In the summer of 2014, a resident of Kansas succumbed to what was thought to be a disease similar to a tick borne disease though the laboratory investigations failed to turn up any evidence for Ehrlichiosis or other similar diseases, including the recently discovered Heartland virus. This disease has now been diagnosed to have been caused by a novel orthomyxovirus, which has been named the Bourbon Virus after the county in which the index case was identified. Here is a video of Dr. Dana Hawkinson, MD, an Infectious Disease specialist from University of Kansas Hospital talking about the new virus:
The CDC has been involved in the ongoing investigation to better understand the epidemiology of this agent. More cases are being rounded up where people with suspected tick borne fever were found to be diagnostic dead ends following investigation for known infectious agents. They will now be investigated for the Bourbon virus to figure out whether this agent can be implicated in further cases. Unless more cases are found, it will be difficult to define its epidemiology and risk factors of acquiring the infection.
In the index case, who happened to be a farmer in Kansas, the disease was rapidly progressing, and within ten days he succumbed to multi-organ failure and septic shock. The patient also complained of fever, myalgia and malaise, which are fairly common symptoms in all such diseases. In addition, he claimed to be suffering from extreme anorexia, something that Dr. Hawkinson also mentions in the video above.
Now, it is not known for sure whether this is a tick borne disease or a mosquito borne disease, and as it is looked at more closely these questions will be answered. Because it is the middle of winter now, it is expected that the disease shall be on a low tide as ticks and mosquito borne diseases decrease in incidence over the winter months. However, ticks rebound earlier than mosquitoes as temperatures start increasing even slightly. Thus, reappearance of the disease before the mosquito season hits in full force could point to the possibility of it being a tick borne disease.
The ProMED mail despatch points out that a number of tick borne viruses have emerged in the recent past, most notably the Heartland virus and severe fever with thrombocytopenia virus (Bunyaviridae: Phlebovirus) in the US and China, respectively. In
addition, other tick borne viruses such as deer tick virus/Powassan virus (Flaviviridae: Flavivirus) appear to be increasing in incidence in regions of the US.
It is going to be interesting to see the epidemiology of the Bourbon virus unravel in the days to come.