Molecular detection of tick-borne rickettsial pathogens in ticks collected from domestic animals from Cauca, Colombia.

The research investigated types of ticks and tick-borne pathogens in Cauca, Colombia. They evaluated the presence of infectious agents in ticks extracted from domestic animals and found that a significant portion of ticks showed signs of carrying disease-causing pathogens, including many types of Anaplasma, Ehrlichia, and Rickettsia.

Research Context

• The researchers conducted the study in Cauca department, Colombia, an agricultural region where most people live in rural areas, hence increasing exposure to ticks and tick-borne diseases.
• The focus of the study was on hard ticks, which are known vectors of a variety of pathogens affecting both humans and animals.

Study Design and Methodology

• At a designated period from August to November 2017, the research team collected ticks from domestic animals-dogs, horses, and cattle-from several rural areas in the region.
• All collected ticks underwent classification according to taxonomic keys, facilitated by the extraction of DNA from the tick pools.
• The researchers used the extracted DNA for two purposes: to molecularly confirm the tick species, and to detect the presence of Anaplasma, Ehrlichia, and Rickettsia species, all of which are potential pathogens that ticks can carry.

Findings and Conclusion

• The team gathered a total of 2809 ticks and grouped them into 602 pools. The morphologically identified tick species consisted of Amblyomma cajennense sensu lato, Dermacentor nitens, Rhipicephalus microplus, and Rhipicephalus sanguineus sensu lato, with additional molecular confirmation of A. cajennense s.l. as Amblyomma patinoi.
• A significant ratio of the tick pools, 95%, tested positive for the presence of Anaplasmataceae family members. Further testing revealed 7.8% and 7.3% positivity to Anaplasma and Ehrlichia species, respectively. Identified pathogens were Anaplasma marginale, Ehrlichia minasensis, and Ehrlichia canis.
• In addition, 16.1% of tick pools tested positive for Rickettsia species, showing a high identity for Rickettsia asembonensis, Rickettsia felis, and Candidatus Rickettsia senegalensis.
• The authors conclude this is the first report that describe the natural infection of ticks with rickettsial pathogens and the occurrence of A. patinoi ticks in the Cauca department, indicating potential health risks to animals and humans in the area due to tick-borne diseases.