Genetic Variants of Anaplasma phagocytophilum Infecting Dogs in Western Washington State

Abstract

Eight dogs from western Washington State suspected of being infected with Anaplasma phagocytophilum because of the finding of morulae in peripheral blood neutrophils were studied for determination of the etiologic agent of disease. All cases were diagnosed between April 2003 and April 2004. Six of the eight dogs had no travel history during the 6 months prior to presentation. Two dogs had traveled within the Northwest United States and Canada. Fever, lethargy, and anorexia were the most common clinical signs in the dogs. Lymphopenia, thrombocytopenia, and an elevated activity of alkaline phosphatase in the serum were the most common laboratory findings. All dogs tested during the acute phase of clinical signs were seropositive for A. phagocytophilum antibodies but negative for Ehrlichia canis antibodies. PCR amplification and direct sequencing of portions of the 16S rRNA gene from the whole blood of all seven dogs that were tested yielded A. phagocytophilum after a comparison to bacterial sequences available in the GenBank database. Five genetic variants were identified based on one or two nucleotide differences in the 16S rRNA gene sequences at nucleotide positions 54, 84, 86, and 120. Individual dogs were infected with more than one variant. Treatment with doxycycline or tetracycline resulted in a rapid resolution of clinical signs. The occurrence of canine granulocytic anaplasmosis in western Washington State suggests that A. phagocytophilum infection should be considered in differential diagnoses of dogs presenting with lethargy, anorexia, fever, and lameness, particularly in the context of lymphopenia, thrombocytopenia, and increased serum alkaline phosphatase. The zoonotic importance of A. phagocytophilum should support an increase in surveillance for horses and people residing in this area.

Infection with Anaplasma phagocytophilum in a young dog: a case report

“…Other authors also reported the detection of specific IgG antibodies by IFA from 2 weeks up to more than six months after infection in dogs suffering from anaplasmosis (Kirtz et al, 2000(Kirtz et al, , 2005Poitout et al, 2005). To the author's knowledge this is the first confirmed case of canine anaplasmosis caused by A. phagocytophilum to be reported in the Czech Republic, where the infection was already suspected (Huml et al, 1996).…”

The Biological Survey of Canada: A Personal History

“…scapularis enzootic cycle. Distinct variants not found in humans have been isolated from deer, other ruminants, horses, dogs, and cats, suggesting only a subset of A. phagocytophilum variants cause disease in humans (Lappin et al 2004;Lester et al 2005;Parola et al 2005a;Poitout et al 2005;Morissette et al 2009). More than one strain may be present in a region, and the relative proportion of each strain may vary regionally (Krakowetz et al 2014).…”

Molecular and serological evidence of Anaplasma phagocytophilum infection of farm animals in the Black Sea Region of Turkey

“…The agent has been recognised for some years as a pathogen of veterinary and medical importance. The bacterium is transmitted by ixodid ticks and infects a wide range of species including domesticated ruminants (Gordon et al, 1932), equids (de la Fuente et al, 2005a), cats (Tarello, 2005), dogs (Poitout et al, 2005), wild animals (Skarphédinsson et al, 2005) and humans (Chen et al, 1994;Petrovec et al, 1997). In the United States the principal vectors are Ixodes scapularis and I. pacificus (Dumler, 1997), while in Europe the main exophilic tick vectors are I. ricinus and I. trianguliceps (Ogden et al, 1998).…”