title: Environmental infestation and rickettsial infection in ticks in an area endemic for Brazilian spotted fever.
abstract: Brazilian spotted fever (BSF), caused by Rickettsia rickettsii, is endemic in the municipality of Americana, southeastern Brazil, where the disease is transmitted by the tick Amblyomma cajennense. This study evaluated the tick fauna and rickettsial infection in free-living ticks that were captured monthly using dry ice traps in areas endemic for BSF in Americana, from July 2009 to June 2010. Two tick species were captured: A. cajennense (6,122 larvae; 4,265 nymphs; 2,355 adults) and Amblyomma dubitatum (7,814 larvae; 3,364 nymphs; 1,193 adults). The immature stages of A. cajennense and A. dubitatum had similar distribution through the 12-month period, with larvae of both species collected in highest numbers between April and July, and nymphs between June and October. The highest numbers of A. cajennense adults were collected between October and December, whereas A. dubitatum adults were collected in relatively similar numbers throughout the 12-month period. Rickettsial infection was evaluated by means of PCR in 1,157 A. cajennense and 1,040 A. dubitatum ticks; only 41 (3.9%) A. dubitatum were found to be infected by Rickettsia bellii. The present study showed that the areas of Americana that are endemic for BSF are characterized by high environmental burdens of A. cajennense and A. dubitatum.
authors.affiliation: Municipal Health Department, Tick Surveillance and Control Program, AmericanaSP, Brazil.
authors.forename: José
authors.initials: J
authors.lastname: Brites-Neto
authors.forename: Fernanda Aparecida
authors.initials: FA
authors.lastname: Nieri-Bastos
authors.forename: Jardel
authors.initials: J
authors.lastname: Brasil
authors.forename: Keila Maria Roncato
authors.initials: KM
authors.lastname: Duarte
authors.forename: Thiago Fernandes
authors.initials: TF
authors.lastname: Martins
authors.forename: Cecília José
authors.initials: CJ
authors.lastname: Veríssimo
authors.forename: Amália Regina Mar
authors.initials: AR
authors.lastname: Barbieri
authors.forename: Marcelo Bahia
authors.initials: MB
authors.lastname: Labruna
mesh_terms: D063147:Animal Distribution; D000818:Animals; D001938:Brazil / Q000453:epidemiology; D019353:Endemic Diseases; D005260:Female; D008297:Male; D012282:Rickettsia Infections / Q000453:epidemiology; D012284:Rickettsia rickettsii / Q000302:isolation & purification*; D012373:Rocky Mountain Spotted Fever / Q000453:epidemiology; D013987:Ticks / Q000382:microbiology*