Molecular epidemiology identifies the expansion of the DENV2 epidemic lineage from the French Caribbean Islands to French Guiana and mainland France, 2023 to 2024.

In 2023, dengue virus serotype 2 (DENV2) affected most French overseas territories. In the French Caribbean Islands, viral circulation continues with > 30,000 suspected infections by March 2024. Genome sequence analysis reveals that the epidemic lineage in the French Caribbean islands has also become established in French Guiana but not Réunion. It has moreover seeded autochthonous circulation events in mainland France. To guide prevention of further inter-territorial spread and DENV introduction in non-endemic settings, continued molecular surveillance and mosquito control are essential.

Etiology of Acute Febrile Illnesses in Adults in the Defense Community in French Guiana.

In tropical countries, acute febrile illnesses represent a complex clinical problem for general practitioners. We describe the prevalence of different etiologies of acute febrile illnesses occurring among French service members and their families, excluding children, in general practice in French Guiana. From June 2017 to March 2020, patients with a fever ≥37.8°C with a duration of less than 15 days who sought medical care at the army medical centers in Cayenne and Kourou were prospectively enrolled. Based on clinical presentation, blood, urine, nasopharyngeal, and stool samples were collected for diagnostic testing for viruses, bacteria, and parasites (by direct examination, microscopic examination of blood smears, culture, serology, or polymerase chain reaction), and standardized biological tests were systematically performed. Among 175 patients retained for analysis, fever with nonspecific symptoms was predominant (46.9%), with 10 Plasmodium vivax malaria cases, 8 dengue infections, and 6 cases of Q fever. The second most frequent cause of acute febrile illness was upper respiratory tract infections (32.0%) due to influenza virus (n = 18) or human rhinovirus (n = 10). Among the causes of acute febrile illness in French Guiana, clinicians should first consider arboviruses and malaria, as well as Q fever in cases of elevated C-reactive protein with nonspecific symptoms and influenza in cases of signs and symptoms associated with upper respiratory tract infections. Despite an expanded microbiological search, the etiology of 51.4% of acute febrile illnesses remain unknown. Further investigations will be necessary to identify the etiology of acute febrile illnesses, including new pathogens, in French Guiana.

Review on Main Arboviruses Circulating on French Guiana, An Ultra-Peripheric European Region in South America.

French Guiana (FG), a French overseas territory in South America, is susceptible to tropical diseases, including arboviruses. The tropical climate supports the proliferation and establishment of vectors, making it difficult to control transmission. In the last ten years, FG has experienced large outbreaks of imported arboviruses such as Chikungunya and Zika, as well as endemic arboviruses such as dengue, Yellow fever, and Oropouche virus. Epidemiological surveillance is challenging due to the differing distributions and behaviors of vectors. This article aims to summarize the current knowledge of these arboviruses in FG and discuss the challenges of arbovirus emergence and reemergence. Effective control measures are hampered by the nonspecific clinical presentation of these diseases, as well as the Aedes aegypti mosquito's resistance to insecticides. Despite the high seroprevalence of certain viruses, the possibility of new epidemics cannot be ruled out. Therefore, active epidemiological surveillance is needed to identify potential outbreaks, and an adequate sentinel surveillance system and broad virological diagnostic panel are being developed in FG to improve disease management.

[Overview of infectious and non-infectious diseases in French Guiana in 2022]. / Panorama des pathologies infectieuses et non infectieuses de Guyane en 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.

Emerging Maripa Hantavirus as a Potential Cause of a Severe Health Threat in French Guiana.

