The heat wave that brought California down this summer was accompanied, besides the hundreds of fires, by perfect conditions for the spread of the West Nile virus. Last year, this mosquito-borne illness has lead to the death of 21 state residents, therefore it is not something that should be taken lightly.

With all the burnt down areas and all the drought that have been going on all throughout the state, there still are numerous sites offering the ideal humidity and temperature conditions for the development of the virus. It’s been noticed that hot weather accelerates the breeding cycle of mosquitoes as well as the replication of the West Nile virus inside the insects. According to UC Davis entomologist Bill Reisen, when the temperature increases from 60 to 90 degrees, the breeding cycle of mosquitoes decreases from ten to about four days.

As Dr. Gil Chavez, chief of the Center for Infectious Diseases at the California Department of Public Health, said, very hot weather and standing water do not add up to a good result.

The way the transmission works goes like this: the virus is acquired by mosquitoes from birds and then passed on to humans. Once a human is bitten, depending on the person’s size and immune system state, it takes from three to twelve days for the symptoms to appear.

In California, the West Nile situation began back in 2004; since then, every summer in July and August, numerous cases are reported. For 2008, only three cases have been signaled so far, one in Tulare County and two in Stanislaus. 

Eastern Contra Costa County has built a mosquito fish aquarium; these fish can eat up to 500 larvae a day. Residents are encouraged to visit the site, grab a batch of fish and populate any stagnant water they are not very comfortable with. There is also a state-managed full-time crew visiting unattended waters, in charge with restoring fish populations.