Arthropod-Borne Virus Surveillance as a Tool to Study the Australian Mosquito Virome

Mosquitoes (n = 4381 in 198 pools) were collected in March and April 2018 to survey the presence of West Nile virus Kunjin strain in mosquito populations around crocodile farms in the Darwin region of the Northern Territory (NT) of Australia. While no Kunjin virus was detected in these mosquitoes, we applied our viral replicative intermediates screening system termed monoclonal antibodies to viral RNA intermediates in cells or MAVRIC to this set of samples. This resulted in the detection of 28 pools with virus replicating in C6/36 mosquito cells and the identification of three insect viruses from three distinct virus classes. We demonstrate the persistence of the insect-specific flavivirus Palm Creek virus in Coquillettidia xanthogaster mosquitoes from Darwin over almost a decade, with limited genetic drift. We also detected a novel Hubei macula-like virus 3 strain in samples from two mosquito genera, suggesting the virus, for which the sequence was originally detected in spiders and soybean thrips, might be involved in a horizontal transmission cycle between arthropods and plants. Overall, these data demonstrate the strength of the optimized MAVRIC system and contribute to our general knowledge of the mosquito virome and insect viruses.

Automated summary

Mosquito samples were collected near crocodile farms in the Darwin region of Australia to study virus population. Although no Kunjin virus was detected, the optimized MAVRIC system identified viruses from three different classes and demonstrated the persistence of an insect-specific flavivirus in mosquitoes. Additionally, a novel Hubei macula-like virus was detected in two mosquito genera, suggesting a possible horizontal transmission cycle between arthropods and plants.