KANSAS CITY, Mo. (AP) - Federal health officials have been working to determine the source of a new virus recently discovered in northwest Missouri, where it sickened two men who live miles apart and who reported having tick bites days before they were hospitalized in 2009.
The Centers for Disease Control and Prevention said in a recently published report it is so far unclear what causes the new virus, which has been named the Heartland virus. But the CDC said an investigation is under way to determine if the illness, which includes symptoms of fever, diarrhea and fatigue, stems from bites from ticks, mosquitoes or other insects. Both patients recovered after about a month.
The authors of the report published in the Aug. 30 issue of the New England Journal of Medicine include CDC scientist Dr. William Nicholson and Dr. Scott Folk, director of infectious diseases at Heartland Regional Medical Center in St. Joseph, where the two men who contracted the virus were treated in June 2009.
Folk said the men - one aged 57, the other 67 - were hospitalized for about 10 days. The men live about 60 miles apart and did not know one another. Folk said he initially suspected both men had contracted a tick-borne infection called ehrlichiosis, which has similar symptoms, so he sent their blood samples to the CDC for identification. He treated both men with the standard antibiotic treatment for ehrlichiosis, but found they didn't respond well.
Robert Wonderly, now 61, of Sheridan, was one of the men infected. He said in a recent interview that when he first came down with the illness he thought he was having a heart attack.
"My chest was real heavy," he said. He went to work at a Maryville factory anyway, but his wife called the doctor who insisted he get checked out. Wonderly was sent to Heartland, where a nurse called Dr. Folk after learning Wonderly had recently been bitten by a tick.
"It's been my experience that people started to feel better within a day or two (of beginning antibiotics). But these patients did not get better," Folk said. "They deteriorated a little bit. Their white blood cell counts got lower before they got higher."
Nicholson said the CDC had been analyzing the specimens for ehrlichiosis but that "it turned out to be something completely unique."
The new virus is a previously undetected phlebovirus, and is suspected to be tick-related, said Laura McMullan, senior scientist at CDC who was also involved in the research. Heartland virus also appears to be from the U.S., and not an import, she said.
"So what is important about the discovery of this virus is it's different from other known phleboviruses, meaning it's something that's unique. We would not have previously suspected that this virus was around in the U.S. without the discovery," she said.
Nicholson said considerably more work remains to be done to fully understand Heartland virus. He said while the two men in northwest Missouri are the only two documented cases, it's likely others have been infected. The CDC has been working with Missouri health officials and other hospitals to determine the prevalence of the virus.
"To identify the full spectrum and what is the true public health impact of this virus we really don't know at this point," Nicholson said. "It would be purely speculative at this point."
CDC researchers have been collecting samples from the two patients' farms to determine if the illness comes from ticks or other insects and what other animals might also be involved. Nicholson said the CDC hopes to know by the end of the year whether the virus is tick-related.
"We hope we would develop vaccines or antiviral therapies but that would be down the road," McMullan said. The immediate need is for prevention, including using insect repellent and wearing long sleeves and pants, the CDC says.
Wonderly said he has vague memories of his hospital stay, but remembers his fever reached about 105 degrees for a few days. He said he still gets tired more easily than before he contracted the virus, but is unsure if it's related to the illness.
"The only thing I care about is if there are other people who've had problems before me, maybe we can (help) them know there's something else to look for," he said.