uma taxa de soropositividade maior entre indivíduos do sexo masculino (49,2%) do que os do feminino (36,2%). Como 98,9% dos indivíduos entrevistados tinham sido previamente vacinados contra a febre amarela, a presença de reações cruzadas com o vírus do dengue e outros Flavivirus não pode ser descartada, mas a exposição recente ao vírus do dengue foi evidenciada pela detecção de anticorpos IgM por ELISA em 12 indivíduos (3,3%).

The authors describe the baseline malaria prevalence and arbovirus seroprevalence among 467 subjects in an ongoing cohort study in rural Amazonia. Most subjects (72.2%) reported one or more previous episodes of malaria, and 15.6% had been hospitalized for malaria, but only 3.6% of individuals five years or older had malaria parasites detected by microscopy (10 with Plasmodium vivax and 4 with P. falciparum). Antibodies to Alphavirus, Orthobunyavirus, and/or Flavivirus were detected by hemagglutination inhibition (HI) in 42.6% of subjects aged five years or older, with a higher seropositivity rate among males (49.2%) than females (36.2%). Since 98.9% of subjects had been immunized for yellow fever, the presence of cross-reactive antibodies to dengue and other Flaviviruses cannot be ruled out, but at least 12 subjects (3.3%) with IgM antibodies to dengue virus detected by ELISA had a putative recent exposure to this virus.

Descrevem-se aqui dados de prevalência de malária e soroprevalência de arboviroses na linha de base de um estudo de coorte, envolvendo 467 indivíduos, atualmente em curso na Amazônia rural. A maioria (72,2%) dos indivíduos relatou um ou mais episódios maláricos prévios, tendo 15,6% deles tido pelo menos uma internação hospitalar motivada pela malária, mas somente 3,6% dos indivíduos com idade igual ou superior a cinco anos tinham plasmódios (Plasmodium vivax em dez e P. falciparum em quatro) diagnosticados por microscopia. Detectaram-se anticorpos contra Alphavirus, Orthobunyavirus e Flavivirus, pelo teste de inibição de hemaglutinação, em 42,6% dos indivíduos com idade igual ou superior a cinco anos, com uma taxa de soropositividade maior entre indivíduos do sexo masculino (49,2%) do que os do feminino (36,2%). Como 98,9% dos indivíduos entrevistados tinham sido previamente vacinados contra a febre amarela, a presença de reações cruzadas com o vírus do dengue e outros Flavivirus não pode ser descartada, mas a exposição recente ao vírus do dengue foi evidenciada pela detecção de anticorpos IgM por ELISA em 12 indivíduos (3,3%).

The authors describe the baseline malaria prevalence and arbovirus seroprevalence among 467 subjects in an ongoing cohort study in rural Amazonia. Most subjects (72.2%) reported one or more previous episodes of malaria, and 15.6% had been hospitalized for malaria, but only 3.6% of individuals five years or older had malaria parasites detected by microscopy (10 with Plasmodium vivax and 4 with P. falciparum). Antibodies to Alphavirus, Orthobunyavirus, and/or Flavivirus were detected by hemagglutination inhibition (HI) in 42.6% of subjects aged five years or older, with a higher seropositivity rate among males (49.2%) than females (36.2%). Since 98.9% of subjects had been immunized for yellow fever, the presence of cross-reactive antibodies to dengue and other Flaviviruses cannot be ruled out, but at least 12 subjects (3.3%) with IgM antibodies to dengue virus detected by ELISA had a putative recent exposure to this virus.