In what is almost certainly a medical first, a physician from my hometown of St. Joseph, Mo., has identified a new viral disease thought to be transmitted by ticks. The virus is related to hantaviruses, which have recently caused at least two deaths at Yosemite National Park, but so far only two confirmed cases have been observed. Because the two farmers who contracted the virus live 60 miles apart, however, researchers from the Centers for Disease Control and Prevention suspect there are probably many more unrecognized cases.
The two patients were first seen by Dr. Scott M. Folk, an infectious diseases specialist at Heartland Regional Medical Center in St. Joseph. Both were hospitalized for fever, fatigue, headache, nausea and diarrhea. The two cases were suspected to be outbreaks of ehrlichiosis, a bacterial infection, but antibiotics failed to help the patients. Both ultimately recovered on their own with supportive care from the hospital. Full recovery required a couple of months.
Folk sent blood samples from the two men to virologist Stuart T. Nichol and his colleagues at the CDC. The researchers reported this week in the New England Journal of Medicine that the samples contained a previously unseen virus. Sequencing of its genome showed the virus, which the researchers call the Heartland virus, is a member of the Bunyaviridae family of RNA viruses, which includes hantaviruses. The new virus is a member of the group called phleboviruses; the 70 distinct members of this family are most often transmitted by sand flies and mosquitoes. Only one member of the group has previously been shown to be transmitted by ticks -- the "severe fever with thrombocytopenia syndrome virus" identified last year in central and northeastern China.