Seattle-area residents who take advantage of the summer evenings outdoors are not alone. Mosquitoes also are enjoying the favorable conditions by finding a tasty meal, especially at dawn and dusk.
Public Health -- Seattle & King County is reminding people to protect themselves against mosquitoes, which can be carriers of the West Nile virus.
Although it was not detected in the county in 2007, health officials had been concerned that the virus would hit the state in high numbers based on the virus progression from east to west.
Instead, eight horses, one dog, and one bird -- all in Yakima County -- contracted the virus.
"It's hard to say ... we have no indication or reason why that was," agency spokeswoman Hilary Karasz said of last year's low numbers.
"We know it can hit somewhere, but we can't predict when. What we do know is that it's pandemic and here to stay, and that people need to protect themselves."
West Nile is transmitted through a bite from an infected mosquito, which can become a carrier after feeding on a bird that has the virus.
The health agency recommends that people use insect repellents containing DEET, picaridin, oil of lemon eucalyptus or IR3535, and wear long-sleeved shirts, long pants and socks.
Mosquitoes need only a saucer-sized amount of water to lay eggs, Karasz said.
"Go out, survey your yard and dump water that is stagnant," she said. "This is all it takes, tipping it out."
The agency also asks the public to report dead crows or any dead bird in the corvid family -- jays, magpies and ravens. A spike in crow deaths in an area may indicate that West Nile is present because the birds can become sick and die quickly from the virus, Karasz said.
West Nile first appeared in Seattle and King County in October 2006 when six birds and a horse tested positive for it.
Rain and warm weather provide breeding grounds for mosquitoes, and it is important for people to continue eliminating or monitoring the water sources near their homes, she said.
According to health officials, most people who are infected with West Nile will not get sick. Those who do -- one in five infected -- develop symptoms such as fever, headache and body aches between three and 14 days after initial contact.
One in 150 people will develop more severe symptoms. Severe symptoms may include headache, high fever, neck stiffness, stupor, disorientation, tremors, convulsions, muscle weakness, paralysis and coma.
People with milder symptoms may recover in a few days. For individuals with serious symptoms, recovery can last for several weeks and neurological effects may be permanent.
People over 65 and individuals with weak immune systems have a higher risk of developing serious symptoms of West Nile, said Dr. Jeff Duchin, chief of communicable diseases at Public Health -- Seattle & King County.
Although cases involving pregnant women and children have been rare, it is still important for those groups to wear protective clothing and use repellent.
"No one should get a mosquito-borne disease if they can prevent it," Duchin said.
There is no specific treatment for West Nile, and there is no vaccine available. Treatment for severe cases may involve hospitalization, intravenous fluids, respiratory support and prevention of secondary infections.
Vaccinations are available for horses, and owners can contact their veterinarian for more information.
As of July 8, 22 cases from eight states had been reported to the Centers for Disease Control and Prevention.
In 2007, there were 3,630 human cases of West Nile from 44 states reported to the CDC and 124 people died from the virus. The first case of West Nile was detected in Uganda in 1937. It appeared in North America in New York in 1999.
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