Rickettsial infection in domestic mammals and their ectoparasites in El Valle de Antón, Coclé, Panamá.

The research examines the presence and significance of Rickettsia bacteria on external parasites of horses and dogs in the town of El Valle de Antón, Panama.

Methodology and Findings

• The investigator team used PCR techniques to check the presence of Rickettsia spp. in ectoparasites, which are creatures that infest outer body surfaces of dogs and horses, and analysed their sera using the immunofluorescence assay.
• 20 horses and 20 dogs were used for the study. Four types of ectoparasites—Rhipicephalus sanguineus, Amblyomma ovale, Amblyomma oblongoguttatum, and Ctenocephalides felis—were found on dogs, with two tick varieties—Amblyomma cajennense and Dermacentor nitens—found on horses.
• The DNA of Rickettsia amblyommii was discovered in pools of A. cajennense, D. nitens, and R. sanguineus, whereas Rickettsia felis was found in C. felis pools.

Prevalence of Infection and Antibodies

• 70% of the horses and 65% of the dogs were seroreactive (meaning their blood serum reacted to an antigen) to the spotted fever group rickettsiae, indicating a widespread presence of the bacteria.
• Blood serum samples from six dogs and five horses reacted to R. amblyommii antigens with titers at least four-fold higher than those for other antigens tested, including Rickettsia bellii, Rickettsia parkeri, Rickettsia rhipicephali, R. felis, and R. rickettsii.
• This suggests that these dogs and horses were infected by Rickettsia amblyommii.

Future Research Scope

• The investigation concludes with a call for further studies. The main goal should be to identify the type of Rickettsia responsible for other positive serological and molecular test results and to understand the ecological importance of those.