Molecular detection of hemotropic mycoplasmas (hemoplasmas) in humans and dogs living on islands and the seashore mainland of Brazil: a One Health approach

BACKGROUND: Although Mycoplasma spp. infection has been recently detected in other vulnerable human populations (indigenous and quilombola communities) in Brazil, no study to date has focused on traditional oceanic island communities and their dogs. To address this research gap, we assessed Mycoplasma spp. infection in humans and dogs living on the mainland seashore and oceanic islands of southern Brazil. METHODS: Humans from three oceanic islands and two coastal mainland municipalities of southern Brazil were sampled, and Mycoplasma spp. infection was determined using quantitative polymerase chain reaction (qPCR) (cycle threshold; Ct ≤ 34.4). Dog samples were collected and tested using the Canine Hemotropic Mycoplasma panel (Idexx Reference Laboratory, Sacramento, CA, USA). To ensure accurate results, samples were also subjected to targeted next-generation sequencing (tNGS), and results were used to construct phylogenetic trees. Epidemiological information was obtained to analyze associated risk factors. RESULTS: A total of 19/304 (6.2%) individuals tested positive to hemoplasmas, with Mycoplasma haemocanis confirmed in 3/304 (1.0%) through 16S ribosomal RNA gene and targeted next-generation sequencing. In addition, 44/290 (15.2%) dogs were positive for hemoplasmas through qPCR testing, with 13/290 (4.5%) for M. haemocanis, 23/290 (7.9%) for Candidatus Mycoplasma haematoparvum, and 8/290 (2.8%) for both. Statistical analysis revealed an association between human positivity and gender and income range, and dog positivity was associated with male gender and access to forest areas. CONCLUSIONS: The concomitant human-dog M. haemocanis detected herein on oceanic islands together with results from previous reports on indigenous and quilombola communities, suggest that socially vulnerable populations have an increased exposure risk. Future studies should be conducted in other vulnerable populations worldwide to fully establish the extent of human-dog Mycoplasma spp.