Tick-Borne Virus Could be Common Cause of Illness
The scientists working at the Centers for Disease Control (CDC) reported last week that the two men, who fell ill after being bitten by ticks and whose symptoms failed to improve with antibiotic treatment, were tested for other tick-borne bacterial diseases, such as Lyme disease, and were found not to be infected. The tests revealed, instead, a previously unknown virus in the patients’ blood. In the paper published in the New England Journal of Medicine McMullan, et al, suggested that the Heartland virus “could be a more common cause of human illness than is currently recognized.”
Symptoms of Heartland Virus Similar to Lyme Disease and Co-infections
One of the men fell ill after a single tick bite, whereas the other suffered some twenty tick bites a day over a two-week period. Both lived on farms and both fell ill with a fever, fatigue, diarrhoea, and low levels of blood platelets (thrombocytopenia) and white blood cells (leukopenia). Such symptoms are common in ehrlichiosis, a potential co-infection with Lyme disease, but neither man was found to have this bacterial infection when tested using polymerase-chain-reaction (PCR). Instead, the men were found to be infected with viruses consistent with members of the Bunyaviridae family and further tests revealed that the viruses were novel members of the phlebovirus genus, not previously identified in the Americas.
Heartland Virus Prognosis
One of the men spent ten days in hospital and initially suffered memory problems and a loss of appetite in addition to the other symptoms. These symptoms have now resolved but the man still experiences fatigue and headaches two years after the tick bite. The second man spent twelve days in hospital and had a variety of symptoms over the next month and a half, including memory problems, fatigue and loss of appetite; he is now symptom-free.
SFTSV in China and Heartland Virus in the US
Researchers are looking to see if the new tick-borne disease is related to another recently discovered tick-borne virus found in central and northeastern China. Like Heartland virus, this virus, called SFTSV, leads to fever and loss of blood platelets in patients. Although lone star ticks are common in the areas in which the American men were infected no ticks carrying Heartland virus have been identified. There remains confusion over whether the virus can be passed between people or whether it is purely a tick-borne disease transmitted through a bite.
Chronic Symptoms After a Tick Bite
In their paper, which has not been officially endorsed by the CDC, the researchers call upon doctors and other health professionals to be mindful of patients who develop fever, headaches, memory problems, loss of appetite and have low blood platelets after a tick bite and who do not improve after antibiotic treatment. Those who have been bitten by a tick and become infected with Lyme disease may wish to talk to their physician about the possibility of Heartland virus being at the root of prolonged suffering where antibiotic treatment has failed to eradicate symptoms but persistent infection is not detectable. Rather than being dismissed as hypochondriacs, or drug-seekers, Chronic Lyme disease patients may, in some cases, simply be misdiagnosed and have contracted both Lyme disease and Heartland virus simultaneously, or the latter by itself.
Misdiagnosing Chronic Lyme Disease
Lone star ticks are not thought to transmit Lyme disease but they may be present alongside the blacklegged ticks that do carry Borrelia burgdorferi. Differentiating the ticks, which can be very small, may be difficult and some tick bites go unnoticed leading to confusion as symptoms arise. Could Chronic Lyme disease be a case of mistaken identity? Is this new tick-borne disease, caused by Heartland virus, really the cause of persistent Lyme disease symptoms?
McMullan, L.K., et al, A New Phlebovirus Associated with Severe Febrile Illness in Missouri, The New England Journal of Medicine, Aug. 30, 2012.