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Overview of infectious and non-infectious diseases in French Guiana in 2022 Source of many myths, French Guiana represents an exceptional territory due to the richness of its biodiversity and the variety of its communities. The only European territory in Amazonia, surrounded by the Brazilian giant and the little-known Suriname, Ariane 6 rockets are launched from Kourou while 50% of the population lives below the poverty line. This paradoxical situation is a source of health problems specific to this territory, whether they be infectious diseases with unknown germs, intoxications or chronic pathologies. Some infectious diseases such as Q fever, toxoplasmosis, cryptococcosis or HIV infection are in common with temperate countries, but present specificities leading to sometimes different management and medical reasoning. In addition to these pathologies, many tropical diseases are present in an endemic and / or epidemic mode such as malaria, leishmaniasis, Chagas disease, histoplasmosis or dengue. Besides, Amazonian dermatology is extremely varied, ranging from rare but serious pathologies (Buruli ulcer, leprosy) to others which are frequent and benign such as agouti lice (mites of the family Trombiculidae) or papillonitis. Envenomations by wild fauna are not rare, and deserve an appropriate management of the incriminated taxon. Obstetrical, cardiovascular and metabolic cosmopolitan pathologies sometimes take on a particular dimension in French Guiana that must be taken into account in the management of patients. Finally, different types of intoxication are to be known by practitioners, especially due to heavy metals. European-level resources offer diagnostic and therapeutic possibilities that do not exist in the surrounding countries and regions, thus allowing the management of diseases that are not well known elsewhere. Thanks to these same European-level resources, research in Guyana occupies a key place within the Amazon region, despite a smaller population than in the surrounding countries. Thus, certain pathologies such as histoplasmosis of the immunocompromised patient, Amazonian toxoplasmosis or Q fever are hardly described in neighboring countries, probably due to under-diagnosis linked to more limited resources. French Guiana plays a leading role in the study of these diseases. The objective of this overview is to guide health care providers coming to or practicing in French Guiana in their daily practice, but also practitioners taking care of people returning from French Guiana. Panorama des pathologies infectieuses et non infectieuses de Guyane en 2022 Source de nombreux mythes, la Guyane représente un territoire exceptionnel par la richesse de sa biodiversité et par la variété des communautés qui la composent. Seul territoire européen en Amazonie, entouré du géant brésilien et du méconnu Suriname, on y lance des fusées Ariane 6 depuis Kourou tandis que 50 % de la population vit en dessous du seuil de pauvreté. Cette situation paradoxale est source de problématiques de santé spécifiques à ce territoire, qu’il s’agisse de maladies infectieuses à germes méconnus, d’intoxications, ou de pathologies chroniques. Certaines maladies infectieuses telles que la fièvre Q, la toxoplasmose, la cryptococcose ou l’infection à VIH sont communes aux pays tempérés, mais présentent en Guyane des spécificités entraînant une prise en charge et un raisonnement médical parfois différents. Parallèlement à ces pathologies, de nombreuses maladies tropicales sont par ailleurs présentes sur un mode endémique et / ou épidémique telles que le paludisme, la leishmaniose, la maladie de Chagas, l’histoplasmose ou la dengue. De plus, la dermatologie amazonienne est extrêmement variée, allant de pathologies rares, mais graves (ulcère de Buruli, lèpre), à d’autres fréquentes et bénignes telles que les poux d’agouti (acariens de la famille des Trombiculidae) ou la papillonite. Les envenimations par la faune sauvage ne sont pas rares, et méritent une prise en charge appropriée au taxon incriminé. Les pathologies obstétricale, cardiovasculaire et métabolique cosmopolites prennent parfois en Guyane une dimension particulière à prendre en compte dans la prise en charge des patients. Enfin, différents types d’intoxication sont à connaître par les praticiens, notamment aux métaux lourds. Les ressources de niveau européen offrent des possibilités diagnostiques et thérapeutiques inexistantes dans les pays et régions des environs, permettant ainsi la prise en charge de maladies peu connues ailleurs. Du fait de ces mêmes ressources de niveau européen, la recherche en Guyane occupe une place clé au sein de la région amazonienne, malgré une population moins nombreuse que dans les pays alentour. Ainsi, certaines pathologies telles que l’histoplasmose du patient immunodéprimé, la toxoplasmose amazonienne ou la fièvre Q ne sont pratiquement pas décrites dans les pays voisins, probablement du fait d’un sous-diagnostic lié à des ressources plus limitées. La Guyane joue ainsi un rôle moteur dans l’étude de ces pathologies. L’objectif de ce panorama est d’orienter les soignants venant ou exerçant en Guyane dans leur pratique quotidienne, mais également les praticiens prenant en charge des personnes au retour de Guyane., MTSI, Vol. 3 No 1 (2023): MTSI-Revue

