Amblyomma Oblongoguttatum Research Articles

<I>Rickettsia bellii</I> and <I>Rickettsia amblyommii</I> in <I>Amblyomma</I> Ticks from the State of Rondônia, Western Amazon, Brazil

This study evaluates the rickettsial presence in Amblyomma ticks from eight areas of the Amazon forest in Rondônia, Brazil. The following tick species (number in parentheses) were examined: Amblyomma ovale Koch (121), Amblyomma cajennense (F.) (41), Amblyomma naponense (Packard) (36), Amblyomma scalpturatum Neumann (35), Amblyomma oblongoguttatum Koch (30), Amblyomma incisum Neumann (27), Amblyomma rotundatum Koch (16), Amblyomma coelebs Neumann (10), and Amblyomma humerale Koch (6). Ticks were examined individually or in pools (2-10 ticks) by polymerase chain reaction (PCR) targeting the gltA gene. The PCR-determined minimal infection rate for each tick species was A. ovale 28%, A. cajennense 27%, A. naponense 0%, A. scalpturatum 11%, A. oblongoguttatum 3%, A. incisum 0%, A. rotundatum 87%, A. coelebs 10%, and A. humerale 50%. Partial sequences of the gltA gene of Rickettsia from A. ovale, A. scalpturatum, A. oblongoguttatum, A. rotundatum, and A. humerale were 99.9% (349/350) identical to Rickettsia bellii. DNA sequences of PCR products from A. cajennense and A. coelebs were 100% (350/350) identical to Rickettsia amblyommii. R. bellii organisms were isolated in Vero cells from A. scalpturatum, A. ovale, A. rotundatum, and A. oblongoguttatum, but only one of the isolates, cultured from A. scalpturatum, was established in continuous cell culture passage. R. amblyommii was isolated from A. cajennense and was successfully established in continuous passage in cell culture. R. amblyommii infection of Vero cells was analyzed by transmission electron microscopy. This study adds South America to the known geographic distribution of R. amblyommii and reports rickettsiae in six Amblyomma species for the first time.

A case of gynandromorphism in Amblyomma oblongoguttatum (Acari: Ixodidae).

During a survey conducted from August to November 1998 to ticks associated with dogs in the rural area of Uruará, in the state of Para, Eastern Amazon region of Brazil, we collected one gynandromorph specimen out of 18 Amblyomma oblongoguttatum Koch specimens collected from dogs. It is a perfect bipartite gynandromorph, reported in this species for the first time.

Ticks (Acari: Ixodidae) associated with rural dogs in Uruará, eastern Amazon, Brazil.

A survey of 124 dogs for ticks was conducted from August to November 1998 in 68 small farms of Uruará municipality in Eastern Amazon-Brazil. We collected 55 ticks from 18 dogs (14.5%). Amblyomma oblongoguttatum Koch, Amblyomma ovale Koch, and Amblyomma cajennense (F.) were found on nine, six, and one dog, respectively. Fourteen small farms (20.5%) had at least one dog with ticks.