Serosurvey of Borrelia in dogs, horses, and humans exposed to ticks in a rural settlement of southern Brazil.

The research study focused on surveying anti-Borrelia burgdorferi antibodies, the bacteria known to cause Lyme disease, in dogs, horses, and humans who were highly exposed to tick bites. This study was conducted in a rural settlement in Paraná State, southern Brazil, using methods like Immunofluorescence antibody test and western blot analysis. However, the researchers concluded that due to the lack of isolation, molecular characterization, absence of competent vectors and the low specificity of the commercial western blot kit, the risk factor analysis might have been impaired.

Study Aim and Methods

• The research aimed at evaluating the presence of anti-Borrelia burgdorferi antibodies in dogs, horses, and humans, all of whom were highly exposed to ticks.
• The participants of the study comprised of 87 residents, and their 83 dogs and 18 horses from a rural settlement in Paraná State, southern Brazil.
• For each of these participants, individual surveys were administered
• The researchers evaluated the serological samples from the participants with an Immunofluorescence antibody test (IFAT). Positive samples were further tested with the western blot (WB) method for confirmation.

Findings

• Anti-Borrelia antibodies were found in 4.6% of humans, 31.3% of dogs, and 38.9% of horses tested.
• All the human participants that tested positive in the IFAT test also confirmed positive in the WB test.
• The ticks identified belonged mostly to dogs and were categorised into Rhipicephalus sanguineus, Amblyomma ovale, and A. cajennense sensu lato.
• All ticks found on horses were identified as A. cajennense s.l.

Limitations

• No significant association was found between age, gender, or presence of ticks with seropositivity to Borrelia sp.
• The researchers identified that the lack of isolation, molecular characterization of the ticks, absence of competent vectors and the suspected low specificity of the commercial WB kit might have impaired the analysis of risk factors associated with seropositivity.

Conclusion

• Although the presence of anti-Borrelia antibodies was identified in dogs, horses, and their owners from the rural settlement, the risk factors could not be thoroughly characterized due to the aforementioned limitations.
• Despite these limitations, the study provides a foundation for further research into Borrelia sp. infections in environments that have a high exposure to tick bites.