Detection of Anaplasma and Ehrlichia bacteria in humans, wildlife, and ticks in the Amazon rainforest.

Tick-borne bacteria of the genera Ehrlichia and Anaplasma cause several emerging human infectious diseases worldwide. In this study, we conduct an extensive survey for Ehrlichia and Anaplasma infections in the rainforests of the Amazon biome of French Guiana. Through molecular genetics and metagenomics reconstruction, we observe a high indigenous biodiversity of infections circulating among humans, wildlife, and ticks inhabiting these ecosystems. Molecular typing identifies these infections as highly endemic, with a majority of new strains and putative species specific to French Guiana. They are detected in unusual rainforest wild animals, suggesting they have distinctive sylvatic transmission cycles. They also present potential health hazards, as revealed by the detection of Candidatus Anaplasma sparouinense in human red blood cells and that of a new close relative of the human pathogen Ehrlichia ewingii, Candidatus Ehrlichia cajennense, in the tick species that most frequently bite humans in South America. The genome assembly of three new putative species obtained from human, sloth, and tick metagenomes further reveals the presence of major homologs of Ehrlichia and Anaplasma virulence factors. These observations converge to classify health hazards associated with Ehrlichia and Anaplasma infections in the Amazon biome as distinct from those in the Northern Hemisphere.

Identification of bluetongue virus and epizootic hemorrhagic disease virus serotypes in French Guiana in 2011 and 2012.

In French Guiana, the sero- and viro-prevalence of Bluetongue virus (BTV) is high but the circulating serotypes remain unknown. No data are available regarding the prevalence of Epizootic hemorrhagic disease (EHD). This study was conducted to assess the prevalence and to identify the circulating serotypes of these two Orbiviruses in this region (BTV and EHDV). Blood samples were collected in main livestock areas, from 122 young cattle between June and August 2011, to perform virological (PCR and viral isolation) and serological (ELISA) analyses. Moreover, samples from sheep and goat showing BTV-like clinical signs and from newly imported animals were analyzed using the same assays. Results confirmed an important viral circulation, with viro- and seroprevalence of 85% and 84% and 60% and 40% for BTV and EHDV, respectively. Ten Orbivirus serotypes were identified (BTV-1, 2, 6, 10, 12, 13, 17 and 24, EHDV-1 and 6). The circulation of many serotypes in intertropical America and in the Caribbean region underlines the need to establish measures to monitor and control animal movements.