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Characterizing the circulation of Mayaro virus (MAYV), an emerging arbovirus threat, is essential for risk assessment but challenging due to cross-reactivity with other alphaviruses such as chikungunya virus (CHIKV). Here, we develop an analytical framework to jointly assess MAYV epidemiology and the extent of cross-reactivity with CHIKV from serological data collected throughout French Guiana (N = 2697). We find strong evidence of an important sylvatic cycle for MAYV with most infections occurring near the natural reservoir in rural areas and in individuals more likely to go to the forest (i.e., adult males) and with seroprevalences of up to 18% in some areas. These findings highlight the need to strengthen MAYV surveillance in the region and showcase how modeling can improve interpretation of cross-reacting assays.

Despite the health, social and economic impact of arboviruses in French Guiana, very little is known about the extent to which infection burden is shared between individuals. We conducted a large multiplexed serological survey among 2697 individuals from June to October 2017. All serum samples were tested for IgG antibodies against DENV, CHIKV, ZIKV and MAYV using a recombinant antigen-based microsphere immunoassay with a subset further evaluated through anti-ZIKV microneutralization tests. The overall DENV seroprevalence was estimated at 73.1% (70.6-75.4) in the whole territory with estimations by serotype at 68.9% for DENV-1, 38.8% for DENV-2, 42.3% for DENV-3, and 56.1% for DENV-4. The overall seroprevalence of CHIKV, ZIKV and MAYV antibodies was 20.3% (17.7-23.1), 23.3% (20.9-25.9) and 3.3% (2.7-4.1), respectively. We provide a consistent overview of the burden of emerging arboviruses in French Guiana, with useful findings for risk mapping, future prevention and control programs. The majority of the population remains susceptible to CHIKV and ZIKV, which could potentially facilitate the risk of further re-emergences. Our results underscore the need to strengthen MAYV surveillance in order to rapidly detect any substantial changes in MAYV circulation patterns.

BACKGROUND: Since the identification of Zika virus (ZIKV) in Brazil in May 2015, the virus has spread throughout the Americas. However, ZIKV burden in the general population in affected countries remains unknown. METHODS: We conducted a general population survey in the different communities of French Guiana through individual interviews and serologic survey during June-October 2017. All serum samples were tested for anti-ZIKV immunoglobulin G antibodies using a recombinant antigen-based SGERPAxMap microsphere immunoassay, and some of them were further evaluated through anti-ZIKV microneutralization tests. RESULTS: The overall seroprevalence was estimated at 23.3% (95% confidence interval [CI], 20.9%-25.9%) among 2697 participants, varying from 0% to 45.6% according to municipalities. ZIKV circulated in a large majority of French Guiana but not in the most isolated forest areas. The proportion of reported symptomatic Zika infection was estimated at 25.5% (95% CI, 20.3%-31.4%) in individuals who tested positive for ZIKV. CONCLUSIONS: This study described a large-scale representative ZIKV seroprevalence study in South America from the recent 2015-2016 Zika epidemic. Our findings reveal that the majority of the population remains susceptible to ZIKV, which could potentially allow future reintroductions of the virus.

Funder: National Research Agency, Funder: Regional Health Agency of French Guiana, Funder: Institut Pasteur Urgence COVID-19 fundraising, BACKGROUND: While Latin America has been heavily affected by the pandemic, only a few seroprevalence studies have been conducted there during the first epidemic wave in the first half of 2020. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional survey was performed between 15 July 2020 and 23 July 2020 among individuals who visited 4 medical laboratories or 5 health centers for routine screening or clinical management, with the exception of symptomatic suggestive cases of covid-19. Samples were screened for the presence of anti-SARS-CoV-2 IgG directed against domain S1 of the SARS-CoV-2 spike protein using the anti-SARS-CoV-2 enzyme-linked immunosorbent assay (ELISA) from Euroimmun. CONCLUSIONS/SIGNIFICANCE: The overall seroprevalence was 15.4% [9.3%-24.4%] among 480 participants, ranging from 4.0% to 25.5% across the different municipalities. The seroprevalence did not differ according to gender (p = 0.19) or age (p = 0.51). Among SARS-CoV-2 positive individuals, we found that 24.6% [11.5%-45.2%] reported symptoms consistent with COVID-19. Our findings revealed high levels of infection across the territory but a low number of resulting deaths, which can be explained by French Guiana's young population structure.

Funder: This study was supported by the “European Regional Development Fund” under EPI-ARBO grant agreement (GY0008695), the “Regional Health Agency of French Guiana”, the “National Center of Spatial Studies”. CF acknowledges funding from Calmette and Yersin allocated by the “Pasteur Institut Department of International Affairs”. N.H. and S.C. acknowledge financial support from the AXA Research Fund, the Investissement d’Avenir program, the Laboratoire d’Excellence Integrative Biology of Emerging Infectious Diseases program (Grant ANR-10-LABX-62-IBEID), the Models of Infectious Disease Agent Study of the National Institute of General Medical Sciences, the INCEPTION project (PIA/ANR-16-CONV-0005), the European Union’s Horizon 2020 research and innovation programme under ZIKAlliance grant agreement No 734548., Characterizing the circulation of Mayaro virus (MAYV), an emerging arbovirus threat, is essential for risk assessment but challenging due to cross-reactivity with other alphaviruses such as chikungunya virus (CHIKV). Here, we develop an analytical framework to jointly assess MAYV epidemiology and the extent of cross-reactivity with CHIKV from serological data collected throughout French Guiana (N = 2697). We find strong evidence of an important sylvatic cycle for MAYV with most infections occurring near the natural reservoir in rural areas and in individuals more likely to go to the forest (i.e., adult males) and with seroprevalences of up to 18% in some areas. These findings highlight the need to strengthen MAYV surveillance in the region and showcase how modeling can improve interpretation of cross-reacting assays.

Funder: National Research Agency, Funder: Regional Health Agency of French Guiana, Funder: Institut Pasteur Urgence COVID-19 fundraising, BACKGROUND: While Latin America has been heavily affected by the pandemic, only a few seroprevalence studies have been conducted there during the first epidemic wave in the first half of 2020. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional survey was performed between 15 July 2020 and 23 July 2020 among individuals who visited 4 medical laboratories or 5 health centers for routine screening or clinical management, with the exception of symptomatic suggestive cases of covid-19. Samples were screened for the presence of anti-SARS-CoV-2 IgG directed against domain S1 of the SARS-CoV-2 spike protein using the anti-SARS-CoV-2 enzyme-linked immunosorbent assay (ELISA) from Euroimmun. CONCLUSIONS/SIGNIFICANCE: The overall seroprevalence was 15.4% [9.3%-24.4%] among 480 participants, ranging from 4.0% to 25.5% across the different municipalities. The seroprevalence did not differ according to gender (p = 0.19) or age (p = 0.51). Among SARS-CoV-2 positive individuals, we found that 24.6% [11.5%-45.2%] reported symptoms consistent with COVID-19. Our findings revealed high levels of infection across the territory but a low number of resulting deaths, which can be explained by French Guiana's young population structure.