Tick-borne diseases in French Guiana: A comprehensive review pinpointing differences from mainland France.

French Guiana (FG), an Amazonian French territory, represents a unique ecological and epidemiological setting for tick-borne diseases (TBDs). In contrast to mainland France, where TBDs are well-documented, data from FG remain scarce. We carried out a systematic review using the PRISMA criteria for our search of the PubMed, ScienceDirect, and SciELO data bases. We identified 68 articles, of which 43 met our inclusion criteria. Data from FG were compared with those originating from mainland France. Albeit highly prevalent in Europe, and notwithstanding detection of a distinct Borrelia species in bird-associated ticks, there have been no confirmed autochthonous cases of Lyme disease in French Guiana. Conversely, Q fever occurs more frequently in this overseas territory than in mainland France, even though its causative agent, Coxiella burnetii, has been detected only one time in a local tick. While Rickettsia spp. are widely present in tick populations, no human rickettsiosis has been reported. As for Anaplasma and Ehrlichia spp., they have been identified in wildlife, domestic animals, and ticks, but with only one documented human case of chronic anaplasmosis, which was caused by a novel species, Candidatus Anaplasma sparouinense. Other pathogens, including Babesia, Bartonella, and filarial nematodes, have been detected in animals or ticks, but without evidence of human infection. Of note, emerging conditions have been described, one example being alpha-gal syndrome, an allergy triggered by tick bites to mammalian meat. To summarize, available data remain limited, and in all likelihood, the burden of TBDs in FG is underestimated. Integrated research combining human, animal and environmental surveillance is needed to more precisely characterize epidemiology, assess risks, and facilitate preventive strategies.