Thursday, May 28, 2015

Time Thogoto Oklahoma, They've Got the Bourbon

Orthomyxoviridae, the familial host of our familiar friend influenza, is making some new headlines after a relatively unimpressive flu season this past winter. It seems as if the midwest will be plagued by the negative stranded, RNA, multipartite genome family of Orthomyxoviridae into the summer, as the relatively new Bourbon virus has been discovered in Oklahoma.

Bourbon virus, a newly categorized member of the genus Thogotovirus, has just been identified in Payne county, Oklahoma. Transmitted by ticks, state health officials are now advising residents of Payne county and the state of Oklahoma to be extra cautious while being active outdoors, making sure to use DEET, other insect repellants, long sleeves, and pants. State epidemiologists also warn that the recent wet weather heading into the summer may cause favorable conditions for an above average tick population.

The new patient is the second identified case of Bourbon virus infection ever. Although the patient recovered from the disease in May of 2014, the public health officials released information to the public that the patient did have the rare viral disease and contracted it within Payne county.

The first person to be identified with Bourbon virus was a resident of Kentucky who came down with a serious viral infection within a week of having received a tick bite. According to the Emerging Infectious Disease report as published by the CDC, the patient was a male older than the age of 50 who had been doing yard work on his property when he realized that he had received several tick bites. The patient removed a large engorged tick from his shoulder just two days before he came down with malaise, nausea, and diarrhea. A day after the original presentation of symptoms, the patient further developed fever, myalgia, chills, anorexia, and arthralgia.

Upon admission to the hospital, the patient experienced diminished consciousness, was running a slight fever of 99.9 degrees fahrenheit, and had an increased blood pressure of 151/65 mmHg. Interestingly, the patient also presented with a papular rash on his trunk. I am not aware of any other Orthomyxovirus that presents initially with a rash before the onset of further symptoms. One other virus that presents early on with a papular rash is Measles Virus, a member of the family Paramyxoviridae. It is believed that many viral rashes, like the typical rash in Measles, presents due to a cell mediated attack on virus that is located within skin cells and the vasculature near the dermis (Klimpel, 1996). This may indicate that the patient mounts an immune response to the Bourban Virus infection early on, but without early supportive treatment, may not be able to keep up with viral replication, and the immune system succumbs to viremia.

The patient then began to develop thrombocytopenia with a platelet count of 72,000 cells/┬ÁL. Thrombocytopenia is seen in many viral infections that also include exanthems, such as Varicella Zoster, Rubella, Mumps, and Parvovirus. Kosoy et al. of the CDC remark that this observed reduction in the patient's platelets coupled with leukopenia is likely secondary to acute bone marrow suppression.

Ultimately, the patient was treated for what the physicians thought was a bacterial infection acquired through tick bite. He was given Doxycycline intravenously 100 mg/hour, followed by a broad spectrum antimicrobial treatment on day 10 of illness. Unfortunately, the patient succumbed to the virus due to progressive heart failure that eventually lead to sustained ventricular tachycardia with persistent hypotension and eventual pulseless electrical activity.

The authors of the Emerging Infectious Disease paper suggest that severe viral febrile illnesses coupled with thrombocytopenia are likely underestimated, as Heartland Virus, and other tick transmitted viral diseases continue to pop up. Hopefully physicians in the midwest are able to recognize these viral symptoms early on so that good supportive treatment can help avoid mortality.

- Marcus Munoz


References:

Klimpel GR. Immune Defenses. In: Baron S, editor. Medical Microbiology. 4th edition. Galveston (TX): University of Texas Medical Branch at Galveston; 1996. Chapter 50. Available from: http://www.ncbi.nlm.nih.gov/books/NBK8423/

Kosoy, Olga I., et al. "Novel Thogotovirus Associated with Febrile Illness and Death, United States, 2014."Emerging infectious diseases 21.5 (2015): 760.

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