Serological Evidence of Lyme disease And Possible Introduction of Borrelia along Migratory Bird Routes in Brazil
The presence of autochthonous Borrelia burgdorferi sensu lato (s.l.) in Brazil has been unproven until recently because this etiological agent has not been isolated in neither human clinical samples nor in ticks collected in probable areas of infection. However, recent studies have shown that migrating birds can transport ticks infected by bioagents between countries and continents. To evaluate serological evidence of human Borrelia-caused infections in Brazil, and to compare these data with the presence of migratory birds, and testing for spatio-temporal correlation between these two events. Spatiotemporal analysis of Lyme disease-reactive human serologies (2009-2016) and sites and times of migratory bird occurrence of in Brazil was conducted. Geographic groupings were analyzed by estimating Kernel density and Moran I Global Index. To evaluate record temporal structuring, data from months when migratory birds occur in Brazil (September to April), were compared with months of onset of symptoms clinically resembling Lyme borreliosis. Analysis of variance was performed to test whether the presence/absence of migratory birds is associated with the frequency of serologies. Results indicate a spatial association between the events (I=0.53). However, analysis of variance found no significant difference between the presence/absence of migratory birds in Brazil and the frequency of Lyme disease reactive serologies (F=0.564, df=1, p=0.456). The observed spatio-temporal pattern suggests that either translocation of infected vectors or the migration of birds with bacteremia from endemic areas may be responsible for human infections of Lyme borreliosis in Brazil. However, more research, monitoring and surveillance (human and animal) are required to support this hypothesis.