Heartland Virus Neutralizing Antibodies in Vertebrate Wildlife, United States, 2009-2014

Abstract

Since its discovery in 2009, the tickborne Heartland virus (HRTV) has caused human illness in Missouri, Oklahoma, and Tennessee USA. To better assess the geographic distribution of HRTV, we used wildlife serology as an indicator. This retrospective evaluation determined that HRTV is widespread within the central and eastern United States.

Keywords: Amblyomma americanum; Bunyaviridae; Heartland disease; Heartland virus; Phlebovirus; United States; ticks; vector-borne infections; vertebrate wildlife serosurvey; viruses; zoonoses.

Figure 1

State-level distribution of Heartland virus case reports in humans and seropositive wildlife, central and eastern United States, 2009–2014. Red indicates states with seropositive animals; gray indicates states with no seropositive animals. Year labels indicate the earliest year of detected HRTV activity. Earliest detection was determined by human case reports in Missouri (1 case) and Oklahoma (3 cases) and wildlife serologic data in all other states.

Figure 2

Geographic groupings of confirmed seropositive animals for Heartland virus neutralizing antibodies, central and eastern United States, 2009–2014. Twenty groups were identified in 13 states. The geographic locations of the groups were subjectively approximated by the counties where seropositive animals were collected (blue circles). Red indicates states with seropositive animals; gray indicates states in which no seropositive animals were detected. Because of the sampling design, the data are qualitative.