“It’s unreal,” said Randy Wishard, the environmental health manager for the Richmond County Health Department.
Mosquito Control has logged 900 complaints so far this year, compared with 512 all of last year, operations manager Fred Koehle said.
“We’re going to double it easily,” he said.
One day Koehle cleared 30 calls off the answering machine, only to come back in the afternoon and find 30 more.
The Centers for Disease Control and Prevention reported 1,590 confirmed human cases in 48 states, including Georgia and South Carolina. Georgia has had 21 confirmed human cases, including one in Columbia County and one in Richmond County, and three deaths. South Carolina reported eight cases with three in Aiken County but no deaths.
Nationally, that is the highest number of human cases since a major outbreak in 2002-03 and the highest since the virus emerged in the U.S. in 1999, said Dr. Lyle R. Petersen, the director of the Division of Vector-Borne Infectious Diseases for CDC. The virus is harbored in almost every place in the country and circulates every year, he said.
“It’s just a matter of how much,” Petersen said. “It’s really a confluence of environmental factors that are important in determining whether an outbreak will occur.”
It can be difficult to predict because it depends on a number of factors, such as the number of birds that are susceptible to the virus and help it circulate, for which there is no accurate count.
One factor could be the heat wave that baked much of the middle of the country, where the highest number of cases are occurring, Petersen said. Past heat waves, such as the one in 2002-03, also coincided with West Nile virus outbreaks, he said.
Hurricane Isaac will probably not help fuel the outbreak even as it hits some of the states, such as Louisiana, with high numbers of cases. Historically, hurricanes have not resulted in more mosquito-borne disease.
Extensive flooding tends to wipe out the small pools of water this particular mosquito likes to breed in, Petersen said.
Hurricane Katrina, which produced a small increase, was an exception, probably because more people were exposed to the elements from extensive damage to homes.
Because of the high number of calls in Richmond County, Mosquito Control has taken to spraying whole streets and is working some Friday and Saturday nights to try to catch up, Koehle said.
Spraying has been shown to help reduce viral transmission, Petersen said.