Heartland virus-associated death in tennessee

Abstract

Background: Heartland virus (HRTV) is a tick-borne phlebovirus recently described in Missouri that is associated with fever, leukopenia, and thrombocytopenia. The virus has also been detected in Ambylomma americanum ticks.

Methods: Here we report the first fatal case of HRTV disease in an 80-year-old Tennessee resident. He was hospitalized with fever, confusion, leukopenia, and thrombocytopenia and developed multiorgan failure and hemorrhage. A tick-borne illness was suspected and testing for ehrlichiosis was negative. He died on hospital day 15, and autopsy specimens were tested for various pathogens as part of an unexplained death evaluation.

Results: HRTV antigens were detected in postmortem spleen and lymph nodes by immunohistochemistry, and HRTV was detected in premortem blood by reverse transcription polymerase chain reaction and by isolation in cell culture.

Conclusions: This case demonstrates that HRTV infection can cause severe disease and death and expands the geographic range of HRTV within the United States.

Keywords: Heartland virus; autopsy; pathology; tick-borne illness; unexplained death.

Figure 1

Liver function test and complete blood count data. Apheresis platelet transfusions are indicated by arrow heads. AST: aspartate aminotransferase; ALT: alanine aminotransferase; PLT: platelet count; WBC: white blood cell count; HGB: hemoglobin.

Figure 2

Pathological features of fatal HRTV case. Spleen demonstrating white pulp depletion and scattered immunoblasts (A). HRTV antigen detected in large hematopoietic cells of lymph node (B) and spleen (C) by immunohistochemistry using fast red chromogen. Original magnifications: 158X(A), 50X(B) and 158X(C)

Figure 3

Phylogeny of phleboviruses including Heartland virus isolates. A maximum likelihood tree that was generated using MEGA version 5 software [8] with 2000 replicates for bootstrap testing is shown. The phylogeny was constructed from a 581 bp region of the NSs ORF of the phleboviral S segment for which there is the broadest diversity of available data in GenBank. Branch lengths are measured in the number of nucleotide substitutions per site.