Borrelia miyamotoi disease an emerging tick-borne illness in the U.S.

1. Borrelia miyamotoi disease (BMD) is characterized by flu-like symptoms and elevated liver enzymes.

2. The majority of patients with confirmed BMD responded well to treatment with oral doxycycline.

Evidence Rating Level: 4 (Below Average)

Study Rundown: Illnesses transmitted via the deer tick (Ixodes scapularis), including Lyme disease, babesiosis and anaplasmosis, are endemic in the northeastern United States. In 2013, the first U.S. case of Borrelia miyamotoi disease (BMD), a novel tick-borne illness, was described. This study sought to identify the common clinical and laboratory characteristics of BMD and to assess the specificity and sensitivity of multiple screening tests for BMD. The most common symptoms associated with BMD were flu-like and included high fever, chills, severe headache and myalgia/arthralgia. Common laboratory findings included increased liver enzymes, neutropenia and thrombocytopenia. A vast majority of patients were successfully treated with a 2- to 4-week course of doxycycline and exhibited no residual symptoms. The most sensitive laboratory test for BMD was real-time PCR performed on whole blood samples. This study is limited in that the samples used may be biased toward more severe cases of BMD, and only 51 of 97 identified patients with BMD were selected for inclusion. However, these findings suggest that BMD may be an emerging tick-borne illness in the Northeastern U.S., and physicians in the region should consider BMD for patients presenting with flu-like symptoms from April through October.

Click to read the study, published today in the Annals of Internal Medicine

Relevant Reading: Borrelia miyamotoi: a widespread tick-borne relapsing fever spirochete

In-Depth [case series]: The authors tested whole blood samples from 11,515 patients located in Massachusetts, Rhode Island, New Jersey and New York that were sent during the period covering April 1, 2013 through October 31, 2014. Of these samples, 97 (0.8%) were positive for BMD via real-time PCR and 51 of those 97 were included in the case series. Notably, 3.1% of the samples were positive for Babesia microti, 1.7% were positive for Borrelia burgdorferi, and 1.4% were positive for Anaplasma phagocytophilum. Serologic testing for the presence of antibodies to B. miyamotoi glycerophosphodiester phosphodiesterase was positive in only 16% of patients with BMD. However, seroconversion was observed in 25 out of 29 available convalescent serum samples. Spirochetal concentrations in BMD patients’ blood samples averaged 7,787 organisms/mL, whereas samples collected from Lyme disease patients during the same time period had an average of 1,718 organisms/mL.

Image: PD

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