title: Anaplasma phagocytophilum DNA amplified from lesional skin of seropositive dogs.
abstract: Canine granulocytic anaplasmosis (CGA) is caused by the rickettsial microorganism Anaplasma phagocytophilum. CGA is typically characterized by fever, thrombocytopenia, lethargy, anorexia, arthropy, and other nonspecific clinical signs. Skin lesions have been described in naturally infected lambs and humans. The pathophysiology of CGA is not entirely clear, and the persistence of the organism after the resolution of clinical signs has been described. The aim of the study was to investigate if A. phagocytophilum can be detected in canine lesional skin biopsies from A. phagocytophilum-seropositive dogs with etiologically unclear skin lesions that improved after the treatment with doxycycline. Paraffin-embedded lesional skin biopsies were allocated into separate groups: biopsies from A. phagocytophilum-seropositive dogs responsive to treatment with doxycycline (n=12), biopsies from A. phagocytophilum-seronegative dogs (n=2), and biopsies in which skin lesions histopathologically resembled a tick bite (n=10). The serological status of the latter group was unknown. Histology of the seropositive and seronegative dog skin lesions did not indicate an etiology. DNA was extracted, and a conventional PCR for partial 16S rRNA gene was performed. Anaplasma phagocytophilum DNA was amplified from 4/12 seropositive dogs' skin biopsies. All sequences were 100% identical to the prototype A. phagocytophilum human strain (GenBank accession number U02521). Anaplasma phagocytophilum was not amplified from the 2 seronegative and 10 suspected tick bite dogs. Serum antibody titers of the PCR-positive dogs ranged from 1:200 to 1:2048. Histopathologically, a mild-to-moderate perivascular to interstitial dermatitis composed of a mixed cellular infiltrate and mild-to-moderate edema was seen in all seropositive dogs. In 8/12 seropositive dogs, vascular changes as vasculopathy, fibrinoid necrosis of the vessel walls, and leukocytoclastic changes were observed. In summary, our results support the hypothesis that the persistence of A. phagocytophilum in the skin may be causative for otherwise unexplained skin lesions in seropositive dogs.
authors.affiliation: Preclinical Institute, Faculty of Veterinary Medicine, Latvia University of Agriculture, Jelgava, Latvia; Institute of Animal Pathology, Vetsuisse-Faculty, University of Bern, Bern, Switzerland. Electronic address: inese.berzina@gmail.com.
authors.forename: Inese
authors.initials: I
authors.lastname: Berzina
authors.affiliation: Institute of Animal Pathology, Vetsuisse-Faculty, University of Bern, Bern, Switzerland.
authors.forename: Christiane
authors.initials: C
authors.lastname: Krudewig
authors.affiliation: Institute for Comparative Tropical Medicine and Parasitology, Ludwig-Maximilians-Universität München, Munich, Germany.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Silaghi
authors.affiliation: Preclinical Institute, Faculty of Veterinary Medicine, Latvia University of Agriculture, Jelgava, Latvia.
authors.forename: Ilze
authors.initials: I
authors.lastname: Matise
authors.affiliation: Latvian Biomedical Research and Study Center, Riga, Latvia.
authors.forename: Renate
authors.initials: R
authors.lastname: Ranka
authors.affiliation: Institute of Parasitology, Vetsuisse-Faculty, University of Bern, Bern, Switzerland.
authors.forename: Norbert
authors.initials: N
authors.lastname: Müller
authors.affiliation: Institute of Animal Pathology, Vetsuisse-Faculty, University of Bern, Bern, Switzerland.
authors.forename: Monika
authors.initials: M
authors.lastname: Welle
mesh_terms: D041081:Anaplasma phagocytophilum / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D000712:Anaplasmosis / Q000382:microbiology* / Q000473:pathology; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001483:Base Sequence; D001706:Biopsy / Q000662:veterinary; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004283:Dog Diseases / Q000382:microbiology* / Q000473:pathology; D004285:Dogs; D004318:Doxycycline / Q000627:therapeutic use; D016873:Ehrlichiosis / Q000382:microbiology / Q000473:pathology / Q000662:veterinary*; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012189:Retrospective Studies; D017422:Sequence Analysis, DNA / Q000662:veterinary; D012867:Skin / Q000382:microbiology / Q000473:pathology
chemical_list: D000907:Antibodies, Bacterial; D004269:DNA, Bacterial; D004318:Doxycycline
keywords: A. phagocytophilum; Histopathology; PCR; Persistent canine granulocytic anaplasmosis; Skin lesions