Discriminating Tonate Virus from Dengue Virus Infection: A Matched Case-Control Study in French Guiana, 2003-2016

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]

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.

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.

Mayaro virus infection in French Guiana, a cross sectional study 2003-2019

Mayaro Virus is an emerging arbovirus which can be responsible of important outbreaks in tropical regions. A retrospective study was performed in French Guiana, an ultraperipheral region of Europe in Amazonia. We identified 17 human cases between 2003 and 2019. The clinical and biological picture was close to Chikungunya with fever and arthralgia. One patient had acute meningo-encephalitis, and 4 had persistent arthralgia. Physicians should be aware of this virus, as imported cases in Europe have already occurred. AUTHOR SUMMARY: Latin America has experienced several epidemics of arboviruses in recent years, some known for a long time, such as the dengue virus, and others of more recent introduction such as the chikungunya or Zika viruses. There are other arboviruses for the moment more discreet which are rife with low noise in several countries of the continent, such as the Mayaro virus. This alphavirus, with a presentation similar to that of the chikungunya virus, is currently confined to transmission by forest mosquitoes, but its potential to be transmitted by coastal mosquitoes such as Aedes aegypti, make it a potential candidate for a continent-wide epidemic. It therefore seems necessary to know this virus as well as possible in order to anticipate the occurrence of a possible new epidemic. We present here a both demographic and clinical study of this endemic arbovirus disease in French Guiana.

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.

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.

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.

Venezuelan Equine Encephalitis Complex Alphavirus in Bats, French Guiana

Although essential for control strategies, knowledge about transmission cycles is limited for Venezuelan equine encephalitis complex alphaviruses (VEEVs). After testing 1,398 bats from French Guiana for alphaviruses, we identified and isolated a new strain of the encephalitogenic VEEV species Tonate virus (TONV). Bats may contribute to TONV spread in Latin America.

Contribution of Research in the West Indies and Northeast Amazonia to Knowledge of the 2014-2015 Chikungunya Epidemic in the Americas

Purpose of Review

Although the chikungunya virus was discovered more than 60 years ago, it has only really been studied since the outbreak in La Reunion in 2005-2006. Ten years later, between 2014 and 2015, the chikungunya virus spread throughout the Americas, affecting millions of people. The objective of this review is to describe the contributions of research on chikungunya virus infection gained from epidemic in the West Indies and the Guiana Shield.

Recent Findings

Prevalence data were similar to those found in the Indian Ocean or Asia during epidemics. Clinically, there is now a better understanding of the typical, atypical, and severe forms. Several studies have insisted on the presence of neurological forms of chikungunya infection, such as encephalitis or Guillain-Barré syndrome. Cases of septic shock due to chikungunya virus as well as thrombotic thrombocytopenic purpura were described for the first time. Given the magnitude of the epidemic and the large number of people affected, this has led to a better description and new classifications of chikungunya virus infections in specific populations such as pregnant women, the elderly, and children. Several studies also described the behavior of populations faced with an emerging disease.

Summary

Current epidemiological data from tropical regions highlights the risk of spreading emerging diseases at higher latitudes, especially concerning arboviruses, since the vector Aedes albopictus is already established in many parts of northern countries. A better understanding of the disease and its epidemic dynamics will foster better management, the crucial importance of which was demonstrated during the COVID-19 epidemic.