We describe the clinical parameters and management of nine confirmed cases of hantavirus pulmonary syndrome reported in French Guiana since 2008. All patients were admitted to Cayenne Hospital. Seven patients were men and the mean age was 48 years (range, 19-71 years). Two phases characterized the disease. The prodromal phase was characterized by fever (77.8%), myalgia (66.7%), and gastrointestinal symptoms (vomiting and diarrhea; 55.6%) starting, on average, 5 days before the illness phase, which was characterized by respiratory failure in all patients. Five patients died (55.6%) and the length of stay in the intensive care unit was 19 days (range, 11-28 days) for survivors. Detection of two back-to-back recent cases highlights the reason to screen for hantavirus infection during the nonspecific phase of the disease, in particular when concomitant pulmonary infection and digestive disorders are observed. Specific longitudinal serological surveys must also be used to identify other potential clinical forms of the disease in French Guiana.

Identification of Neotropical Culex Mosquitoes by MALDI-TOF MS Profiling.

The mosquito (Diptera: Culicidae) fauna of French Guiana encompasses 242 species, of which nearly half of them belong to the genus Culex. Whereas several species of Culex are important vectors of arboviruses, only a limited number of studies focus on them due to the difficulties to morphologically identify field-caught females. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a promising method for the identification of mosquitoes. Culex females collected in French Guiana were morphologically identified and dissected. Abdomens were used for molecular identification using the COI (cytochrome oxidase 1) gene. Legs and thorax of 169 specimens belonging to 13 Culex species, (i.e., Cx. declarator, Cx. nigripalpus, Cx. quinquefasciatus, Cx. usquatus, Cx. adamesi, Cx. dunni, Cx. eastor, Cx. idottus, Cx. pedroi, Cx. phlogistus, Cx. portesi, Cx. rabanicolus and Cx. spissipes) were then submitted to MALDI-TOF MS analysis. A high intra-species reproducibility and inter-species specificity of MS spectra for each mosquito body part tested were obtained. A corroboration of the specimen identification was revealed between MALDI-TOF MS, morphological and molecular results. MALDI-TOF MS protein profiling proves to be a suitable tool for identification of neotropical Culex species and will permit the enhancement of knowledge on this highly diverse genus.

Dynamics of SARS-CoV-2 lineages in French Guiana in 2020-2021: 4 epidemic waves with cross-influences from Europe and South America.

Since the first cases of SARS-CoV-2 infection in Wuhan in December 2019, this RNA virus gave rise to different viral lineages with different virological, epidemiological and immunological properties. Here we describe the dynamics of circulation of SARS-CoV-2 lineages in an Amazonian South American French overseas territory, French Guiana (FG). The data analyzed are based on the general epidemic course, and genomic surveillance data come from whole genome sequencing (WGS) as well as typing PCRs. From March 2020 to October 2021, four COVID-19 epidemic waves were observed in FG with an evolution of viral lineages influenced by virus introductions from continental France and above all by land-based introductions from neighbouring countries. The third epidemic wave from March to June 2021 was driven by a predominant Gamma introduced from Brazil and a less frequent Alpha introduced from France. This coexistence was completely substituted by Delta that initiated the fourth epidemic wave.

Special Issue: "Viral Genetic Diversity".

Some say that small is beautiful, and if beauty could be measured by levels of diversity and complexity, we could definitely say that viruses are beautiful [...].

Tonate Virus and Fetal Abnormalities, French Guiana, 2019.

We report a case of vertical transmission of Tonate virus in a pregnant woman from French Guiana. The fetus showed severe necrotic and hemorrhagic lesions of the brain and spinal cord. Clinicians should be made aware of possible adverse fetal outcomes in pregnant women infected with Tonate virus.

The Influence of Habitat on Viral Diversity in Neotropical Rodent Hosts.

