Deer Keds: A New “Canary” in the Coal Mine
Written by UMass Amherst senior biology major, Cayla McGonigle
A report on the “Detection of Anaplasma phagocytophilum DNA in Deer Keds: Massachusetts, USA” was recently published in the journal Insects. The paper was authored by Dr. Patrick Pearson—a post-doctoral fellow in the Laboratory of Medical Zoology (LMZ) and contributor to NEWVEC. The study presents a new way for us to view deer keds. Most people—if they know about keds at all—view them as simple, pesky little bugs, but it turns out that they may actually help us monitor pathogens in deer, which could be a big deal for public health.
At first glance, deer keds resemble ticks, but they’re totally different. First of all, keds are insects and ticks are arachnids (ticks have eight legs as adults). Deer keds are also larger in size and more mobile than ticks. Keds prefer white-tailed deer as their hosts and so, luckily, do not usually bite humans. If they do, minor skin irritation is the common reaction.
Dr. Pearson used molecular methods to determine whether tick-borne pathogens were present in 99 deer keds collected from white-tailed deer during the 2023 Massachusetts deer hunting season. Approximately one-third of the collected keds carried Anaplasma phagocytophilum (Ap), which is a tick-borne bacterium that causes anaplasmosis (a disease with flu-like symptoms). At this time, it is unknown if keds can spread this disease since we don’t know if they are competent vectors. Keds might be used as a sentinel for deer-associated pathogens because they act like a sponge sucking up all the pathogens in their host deer. Additionally, since they only feed on one host (unlike a tick, which feeds on three different individual hosts in its lifetime), anything in the keds is likely to have come from that one host.
We don't yet know if keds can transmit Anaplasma phagocytophilum. For that to be possible, a ked would have to acquire Ap from a host, pass it to their offspring, then the ked would have to survive long enough for it to be passed back to another host when the ked starts feeding. This work has opened up the door to more questions that need to be answered.
