Biology subjects

Tanianis-Hughes, J.

Publications and source records attributed to Tanianis-Hughes, J..

3 recordsLinked to original sources

bioRxiv2025

Lack of Vector Competence in UK Culex pipiens molestus for Oropouche Virus

Oropouche virus (OROV) is an orthobunyavirus (Peribunyaviridae) that has caused recurrent outbreaks in South America and has recently expanded into the Caribbean, with various biting midge and mosquito species considered vectors. Recent imported cases to Europe and North America have raised concerns about the potential for local transmission in non-endemic areas. To assess this risk in the United Kingdom, we investigated the vector competence of Culex pipiens molestus (Cx. molestus), a human-biting mosquito common in urban environments. Laboratory-reared adult females were fed a bloodmeal containing a Cuban 2024 OROV outbreak strain (240023) and maintained at 27{degrees}C. Of 64 individuals tested at 12-s14 days post-infection via plaque assay, none were positive for OROV in bodies, indicating no evidence of infection and subsequently limited or no vector competence potential. These results provide evidence that UK populations of Cx. molestus are unlikely to support OROV transmission, thereby refining assessments of OROV emergence risk in temperate settings. Further studies are needed to test other putative UK mosquito vectors, as well as Culicoides biting midge species to fully assess the potential for OROV transmission in this region.

microbiology↗

bioRxiv2025

Impact of temperature on vector competence of Culex pipiens molestus: implications for Usutu virus transmission in temperate regions

IntroductionUsutu virus (USUV) has been detected annually in the southeast of England since 2020. USUV RNA has been identified in wild birds and mosquito populations, and exposure of captive birds to USUV at Zoological Society of London (ZSL) has also been confirmed. Since its first detection in London, USUVs distribution has expanded across the South East, highlighting a need to understand the transmission dynamics of this virus in the UK. The primary vectors of USUV in the UK are likely Culex pipiens mosquitoes. Two biotypes have been identified, the bird-feeding Cx. pipiens pipiens and Cx. pipiens molestus which shows no restriction in host preference. The latter may play an important role in transmitting USUV from birds to humans. MethodsA laboratory colony of Cx. pipiens molestus mosquitoes were orally infected with the London strain of USUV and, incubated at 22 {degrees}C, 20 {degrees}C and 18{degrees} C for up to 28 days. Body samples and mosquito saliva samples were collected and analysed using a quantitative real-time reverse transcription PCR to determine infection and transmission potential, respectively. ResultsUSUV RNA was detected in all sample times at all temperatures assessed; with the highest temperature (22 {degrees}C) showing the greatest proportion of saliva and body positive samples. At this temperature, there was also an eight-fold increase in the relative viral copy number in the mosquito bodies, which was unobserved at other experimental temperatures. When a more sensitive PCR assay was used at the lowest experimental temperature used (18 {degrees}C) USUV RNA was present in the mosquito saliva and body samples for longer and showed a greater proportion of positive samples when compared to 20 {degrees}C. ConclusionThis study has demonstrated that Cx. pipiens molestus may be able to transmit USUV at 22 {degrees}C. Active replication of USUV was identified in the mosquito bodies at 22 {degrees}C but could not be demonstrated at lower temperatures, suggesting that 20 {degrees}C to 22 {degrees}C may be an important temperature threshold in USUV replication and transmission. Utilisation of a more sensitive assay for the lower experimental temperatures revealed that USUV was detectable at 18 {degrees}C. Therefore, when conducting infection studies on temperate mosquito-borne viruses, it is important to consider assay sensitivity.

molecular biology↗

bioRxiv2024

UK mosquitoes are competent to transmit Usutu virus at native temperatures

Usutu virus (USUV) is an emerging zoonotic virus transmitted primarily by Culex mosquitoes. Since its introduction into Europe from Africa during the late 20th century, it has caused mortality within populations of passerine birds and captive owls, and can on occasion lead to disease in humans. USUV was first detected in the UK in 2020 and has become endemic, having been detected in either birds and/or mosquitoes every subsequent year. Importantly, the vector competence of indigenous mosquitoes for the circulating UK (London) USUV strain at representative regional temperatures is still to be elucidated. This study assessed the vector competence of five field-caught mosquito species/biotypes, Culex pipiens biotype molestus, Culex pipiens biotype pipiens, Culex torrentium, Culiseta annulata and Aedes detritus for the London USUV strain, with infection rates (IR) and transmission rates (TR) evaluated between 7 to 28 days post-infection. Infection and transmission were observed in all species/biotypes aside from Ae. detritus and Cx. torrentium. For Cx. pipiens biotype molestus, transmission potential suggests these populations should be monitored further for their role in transmission to humans. Furthermore, both Cx. pipiens biotype pipiens and Cs. annulata were shown to be competent vectors at 19{degrees}C indicating the potential for geographical spread of the virus to other UK regions.

ecology↗