title: Molecular epidemiology of the emerging zoonosis agent Anaplasma phagocytophilum (Foggie, 1949) in dogs and ixodid ticks in Brazil.
abstract: BACKGROUND
  Anaplasma phagocytophilum is an emerging pathogen of humans, dogs and other animals, and it is transmitted by ixodid ticks. The objective of the current study was a) detect A. phagocytophilum in dogs and ixodid ticks using real-time Polymerase Chain Reaction (qPCR); and b) Determine important variables associated to host, environment and potential tick vectors that are related to the presence of A. phagocytophilum in dogs domiciled in Rio de Janeiro, Brazil.
  
  
  METHODS
  We tested blood samples from 398 dogs and samples from 235 ticks, including 194 Rhipicephalus sanguineus sensu lato, 15 Amblyomma cajennense, 8 Amblyomma ovale and 18 pools of Amblyomma sp. nymphs. A semi-structured questionnaire was applied by interviewing each dog owner. Deoxyribonucleic acid obtained from ticks and dog buffy coat samples were amplified by qPCR (msp2 gene). The sequencing of 16S rRNA and groESL heat shock operon genes and a phylogenetic analysis was performed. The multiple logistic regression model was created as a function of testing positive dogs for A. phagocytophilum.
  
  
  RESULTS
  Among the 398 blood samples from dogs, 6.03% were positive for A. phagocytophilum. Anaplasma phagocytophilum was detected in one A. cajennense female tick and in five R. sanguineus sensu lato ticks (four males and one female). The partial sequences of the 16S rRNA, and groESL genes obtained were highly similar to strains of A. phagocytophilum isolated from wild birds from Brazil and human pathogenic strains. The tick species collected in positive dogs were R. sanguineus sensu lato and A. cajennense, with A.cajennense being predominant. Tick infestation history (OR = 2.86, CI = 1.98-14.87), dog size (OR = 2.41, IC: 1.51-12.67), the access to forest areas (OR = 3:51, CI: 1.52-16.32), hygiene conditions of the environment in which the dogs lived (OR = 4.35, CI: 1.86-18.63) and Amblyomma sp. infestation (OR = 6.12; CI: 2.11-28.15) were associated with A. phagocytophilum infection in dogs.
  
  
  CONCLUSIONS
  This is the first report of A. phagocytophilum in ixodid ticks from Brazil. The detection of A. phagocitophylum in A. cajennense, an aggressive feeder on a wide variety of hosts, including humans, is considered a public health concern.
authors: Epidemiology and Public Health Department, IV-UFRRJ, Seropédica, Rio de Janeiro, Brazil. huarrisson@yahoo.com.br.
authors: Huarrisson A
authors: HA
authors: Santos
authors: Sandra M G
authors: SM
authors: Thomé
authors: Cristiane D
authors: CD
authors: Baldani
authors: Claudia B
authors: CB
authors: Silva
authors: Maristela P
authors: MP
authors: Peixoto
authors: Marcus S
authors: MS
authors: Pires
authors: Gabriela L V
authors: GL
authors: Vitari
authors: Renata L
authors: RL
authors: Costa
authors: Tiago M
authors: TM
authors: Santos
authors: Isabele C
authors: IC
authors: Angelo
authors: Leandro A
authors: LA
authors: Santos
authors: João L H
authors: JL
authors: Faccini
authors: Carlos L
authors: CL
authors: Massard
mesh_terms: D041081:Anaplasma phagocytophilum / Q000235:genetics* / Q000302:isolation & purification*; D000818:Animals; D001938:Brazil / Q000453:epidemiology; D021821:Communicable Diseases, Emerging / Q000453:epidemiology*; D004283:Dog Diseases / Q000453:epidemiology / Q000382:microbiology; D004285:Dogs; D016873:Ehrlichiosis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D026863:Ixodidae / Q000382:microbiology*; D008297:Male; D017720:Molecular Epidemiology; D016017:Odds Ratio; D010802:Phylogeny; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D015047:Zoonoses / Q000453:epidemiology / Q000382:microbiology*
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S