Via Emerging Infectious Diseases: Novel Thogotovirus Species Associated with Febrile Illness and Death, United States. I mentioned this case in a December post. Excerpt from the discussion:
Using traditional techniques (i.e., PRNT and culturing on animal cells) in combination with NGS, we isolated a novel virus from a blood sample collected 9 days after illness onset from a previously healthy man. It is likely that this novel Thogotovirus species, which we are proposing to call Bourbon virus after the county of residence of the patient, was the cause of his illness.
Although it is unclear what role the virus played in the death of the patient, the high level of viremia, as shown by multiple isolations from the blood of the patient 2 days before his death, suggests that this might have contributed to the death of the patient.
The patient had a history of tick exposure, as well as symptoms and laboratory findings (i.e., leukopenia and thrombocytopenia) consistent with a tickborne illness. Several tickborne pathogens, such as Ehrlichia chaffensis, Rickettsia, and Heartland virus, are present in eastern Kansas and adjacent areas (17–19). However, the patient did not respond to doxycycline therapy initiated 3 days after illness onset and had negative results for these and other tickborne pathogens.
Of the 7 symptomatic human infections that have been associated with viruses in the genus Thogotovirus, most case-patients have had neurologic findings (e.g., meningitis, encephalitis) without any described abnormalities in blood counts (9,11). Although cerebrospinal fluid was not tested for the patient reported, his clinical signs and symptoms were not suggestive of neurologic infection. Furthermore, the patient did not have any respiratory symptoms that would be expected with other viruses that are known human pathogens in the large family of Orthomyxoviridae, such as influenza virus (1).
Phylogenetic analyses indicated that Bourbon virus is most closely related to Dhori and Batken viruses. However, the branch lengths suggest a relatively distant evolutionary distinction of Bourbon virus from Dhori and Batken viruses, which have only been described in the Eastern Hemisphere. Dhori, Batken, and Thogoto viruses have been identified in various hard tick species (1). However, Batken virus also has been identified in mosquitoes (1).
It is currently unknown how Bourbon virus is transmitted to humans. However, illness onset of the patient in late spring and a history of finding an embedded tick before becoming ill support the notion that Bourbon virus might be transmitted by ticks. Therefore, to potentially prevent Bourbon virus disease, as well as other tickborne diseases, persons should be advised to avoid tick bites by using an insect repellent registered with the US Environmental Protection Agency to be effective against ticks, wearing long sleeves and pants, avoiding bushy and wooded areas, and performing tick checks after spending time outdoors.
