Ticks are ectoparasites spread worldwide and are well known as vectors of many viruses of great importance to human and animal health. However, the viral diversity in ticks is still poorly understood, particularly in South America. Here we characterized the viral diversity present in Rhipicephalus microplus parasitizing cattle in the southern region of Brazil using metagenomics. Our study revealed the presence of viruses that had not been previously described in the region, including lihan tick virus (Phenuiviridae family) and wuhan tick virus 2 (Chuviridae family), as well as expands the biogeography of jingmen tick virus (Flaviviridae family) in Brazil. Also, we described three novel tymoviruses (Tymovirales order), named guarapuava tymovirus-like 1 to 3. We described the genomic and phylogenetic characterization of these viruses. Our study sheds light on the viral diversity of Rhipicephalus microplus in South America, and also expands the biogeography of tick viruses that were previously described only in Asia.

Chapparvoviruses are a highly divergent group of parvoviruses (family Parvoviridae) that have recently been identified via metagenomic sampling of animal faeces. Here, we report the sequences of six novel chapparvoviruses identified through both metagenomic sampling of bat tissues and in silico screening of published vertebrate genome assemblies. The novel chapparvoviruses share several distinctive genomic features and group together as a robustly supported monophyletic clade in phylogenetic trees. Our data indicate that chapparvoviruses have a broad host range in vertebrates and a global distribution.

The World Health Organization considers the Zika virus (ZIKV) outbreak in the Americas a global public health emergency. The neurologic complications due to ZIKV infection comprise microcephaly, meningoencephalitis, and Guillain-Barré syndrome. We describe a fatal case of an adult patient receiving an immunosuppressive regimen following heart transplant. The patient was admitted with acute neurologic impairment and experienced progressive hemodynamic instability and mental deterioration that finally culminated in death. At autopsy, a pseudotumoral form of ZIKV meningoencephalitis was confirmed. Zika virus infection was documented by reverse trancriptase-polymerase chain reaction, immunohistochemistry, and immunofluorescence and electron microscopy of the brain parenchyma and cerebral spinal fluid. The sequencing of the viral genome in this patient confirmed a Brazilian ZIKV strain. In this case, central nervous system involvement and ZIKV propagation to other organs in a disseminated pattern is quite similar to that observed in other fatal Flaviviridae viral infections.

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The genus Phlebovirus includes the sandfly fever viruses and tick-transmitted uukuviruses. Sandfly fever group viruses have been isolated from various vertebrate species and from phlebotomines and occasionally alternative arthropods, e.g. mosquitoes, or ceratopogonids of the genus Culicoides. Uukuniemi serogroup viruses have been isolated from various vertebrate species and from ticks. Despite the public health importance of some viruses of the genus, the genomic diversity of phleboviruses that could be incriminated as causative of human or veterinary diseases remains underestimated. Here we describe the nearly complete sequences and genomic characterization of two phleboviruses belonging to the Bujaru antigenic complex: the prototype species and the Munguba virus. Furthermore, six previously unclassified phleboviruses isolated in Brazil were also sequenced and characterized: Ambe, Anhanga, Joa, Uriurana, Urucuri and Tapara viruses. The results of the phylogenetic analysis indicated that these viruses group with viruses of three antigenic complexes (Bujaru, Tapara and frijoles clades), with two unclassified phleboviruses. We also performed genomic reassortment analysis and confirmed that there were no events for the viruses described in this study, but we found a new potential reassortment in Medjerda Valley virus, which contains S and L segments of Arbia virus, and probably a unique M segment, both viruses circulate in the same geographic region, indicating these two isolates represent two distinct viruses. This study provides insights into the genetic diversity, classification and evolution of phleboviruses.

BackgroundChikungunya (CHIKV) virus is an important mosquito-borne virus causing outbreaks of acute febrile illness with arthropathy. The detection of specific antibodies against CHIKV is used for diagnosis after the acute viremic phase of the disease. However, a major challenge for serologic diagnosis of CHIKV and other alphaviruses is the cross-reactivity of antibodies to common antigens among these viruses. In the present study, we have developed an enzyme-linked immunosorbend assay using a recombinant envelope protein 2 of CHIKV produced in Escherichia coli system, as a capture antigen.ResultsHigh titers (1600 to 12,800) of anti-CHIKV antibodies were detected in human sera analyzed by the CHIKV assay, suggesting it may detect low levels of the antibodies presence. On the other side, cross-reactivity was not observed in mouse hyperimmune sera to Mayaro virus and other alphaviruses analyzed by the CHIKV immunosorbend assay, suggesting it is a CHIKV-specific test. Fifty-nine human serum samples of CHIKV infection suspected cases were tested for immunoglobulin G (IgG) and M (IgM) antibodies detection using the CHIKV immunosorbend assay. A total of 44% (26/59) of samples were positive for IgG to CHIKV, determining 89.66% sensitivity and 100% specificity when the assay is compared to a CHIKV-specific neutralization assay. In addition, 40.6% (24/59) of samples were positive for IgM, determining 92.48% sensitivity and 79.04% specificity by a Bayesian method in the absence of a gold standard. Moreover, CHIKV immunosorbend assay showed similar sensibilities to a commercial immunochromatography assay (Lumiquick, USA) for CHIKV IgG and IgM detection.ConclusionIn short, we have developed a rapid, simple, specific and sensitive CHIKV immunosorbend assay for IgG and IgM detection and our results showed potential applicability on the diagnosis of infections by this virus.Electronic supplementary materialThe online version of this article (10.1186/s12985-018-1028-1) contains supplementary material, which is available to authorized users.

The Hepeviridae comprise single-stranded positive-sense RNA viruses classified into two genera, Orthohepevirus and Piscihepevirus. Orthohepeviruses have a wide host range that includes rodents, but previous studies had been restricted to rodents of the Muridae family. In this study, we applied a high-throughput sequencing approach to examine the presence of orthohepeviruses in rodents from São Paulo State, Brazil. We also used RT-PCR to determine the frequency of orthohepeviruses in our sampled population. We identified novel orthohepeviruses in blood samples derived from Necromys lasiurus (1.19%) and Calomys tener (3.66%). Therefore, our results expand the host range and viral diversity of the Hepeviridae family.