SIOUX CITY | Itchy, pink bumps inflicted by pesky mosquitoes may seem synonymous with summer in the Midwest, but experts say these bites, which could be life-altering or even life-ending for some, should be avoided at all costs.
West Nile virus, a mosquito-borne virus that causes a serious neurological infection in less than 1 percent of the people it infects, is circulating once again in Northwest Iowa. The season typically lasts from late summer into early fall.
The first human case of the virus recorded in the state this season was in Ida County late last month. Around the same time, Siouxland District Health Department deputy director Tyler Brock said West Nile virus began showing up in Woodbury County's mosquito pools.
"We're starting to see more activity in some of our mosquito pools both locally and around the state," he said. "This is the time we know the virus is circulating."
Most cases of West Nile virus are mild and go unreported. Those who do develop symptoms may experience fever, tiredness, muscle aches, skin rash, swollen lymph nodes, nausea and abdominal pain for three to 10 days.
"Those that recover, eventually recover without any treatment," said Daniel Lamptey, an infectious disease specialist at Mercy Medical Center. "Some of them actually think they've had the flu or some kind of viral illness."
The first case of West Nile virus was detected in Uganda in 1937. The virus was found in the United States in 1999, with the first outbreak occurring in New York City. Human cases of West Nile virus have been reported every year in Iowa since 2002, according to the Iowa Department of Public Health.
The virus has been identified in humans in Woodbury County five of the last seven years. As many as nine cases of West Nile virus were recorded in the county in 2013. While Brock said he can't forecast West Nile virus activity so early in the season, he said he expects at least a few human cases to turn up in Woodbury County.
A hot, dry summer doesn't particularly bode well for the mosquito population, but their numbers are likely to ramp up after heavy rainfall. Mosquitoes lay their eggs in fresh or stagnant water that may be found in abandoned barrels, plastic swimming pools, bird baths and any other containers that can hold water.
Each year, the Iowa Department of Public Health, State Hygienic Laboratory, the Iowa State University Department of Entomology, the Iowa Department of Agriculture and Land Stewardship, and several local health departments partner to monitor West Nile virus activity in the state.
Siouxland District Health Department sends mosquitoes collected in its traps to Iowa State University. Entomologists then separate the mosquitoes by species before testing them for West Nile virus.
"When they get 50 or 100 of the same type, they will put them all together and they literally blend them up and test them for viruses," Brock said. "We have no idea which mosquito tested positive."
The people at greatest risk for developing West Nile virus neuroinvasive disease after being bit by an infected mosquito are the elderly, as well as individuals who are undergoing chemotherapy for cancer, have had an organ transplant or lack a cell surface protein known as CCR5. Signs of West Nile virus neuroinvasive disease include stiff neck, sleepiness, disorientation, coma, tremors, convulsions and paralysis.
During his time in Siouxland, Lamptey has seen three cases of West Nile virus neuroinvasive disease, which were diagnosed via spinal tap. He said two of those patients recovered, while the third, who was very old and had other chronic conditions, ended up dying. There are no medications available to treat West Nile virus, according to Lamptey, who said patients who are hospitalized are offered supportive treatment.
"The symptom that we worry about the most is the neuroinvasive disease -- that's when the brain itself gets involved," he said. "The disease ranges from a mild, self-limited, confusional state to severe encephalopathy, where people become comatose."
Both Brock and Lamptey urge residents to wear insect repellent containing DEET and long sleeves and pants while outdoors during peak mosquito biting times.
"The biggest thing is to really try to avoid mosquito bites," Brock said.