Detection, genetic diversity, and factors associated with infection by hemotropic mycoplasmas in rodent and marsupial populations in regions of the states of Rio de Janeiro and Parana, Brazil

Abstract

Hemotropic mycoplasmas, also known as hemoplasmas, are found in several animal species around the world. New species and genotypes of mycoplasmas have been described recently but much more remains to be discovered, especially in wildlife. The objective of this study was to investigate the presence of hemotropic mycoplasmas and diversity of the 16S rDNA sequence fragment in populations of small nonflying mammals in regions with different phytophysiognomies in the states of Rio de Janeiro and Parana, Brazil, as well as to evaluate environmental and animal factors influencing infection rates. Of the 257 animals sampled, 33.8 % (n = 87) were considered positive by conventional PCR. Of the 230 samples from wild rodents (Cricetidae), 36.5 % (n = 84) amplified hemotropic mycoplasma DNA, followed by synanthropic rodents (Muridae) (12.5 %, n = 2/16), and marsupials (Didelphidae) (9.0 %, n = 1/11). The regions with the highest frequency of positivity were Ponta Grossa (46.5 %, n = 27/58) and Cruz Machado (46.1 %, n = 24/52), followed by Nova Friburgo (30.8 %, n = 33/107), and Lidianopolis (12.5 %, n = 5/40). Oligoryzomys had the highest rate of infection (78.5 %), statistically different from Oxymycterus spp. (40.0 %), Akodon spp. (27.0 %) and Sooretamys (8.3 %). Males had a higher prevalence of Mycoplasma spp., being 3.97 times more likely to be positive for hemoplasma than females. Phylogenetic analysis grouped the sequences from this study into two clades, A and E, together with other hemoplasma sequences previously detected in small wild and synanthropic rodents from Brazil, Hungary, and Japan. Haplotype network reveals exclusive haplotypes for wild and synanthropic rodents. Our study reveals considerable genetic diversity suggesting the circulation of at least two species among sequences from this study and highlights the importance of considering environmental and biological factors in the epidemiology of these infections in wild mammals.

Keywords: Atlantic forest; Epicellular bacteria; Hemoplasmas; Phylogeny; Small mammals.