New Human Tick-borne Virus Identified

Another day, another new infectious disease. In the midst of a record-breaking West Nile virus outbreak that has claimed 66 lives and infected almost 1,600 in 2012, we have a new threat from my least favorite external parasite, the tick. This newly discovered virus dubbed the “Heartland virus” is yet another reason to protect you and your pet from ticks this fall.

The CDC is reporting that in 2009 two Missouri farmers fell sick after being bitten by ticks.  One man reported a single bite while the second estimated about 20 tick bites per day during a two-week period. Both initially experienced memory loss, decreased appetite, fever, diarrhea, and low platelet and white blood cell counts, all consistent with a relatively common tick-borne bacterial infection, ehrlichiosis. The first patient spent 10 days in the hospital while the other patient stayed 12 days. Both were treated with appropriate antibiotics but failed to get better. Eventually both improved but for one of the men the symptoms lingered. That’s what ultimately attracted the attention of the CDC.

The first patient, who recalled only a single tick bite, continued to have memory problems, decreased energy levels, and frequent headaches for the next two years. No one knew why. Meanwhile, a new tick-borne virus was identified in China late last year. Known as SFTSV, this infection shared the same clinical signs as those reported in the Missouri farmers. This led CDC researcher Dr. Laura McMullan to reopen those cases to search for a connection. Was it the same virus? A mutation? She needed to know because the Chinese were reporting mortality rates with their new disease as high as 12%.

Turns out she was right. The virus is related to SFSTV and demonstrates how little we understand about the unseen world of tiny ticks, parasitic insects, and the diseases they may carry. In the New England Journal of Medicine article in which the findings were published, the authors warn, “This virus could be a more common cause of human illness than is currently recognized.” Another good reason to avoid tick bites.

The Heartland virus takes its name because it is believed to be spread by ticks common in the Southeast. The lone star tick is the most common species of tick in Missouri. It’s also a common tick in North Carolina, the Southeast, and along the entire Atlantic coast. To date no ticks have been found carrying the Heartland virus. It’s unknown if the new disease can be spread from one person to another or even if the disease is definitively spread by tick bites or if another insect or factor is involved. The CDC published its early findings in order to help any patients bitten by ticks that fail to improve after antibiotic treatment.  At this point Heartland virus is not believed to carry a significant risk or death or serious illness. It does not appear to affect animals.

Now is the time to protect both you and your pet from ticks. Talk to your vet about a safe and effective tick preventive for your dog and cat. Wear long pants, use a tick repellent containing at least 20% DEET, and avoid high grass and wooded areas whenever possible to reduce your risk of tick bites.