August 2021

"Acarologic" venture

​In February 2021, this tick was removed from a 4-year-old male castrated Jack Russell Terrier from Texas, and sent to the parasitology lab for identification. The lab worker was able to take pictures showcasing key features for identifying this specimen, as seen below. 

Image 1: Key features for identification. 

What's your diagnosis?

​This is Ixodes cookei, the groundhog tick or woodchuck tick. Female Ixodes cookei can be differentiated from other Ixodes species based on their angular scutum shape and relatively short palps.  Females of Ixodes scapularis will instead have a rounded, oval shaped scutum, and longer palps, as seen in Image 2 (right).
 
Groundhog ticks are found throughout eastern North America. In northeastern states, the upper Midwest, and eastern Canada, this tick serves as a vector for Powassan virus and may also transmit Borrelia burgdorferi. In Canada, adult Ixodes cookei are most active in the summer but in the southern US this tick is more commonly found in the winter months.

Image 2: Adult female Ixodes cookei (left) and Ixodes scapularis (right).