February Sneak Peek
Canine Anaplasmosis – A Tale of Two Bacteria
By Luke Peterson, DVM
Recently, one of our club members Keith Turnquist had a beagle treated for an acute Anaplasmosis infection. Anaplasmosis is a tick-borne disease, but is not as well-known to as many as Lyme disease. There are four predominant tick-borne bacterial infections in dogs: Lyme disease, Anaplasmosis, Ehrlichiosis, and Rocky Mountain Spotted Fever. Central and Northern Wisconsin have been endemic areas for Lyme and Anaplasma for as long as either of these diseases have been identified (early ‘80s for Lyme, Mid ‘90s for Anaplasma). Ehrlichiosis is present in the southernmost part of the state and appears to be making its way north, and Rocky Mountain Spotted Fever is rarely seen. By the numbers, from 2007-2012, one diagnostic company had 41,000 Lyme positive results, 22,000 Anaplasma positives, and 1200 Ehrlichia positives with the number of Anaplasma cases continuing to increase with each year.
Anaplasma has been a catch all for tick-borne disease caused by either Anaplasma phagocytophilum or Anaplasma platys. These bacteria are transmitted by different tick species and cause different clinical illness with A. phagocytophilum being the more common of the two. A phagocytophilum is transmitted by deer-ticks (the same as Lyme) whereas A. platys is transmitted by wood ticks. Not surprisingly, the geographical distribution of Lyme and A. phagocytophilum in the United States are nearly the same, predominately Minnesota, Wisconsin, and the Upper Northeast. Also, it’s not uncommon to see dogs co-infected with A. phagocytophilum and Lyme disease.
A. phagocytophilum infected dogs vary in their severity of disease with the average onset of disease occurring 1-2 weeks following transmission from the tick. Many infected dogs will never show any signs and clear the infection on their own. Mild signs may be very subtle to identify and are seen as decreased stamina or performance and a mild decrease in appetite. The most common clinical signs are lameness, joint pain, fever, complete inappetence, and lethargy. Less commonly, vomiting, diarrhea, coughing, and labored breathing may be seen, and most rarely, some dogs will also have seizures.
A. platys infected dogs experience cyclic changes in their platelets. This bacterium invades platelets which are then destroyed by the dog’s immune system in an attempt to clear the infection, ultimately resulting in low platelets. With low platelets, dogs will spontaneously ooze blood from blood vessels. The most common clinical signs seen are bruising and bleeding. Bruising is most often seen on the skin near the groin or abdomen where less hair is present. Bleeding may occur from the nose, mouth, gastrointestinal tract, or from the urinary tract. Dogs with gastrointestinal bleeding may vomit dark liquid which is digested blood, have black-tarry diarrhea (digested blood), or have red blood in their stool of bleeding from the colon.
Be sure to finish this article on page 8 of our February issue!