French Guiana Research Articles

Infant congenital cardiac mortality and univentricular hearts in Latin America and Caribbean: A population-based study in French Guiana

Infant congenital cardiac mortality and univentricular hearts in Latin America and Caribbean: A population-based study in French Guiana

Nitrate Uptake and Primary Production Along the Amazon River Plume Continuum

AbstractThe Amazon River plume (ARP) has been shown to support high rates of nitrogen fixation and primary production. However, nitrogen fixation alone cannot account for total primary production determined in the region, hinting that other nitrogen uptake processes might play a role. For the first time, we measured nitrate uptake rates in the ARP during three cruises in May 2018, June 2019 and April/May 2021, along with primary production rates and an analysis of phytoplankton community composition via high performance liquid chromatography. Based on a classification according to the salt content the region was divided into estuarine (ES), mesohaline (MH) and oceanic (OC) stations. Primary production was light limited near the river mouth at ES stations and was maximal off the coasts of French Guiana and Suriname, where also nitrate uptake was highest with rates of 11.4 mmol m−2 d−1. The role of eddies pinching off a deflecting plume are discussed as possible reason for higher nutrient concentrations at the MH stations. Surprisingly, at most MH stations north of 5°N, nitrate uptake rates were low despite the presence of sufficient substrate concentration (up to 1.44 μM nitrate). Diatoms, dinoflagellates or Synechococcus sp. dominated phytoplankton communities. OC stations showed lowest productivity rates in accordance with oligotrophic conditions. However, rates seem to be sufficient to completely deplete the remaining riverine nitrate, preventing its export to the open ocean.

Two New Species of Melucha Amyot and Serville, 1843 from French Guiana (Hemiptera: Heteroptera: Coreidae: Nematopodini), with a Revised Key to the Species

Two new species of Melucha Amyot and Serville, 1843 collected in French Guiana are described: M. edictum new species and M. flatilis new species. Dorsal photographs are provided as well as photos of male genital capsules and parameres where available. A key to the 15 known species is included.

An Investigation of Mucosal Leishmaniasis in the Military Health System.

Leishmaniasis is a protozoal infection with an increased risk of transmission to those serving in the U.S. Military due to theaters of operation in endemic regions. There has, in recent decades, been robust experience with old-world leishmaniasis in the Military Health System (MHS); however, new-world leishmaniasis, which may result in mucosal leishmaniasis, has been less studied. A total of 88 patients from 2012 to 2022 with diagnosis codes for "mucocutaneous leishmaniasis" or "leishmaniasis, unspecified" were identified in the Military Data Repository and reviewed. Within this cohort, upon medical records review, there were 2 cases of leishmaniasis that met inclusion criteria. Case 1 was a 28-year-old active duty male with recent travel to Belize who presented with a mucosal lip lesion that was biopsied and had inconclusive species confirmation but was thought to be either L. braziliensis or L. mexicana. The second case involved a 30-year-old active duty male with a history of travel to French Guiana who had a cutaneous lesion on his left hand that was identified as L. guyanensis, a causative species for mucosal leishmaniasis. Neither had evidence of any further mucosal involvement on otolaryngologic evaluation, and both subsequently received systemic therapy with a good clinical response. Although only 2 cases were identified over an 11-year period, this disease remains an important medical consideration when conducting military operations within Central and South America, as both cases had recent military-specific travel to areas endemic for leishmaniasis.

Yield and growth duration of Maroon rice landraces measured in traditional settings

AbstractRice, the most consumed cereal worldwide, has two domesticated species: Asian and African rice. Commercial cultivars, almost all Asian rice, are mostly selected for high yields. Traditional landraces are often selected for different traits, such as time to maturity or resistance against common stress factors, including bird attacks and poor soils. Maroons, descendants of enslaved Africans in Suriname and French Guiana, cultivate a rich diversity of rice landraces. They categorize landraces into short, medium, and long-maturation and maintain that fast-ripening crops with moderate yields facilitated their flight from enslavement, while once settled in a safe place, there was time for landraces with longer ripening periods and higher yields. Previous authors assumed that all Maroon landraces had low yields (700–1000 kg/ha), but their performance in traditional farming systems had never been investigated. We followed the growth and harvest of 28 Maroon rice landraces and two commercial cultivars in Maroon farmer fields, using traditional farming methods, at three locations. We show that, in farmer-managed fields, Maroon rice can yield 2600 kg/ha (average 1665 kg/ha), without any agrochemicals or machinery. Contrastingly, the commercial cultivars in Maroon farmer fields had a low yield (625–1205 kg/ha), partly due to bird predation. The maturation time varied between 110 and 183 days, but the three Maroon maturation categories showed significant overlap. Our study indicates that Maroon rice performance can only be fairly evaluated if measurements are taken in traditional Maroon farming systems, since this is the environment in which these landraces were originally selected.

