The Heartland virus (HRTV) is a novel, tick-borne Phlebovirus discovered in northwestern Missouri by Dr. Scott Folk of Heartland Regional Medical Center in St. Joseph, Missouri.
The virus first appeared in humans in June 2009 when two farmers, living 60 miles (97Â km) apart, presented with the following symptoms: fever, fatigue, diarrhea, thrombocytopenia, and leukopenia.
It is a member of the Bhanja virus serocomplex; the recently discovered <i>SFTS virus from China is a related species causing a similar disease.
The virus has been traced by researchers from the CDC and Missouri Western State University back to the Lone Star Tick, which transmits the virus to people when feeding on blood. Work continues as of 2013 to identify the reservoir host.
Characteristics
The Heartland virus is part of the Bunyaviridae family of viruses which contain 3 segments of -ssRNA. The genus of the virus is Phlebovirus and the species is the Heartland virus.
Transmission
The Heartland virus has been isolated from the Lone Star Tick (Amblyomma americanum). The phleboviruses, in general, can be transmitted by mosquitoes, ticks and sand flies. Patients in all known cases of the Heartland virus in the United States reported being bitten by ticks in the previous 14 days. The reservoir host has yet to be identified.
Signs and symptoms
Fever in excess of 100.4°F (38°C), lethargy (weakness), headaches, myalgia (muscle pain), loss of appetite, nausea, diarrhea, weight loss, arthralgia (joint pain), leukopenia (low white blood cells) and thrombocytopenia (low platelets). Elevated liver transaminases may also be present.
Risk factors
All known cases reported in the United States have been reported in three states: Missouri, Tennessee, and Oklahoma. Patients in all currently known cases spent a fair amount of time outdoors in regions where ticks were endemic, all patients were aged over 50. All cases occurred from May - September.
Diagnosis
Diagnosis is currently through the elimination of other causes of infectious diseases with related symptoms like ehrlichiosis and anaplasmosis; or if the patient fails to respond to treatment with the antibiotic doxycycline. RT-PCR may then be used to detect viral ssRNA in the blood. Antibody titers against the virus may also be used to indicate infection with the Heartland virus.
Treatment
Treatment is non-specific. Antibiotics are not useful against viruses. Intravenous fluid administration and medications for the relief of pain are currently the best options.
Prevention
Use insect repellents on yourself and your gear. Completely cover your body with long sleeves and pants. Avoid bushy and wooded areas. Perform thorough tick checks after spending time outdoors and remove any tick found immediately.
If you encounter a tick on your body or your animal, remove the tick by the head. Squeezing the abdomen of a tick while it is attached can force bacteria and viruses into the bite wound. Squishing the unattached tick to kill it can release bacteria and viruses from the abdomen of the tick which may then be able to enter a wound or burrow through skin.