Drought not slowing spread of West Nile

Amanda Larson shares an after-school moment with Hailey, 7, and Nathan, 5, in their Volga home. Larson spent more than a week in the hospital and is now recovering at home after contracting West Nile Meningeal Encephalitis. She thinks her illness traces back to July 20, when she spent time out in her yard. Photo by John Kubal/Register

• South Dakota especially hard hit

BROOKINGS – Unpredictability: if there's one word that could be used to describe the who, what, where, when, why of the West Nile virus, that's it.

One man working in a team effort to bring a "predictability factor" to an illness that in a worst-case scenario can cripple or kill is Michael Hildreth. He's an entomologist and professor in South Dakota State University's departments of Biology and Microbiology and of Veterinary and Biomedical Sciences.

By way of graphic self-description, Hildreth said, "I'm a parasitologist, so I study anything that lives inside you or anything that sucks things out of you – the mosquitoes and internal parasites, tapeworms, that kind of stuff."

He's been working on West Nile issues for the past 10 years.

As of Aug. 31, South Dakota is reporting 98 cases of West Nile virus, with one death and 45 percent of those infected requiring hospitalization. Ages range from 12 to 80 years old.

Texas has been hardest hit with 45 percent of the nation's reported cases; South Dakota, Louisiana, Mississippi, Oklahoma, and Michigan are the other hardest hit states.



'We don't know, don't ask'

Since large infestations of mosquitoes are usually associated with wetter years, a question being asked this year is why so much West Nile virus when much of the nation is abnormally dry or suffering drought.

"This year there's just a lot more virus out there," Hildreth said.

Looking back to 2010, he added, "We had the highest population of culex tarsalis mosquitoes that we'd ever seen in Brookings County. That was true statewide.

"Lots of vector mosquitoes, but for whatever reason it didn't amplify in the birds. We don't know why; so don't ask. It's driving me crazy. There's a few things about this story that just keeps me up at night."

Hildreth is able to explain the West Nile virus in simple, layman's terms: "This is a bird virus. We're a secondary host. Birds are very suspectible.

"A person would have to get bitten by a tarsalis; and that tarsalis would have to be infected in order for that person to have a chance of picking up the infection. Not everybody is suseptible to infection.

"Once you've had the disease, the dogma is that you don't get it again. They call that 'lifelong immunity.'"



Why worse some years

Hildreth is among those scientists and researchers who want to know why the virus ampifies in birds more in some years than in others.

He said, "There's lots of people, brighter people than me, that are trying to figure that out. They want to be able to predict this.

"They want to be able to say in May this is going to be a bad year because these are the conditions that would enable that virus to amplify."

A "predictability factor" is the main focus of the research in which Hildreth is participating.

There is some predictability at present, with a network of South Dakota cities – Sioux Falls, Watertown, Brookings, Aberdeen and Pierre – collecting mosquitoes and sending them to Pierre for testing that can determine if the West Nile virus is amplifying.

Hildreth said, "We saw in June that this thing was starting to amplify and we started putting the word out that this is going to be a bad year."

But that only gives a two- to three-week warning period "before humans start to get infected."

Considering again the wet versus dry conditions and numbers of mosquitoes tied to them, he explained, "There are 42 different species of mosquitoes; two of those species make up about 90 percent of the mosquitoes found in our state.

"One is a 'nuisance mosquito'; the other is the culex tarsalis. Tarsalis can handle drier conditions better."

Hildreth added of the issue of susceptibility: "There are places and times where getting bitten puts one greater at risk. Culex feeds later at night than nuisance mosquitoes."



'Teeny, tiny bits and pieces'

The statistics of the West Nile virus are the stuff of the Centers for Disease Control and Prevention and state health departments. In human terms, each person infected has to face the reality of dealing with it. And many times the sickness the virus brings can impact a family, friends and community.

Such was the case for the Larson family of Volga: John and Amanda Larson, and their children, Nathan, 5, and Hailey, 7.

Amanda, 30, is able to piece it all together. It began July 20, at a family gathering at the Larson home at which her sister, a niece and nephew were also present.

She recalls, "We were all outside, and my legs were covered with mosquitoes; I don't really remember getting bit by any mosquitoes this year, other than that one night. I'm going with that date."

On July 30, Monday, Amanda thought she was getting a migraine headache. The next day, while working, she texted her husband: "I feel like I got hit by a truck. My head hurts so bad."

On Wednesday, her aunt came over to help her get out of bed. Amanda shut down her day-care facility. Her aunt took her to the Brookings Medical Clinic, which immediately sent her to the Brookings hospital emergency room.



Losing track of time

"I was so sick; I was out of it," Amanda said. She added that she felt like she "was there for only a few minutes."

Laughing, she added, "They tell me I was there for five or six hours before I got sent to Sanford (Hospital, Sioux Falls)."

She later learned that while in Brookings she had tested postive for meningitis; but since there was uncertainty as to whether it was bacterial or viral, a treatment regimen for bacterial infection was started: antiobiotics, pain medication and fluids.

"I actually never learned I had West Nile until my seventh day in the hospital," she said. "I remember teeny, tiny bits and pieces from the time I left my house that Wednesday until probably the seventh day. I don't know if they weaned me off pain medicines or if the fever and all that stuff was starting to break."

Amanda returned home to Volga on Aug. 8. She continues to recover, but she hasn't reopened her day-care center.

"I still have fevers; they say that's my body's way of trying to work West Nile out of my system." She also tires easily. And while she "wants so desparately to get back to work," she appreciates that she has to pace herself. The recurring fevers are her body's way of saying "you're overdoing it."



Used to chaos

Amanda admits that she's "so used to the crazy chaos of having day-care," some days up to a dozen children, "depending on the day." She opened her facility about seven years ago, following graduation from SDSU with a bachelor's degree in early childhood development.

John, who works for 3M in Brookings, has lived in Volga since he was a fifth-grader; Amanda is a Volga native. Both attended and graduated from Sioux Valley High School.

She sees herself blessed with an "amazing family and friends and the Brookings and Volga communities." She has received many prayers and cards: "It's so overwhelming."

In a way, the effect that the West Nile virus had on one family in Volga shows how unpredictable it can be when it strikes.

Amanda said, "You never expect yourself to get in a situation where you're that sick. I learned how sick I was from everybody else.

"You don't ever expect that you're going to be the one to get it. We were silly. I never put bug spray on this year. I hadn't noticed the mosquitoes were that bad."

That evening of July 20, Amanda learned otherwise; but, she added, "My kids didn't have a bug-bite on them."



Editor's note: Amanda's friends and family are holding a benefit dinner and auction to help defray some of the costs of her illness. It's scheduled for Friday, Sept. 14, at 7 p.m. in the Volga City Auditorium.



Contact John Kubal at jkubal@-brookingsregister.com.