Biogeochemical plumbing of pioneer mangrove intertidal flats in French Guiana

Migrating mudbanks are characteristic features of the vast Amazon-Guianas coastline along Northeastern South America. As illustrated by sites in French Guiana, consolidating mudflats that periodically transition to mangrove forest are permeated by extensive crustacean burrow systems, sometimes in isolation but more often in close association with morpho-sedimentary structures such as tidal pools and channels. Burrow structures are critical to mangrove growth. In this study, we evaluated the ways in which burrows act as complex conduits that plumb deposits for solute exchange with overlying water. We sampled burrows during low tide when irrigation is inhibited and burrow water rapidly becomes anoxic. The products of diagenetic reactions, for example: NH4+, N2, and Si(OH)4, build up with time, revealing sedimentary reaction rates and fluxes. When oxygenated, burrow walls are zones of intense coupled redox reactions such as nitrification-denitrification. Build-up often is lower in burrows connected directly to tidal pools where photosynthetic activity consumes remineralized nutrients, and burrows can remain periodically irrigated at low tide. During flood, burrows, particularly those that connect tidal pools laterally to channels, can be rapidly flushed and oxygenated as channel water rises and then spreads across flats. Burrow flushing produces enhanced concentrations of nutrients within the leading edge of the flood as seawater moves progressively towards and into adjacent mangroves. Estimates of burrow volumes obtained from drone surveys together with burrow solute production rates allow upscaling of burrow-sourced metabolite fluxes; however, these are extremely variable due to variable burrow geometries, connections between burrows, pools, and channels, and burrow water residence times (oxygenation). The flushing of burrows during flood results in a rectification of sediment-water fluxes shoreward and enhances the delivery of nutrients from the flats into adjacent mangroves and pools, presumably stimulating colonization and forest growth.

Spatiotemporal Analysis of Total Suspended Solids in Water Bodies and Mapping Mining Areas in Suriname and French Guiana

Spatiotemporal Analysis of Total Suspended Solids in Water Bodies and Mapping Mining Areas in Suriname and French Guiana

Evaluation of the Hg Contamination from Gold Mining in French Guiana at the Watershed Scale Using Hg Isotopic Composition in River Sediments

Evaluation of the Hg Contamination from Gold Mining in French Guiana at the Watershed Scale Using Hg Isotopic Composition in River Sediments

Are plant traits drivers of endophytic communities in seasonally flooded tropical forests?

In the Amazon basin, seasonally flooded (SF) forests offer varying water constraints, providing an excellent way to investigate the role of habitat selection on microbial communities within plants. However, variations in the microbial community among host plants cannot solely be attributed to environmental factors, and how plant traits contribute to microbial assemblages remains an open question. We described leaf- and root-associated microbial communities using ITS2 and 16 S high-throughput sequencing and investigated the stochastic-deterministic balance shaping these community assemblies using two null models. Plant ecophysiological functioning was evaluated by focusing on 10 leaf and root traits in 72 seedlings, belonging to seven tropical SF tree species in French Guiana. We then analyzed how root and leaf traits drove the assembly of endophytic communities. While both stochastic and deterministic processes governed the endophyte assembly in the leaves and roots, stochasticity prevailed. Discrepancies were found between fungi and bacteria, highlighting that these microorganisms have distinct ecological strategies within plants. Traits, especially leaf traits, host species and spatial predictors better explained diversity than composition, but they were modest predictors overall. This study widens our knowledge about tree species in SF forests, a habitat sensitive to climate change, through the combined analyses of their associated microbial communities with functional traits. We emphasize the need to investigate other plant traits to better disentangle the drivers of the relationship between seedlings and their associated microbiomes, ultimately enhancing their adaptive capacities to climate change.

Rhamphempis, a New Genus of Empidini (Diptera: Empididae: Empidinae) of the New World, with Descriptions of Five New Species from French Guiana and the Eastern United States.

