Dengue fever has been a public health problem in the Caribbean region since 1981, when it first reappeared in Cuba. In 1989, it was reported in Martinique and Guadeloupe (two French islands 200 km apart); since then, DENV has caused several epidemics locally. In 2019–2021, DENV-1, DENV-2, and DENV-3 were detected. Serotype distribution was differentiated, with DENV-2 and DENV-3 predominating in Guadeloupe and Martinique, respectively. Complete genome sequencing was carried out on 32 specimens, and phylogenic analysis identified the circulation of genotype V for DENV-1, cosmopolitan genotype for DENV-2, and genotype III for DENV-3. However, two distinct circulating groups were identified for DENV-1 and DENV-3, suggesting independent introductions. Overall, despite the context of the COVID-19 pandemic and the associated travel restrictions, these results confirm the active circulation of DENV and specific epidemiological features on each of the two islands. Such differences may be linked to the founder effect of the various introduction events, and to local factors such as the population immunity and the transmission capacity of the vectors. Further genomic and epidemiological characterization of DENV strains remains essential to understand how dengue spreads in each specific geographical context and to prevent future epidemics.

The human immunodeficiency virus-type 1 (HIV-1) subtype B has probably been circulating on the island of Hispaniola since the 1960s, but information about the early viral history on this Caribbean island is scarce. In this study, we reconstruct the dissemination dynamics of early divergent non-pandemic subtype B lineages (designated B_CAR) on Hispaniola by analyzing a country-balanced dataset of HIV-1 B_CAR pol sequences from Haiti (n = 103) and the Dominican Republic (n = 123). Phylogenetic analyses supported that B_CAR strains from Haiti and the Dominican Republic were highly intermixed between each other, although the null hypothesis of completely random mixing was rejected. Bayesian phylogeographic analyses placed the ancestral B_CAR virus in Haiti and the Dominican Republic with the same posterior probability support. These analyses estimate frequent viral transmissions between Haiti and the Dominican Republic since the early 1970s onwards, and the presence of local B_CAR transmission networks in both countries before first AIDS cases was officially recognized. Demographic reconstructions point that the B_CAR epidemic in Hispaniola grew exponentially until the 1990s. These findings support that the HIV-1 epidemics in Haiti and the Dominican Republic have been connected by a recurrent bidirectional viral flux since the initial phase, which poses a great challenge in tracing the geographic origin of the B_CAR epidemic within Hispaniola using only genetic data. These data also reinforce the notion that prevention programs have successfully reduced the rate of new HIV-1 transmissions in Hispaniola since the end of the 1990s.

The Caribbean and South American French Overseas Territories (CSAFOT) are the regions most heavily affected by the Human Immunodeficiency Virus type 1 (HIV-1) epidemic in France. Although dominated by HIV-1 subtype B, the detection of non-B subtypes and the great proportion of HIV-positive persons born abroad demonstrated the potential for local spread of non-B subtype strains in CSAFOT. To reconstruct the epidemiologic dynamics of major non-B subtype clusters spreading in CSAFOT, we conducted phylogenetic and evolutionary analyses of 2,523 HIV-1 pol sequences collected from patients living in Martinique, Guadeloupe, and French Guiana from 1995 to 2018. A large variety of HIV-1 non-B subtype strains (eight subtypes, twelve CRFs, and multiple URFs) have been introduced in CSAFOT and their prevalence significantly increases over time in Martinique and Guadeloupe. We identified twelve major transmission networks of non-B subtypes (CRF02_AG and subtypes A3, C, D, and F1) that probably arose in Guadeloupe, Martinique, French Guiana, and mainland France between the late 1970s and the middle 2000s. Phylogeographic analyses support frequent non-B subtype viral transmissions within CSAFOT as well as transatlantic transmission between CSAFOT and mainland France. Domestic transmission networks of non-B subtype variants in CSAFOT comprise both men having sex with men and heterosexual individuals from different age groups. Different HIV-1 non-B subtype variants were sequentially introduced in CSAFOT between the late 1970s and the middle 2000s and are currently spreading through domestic, regional, and/or transatlantic networks of individuals from different age and risk groups.

Fc gamma receptors (FcγRs) control humoral and cellular immune responses and maintain the immune system balance. Functional polymorphisms of FcγRs, whose prevalence was dependent on ethnic origin, were found to be associated with systemic lupus erythematosus (SLE) or kidney injuries in several ethnic groups. We aimed at investigating the association between the functional single-nucleotide polymorphisms (SNPs) of FcγRIIa-H131R (rs1801274), FcγRIIb-I232T (rs1050501), FcγRIIIa-V158F (rs396991) and FcγRIIIb variants (NA1 and NA2) and lupus erythematosus systemic in an indigenous African Caribbean population. We compared the frequencies of the functional SNPs of FCGR2A (FcγRIIa-H131R, rs1801274), FCGR2B (FcγRIIb-I232T, rs1050501), FCGR3A (FcγRIIIa-V158F, rs396991) and FCGR3B variants (FcγRIIIb NA1 and NA2) between lupus and healthy controls in an indigenous African Caribbean population. We highlighted an association between the FCGR3B-NA1/NA1 and FCGR3A-158F alleles and systemic lupus erythematosus, in addition to an association between FCGR2A-131R and lupus nephritis. Furthermore, an increase in the 131R-158V haplotype in lupus nephritis (30.4%) vs. lupus non-nephritis (15.8%) was noticed. Surprisingly, in spite of the high frequency of the FCGR2B-232T allele in our population, our study did not highlight any association of this allele either with SLE or lupus nephritis (a severe and frequent form of SLE). CD72-Hap1, which has been shown to confer resistance to SLE against T232 allele, was not enhanced in the control group. Our results emphasize an association between FCGR2A-131R and lupus nephritis with a distinctive FCGR polymorphism distribution in an indigenous African Caribbean population, confirming the important variation in the FCGR locus depending on ethnic origin.