Infected O.C. mosquitoes signal start of West Nile virus season
May 17, 2016
Updated 8:40 p.m.
Culex quinquefasciatus, or Southern House mosquito, is the primary vector for West Nile virus.JAMES GATHANY,
SCIENTIFIC PHOTOGRAPHER, CDC
Tips
• Eliminate standing water around your house.
• Repair window and door screens.
• Wear a repellent containing DEET, Picaridin, oil of lemon eucalyptus or IR 3535.
Report a problem
By JENNA
CHANDLER /
STAFF WRITER To report dead birds or neglected pools – mosquitoes like to lay their eggs in
standing water – call the Orange County Mosquito and Vector Control District at
714-971-2421.
A new season of West Nile virus – a potentially deadly disease spread by mosquitoes – is
underway in Orange County.
Orange County Mosquito and Vector Control District officials say they collected
mosquitoes Friday in La Habra and Seal Beach that tested positive for the virus, meaning
that the insects are capable of spreading it to humans.
http://www.ocregister.com/articles/virus-­‐716204-­‐nile-­‐west.html West Nile virus season typically runs from May to October, when the weather is warm and
dry.
“It’s strikingly on time,” said Jared Dever, a vector control spokesman.
West Nile virus infection rates have intensified in Orange County the past couple of years,
with back-to-back epidemics in 2014 and 2015 that struck 377 people and killed 17.
Many people infected with West Nile never show symptoms, but among those who do, many
develop neurological complications, such as meningitis or encephalitis, which can lead to
lifelong disabilities. Of last year’s 97 reported cases, 71 were neuro-invasive and five
asymptomatic, according to OC Health Care Agency data.
Dever said it’s difficult to forecast how this season will unfold. But if there’s a high number of
infected mosquitoes and birds, the district could launch an aerial attack, spraying low doses
of the pesticide Duet from an airplane over targeted neighborhoods to kill adult mosquitoes.
Hundreds of parents have protested that proposal. Though Duet – which is highly toxic to
bees – is registered with the Environmental Protection Agency, Dr. Dean Baker, director of
UC Irvine’s Center for Occupational and Environmental Health, has said the EPA does not go
far enough in testing the pesticide’s health effects on children.
District trustees are expected to talk about who has the authority to pull the trigger on aerial
spraying at their Thursday meeting. Last month, trustees voted not to give the district’s
manager unilateral power to make that decision.
“That’s definitely something the district manager wants to discuss at the board meeting, the
alternative to ‘adulticiding,’ bolstering outreach and education, and the authority to do the
aerial application, that was left largely unresolved,” Dever said.
West Nile virus seasons weren’t always so unpredictable.
Scientists once knew that every fourth year – most recently 2004, 2008 and 2012 – would
bring a high number of human infections. The four-year waves coincide with the life cycle of
birds, an important part of the West Nile virus transmission cycle.
Mosquitoes pick up the virus after biting an infected bird, then pass it on to more birds. Once
a bird has the disease, it becomes immune for its short life, but its offspring will be
susceptible.
The years 2014 and 2015, however, “didn’t play by the rules,” Dever said, and officials do not
know why.
Contact the writer: [email protected] and @jennakchandler on Twitter
http://www.ocregister.com/articles/virus-­‐716204-­‐nile-­‐west.html