The genus Rhamphempisgen. nov. (Diptera: Empididae: Empidinae: Empidini) is described and includes the following five new species from French Guiana and the USA: Rhamphempis concavasp. nov. (France: French Guiana, Roura); R. distinctasp. nov. (France: French Guiana, Roura); R. mirificasp. nov. (France: French Guiana, Régina); R. montreuilisp. nov. (Type species, France: French Guiana, Mitaraka, Roura, St-Georges-de-l'Oyapock); and R. septentrionalissp. nov. (USA: Maryland, College Park). The genus differs from other empidine genera by the following combination of characters: scape and postpedicel lengthened, proboscis long, strongly sclerotised with labella as long as prementum bearing annulations, wing with R2+3 somewhat shortened, more or less recurved at pterostigma, R4+5 unforked, base of abdomen yellowish in male, brownish to blackish in female, male pregenital segments strongly modified and postabdomen more or less downcurved, presence of large surstylus, very fine and long phallus. The genus is fully illustrated and keyed along with a discussion of its peculiar disjunct geographic distribution and its phylogenetic relationship within the tribe Empidini.

Bone and Joint Infections in Children With Sickle Cell Disease in French Guiana: A 13-Year Retrospective Multicenter Review.

Sickle cell disease (SCD) is a genetic disorder with a high infectious morbidity and mortality and a heterogeneous distribution in France. One of the challenges is to differentiate a bone and joint infection (BJI) from a vaso-occlusive crisis. This challenge is particularly prevalent in French Guiana, an overseas territory with the highest incidence of SCD in France. The aim of this study was to describe the epidemiology of BJI in children with SCD in French Guiana. This was a retrospective multicentric descriptive study of SCD patients living in French Guiana aged under 18 and diagnosed with a BJI between 2010 and 2022. These BJI were divided into 2 groups: those with microbiological documentation (d-BJI) and those without microbiological identification (ud-BJI). A total of 53 episodes of BJI in 42 patients (mean age 7.2 years) were reported. Clinical symptoms on arrival were comparable between the d-BJI and ud-BJI groups. Patients in the d-BJI group had longer average hospital stays (40.4 days vs. 16.8 days, P = 0.01) and Salmonella spp. were the most identified bacteria (n = 8/13). White blood cell count was greater in the d-BJI group (30.3 G/L vs. 18.G/L, P = 0.01) and a collection was more frequently identified on imaging (11/13 vs. 16/40, P = 0.01) in this group. Initial in-hospital antibiotic therapy was longer in the d-BJI group (17.2 days vs. 12.8, P = 0.02), as were infection-related complications (9/13 vs. 12/40 P = 0.01). BJI in children with SCD is not sufficiently microbiologically documented. Progress must be made to improve the documentation of BJI.

Exploring fine-scale urban landscapes using satellite data to predict the distribution of Aedes mosquito breeding sites

BackgroundThe spread of mosquito-transmitted diseases such as dengue is a major public health issue worldwide. The Aedes aegypti mosquito, a primary vector for dengue, thrives in urban environments and breeds mainly in artificial or natural water containers. While the relationship between urban landscapes and potential breeding sites remains poorly understood, such a knowledge could help mitigate the risks associated with these diseases. This study aimed to analyze the relationships between urban landscape characteristics and potential breeding site abundance and type in cities of French Guiana (South America), and to evaluate the potential of such variables to be used in predictive models.MethodsWe use Multifactorial Analysis to explore the relationship between urban landscape characteristics derived from very high resolution satellite imagery, and potential breeding sites recorded from in-situ surveys. We then applied Random Forest models with different sets of urban variables to predict the number of potential breeding sites where entomological data are not available.ResultsLandscape analyses applied to satellite images showed that urban types can be clearly identified using texture indices. The Multiple Factor Analysis helped identify variables related to the distribution of potential breeding sites, such as buildings class area, landscape shape index, building number, and the first component of texture indices. Models predicting the number of potential breeding sites using the entire dataset provided an R² of 0.90, possibly influenced by overfitting, but allowing the prediction over all the study sites. Predictions of potential breeding sites varied highly depending on their type, with better results on breeding sites types commonly found in urban landscapes, such as containers of less than 200 L, large volumes and barrels. The study also outlined the limitation offered by the entomological data, whose sampling was not specifically designed for this study. Model outputs could be used as input to a mosquito dynamics model when no accurate field data are available.ConclusionThis study offers a first use of routinely collected data on potential breeding sites in a research study. It highlights the potential benefits of including satellite-based characterizations of the urban environment to improve vector control strategies.

