The Tick Days of Summer

Jul 30, 2013 | Reem Sharhan | Outbreak News

Recent news reminds us that, this summer, ticks have more to pass on to us than the infamous Lyme disease. Early this month, the medical journal Annals of Internal Medicine published a case report of two patients who had what seemed like anaplasmosis, a tick-borne disease. Instead, they found DNA of a recently discovered tick-borne bacterium, Borrelia miyamotoi.

The bacterium was first detected in ticks by a group of Japanese and American researchers, but the first human cases were not documented until six years later in Russia. Similarly, in the United States, ticks were found carrying B. miyamotoi in Connecticut in 2001, but it was not identified as the disease-causing agent in a patient until recently. In January 2013, researchers from Tufts and Yale universities described cases of B. miyamotoi in humans in separate articles in the New England Journal of Medicine. Durlan Fish, a professor of epidemiology at Yale school of public health said that the discovery of this disease is unique in that this was the first time their group of scientists had found an infectious tick-borne organism before they found the disease in a human; conversely, they usually find the disease in an epidemic, and next, they investigate the causative agent of that disease.

Borrelia miyamotoi, a spirochete bacterium belonging to the Borrelia genus, is closely related to the causative agent of Lyme disease, Borrelia burgdorferi. Both bacteria are carried by the deer tick, Ixodes scapularis. A deer tick bite can transmit one type of bacteria or the other, and in some cases, it can infect with both simultaneously. Patients infected with B. miyamotoi alone present symptoms that are very similar to those of Lyme disease, including headache, high fever, as well as joint and muscle pain. With Borrelia miyamotoi, however, the bull’s eye rash that is characteristic of Lyme disease is not present.

As a result of these similarities in clinical manifestations of the two diseases, and since some doctors are unaware of B. miyamotoi as a possible causative agent of such symptoms, some doctors are left puzzled when their patients come back negative for Lyme disease. On a more positive note, there are studies showing that B. miyamotoi responds to the same medication used for Lyme disease. In a correspondence by Peter Krause, M.D. to the New England Journal of Medicine, one case in the United States was reported as successfully treated with the antibiotic doxycycline. Nevertheless, on its website, the NIH states that there are no medications specified to Borrelia miyamotoi at the moment.   

While medical researchers look for answers to find the proper treatment for this new disease (and maybe a name for it), all we can do is continue our vigilant efforts to avoid tick bites while enjoying the summer. Outdoor activities such as hiking, camping, and gardening put us at a much higher risk of being bitten, especially in the warmer months when ticks are more active. The NIH advises taking these precautions if there is a possibility of exposure to the bug: wearing clothes that entirely cover body and carefully tucking pants into socks, using bug repellents with at least 20 percent DEET, and thoroughly and regularly checking self, children, and pets for attached ticks after retuning from the outdoors.  

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