New breed of mosquito may carry viruses
A mosquito, which is active all year round, rather than just in the warmer months, is raising concerns about the role it may play in the transmission of viruses in Australian cities, new research shows.
The research has also prompted warnings to local authorities that by increasing underground water storage in our cities, they could be creating new habitats for the mosquito pest.
A three-year study by University of Sydney researchers has been looking at the Culexmolestus, more commonly known as the ‘London Underground Mosquito’.
Dr Cameron Webb, from the University’s Department of Medical Entomology and Pathology said the mosquito was named for its ability to feast on Londoners who took shelter in the underground train network during the bombings of the city in World War II.
“One of the most important findings of this study was that an analysis of weekly mosquito trapping over a 13 month period indicated that the mosquito remains active over cooler months, whereas almost all other mosquitos disappear during winter,” Dr Webb said.
“The mosquito is unique in that it prefers to live in underground environments but there are now concerns regarding the role this mosquito may play in the transmission of mosquito-borne viruses in Australian cities.
“We normally think of mosquitos being a problem in the tropical regions of the world but as the outbreak of West Nile virus in North America last year showed us, temperate regions of the world are at risk too.
“It is a common misconception that mosquito-borne diseases in Australia are limited to our northern states. Disease caused by Ross River virus and Barmah Forest virus are commonly reported from southern states and, increasingly, at the fringes of cities such as Sydney, Melbourne and Perth.”
Dr Webb is the team leader of the study which has been published in this month’s edition of the Australian Journal of Entomology.
The research shows that the mosquito has been collected in more than 230 locations across Australia. However, no specimens have been reported from Queensland or the Northern Territory.
Dr Webb said populations of this mosquito had not been the focus of substantial research in Australia for more than 50 years.
“The project was designed to address the gaps in our knowledge of this species with a view to assisting in the assessment and management of mosquito-borne disease risk in our cities,” he said.
“Genetic analysis of specimens from throughout Australia, as well as Asia, Europe and North America, indicate that the species was most likely introduced from Japan.”
It has long been suspected that the mosquito hitched a ride to Australia with military movements into Victoria during WWII.
“The results of this study support that theory. This research project has filled some gaps in our knowledge of this often overlooked and unusual mosquito,” Dr Webb said.
“The implications from this research are that local authorities must be mindful of this mosquito’s ability to exploit unexpected underground habitats. As we increase water storages in metropolitan regions of Australia, we must be careful not to create new underground habitats for this pest mosquito.
Much of the work for the project was conducted by PhD candidate Nur Abu Kassim who was awarded a scholarship from the Ministry of Higher Education Malaysia and Unversiti Sains Malaysia to undertake her PhD in Australia.
Image by John Tann on Flickr, used under Creative Commons licence