Rodents are important reservoirs of numerous viruses, some of which have significant impacts on public health. Ecosystem disturbances and decreased host species richness have been associated with the emergence of zoonotic diseases. In this study, we aimed at (a) characterizing the viral diversity in seven neotropical rodent species living in four types of habitats and (b) exploring how the extent of environmental disturbance influences this diversity. Through a metagenomic approach, we identified 77,767 viral sequences from spleen, kidney, and serum samples. These viral sequences were attributed to 27 viral families known to infect vertebrates, invertebrates, plants, and amoeba. Viral diversities were greater in pristine habitats compared with disturbed ones, and lowest in peri-urban areas. High viral richness was observed in savannah areas. Differences in these diversities were explained by rare viruses that were generally more frequent in pristine forest and savannah habitats. Moreover, changes in the ecology and behavior of rodent hosts, in a given habitat, such as modifications to the diet in disturbed vs. pristine forests, are major determinants of viral composition. Lastly, the phylogenetic relationships of four vertebrate-related viral families (Polyomaviridae, Flaviviridae, Togaviridae, and Phenuiviridae) highlighted the wide diversity of these viral families, and in some cases, a potential risk of transmission to humans. All these findings provide significant insights into the diversity of rodent viruses in Amazonia, and emphasize that habitats and the host's dietary ecology may drive viral diversity. Linking viral richness and abundance to the ecology of their hosts and their responses to habitat disturbance could be the starting point for a better understanding of viral emergence and for future management of ecosystems.

Outbreak of Oropouche Virus in French Guiana.

Oropouche fever is a zoonotic dengue-like syndrome caused by Oropouche virus. In August-September 2020, dengue-like syndrome developed in 41 patients in a remote rainforest village in French Guiana. By PCR or microneutralization, 23 (82.1%) of 28 tested patients were positive for Oropouche virus, documenting its emergence in French Guiana.

Spatial Distribution and Burden of Emerging Arboviruses in French Guiana.

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.

Breakthrough Infections of SARS-CoV-2 Gamma Variant in Fully Vaccinated Gold Miners, French Guiana, 2021.

An outbreak of severe acute respiratory syndrome coronavirus 2 caused by the Gamma variant of concern infected 24/44 (55%) employees of a gold mine in French Guiana (87% symptomatic, no severe forms). The attack rate was 60% (15/25) among fully vaccinated miners and 75% (3/4) among unvaccinated miners without a history of infection.

Ecology, evolution, and epidemiology of zoonotic and vector-borne infectious diseases in French Guiana: Transdisciplinarity does matter to tackle new emerging threats.

French Guiana is a European ultraperipheric region located on the northern Atlantic coast of South America. It constitutes an important forested region for biological conservation in the Neotropics. Although very sparsely populated, with its inhabitants mainly concentrated on the Atlantic coastal strip and along the two main rivers, it is marked by the presence and development of old and new epidemic disease outbreaks, both research and health priorities. In this review paper, we synthetize 15 years of multidisciplinary and integrative research at the interface between wildlife, ecosystem modification, human activities and sociodemographic development, and human health. This study reveals a complex epidemiological landscape marked by important transitional changes, facilitated by increased interconnections between wildlife, land-use change and human occupation and activity, human and trade transportation, demography with substantial immigration, and identified vector and parasite pharmacological resistance. Among other French Guianese characteristics, we demonstrate herein the existence of more complex multi-host disease life cycles than previously described for several disease systems in Central and South America, which clearly indicates that today the greater promiscuity between wildlife and humans due to demographic and economic pressures may offer novel settings for microbes and their hosts to circulate and spread. French Guiana is a microcosm that crystallizes all the current global environmental, demographic and socioeconomic change conditions, which may favor the development of ancient and future infectious diseases.

Paramyxovirus circulation in bat species from French Guiana.

