Veterinary Medicine - April 2008 - (Page 213)

West. Ixodes ricinus is the primary vector in Europe. The organism can infect a wide range of mammals, including dogs, cats, horses, ruminants, people, and many wildlife species. White-tailed deer and several species of small rodents are considered the primary reservoir hosts. It is suspected that transmission to susceptible mammalian hosts requires prolonged tick attachment and feeding of 24 hours or more.4 Clinical and laboratory ﬁndings Clinical disease in dogs is most often associated with the acute, bacteremic phase of infection. The duration and severity of the clinical ndings during the acute phase of the disease can vary greatly and can last from one to several days.5 Chronic, subclinical, persistent infections have been documented for more than ve-and-a-half months in dogs experimentally inoculated with a Swedish isolate of A. phagocytophilum and for almost one year in dogs inoculated with a human isolate from New York (NY18).6,7 However, no con rmed reports of clinical disease occurring in animals known to be chronic carriers exist. It is unknown whether a chronic carrier state can later result in chronic disease. Clinical disease has most often been reported in dogs 8 years of age or older.2,8 Golden retrievers and Labrador retrievers are overrepresented in most reports, but it is uncertain whether this is the result of breed susceptibility, frequency of exposure in these breeds, or breed popularity.2,8,9 tance to move. The most frequently observed clinical ndings in dogs that would alert you to A. phagocytophilum infection are joint pain and lameness resulting from polyarthritis. Other less commonly observed clinical signs include gastrointestinal problems such as vomiting, diarrhea, or both or respiratory signs such as coughing and labored breathing. Central nervous system disease (meningitis) can also occur, resulting in seizure activity, ataxia, or neurologic manifestations such as dullness or stupor, but these ndings are infrequently observed. Because many animals present with clinical signs of polyarthritis and possibly a history of tick exposure, clinical signs of canine anaplasmosis may be indistinguishable from those seen with Lyme disease. In addition, both diseases are transmitted by the same tick vectors and have similar geographic distributions. Laboratory test results. Abnormalities in laboratory test results may vary during the acute phase of the disease. Test results will likely be normal in persistently infected, subclinical carriers. The most common hematologic abnormality noted in clinically affected dogs is a mild to severe thrombocytopenia, seen in more than 80% of acutely infected dogs.2,8,11 Additionally, many animals will initially have lymphopenia but later may develop a reactive lymphocytosis. Rarely, neutropenia is seen. Membrane-bound vacuoles of intracytoplasmic organisms (morulae) can sometimes be observed in circulating neutrophils and, rarely, in eosinophils in acutely infected dogs. A mild to moderate nonregenerative anemia is occasionally seen. Common serum biochemical abnormalities include elevated serum alkaline phosphatase activity and mild to moderate hypoalbuminemia and hyper brinogenemia.2 The hypoalbuminemia usually resolves quickly once animals are afebrile. Clinical signs. A high seroprevalence in people and dogs living in endemic areas10 suggests that many infections result in a mild, u-like disease that is self-limiting or in a subclinical infection. Animals with clinical disease associated with acute infection often have vague signs of illness including fever, lethargy, malaise, anorexia, and general muscle pain resulting in reluc- VETERINARY MEDICINE April 2008 213 http://www.meridiananimalhealth.com http://www.meridiananimalhealth.com

Table of Contents Feed for the Digital Edition of Veterinary Medicine - April 2008

Veterinary Medicine - April 2008 Contents Letters Leading Off The Veterinary Medicine Interview: Dr. Barrak Pressler Idea Exchange Help! My Dog Licks Everything An Update on Anaplasmosis in Dogs CE Form Advertiser Index Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - April 2008

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