The role of changing landscape in the dispersal of a soil‐feeding termite in Suriname and French Guiana

Abstract Neotropical forest ecosystems harbour significant biodiversity. To develop effective insect conservation practices, it is important to understand the factors that influence the diversity and population structure of the species. Dispersal, a key determinant of population structure, is well studied in termites nesting in wood, for which it can be influenced by wood transport, or in termites living in urban environments. However, understanding the dispersal of termites whose mobility remains unaffected by wood transport remains understudied. We investigated the dispersal of Embiratermes neotenicus, a soil‐feeding species with short dispersal distance, in the Neotropical region, where both intact and degraded forests exist. Using mitochondrial and nuclear data, we analysed genetic diversity, structure and factors contributing to population differentiation in Suriname and French Guiana at multiple scales for 70 colonies. The population in French Guiana is the ancestral population in the region that subsequently expanded. Significant genetic differentiation between populations was observed, with distinct patterns identified in Suriname and French Guiana. The Suriname population showed higher genetic diversity and no subpopulation differentiation, whereas the French Guiana population showed substructure into distinct genetic clusters. Analyses at the scale of all colonies suggest the influence of landscape features, such as the Maroni River, on genetic differentiation. At the local scale, genetic differentiation between colonies increases with forest alteration, even when this does not include major changes in forest cover. Our results highlight the sensitivity of soil‐feeding termite populations to habitat change. We argue that multi‐scale studies are needed for a comprehensive understanding of genetic patterns, especially for species with short dispersal distances.

Use of miltefosine in the treatment of cutaneous leishmaniasis in French Guiana

Use of miltefosine in the treatment of cutaneous leishmaniasis in French Guiana

Research in an intercultural context: mediator-investigators of epidemiological health studies, bridges between two worlds.

ContextFrench Guiana is a French overseas department where very different linguistic, cultural and societal populations live together in a small area. Health issues and their specific epidemiological profiles call for research projects crossing several cultures. In this context, health mediators have a role to play in research. The aim of this study was to describe the perceptions, attitudes and opinions on research of mediators and researchers collaborating on research projects, and to describe the strengths and difficulties encountered during this cooperation.MethodsThe Inter-med project was conducted in French Guiana between February 2022 and April 2023 on the base of semi-directive interviews with mediators, or researchers, all working in health research in the intercultural context of French Guiana. The socio-demographic characteristics of the participants were described. An inductive thematic analysis was carried out on all the interviews, and word occurrence analysis on certain themes. The information was triangulated with field coordination notebooks from two epidemiological surveys conducted in French Guiana between 2021 and 2022.ResultsA total of 26 semi-structured interviews were conducted and 1,328 notebook pages analyzed. Mediation was described as an indispensable interface between the world of research and that of the population targeted by a survey. Mediators have a role to play at different stages of projects, in respect of good clinical practice, ethics and legislation. They act as interfaces between languages, concepts and representations. Their profession remains under-defined and under-dimensioned. The jobs offered are often precarious. Mediation work is emotionally costly, calls on soft skills and requires a combination of rigor and flexibility. All these aspects are implemented in the specific world of research, where there are common concepts and divergent perceptions. Researchers and mediators converge on a common goal: improving health.ConclusionThis study covers several aspects of the development and implementation of research projects. Respect for good clinical practice and people, transparency and data quality are redundant concerns, and this study touches on ethnocentrism, stigmatization and cultural representations. This study points out that the integration and recognition of mediators could be beneficial in research conducted in a cross-cultural context.

An Observational Study of Sexual Assaults in French Guiana During 2019-2020.

Sexual violence is a major public health issue, including in French Guiana. The feeling of insecurity is significant in this part of France. Sexual violence is an important reason for consultation in forensic and emergency medicine. The challenge is to provide care within the first 72 hours, particularly in medicolegal terms and for infectious disease management. The objectives of our study were, firstly, to establish the epidemiology of sexual assaults at Cayenne General Hospital (CGH), and secondly, to evaluate the management of these victims. From January 1st, 2019 to December 31st, 2020, we conducted a single-center retrospective descriptive study including patients who were consulted for sexual assaults in the Forensic medicine and the Emergency departments of CGH. Over this period, 400 sexual assault victims were consulted. Most of them, were women (87%) with a median age of 13 years-old [8; 17.5]. The aggressor was mostly male (99%) frequently known by the victim (87%) and from her family (39%). Suspected assaults represented 19% of consultations. The most frequent assault on women was penile-vaginal penetration (82%) and penile-anal penetration (77%) on men. The delay of consultation was superior to 72 hours in 60% of the cases. A psychological follow-up was recommended for 62% of these victims. This work allowed to identify a young and female population at risk, most often assaulted by a male known to her. Most of the patients consulted more than 72 hours after the assault. Our study highlights the need for prevention actions in French Guiana focusing on this population at risk.

Identifying suicidal risk factors in the French Overseas Territories with multimethod psychological autopsy (AUTOPSOM): a mixed-methods study protocol

IntroductionUnderstanding suicide in more isolated territories is a challenge because of the entanglement of cultural identity with historical, geographical and sociocultural specificities. This knowledge is a necessary precondition for the...