Bats are recognized as reservoirs of numerous viruses. Among them, paramyxoviruses, for example, Hendra and Nipah viruses, are highly pathogenic to humans. Nothing is known regarding the circulation of this viral family in bats from French Guiana. To search for the presence of paramyxoviruses in this territory, 103 bats of seven different species were sampled and screened using a molecular approach. Four distinct paramyxovirus sequences were detected from three bat species (Desmodus rotundus, Carollia perspicillata, and Pteronotus alitonus) at high prevalence rates. In D. rotundus, two types of paramyxovirus co-circulate, with most of the bats co-infected. The phylogenetic analysis of these sequences revealed that three of them were closely related to previously characterized sequences from D. rotundus, C. perspicillata, and P. parnellii from Brazil and Costa Rica. The fourth sequence, identified in D. rotundus, was closely related to the one detected in P. alitonus in French Guiana and to previously described sequences detected in P. parnellii in Costa Rica. All paramyxovirus sequences detected in this study are close to the Jeilongvirus genus. Altogether, our results and those of previous studies indicate a wide geographical distribution of these paramyxoviruses (from Central to South America) and suggest potential cross-species transmissions of paramyxoviruses between two different bat families: Mormoopidae (P. alitonus) and Phyllostomidae (D. rotundus). In addition, their closeness to paramyxoviruses identified in rodents emphasizes the need to investigate the role of these animals as potential reservoirs or incidental hosts. Finally, the high prevalence rates of some paramyxoviruses in certain bat species, associated with the presence of large bat colonies and, in some cases, their potential proximity with humans are all parameters that can contribute to the risk of cross-species transmission between bat species and to the emergence of new paramyxoviruses in humans, a risk that deserves further investigation.

Detection and Phylogenetic Characterization of a Novel Herpesvirus in Sooty Terns Onychoprion fuscatus.

Since 2005, we have recorded annual episodes of alphaherpesvirus outbreaks in chicks of magnificent frigatebird Fregata magnificens on the Ile du Grand Connétable Nature Reserve in French Guiana. In 2009, we found sooty terns, Onychoprion fuscatus, that live sympatrically with frigatebirds, with visible clinical signs of a potential viral infection. To determine if the symptoms observed in sooty terns could be associated with an alphaherpesvirus previously identified in frigatebirds, we carried out molecular screening of samples collected from seven individuals. We identified and characterized a novel viral sequence from five birds. BLAST searches, pairwise nucleotide, and amino acid sequence comparisons, as well as phylogenetic analyses confirmed that the sequence belonged to the Herpesviridae family, of the Alphaherpesvirinae subfamily. We observed that it clustered with strains isolated from Podargidae (Caprimulgiformes), Columbiformes, and Falconiformes, but was distinct from the frigatebird herpesvirus. We have tentatively named it Onychoprion fuscatus alphaherpesvirus 1, (OfusAHV1). These two sequences, although found syntopic on the Ile du Grand Connétable, belong to two distinct alphaherpesvirus strains. Thus, the clinical symptoms showed by sooty terns do not likely result from a cross-species transmission event. Future work is needed to better characterize the virus and to investigate herpesvirus prevalence in healthy, free-ranging sooty terns, and to assess the impact of the virus on population viability.

Novel herpesviruses in neotropical bats and their relationship with other members of the Herpesviridae family.

In the past decade, a large number of studies have detected herpesvirus sequences from many bat species around the world. Nevertheless, the discovery of bat herpesviruses is geographically uneven. Of the various bat species tested to date, only a few were from the New World. Seeking to investigate the distribution and diversity of herpesviruses circulating in neotropical bats, we carried out molecular screening of 195 blood DNA samples from 11 species of three bat families (Phyllostomidae, Mormoopidae, and Molossidae). Using polymerase chain reaction amplification, with degenerate consensus primers targeting highly conserved amino acid motifs of the herpesvirus DNA polymerase and Glycoprotein B genes, we characterized novel viral sequences from all tested species. BLAST searches, pairwise nucleotide and amino acid sequence comparisons, as well as phylogenetic analyses confirmed that they all belonged to the Herpesviridae family, of the Beta- and Gammaherpesvirinae subfamilies. Fourteen partial DNA polymerase gene sequences, of which three beta- and 11 gamma-herpesviruses, were detected. A total of 12 partial Glycoprotein B gene sequences, all gamma-herpesviruses, were characterized. Every sequence was specific to a bat species and in some species (Desmodus rotundus, Carollia perspicillata, and Pteronotus rubiginosus) multiple viruses were found. Phylogenetic analyses of beta- and gammaherpesvirus sequences led to the identification of bat-specific clades. Those composed of sequences obtained from different bat species belonging to distinct subfamilies follow the taxonomy of bats. This study confirms the astonishing diversity of bat herpesviruses and broadens our knowledge of their host range. Nevertheless, it also emphasizes the fact that, to better appreciate the evolutionary history of these viruses, much remains to be done at various taxonomic levels.

