title: Investigation of tick vectors of Hepatozoon canis in Brazil.
abstract: Hepatozoon canis is a common apicomplexan parasite of dogs. In Brazil, in addition to Rhipicephalus sanguineus, Amblyomma ovale, Amblyomma cajennense, and Rhipicephalus (Boophilus) microplus have been suggested to act as vectors. The present study aimed to evaluate, under controlled conditions, the acquisition of H. canis by A. ovale, R. sanguineus, and A. cajennense after feeding on naturally infected dogs. Cytological and histophatological examinations were performed to recover oocysts and other sporogonic stages of the protozoan from the experimentally infected nymphs and adults. None of the R. sanguineus (n=30) or A. cajennense nymphs (n=15) that were dissected after feeding on H. canis naturally infected dogs became infected by the hemoparasite. Likewise, none of the R. sanguineus (n=165) and A. cajennense (n=114) adult ticks that were fed as nymphs on dogs demonstrated infection. Additionally, A. cajennense adult ticks were incapable of acquiring the infection, since no parasite was found in 62 adults that fed on H. canis-infected dogs. With regard to A. ovale ticks, 2 different infestations were carried out. Firstly, a dog with naturally occurring hepatozoonosis was infested with A. ovale adults originating from Rondônia, Brazil. Ticks fed to full engorgement. A total of 31 adults was collected from the dog and dissected on the third day after natural detachment. Oocysts were detected in 13 (42%) of the ticks. The second experimental infestation was carried out using adult ticks originating from São Paulo, Brazil. Surprisingly, of the 103 dissected ticks, only one (1%) contained oocysts in the hemocoel. No other sporogonic stage was found. Results indicate that different strains of A. ovale ticks may exist in Brazil with different susceptibilities to pathogens. Furthermore, it is possible that R. sanguineus and A. cajennense have little or no importance in the transmission of H. canis in rural areas of Brazil.
authors.affiliation: Departamento de Parasitologia do Instituto de Biociências, Universidade Estadual Júlio de Mesquita Filho, Distrito de Rubião Júnior s/n, CEP 18618-970, Botucatu, São Paulo, Brazil.
authors.forename: Larissa de Castro
authors.initials: Lde C
authors.lastname: Demoner
authors.forename: Adriano Stefani
authors.initials: AS
authors.lastname: Rubini
authors.forename: Karina dos Santos
authors.initials: Kdos S
authors.lastname: Paduan
authors.forename: Betina
authors.initials: B
authors.lastname: Metzger
authors.forename: João Marcelo Azevedo
authors.initials: JM
authors.lastname: de Paula Antunes
authors.forename: Thiago Fenandes
authors.initials: TF
authors.lastname: Martins
authors.forename: Maria Izabel Camargo
authors.initials: MI
authors.lastname: Mathias
authors.forename: Lucia Helena
authors.initials: LH
authors.lastname: O'Dwyer
mesh_terms: D000818:Animals; D001096:Arachnid Vectors / Q000469:parasitology*; D001938:Brazil; D003044:Coccidia / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D003048:Coccidiosis / Q000469:parasitology / Q000635:transmission / Q000662:veterinary*; D004283:Dog Diseases / Q000469:parasitology / Q000635:transmission*; D004285:Dogs; D005260:Female; D026863:Ixodidae / Q000469:parasitology*; D008297:Male; D009758:Nymph; D033661:Oocysts; D048508:Rhipicephalus sanguineus / Q000469:parasitology*
keywords: Amblyomma cajennense; Amblyomma ovale; Brazil; Hepatozoon canis; Rhipicephalus sanguineus; Transmission