When the CDC names a new microbe one of its top threats, and that threat is spread by ticks, those of us in the Lyme endemic regions of New England sit up and take notice.
Meet the Heartland Virus, the first U.S. discovered member of a large group of phleboviruses that cause a variety of fevers, from limited to hemorrhagic. Being transmitted by ticks, the Heartland would be classified as a member of the Uukuniemi group. The other grouping is transmitted by sand flies, though it makes me wonder about our black fly population here in Maine.
Wikipedia’s phlebovirus entry ends there, listing off all the Heartland virus’s cousins and extended family. Nothing about its likely symptoms and treatment.
Medline isn’t much more use, listing Heartland virus only ten times and documenting that the virus did exist in ticks on the infected farmers’ fields. (here). Researchers: “found antibodies against virus nucleoproteins in 10%-18% of samples from cattle, sheep, goats, deer, and elk in 24 Minnesota counties.”
If we look broadly at Heartland Virus, it comes from a larger family Bunyaviridae, which includes Crimean–Congo hemorrhagic fever (CCHF) and Tomato spotted wilt virus (TSWV), which makes me either want to run screaming or to laugh. I’m sure spotted wilt is no laughing matter, I’d just much prefer it to anything with hemorrhagic in the name. But evidently it is already here according to the always reliable? wikiworld: “Hanta virus or Hantavirus Hemorrhagic fever, common in Korea, Scandinavia, Russia, and western North America, is associated with high fever, lung edema and pulmonary failure. Mortality is around 55%.”
In confirming hantavirus in the U.S., (on medline) a twenty year surveillance confirmed 624 cases of Hantavirus in the U.S. Most of those occurred west of the Mississippi with rodents as likely carriers. So it is possible that Heartland Virus is simply a mutation of an existing problem rather than an entirely new virus.
Dropping down from the larger family to the Phleboviruses again, Heartland virus is most similar to Rift Valley Fever Virus. That virus can be fatal, but only becomes serious in about 2% of cases. Most individuals get a mild fever and recover.
But Rift Valley is spread by mosquitoes, not ticks that can remain on the body much longer. Anyone who has followed the Lyme disease discussion knows that “full recovery” means some lasting effects for some patients.
By putting it at the top of the threats list, the CDC is virtually guaranteeing heightened awareness, testing, and increased diagnosing of a disease that may have been here for some time. In ten years time we may see a sudden “epidemic” of Heartland Virus where none had been diagnosed before. I hope we will develop treatments and care for patients before then.