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October 10, 2009

Spinose Ear Tick

Blogging has been a little hit & miss lately. Sorry. It is not that we haven't been busy, or that there haven't been interesting cases, to the contrary. It seems like we've had a rash of crazy trauma cases, and those aren't the type of thing that lend themselves to blogging. It's not like you can ask an owner if you can stop and take picture of the bleeding, mangled dog before you begin treatment. And asking whether or not you can blog about their poor pet seems in bad taste. So, that's how it has been.

Anyway, last week we had a rather mundane "check dog ears" from the western part of the county. And this is what we found -- a spinose ear tick (Otobius megnini). The spinose ear tick can infest many warm blooded animals, but seems to prefer cows, horses, dogs, cats, and even humans. It can be a real problem in livestock, causing poor condition with heavily infested cattle. We have seen several of these ticks in the past few years, all from the relatively arid parts of Whitman county. In dogs, infestation of the spinose tick causes severe head shaking, pain, and digging at the ear. Severe oozing skin infections can result from the bite. Most people assume that there is just a grass seed or awn in the ear canal.

As it turns out, only the nymph and larval stages of this tick feed on blood. The adults apparently do not feed at all, and can live for up to 2 years. The feeding stages of this tick like to crawl into ears, especially deep into the horizontal canal and attach to the skin where they feed on blood and wax in the ear. The spinose ear tick can cause tick paralysis and can also spread diseases such as Q-fever, tularemia, Colorado tick fever, and Rocky Mountain spotted fever (although not necessarily in this area of the country). Treatment for infestation involves applying an acaricide solution (typically permethrin or amitraz) directly into the ear canal if the tick cannot be removed manually. In cattle, permethrin impregnated ear tags are helpful in prevention of infestation.

Kind of gives you the creeps, huh?