From CW Dick Lab blog
by Christopher Dick, associate professor, ecology and evolutionary biology; associate curator and associate chair for museum collections, U-M Herbarium; director; E.S. George Reserve
Summary: The tick Ixodes scapularis transmits Lyme Disease and is expanding its range across the eastern U.S. As we discovered recently, basic tick ID skills relevant to disease treatment appear to be lacking in the medical community.
Last week Herbarium associate Mike P. sent a staff email to warn us of deer ticks. After doing some outdoor work west of Ann Arbor he found an engorged tick on his chest (genus Ixodes) that left a small rash. The tick (see above photo) looked like an adult of the blacklegged tick Ixodes scapularis, which transmits the bacteria that causes Lyme Disease.
The doctor prescribed antibiotics as a preventative while waiting for the tick to be identified. Meanwhile, Barry OConnor, acarologist and curator in the UMMZ, saw a photo of the tick (via one of my tweets) and asked to examine the specimen. From the photo it wasn’t possible to distinguish the blacklegged tick from the more common groundhog tick, Ixodes cookei. Groundhog tick is “only” a vector for viral Powassan fever, which cannot be treated with antibiotics.
It turns out the medical lab identified the specimen simply as “Ixodes sp.” then threw it away.
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| Blacklegged ticks are undergoing a range expansion in the eastern U.S. A Michigan study found that 40-45% of I. scapularis adults carry the Lyme Disease bacteria. |