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For Immediate Release •
June 27, 2008
Staff Contact: Chana Goussetis, Health Communications Specialist, Boulder County Public Health, 303-441-1457
View the most recent Press Releases.
For more West Nile Virus Information
JUNE 27, 2008 - State health officials have confirmed the first two human cases of West Nile virus for the 2008 season. The cases were reported from Boulder and Logan counties. Both patients are recovering from their illnesses.
John Pape, an epidemiologist who specializes in animal-related diseases at the Colorado Department of Public Health and Environment, explained, “West Nile virus season is here. Now is the time to take precautions against West Nile virus, which is a preventable disease.
“West Nile virus can be avoided by eliminating mosquito breeding grounds in back yards, wearing insect repellent and using other methods to avoid mosquito bites when outdoors.”
The cooperative surveillance conducted by state and local health departments started on June 1 has shown Culex mosquito populations are still low but increasing. Historically, populations of Culex mosquitoes, which transmit West Nile virus, start to rapidly increase this time of year as temperatures begin to rise. “Typically around the first week of July we start detecting our first positive mosquitoes, which the human cases show, already are out there,” Pape said.
He said each season this virus will be present and circulating around the state. The severity of the season will depend on the weather.
“Within the next couple weeks we will have an idea of how severe or mild this season may be,” he said.
Pape said 2007 was the second most active season for West Nile virus cases following the 2003 epidemic. Last year, Colorado reported 576 cases with 7 deaths. Ninety-nine cases, or 17 percent, had meningitis or encephalitis, indicating the virus had entered the central nervous system. “However, we know that even West Nile fever, the less severe form, can cause significant illness, last for weeks to months and can result in people being hospitalized. Prevention is the key,” Pape emphasized.
In reviewing statewide surveillance data from 2003 to 2006, Pape said patterns of human infections have emerged. “Approximately 85 percent of people who became ill with West Nile virus were infected when bitten by an infected mosquito during a six-week period from July 1 through the second week of August. Therefore, we are entering the peak season of West Nile virus transmission,” explained Pape.
Infected mosquitoes continue to feed through September and early October, depending on the weather, but fewer than 10 percent of human cases are contracted after Labor Day, Pape explained. “July and August are the highest-risk months of being infected, and people should be extra diligent during this time and use whatever methods available to avoid mosquito bites. This is particularly important one hour before sunset through around midnight, when Culex mosquitoes are most actively feeding,” he said.
Pape said that individuals can reduce the number of mosquitoes by cleaning out gutters and other places around their homes where there are pools of standing water that are good breeding places for mosquitoes. Such breeding grounds include empty flowerpots, plastic swimming pools or old tires. “If you have a birdbath, remember to change the water at least weekly. This also is a good time to repair torn window and door screens,” he said.
Additional precautions to take against West Nile virus include the following:
· Use precautions or avoid outdoor activities, such as gardening at dawn and after dusk when mosquitoes are most active.
· If outside at dawn or after dusk, cover up by wearing light, loose-fitting pants and long-sleeved shirts, shoes and socks.
· Use approved mosquito repellents containing DEET, picaridin or oil of lemon eucalyptus. DEET products generally provide the longest protection. The other repellents work but must be applied more frequently. Follow the product label for correct use. Products with 10 percent or less DEET are recommended for children.
Colorado has experienced five full seasons of West Nile virus transmission, each with different levels of transmission. In 2006, there were 345 cases reported with seven deaths. The mildest year thus far was 2005, when Colorado had 106 human cases and two deaths. In 2004, cases were moderate with a total of 291 human cases, including four deaths. This represented a sharp downturn from the first full season of West Nile virus in Colorado in 2003 when there were 2,947 confirmed human cases of the disease and 63 deaths. Only 14 cases were reported in 2002, when the virus was first detected in the state in August of that year. Overall, Colorado has recorded 4,280 human cases and 83 deaths, although the total number of identified cases represents only a small proportion of persons who actually became ill during this time.
Pape advised anyone who finds a dead bird to call the Colorado Health Emergency Line for the Public (CoHELP) at 1-877-462-2911. Mosquitoes feed on infected birds and then pass on the virus to humans. In addition to taking reports of dead birds, staff can answer most questions about West Nile virus. The Rocky Mountain Poison and Drug Control Center operates the hotline under contract with the Department of Public Health and Environment.
Prevention tips and additional information about West Nile virus is available online at www.FightTheBiteColorado.com.
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