The insect-specific Palm Creek virus modulates West Nile virus infection in and transmission by Australian mosquitoes

Hall-Mendelin, Sonja, McLean, Breeanna J., Bielefeldt-Ohmann, Helle, Hobson-Peters, Jody, Hall, Roy A. and van den Hurk, Andrew F. (2016) The insect-specific Palm Creek virus modulates West Nile virus infection in and transmission by Australian mosquitoes. Parasites and vectors, 9 1: . doi:10.1186/s13071-016-1683-2

Author Hall-Mendelin, Sonja
McLean, Breeanna J.
Bielefeldt-Ohmann, Helle
Hobson-Peters, Jody
Hall, Roy A.
van den Hurk, Andrew F.
Title The insect-specific Palm Creek virus modulates West Nile virus infection in and transmission by Australian mosquitoes
Journal name Parasites and vectors   Check publisher's open access policy
ISSN 1756-3305
Publication date 2016-07-25
Sub-type Article (original research)
DOI 10.1186/s13071-016-1683-2
Open Access Status DOI
Volume 9
Issue 1
Total pages 10
Place of publication London, United Kingdom
Publisher BioMed Central
Collection year 2017
Language eng
Formatted abstract
Background: Insect-specific viruses do not replicate in vertebrate cells, but persist in mosquito populations and are highly prevalent in nature. These viruses may naturally regulate the transmission of pathogenic vertebrate-infecting arboviruses in co-infected mosquitoes. Following the isolation of the first Australian insect-specific flavivirus (ISF), Palm Creek virus (PCV), we investigated routes of infection and transmission of this virus in key Australian arbovirus vectors and its impact on replication and transmission of West Nile virus (WNV).
Methods: Culex annulirostris, Aedes aegypti and Aedes vigilax were exposed to PCV, and infection, replication and transmission rates in individual mosquitoes determined. To test whether the virus could be transmitted vertically, progeny reared from eggs oviposited by PCV-inoculated Cx. annulirostris were analysed for the presence of PCV. To assess whether prior infection of mosquitoes with PCV could also suppress the transmission of pathogenic flaviviruses, PCV positive or negative Cx. annulirostris were subsequently exposed to WNV.
Results: No PCV-infected Cx. annulirostris were detected 16 days after feeding on an infectious blood meal. However, when intrathoracically inoculated with PCV, Cx. annulirostris infection rates were 100 %. Similar rates of infection were observed in Ae. aegypti (100 %) and Ae. vigilax (95 %). Notably, PCV was not detected in any saliva expectorates collected from any of these species. PCV was not detected in 1038 progeny reared from 59 PCV-infected Cx. annulirostris. After feeding on a blood meal containing 107 infectious units of WNV, significantly fewer PCV-infected Cx. annulirostris were infected or transmitted WNV compared to PCV negative mosquitoes. Immunohistochemistry revealed that PCV localized in the midgut epithelial cells, which are the first site of infection with WNV.
Conclusions: Our results indicate that PCV cannot infect Cx. annulirostris via the oral route, nor be transmitted in saliva or vertically to progeny. We also provide further evidence that prior infection with insect-specific viruses can regulate the infection and transmission of pathogenic arboviruses.
Keyword Aedes aegypti
Aedes vigilax
Culex annulirostris
Insect-specific flavivirus
Palm Creek virus
West Nile virus
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes Article number 414

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Chemistry and Molecular Biosciences
School of Veterinary Science Publications
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Created: Fri, 29 Jul 2016, 10:33:22 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences