Utah agencies tracking the West Nile virus and preventing its spread are winding down the 2004 campaign. But they caution that until temperatures drop to 27 degrees for two to three days, mosquitoes can continue to bite.
The virus was detected in 11 of Utah's 29 counties this year. In all, the virus was found in 11 humans, five horses, 28 sentinel chickens, three dead birds and 144 mosquito batches.
This was the virus' second year in Utah, which historically has been the worst year for a virus, with a dramatic increase in cases expected. It didn't happen that way in Utah. Officials credit a combination of unprecedented multi-agency collaboration on mosquito-control efforts, including eradicating mosquitoes at the larvae stage, a public education campaign on how to avoid being bitten and a heap of help from Mother Nature.
The Salt Lake Mosquito Abatement District, for example, "did at least twice as much killing of larvae in water and twice as much spraying for adult mosquitoes," said Sammie Dickson, who directs the district's efforts. "It was an all-out assault. We started early in the year."
Even more important, he said, Mother Nature was cooperative. The first virus-positive mosquitoes showed up about when expected, in early August. Then the weather flipped with an early, two-week period of cool temperatures that Dickson said "prevented what could have been a number of cases in Salt Lake City. That probably occurred up and down" the state. "Mosquito Abatement deserves some credit, and Mother Nature a lot of credit."
Utah abatement efforts were different from those of some neighboring states and so were the results, he said. Grand Junction, Colo., had 125 human cases, a high number for a city of its size. Just over the state border in Utah, Moab and Uintah County had some virus-bearing mosquitoes, but very low numbers of infections.
"I would venture to say Colorado did a lot of aerial spraying, but not until there were human cases. Moab and Uintah did extensive larvae control from early on. They deserve a pat on the back," he said.
Health officials were happy that so many people also apparently paid attention to the "Fight the Bite" education campaign, designed to get people to wear DEET-containing products and take other measures to prevent infection when outdoors from dusk to dawn, when the mosquitoes carrying West Nile bite.
They also took DEET products into vulnerable populations, handing out DEET wipes at outdoor concerts and to migrant populations and the homeless, said Jana Kettering, health spokeswoman. Staffers made hundreds of education presentations in community locations like nursing homes and schools. The Utah Advertising Federation created an ad campaign, and local TV and radio stations aired it voluntarily. And officials from state and local health departments, Wildlife Resources, Agriculture and Food, the Utah Public Health Laboratory and others held educational sessions with members of the media so reporters would understand how the disease spreads and infects people and how that spread can be prevented, as well as how the state intended to respond to the threat.
"We instituted an approach that was massive in scale," said Kettering. "It's hard to recall another team approach such as this one on any other infectious disease. It's definitely a model we plan to use for SARS and influenza and others in the future."
With West Nile, that emphasis was on taking a creative and aggressive approach to tackling a statewide concern. For instance, she said, mosquito abatement experts even had "kids on bikes throwing stuff that kills mosquitoes into puddles in parks."
She also noted that there was not much overlap between 2003's mosquito year and 2004's. Only in Duchesne, Emery and Utah counties was the virus detected both years, said Kettering, most likely because of the massive effort targeting areas where the virus was known to have already been present.