Clinicians are asked to be on the lookout beginning in May for cases of Heartland virus disease, the characteristic symptoms of which are fever, leukopenia, and thrombocytopenia.
In its weekly Morbidity and Mortality report issued March 28, the Centers for Disease Control and Prevention urges health care providers to consider Heartland-virus testing in patients with these symptoms, without other likely explanation, who are negative for Ehrlichia and Anaplasma or have not responded to doxycycline (MMWR Morb. Mortal. Wkly. Rep. 2014 March 28;63:270-1).
The CDC’s Dr. Daniel M. Pastula contributed to the report on Heartland virus. Clinicians with questions may contact state health departments or the CDC Arbovirus Diseases Branch, at 970-221-6400.
Courtesy CDC
No medication exists to prevent or treat Heartland virus disease, which is carried by the Lone Star tick.
Heartland virus disease was first identified in 2009 through two cases in Missouri, both farmers, who were hospitalized with fever, leukopenia, and thrombocytopenia. The virus was presumed then to be tick borne.
In 2012 and 2013, six confirmed cases of Heartland virus disease were reported; four patients required hospitalization, and one with comorbidities died. Five cases occurred in Missouri, and the remaining case was in Tennessee; all occurred in men aged 50 years and older. The cases were reported from May to September, with half reported in May.
The disease is confirmed through laboratory evidence of recent Heartland virus infection along with a clinically compatible illness, defined as a fever of 100.4°F or greater, white blood cell count below 4,500 cells/mm3, and platelet count below 150,000/mm3. Other symptoms reported have included fatigue, anorexia, headache, nausea, myalgia, and arthralgia.
Last year, Heartland virus was isolated for the first time from the lone star tick (Amblyomma americanum), which has a wide distribution in the United States and is a known vector of other diseases. A CDC report from 2003 warned that its importance would likely grow as a vector of zoonotic pathogens affecting humans, because of environmental and demographic factors, and that cases of human disease mediated by A. americanum would increase.
As no medication exists to prevent or treat Heartland virus disease, insect repellent and long-sleeved clothing are recommended for prevention, along with avoidance of bushy or wooded areas. People exposed to these should perform tick checks after spending time outdoors, the CDC said.