Stormwater retention ponds could spread deadly mosquito virus
Stormwater retention ponds that are increasingly used in the US to reduce contaminants from roads and pavements being washed into water courses - and to prevent flooding, could be aiding the spread of the mosquito-borne West Nile virus that has claimed 12 lives so far this summer.
The Washington Post reports that as concern over the mosquito-borne virus heightens, the effort to create new ponds and clean up old ones has pit two environmental causes against each other.
There are thousands of stormwater ponds in the Washington area, with more being created every year, often near businesses and homes. However, so far this year, the virus, which causes inflamation of the brain, has been reported in 37 states in central and eastern regions of the US, as well as the District of Columbia and New York City this year. By 21 August there had been 253 human cases, including 12 deaths, according to the US Department of Health and Human services.
Last year only 66 people were diagnosed with the virus, of which nine died, and in 2000 and 1999, there were 21 and 62 reported cases respectively, with two people dying in 2000 and seven the year before.
The virus is a disease of birds, with 110 species known to have been infected, which passes to humans through mosquitoes.
Although many ponds are designed to drain and dry within 48 hours, a recently published study reveals that even the best designed basins harbour mosquitoes because their drains clog up and city employees are unable to keep up their maintenance, reports the newspaper.
“It drives us crazy,” Cyrus Lesser, chief of the mosquito control section of the Maryland Department of Agriculture is reported as saying in the Washington Post. The ponds “are everywhere, and they give us fits. The worst part is that they are being installed adjacent to business and residential areas, right next to where people live.”
The US Department of Health has provided an additional US$14 million funding in the last couple of weeks to help the worst affected states strengthen their efforts to combat the virus. People are warned to avoid being bitten by mosquitoes, and to report dead birds to state and local health departments.