Virus-Carrying Mosquitoes Spreading to New Regions

Scientists track carriers of dengue and chikungunya infection

By Mary Elizabeth Dallas

Monday, July 6, 2015

MONDAY, July 6, 2015 (HealthDay News) -- Mosquitoes typically found in tropical regions are expanding into new areas, including the United States, where they could transmit disease, a new study finds.

Once introduced through major shipping routes, mosquitoes carrying viruses such as dengue and chikungunya spread quickly over land, according to the Oxford University researchers.

The study findings were published recently in the journal eLife.

Using detailed records, including national entomological surveys, the scientists created global distribution maps of two species of dengue- and chikungunya-carrying mosquitoes.

"Given the lack of a vaccine or any antiviral treatment for either virus and the debilitating pain they both cause, knowing where the mosquitoes are spreading to and where they might turn up next is crucial for helping to protect communities," study first author Moritz Kraemer, a doctoral student in epidemiology at Oxford in England, said in a journal news release.

The tiger mosquito (Aedes albopictus) has rapidly expanded in parts of the United States, southern Europe and China over the past 10 to 15 years, the researchers found.

Cities around the world are especially vulnerable to the spread of the yellow fever mosquito, Aedes aegypti. This insect also carries the other viruses and lays its eggs in containers such as abandoned tires and buckets. Although this mosquito can be found in Brazil, China, Taiwan and the United States, yellow fever infection from a mosquito bite isn't common in the United States, the researchers noted.

Dengue fever, the world's most common insect-borne virus, causes 100 million infections every year. And the spread of the chikungunya virus into the Americas has already caused more than 1 million cases of disease, according to the study.

"We have made our data openly available so they can be used straight away to help protect people against these viruses about which we still know so little and have so few defenses," study lead author Simon Ha said in a journal news release.

SOURCE: eLife, news release, June 30, 2015

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