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| March 19, 2006 Mosquito Season Predicted to Arrive Early This Year The University of California and mosquito abatement districts are predicting that the mosquito season and the West Nile virus will arrive earlier this year. Gregory Lanzaro, entomology professor and director of the UC Davis Center for Vectorborne Diseases, said standing water from winter storms, warmer temperatures and longer daylight hours mean breeding and blood-sucking by the Culex mosquitoes, the principal carriers of the virus. "These conditions are like their wake-up call. The mosquitoes that were infected with WNV before they went into their semi- hibernation or diapause, still have the virus. They're loaded and ready to go,'' Lanzaro said. The Culex mosquitoes are usually the most active in California from April to October, but unseasonable spring-like weather awakens them like an alarm clock, Lanzaro said. The Culex female lives about three weeks and can lay 250 eggs in her lifetime. Last year the virus, transmitted by a mosquito bite, killed 18 people in California and infected 900 others. The virus was found in all 58 counties. UC Davis medical entomologist Robert Washino predicts a very high mosquito population. Washino said long-term studies show heavy snow packs in the Sierra Nevada Mountains, a series of hard-hitting storms with abnormally high rainfall in the Central Valley and spring-like weather accompany high mosquito populations. Prevention starts with eliminating standing water on your property,'' said David Brown, manager of the Sacramento-Yolo Mosquito and Vector Control District. Sacramento County was the nation's hot spot regarding the virus last year with 175 human cases. The virus also infects and kills horses and birds. Health officials estimate one in five people bitten by an infected mosquito become ill and less than 1 percent of infected individuals will require hospitalization. People over age 50 and the immune-compromised are most susceptible to the disease. Most WNV infections are mild with flu-like symptoms. Severe infections can cause stiff necks, disorientation, coma, tremors, convulsions, muscle weakness, paralysis and rarely death, Lanzaro said. The most serious symptom is encephalitis, or inflammation of the brain.
Contact: |
UC Mosquito Research Program - Department of Entomology - UC Davis - UC Agriculture and Natural Resources
One Shields Avenue, Davis, CA 95616
© 2006, The Regents of the
University of California.
Comments or Questions: Nancy Dullum, Program Assistant
Last updated:
03/20/2006