W. Nile spraying
Excerpts from the Sacramento Bee:
"State health officials and toxicologists said the insecticide is benign to humans and mammals at the low concentrations that will be used. The active ingredients are pyrethrins, natural insecticides produced by chrysanthemum flowers, that readily degrade in sunlight...
The number of reported cases of Sacramento County residents infected with the virus rose to 21 on Thursday, the most of any California county, state health records show. Last year's toll was 3.
Brown said some traps in northern Sacramento County have turned up rates as high as one in 10 mosquitoes infected.
"That's extremely high," he said, noting that state guidelines for West Nile virus surveillance suggest that an infection rate much lower - one in 200 - is very high.
Dr. Glennah Trochet, the county public health officer, said the high insect infection rate means, "we are going to have a lot of cases coming in."
The county also has experienced a high number of infected birds, said Vicki Kramer, chief of the vector-borne disease section at the state Department of Health Services.
"All these are high indications that the risk of transmission is increasing." Kramer said. "So it's prudent to initiate large scale control - the best weapon we have right now from preventing people from getting sick."
About 80 percent of people with West Nile virus infections don't feel sick, health officials say.
About 20 percent will get flu-like symptoms, including headache, fever, fatigue and body aches. Less than 1 percent become gravely sick with neurological illnesses such as meningitis and encephalitis. Neuroinvasive cases can be fatal. The virus killed 28 people in California last year."
Full article: http://www.sacbee.com/content/news/sacramento/story/13357266p-14199048c.html
Also from the Sacramento Bee:
"Brown said the unusual combination of heavy rains into mid-June, followed by a stretch of 100-degree-plus days, sent mosquito populations soaring.
"I would love to have given people a month's notice," Brown said. "I don't think anyone thought it would hit this hard, this fast, this early.""
Full Article: http://www.sacbee.com/content/news/medical/story/13381617p-14223184c.html
Pyrethrins:
http://pmep.cce.cornell.edu/profiles/extoxnet/pyrethrins-ziram/pyrethrins-ext.html
http://www.pesticideinfo.org/Detail_Chemical.jsp?Rec_Id=PC34291
http://www.atsdr.cdc.gov/tfacts155.html
www.cdpr.ca.gov/docs/empm/pubs/pyrethfate.pdf
Sacramento, Spraying, and W. Nile
http://www.sacdhhs.com/article.asp?ContentID=391 - also has many other links to info