Enhanced arbovirus surveillance with deep sequencing: Identification of novel rhabdoviruses and bunyaviruses in Australian mosquitoes
ABSTRACT Viral metagenomics characterizes known and identifies unknown viruses based on sequence similarities to any previously sequenced viral genomes. A metagenomics approach was used to identify virus sequences in Australian mosquitoes causing cytopathic effects in inoculated mammalian cell cultures. Sequence comparisons revealed strains of Liao Ning virus (Reovirus, Seadornavirus), previously detected only in China, livestock-infecting Stretch Lagoon virus (Reovirus, Orbivirus), two novel dimarhabdoviruses, named Beaumont and North Creek viruses, and two novel orthobunyaviruses, named Murrumbidgee and Salt Ash viruses. The novel virus proteomes diverged by ≥50% relative to their closest previously genetically characterized viral relatives. Deep sequencing also generated genomes of Warrego and Wallal viruses, orbiviruses linked to kangaroo blindness, whose genomes had not been fully characterized. This study highlights viral metagenomics in concert with traditional arbovirus surveillance to characterize known and new arboviruses in field-collected mosquitoes. Follow-up epidemiological studies are required to determine whether the novel viruses infect humans.
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ABSTRACT: In the present review article epidemiology of Japanese encephalitis, disease incidences and its control measures have been described in detail. Among important reasons of JE outbreak are registered demographic clustering, ecological imbalance, and insecticide resistance in target mosquito species, poor economy, lack of socio cultural environment and timely therapeutics. Other complex reasons are negative anthropogenic activities like mixed agro-pig farming practices, paddy farming and sanitation. Water contamination led to the spillovers of the virus from its wildlife reservoir into pig population as well as other vertebrate hosts. This article also explains emergence of new mutant variants/ new genotypes /ecological strains of JE virus and its spread in endemic to non-endemic areas. Due to re-circulation of virus among various hosts and insect vectors, disease is causing vey high mortality and morbidity in rural and suburban endemic areas. In addition, presence of revertants in overlapping generations of virus joins and reorganizes distanced epidemiology in the area. It has led to induction of high sero-conversion rate in patients. Present review aims to explain all the reasons of JE epidemics, and justify need of proper surveillance, rapid diagnosis, long term safer immunization, vector control and socio-clinical management of JE infection. This article emphasized an urgent need of potential immunization, implementation of planning to improve economic, environmental and socio-cultural conditions. It also strongly indicates need of regular surveillance and immunization of JE affected population to maintain high therapeutic standards to control JE epidemics.American Journal of Infectious Diseases and Microbiology,. 01/2015; 3(3 1):38-64.
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ABSTRACT: The Mapputta serogroup tentatively contains the mosquito-associated viruses Mapputta, Maprik, Trubanaman and Gan Gan. Interestingly, this serogroup has previously been associated with an acute epidemic polyarthritis-like illness in humans; however, there has been no ensuing genetic characterisation. Here we report the complete genome sequences of Mapputta and Maprik viruses, and a new Mapputta group candidate, Buffalo Creek virus, previously isolated from mosquitoes and detected by serology in a hospitalised patient. Phylogenetic analyses indicate that the group is one of the earliest diverged groups within the genus Orthobunyavirus of the family Bunyaviridae. Analyses show that these three viruses are related to the recently sequenced Australian bunyaviruses from mosquitoes, Salt Ash and Murrumbidgee. A notable feature of the Mapputta group viruses is the absence of the NSs (non-structural) ORF commonly found on the S segment of other orthobunyaviruses. Viruses of the Mapputta group have been isolated from geographically diverse regions ranging from tropical Papua New Guinea to the semi-arid climate of south-eastern Australia. The relevance of this group to human health in the region merits further investigation.PLoS ONE 01/2015; 10(1):e0116561. · 3.53 Impact Factor
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ABSTRACT: Several new viruses have emerged during farming of salmonids in the North Atlantic causing large losses to the industry. Still the blood feeding copepod parasite, Lepeophtheirus salmonis, remains the major challenge for the industry. Histological examinations of this parasite have revealed the presence of several virus-like particles including some with morphologies similar to rhabdoviruses. This study is the first description of the genome and target tissues of two new species of rhabdoviruses associated with pathology in the salmon louse. Salmon lice were collected at different Atlantic salmon (Salmo salar) farming sites on the west coast of Norway and prepared for histology, transmission electron microscopy and Illumina sequencing of the complete RNA extracted from these lice. The nearly complete genomes, around 11 600 nucleotides encoding the five typical rhabdovirus genes N, P, M, G and L, of two new species were obtained. The genome sequences, the putative protein sequences, and predicted transcription strategies for the two viruses are presented. Phylogenetic analyses of the putative N and L proteins indicated closest similarity to the Sigmavirus/Dimarhabdoviruses cluster, however, the genomes of both new viruses are significantly diverged with no close affinity to any of the existing rhabdovirus genera. In situ hybridization, targeting the N protein genes, showed that the viruses were present in the same glandular tissues as the observed rhabdovirus-like particles. Both viruses were present in all developmental stages of the salmon louse, and associated with necrosis of glandular tissues in adult lice. As the two viruses were present in eggs and free-living planktonic stages of the salmon louse vertical, transmission of the viruses are suggested. The tissues of the lice host, Atlantic salmon, with the exception of skin at the attachment site for the salmon louse chalimi stages, were negative for these two viruses.PLoS ONE 11/2014; 9(11):e112517. · 3.53 Impact Factor