Heartland Virus Disease

Heartland virus is a phlebovirus. It was first found in patients in Missouri in 2009. CDC says the Lone Star tick is mainly responsible for spreading it to people. The disease is uncommon. As of November 2022, CDC reported more than 60 cases across the eastern, southeastern, and south-central US. Its early symptoms look a lot like ehrlichiosis, another Lone Star tick illness. That is one reason doctors consider it when an ehrlichiosis-like illness does not improve with standard antibiotics. Because it is a virus, antibiotics do not treat it.

• Fever
• Fatigue (feeling very tired)
• Decreased appetite
• Headache
• Nausea
• Diarrhea
• Muscle or joint pain
• Lower-than-normal white blood cell count (leukopenia) on lab tests
• Lower-than-normal platelet count (thrombocytopenia) on lab tests
• Mild to moderate rise in liver enzymes (transaminases)

A few days to several weeks after a tick bite. CDC says the incubation period (the time from tick bite to feeling sick) ranges from a few days to several weeks. Most patients reported being exposed to ticks in the two weeks before they got sick. Most became ill between May and September.

Heartland virus disease is diagnosed based on symptoms, a history of tick exposure or time where the Lone Star tick lives, and lab tests. Routine blood work often shows low white blood cell counts, low platelet counts, and mildly high liver enzymes. There is no commercial test in the US. Molecular (RT-PCR) and antibody tests are done at CDC, with samples sent through state health departments. Doctors may think of Heartland virus in patients being treated for ehrlichiosis who do not improve on doxycycline.

There are no antiviral medicines or vaccines for Heartland virus. Antibiotics do not treat it because it is a virus. Care is supportive, which means easing symptoms with rest, fluids, and over-the-counter medicine for fever and pain. Some patients have needed hospital care for supportive treatment. Rarely, severe illness and death have occurred, most often in people with weakened immune systems or several other health problems. Anyone who feels ill after a tick bite should contact a doctor.

There is no vaccine, so preventing tick bites is the best protection. CDC recommends EPA-registered insect repellents, such as those with DEET, picaridin, IR3535, oil of lemon eucalyptus, PMD, or 2-undecanone. It also recommends treating clothing and gear with 0.5% permethrin. Avoid tall grass and brushy areas where Lone Star ticks wait for hosts. After being outdoors, check your whole body for ticks and shower within about two hours. Tumble dry clothes on high heat for 10 minutes to kill any ticks. Check pets and gear too, and remove any attached tick right away.

Heartland virus cases have been reported in the eastern, southeastern, and south-central United States, matching the Lone Star tick's range. Reported cases have clustered in states across the Midwest and South, including Missouri and nearby areas. But the tick's range is growing. Cases are still rare. The true number of infections may be higher than reported, because the disease can be mistaken for other illnesses.