West Nile poses a threat, despite dry weather

Although no cases have been reported this summer, officials say it’s prime time for the virus.

Bryan Roth

With an unusually dry summer slowly winding down, prime season for West Nile virus is here, officials say.

So far, there have been no reports of the disease in either Monroe or Ontario counties, but Monroe County Department of Health spokesman John Ricci said the threat heightens at the end of August and early September.

“I don’t know that anyone completely understands why this year West Nile just seems to not have surfaced as it has in past years,” he said. “We want people to still be aware that the problem could still arise and we don’t want people to become complacent and ignore it should the mosquito population pick up.”

Six reports of dead birds with the virus and 22 infected mosquito pools have been reported in New York as of Aug. 10. That’s drastically down from last year’s tally of 264 dead birds, 380 infected mosquito pools, and 23 infected humans and two horses. Four of those human infections resulted in death, although that only occurs in about 1 in 150 human cases.

Bob King, director of the Agricultural and Life Sciences Institute at Monroe Community College, said the lack of rainfall is a big reason for the decrease. In order for mosquitoes to lay eggs and find a comfortable habitat, there needs to be pooling of water.

The area experienced its driest May ever, and the rest of the summer has been far behind normal as well.

According to the National Climatic Data Center, the average rainfall for May in Rochester between 1920 and 1995 was 2.6 inches. This year, the area only got 0.24 inches of rain. June’s total of 2.3 inches was behind the average of 2.8, as was July’s 2.31, which was less than the 2.8 average.

With a heavy rain, mosquitoes could start laying eggs again in only take a few days, King said. Buckets, pool covers and other things that collect water act as breeding grounds.

“It only takes four days for mosquitoes to breed and when we have these dry spells, people may be lackadaisical as it relates to proper maintenance,” King said. “It wouldn't take much, but a quarter inch of rain to fill ... rain catchers could have a mosquito population explode starting day four.”

The collection of infected birds is also down this year, according to state Department of Environmental Conservation wildlife pathologist Ward Stone.

Stone, who works out of the Delmar office, said that in a “good” reporting year, they usually receive notification of about 3,000 birds. So far, they’ve only had a few hundred, which is about 300 birds behind the amount at this time last year.

“We have to watch and see what happens in the coming weeks because it has the potential to build up high, depending on what the weather does,” he said. “It’s time for people to be cautious, whether they’re hearing reports in their area or not. A lack of reports could be lack of submissions and testing more than anything else.”

While the East has had it relatively easy this summer, it hasn’t been the case for states west of the Mississippi River. In the northeast, Pennsylvania is the only state to have reported a human disease case.

California had reported 64 human cases as of Aug. 7 with South Dakota having the second most at 46.

The most common form of transmission is through mosquito bites after the bugs have fed on infected birds. Once in the mosquito’s blood, the virus can be injected into humans and animals. Typical warning signs in humans are flu-like symptoms.

In order to avoid the risk of West Nile virus, officials suggest using insect repellent, avoid pooled water and prime mosquito time, which is usually from dusk to dawn.
King said residents should stay up to date with what’s going on and to keep an eye on the weather.

“The rain has been lighter than average, absolutely,” King said. “But, we may get all our rain in a four- to five-day period and we’re right back it mosquito haven.”

To report a dead bird believed to have West Nile virus, call 866-537-BIRD. For more information on West Nile virus, visit the Centers for Disease Control at cdc.gov.

West Nile a problem for birds, too

Even though humans in New York have had an easy time with West Nile virus this year, state Department of Environmental Conservation wildlife pathologist Ward Stone said local bird populations haven’t had it so easy.

Crows are common targets of the virus, but Stone said other birds like the black-capped chickadee, blue jay and Bicknell’s thrush have started to dwindle as well.
“About 20 species of birds have declined since 1999, when West Nile came in,” he said. “Some bird populations just can’t take a whole extra lot of mortality.”

From 2001 to 2006, the state Department of Health reported that 4,279 dead birds were found with the virus. Of that number, 85 were in Monroe County and 40 were in Ontario County.

Monroe County Department of Health Spokesman John Ricci said the number of overall bird testings is down in the area.

“It could be a function that residents are finding fewer dead birds to notify us about or maybe people are just seeing fewer crows,” he said.

Stone said that since he and a team of scientists discovered West Nile in the state in 1999, he’s been agonizing over how it affects the bird populations. There’s no sure-fire way of knowing exactly what is happening to them.

“I wrote some e-mails on it and letters but so far there hasn’t been much of a response,” he said. “This is a day and age of when more infections and parasites are introduced and we don’t even know what’s going on with West Nile with our own bird population.

Not that many people are paying attention to it and they should.”

Fast Facts

This summer has been light with West Nile Virus reports compared to other years: