Scientists decode West Nile mosquito’s DNA

WASHINGTON - An international team of researchers has cracked the DNA sequence of the mosquito species whose bite transmits West Nile virus, St. Louis encephalitis virus and the microscopic worm responsible for elephantiasis.

“Culex pipiens quinquefasciatus is the most widely distributed mosquito in the world, and in terms of disease transmission to humans it’s one of the three most important mosquito species,” said University of Texas Medical Branch professor Stephen Higgs.

“Our basic question is why do certain mosquito species transmit a particular virus and other mosquito species do not? Why don’t they all carry all the viruses? We don’t know, but now we have three different systems for comparative studies to investigate interactions between viruses and mosquitoes,” said UTMB assistant professor Dana Vanlandingham.

In the first of the Science papers researchers announce that they have identified all of Culex quinquefasciatus’ 18,883 genes. The second paper focuses specifically on that immune response.

UTMB’s biosafety level 3 laboratories contributed significantly to its data on West Nile virus by allowing researchers to safely infect Culex mosquitoes with West Nile virus and then extract genetic material that provided information on the mosquitoes’ response to the virus.

“There have been about a million human infections with West Nile in the United States and, presumably, hundreds of millions of bird infections. Almost every one of those infections was started by a mosquito bite,” Higgs said.

“We’ve been able to see some parts of the Culex West Nile virus picture, but we haven’t had the appropriate tools for detailed genetic studies. This work will provide the base for a lot of people to investigate mosquito-borne pathogens, from multiple angles,” Vanlandingham said.

The study will appear in the Oct. 1 issue of Science. (ANI)