Phylogeny and taxonomic revision of Metacephalus (Insecta: Hemiptera: Cicadellidae) with description of seven new leafhopper species.

Metacephalus Delong and Martinson, 1973 includes leafhopper species from Argentina, Bolivia, Brazil, Colombia, Ecuador (new record), Guyana, French Guiana (new record), Panama, Peru, and Venezuela. In the present revisionary study, we describe seven new species of Metacephalus, propose one species synonymy (M. cinctus as junior synonym of M. facetus), and provide new country records for species, considerably expanding knowledge about species distributions. The study also provides redescriptions and photographs of diagnostic characters for 12 previously described valid species and an identification key to all 21 species of Metacephalus. Molecular phylogenies of Metacephalus species are hypothesized based on maximum likelihood and Bayesian inference analyses of 1,387 bp of mitochondrial Cytochrome Oxidase I and 16S rDNA and nuclear histone H3. Results of the molecular phylogeny generated herein provided a base for understanding character homologies when presenting morphological diagnoses of Metacephalus species and exposed a high level of convergent characters in color pattern and male genitalia morphology usually used in morphological taxonomy of this group of leafhoppers.

Morphological and molecular data suggest the presence of cryptic diversity within Dermacentor nitens (Acari: Ixodidae) in Colombia</p >

Of the 44 species within the genus Dermacentor (Acari: Ixodidae) worldwide, nine are found in the Neotropics and four are endemic to this region. In Colombia, located in the northwestern corner of South America, there are two species of the genus: Dermacentor imitans restricted to the trans-Andean Pacific region, and Dermacentor nitens widely distributed in the country. Elsewhere, D. nitens is found in both the Nearctic and Neotropics, from southern USA to northern Argentina. In the Neotropics, D. nitens is widely distributed including records in Caribbean islands. Molecular analyses of D. nitens collected in the Amazon region of Colombia have shown genetic differences with specimens from other localities of the country, although morphological differences have not been explored. We performed morphological and molecular comparisons of individuals from two natural regions of Colombia: the Orinoquia, and the Amazon. The morphological and morphometric results show that females and males are grouped in two morphotypes: morphotype I from the Orinoquia region, and morphotype II from Leticia in the Amazon region. The molecular analyses supported the morphological results and showed the formation of two well-differentiated sister clades within D. nitens, with divergences between both morphotypes of 3–4% and 5–6% for the 16S rRNA and COI genes, respectively. Species delimitation analyzes and the Poisson Tree Processes model tentatively suggest the presence of two species within the sequences associated with D. nitens in Colombia. The first represented by the sequences from the Orinoquia region evaluated here, together with sequences from other regions of Colombia and other Neotropical countries such as Brazil, Panama, and French Guiana. The second is represented by the sequences of individuals from Leticia, in the Amazon region of Colombia. The results highlight that D. nitens might represent a species complex, but further sampling, experimental crosses, and studies at the level of complete genomes should be performed to obtain additional evidence for species recognition.

Predicting the potential distribution and coexistence of Chagas disease vectors in the Americas.

Predicting the potential distribution and coexistence of suitable geographic areas for Chagas disease vectors in the Americas is a crucial task for understanding the eco-epidemiological dynamics of this disease. The potential distribution and coexistence of 3 species-Rhodnius prolixus (Hemiptera: Reduviidae), Cavernicola pilosa (Hemiptera: Reduviidae), and Rhodnius pictipes (Hemiptera: Reduviidae) were modeled. Presence records were obtained and environmental variables were selected based on correlation analysis, Jackknife analysis and knowledge of the biology and natural history of the species. The MaxEnt algorithm included in the kuenm package of R software was used for modeling the potential distribution, and various scenarios of the BAM diagram (Biotic, Abiotic, and Movement variables) were evaluated. The variables contributing to the final models were different for each species. Rhodnius pictipes showed a potential distribution in South America, particularly in Brazil, Bolivia, Peru, Colombia, Venezuela, Guyana, and Suriname. Areas with environmentally suitable conditions for R. prolixus were located in southern Brazil, Peru, Colombia, southern Mexico, Guatemala, El Salvador, and Honduras, whereas for C. pilosa they were in southeastern Brazil, southeastern Central America, Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname, and French Guiana. Co-occurrence analysis revealed distinct patterns in the neotropical region, with some areas indicating the potential distribution of 1 or more species. In Brazil, occurrence and co-occurrence areas were concentrated in the northwest and southeast regions. Overall, this study provides valuable information on the potential distribution and coexistence of vectors, which can inform targeted vector control strategies and contribute to global efforts in combating Chagas disease.