West Nile Virus in Iowa

An Iowa man has tested positive for West Nile virus, marking the first confirmed human case in the state.

The 50-year-old Lee County resident was hospitalized for nine days, but has been released, said Kevin Teale, communications director for the Iowa Department of Public Health. The man’s identity has not been released.

The mosquito-borne illness has killed 21 people around the United States, and experts said things will get worse before they get better.

Thomas Gahan, public health microbiologist for the University of Iowa, said the peak of the West Nile virus season occurs during the first two weeks of September.

He said the number of cases being reported should begin to decrease in mid-to-late September.

“We’ve been rather fortunate so far because the mosquito population in Iowa has been almost nonexistent,” said Wayne Rowley, professor of entomology.

The Centers for Disease Control and Prevention has reported more than 450 human cases of the virus in the United States. Infected birds, horses and chickens were found in 75 Iowa counties. More than 80 dead birds and 35 horses have tested positive for the virus in the state.

The effects of West Nile

The virus is transmitted from birds to humans via mosquitoes. Humans cannot contract the virus by handling a contaminated animal or by contact with another infected human. Crows and blue jays are more sensitive to the virus, and the mortality rate is higher.

There is a vaccination available for horses. Rowley said it is important to get horses vaccinated.

There is no human vaccine, however. Additionally, West Nile, like all viruses, is untreatable.

Gahan said the virus is associated with a wide range of symptoms in humans from headache to seizures, depending upon the severity of the illness.

“The symptoms are very similar to flu symptoms,” he said. “Usually people are forced to go to the doctor because of the headache.”

He said in many cases, the headache can get quite severe.

“They end up knowing there is something wrong,” Gahan said.

“I think folks probably have a sense of a headache that might be different than a routine headache. In those cases, they may want to seek medical advice.”

Rowley said in extreme cases the virus can cause West Nile encephalitis, or swelling of the tissue lining the brain, which can be deadly.

“Usually, severe illness is in less than 1 percent of the cases,” Gahan said.”Those folks are usually the elderly or may be immunosupressed due to conditions like organ transplant or diabetes, or another such illness.”

Rowley said in the majority of the West Nile virus cases that caused death, the victim was over 65. The CDC encourages people who are feeling ill and showing flu-like symptoms to visit their doctor.

“Most people who get the virus get some flu-like symptoms, but a lot of people had antibodies in their system,” Rowley said.

He also said people with the antibodies may not know they are infected.

Countering the threat

Rowley has been working with the entomology department in trapping mosquitoes all over the state. He said the trapped mosquitoes are separated according to species and sent to the University of Iowa for testing.

“Des Moines, Polk County and Ames have organized mosquito-control programs and many small towns have ultra-low volume foggers or sprayers,” Rowley said.

He said larger cities like Davenport and Cedar Rapids are not spraying for mosquitoes.

Gahan said the bite of a mosquito infected with the virus is no different than the bite of an uninfected mosquito.

The threat won’t last much longer, if the weather cooperates, he said.

“I would hope things would kind of be settling down in the next few weeks with the fall weather,” Gahan said. “There will be decreased mosquito activity and we can hope for cooler weather.”

In the meantime, he said, students need to protect themselves from mosquitoes.

“Until it gets cold, everyone needs to be aware the virus is common,” Rowley said. “Mosquito repellents with DEET (N,N-diethyl-meta-toluamide) just work.”

Of other products, such as citronella, Rowley said “they just don’t work in this situation.”

Gahan said the best form of prevention is avoidance of mosquitoes.

“If you’re going out in the evenings, use repellents that contain DEET,” Gahan said. “Wear light-colored clothing and long sleeves to minimize the amount of skin visible.”

Gahan said students who are involved in outdoor activities need to use personal protective measures. Rowley said mosquito repellent that contains 15 to 35 percent DEET should be effective.

The CDC recommends getting rid of areas where mosquitos may lay eggs.

“We are seeing this is a rapidly emerging infection here in Iowa,” Teale said. “It clearly has grown by leaps and bounds.”

The virus appeared in the United States in 1999, according to the CDC.

Teale said last year there was only one case of the virus in Iowa – a dead bird in Scott County.