A hybrid swarm of manatees along the Guianas coastline, a peculiar environment under the influence of the Amazon River plume.

The West Indian (Trichechus manatus) and Amazonian (T. inunguis) manatees have a sympatric occurrence at the mouth of the Amazon River. A result of this interspecific encounter is the occurrence of hybrids, which are frequently found along the coasts of Amapá state in Brazil, French Guiana and Guyana. Here we present new genetic evidence indicating the occurrence of a hybrid swarm along the Guianas Shield coastline, which is an interspecific hybrid zone that also separates T. manatus populations located east (Brazil) and west (Caribbean, Gulf of Mexico, Florida and Antilles). In addition, we suggest that this hybrid population occupies a peculiar mangrove-rich environment under strong influence of the Amazon River plume, which requires an independent management and should be considered a special conservation area.

Capillary leak-syndrome triggered by Maripa virus in French Guiana: case report and implication for pathogenesis.

BACKGROUND: We report hereby a severe case of Hantavirus Pulmonary Syndrome" (HPS) induced by Maripa virus in French Guiana and describe the mechanism of severity of the human disease. CASE PRESENTATION: A 47-year- old patient started presenting a prodromic period with fever, dyspnea, cough and head ache. This clinical presentation was followed by a rapid respiratory, hemodynamic and renal failure leading to admission in the ICU. Biological exams revealed an increased haematocrit level with a paradoxical low protein level. Echocardiographic and hemodynamic monitoring showed a normal left ventricular function with low filling pressures, an elevated extravascular lung water index and pulmonary vascular permeability index. These findings were compatible with a capillary leak-syndrome (CLS). CONCLUSIONS: The severity of HPS caused by the virus Maripa in French Guiana can be explained by the tropism of hantavirus for the microvascular endothelial cell leading to a CLS.

Leukocyte Profiles Reflect Geographic Range Limits in a Widespread Neotropical Bat.

Quantifying how the environment shapes host immune defense is important for understanding which wild populations may be more susceptible or resistant to pathogens. Spatial variation in parasite risk, food and predator abundance, and abiotic conditions can each affect immunity, and these factors can also manifest at both local and biogeographic scales. Yet identifying predictors and the spatial scale of their effects is limited by the rarity of studies that measure immunity across many populations of broadly distributed species. We analyzed leukocyte profiles from 39 wild populations of the common vampire bat (Desmodus rotundus) across its wide geographic range throughout the Neotropics. White blood cell differentials varied spatially, with proportions of neutrophils and lymphocytes varying up to six-fold across sites. Leukocyte profiles were spatially autocorrelated at small and very large distances, suggesting that local environment and large-scale biogeographic factors influence cellular immunity. Generalized additive models showed that bat populations closer to the northern and southern limits of the species range had more neutrophils, monocytes, and basophils, but fewer lymphocytes and eosinophils, than bats sampled at the core of their distribution. Habitats with access to more livestock also showed similar patterns in leukocyte profiles, but large-scale patterns were partly confounded by time between capture and sampling across sites. Our findings suggest that populations at the edge of their range experience physiologically limiting conditions that predict higher chronic stress and greater investment in cellular innate immunity. High food abundance in livestock-dense habitats may exacerbate such conditions by increasing bat density or diet homogenization, although future spatially and temporally coordinated field studies with common protocols are needed to limit sampling artifacts. Systematically assessing immune function and response over space will elucidate how environmental conditions influence traits relevant to epidemiology and help predict disease risks with anthropogenic disturbance, land conversion, and climate change.