Meat-Borne-Parasite: A Nanopore-Based Meta-Barcoding Work-Flow for Parasitic Microbiodiversity Assessment in the Wild Fauna of French Guiana.

French Guiana, located in the Guiana Shield, is a natural reservoir for many zoonotic pathogens that are of considerable medical or veterinary importance. Until now, there has been limited data available on the description of parasites circulating in this area, especially on protozoan belonging to the phylum Apicomplexa; conversely, the neighbouring countries describe a high parasitic prevalence in animals and humans. Epidemiological surveillance is necessary, as new potentially virulent strains may emerge from these forest ecosystems, such as Amazonian toxoplasmosis. However, there is no standard tool for detecting protozoa in wildlife. In this study, we developed Meat-Borne-Parasite, a high-throughput meta-barcoding workflow for detecting Apicomplexa based on the Oxford Nanopore Technologies sequencing platform using the 18S gene of 14 Apicomplexa positive samples collected in French Guiana. Sequencing reads were then analysed with MetONTIIME pipeline. Thanks to a scoring rule, we were able to classify 10 samples out of 14 as Apicomplexa positive and reveal the presence of co-carriages. The same samples were also sequenced with the Illumina platform for validation purposes. For samples identified as Apicomplexa positive by both platforms, a strong positive correlation at up to the genus level was reported. Overall, the presented workflow represents a reliable method for Apicomplexa detection, which may pave the way for more comprehensive biomonitoring of zoonotic pathogens.

Molecular epidemiology of Candida africana isolates collected from vagina swabs in French Guiana.

Previous molecular studies have shown that Candida africana corresponds to the clade 13 of Candia albicans. It has been mostly involved in vulvovaginal candidiasis worldwide but few data exist in South America. The aim of our study was to investigate the prevalence of C. africana in women living in French Guiana. For this, we first set up a fluorescent-intercalating-dye-real time Polymerase Chain Reaction (PCR) targeting the hyphal wall protein 1 gene. The test was applied to 212 C. albicans isolates collected from May to August 2019 from vaginal swabs, allowing the identification of six women harboring C. africana (eight isolates). The in vitro susceptibility of these eight isolates to six antifungal drugs was also evaluated. No demographics or clinical-specific features could be demonstrated. Genetic diversity of those isolates was analyzed through multilocus sequence typing and showed that diploid sequence type 182 was predominant (n = 6) and allowed the report of a new diploid sequence type.

Candida africana, the clade 13 of C. albicans, is characterized by specific genetic and phenotypic traits. Using a new molecular technique, we report a high prevalence of C. africana in vaginal swabs from patients living in French Guiana. The worldwide predominant genotype was detected in all but one patient.

Novel Species of Brucella Causing Human Brucellosis, French Guiana.

Human brucellosis is a zoonoses caused by bacteria of the genus Brucella. Infection results in subacute or chronic debilitating disease with nonspecific clinical manifestations and is often associated with consuming unpasteurized dairy products. We report 2 cases of brucellosis in male patients who were hospitalized in distinct towns of French Guiana, an overseas territory of France located on the northeastern shore of South America. Both men were citizens of Brazil working as clandestine goldminers in the deep Amazonian rainforest. Characterization of the 2 bacterial isolates revealed that they represent a potential new species of Brucella. Medical practitioners working in contact with wildlife in this region of the world should be aware of the existence of these pathogens and the potential for human infection.

Atovaquone exposure and Pneumocystis jirovecii cytochrome b mutations: French data and review of the literature.

Pneumocystis jirovecii is a transmissible fungus responsible for severe pneumonia (Pneumocystis pneumonia [PCP]) in immunocompromised patients. Missense mutations due to atovaquone selective pressure have been identified on cytochrome b (CYB) gene of P. jirovecii. It was recently shown that atovaquone prophylaxis can lead to the selection of specific P. jirovecii CYB mutants potentially resistant to atovaquone among organ transplant recipients. In this context, our objectives were to provide data on P. jirovecii CYB mutants and the putative selective pressure exerted by atovaquone on P. jirovecii organisms in France. A total of 123 patients (124 P. jirovecii specimens) from four metropolitan hospitals and two overseas hospitals were retrospectively enrolled. Fourteen patients had prior exposure to atovaquone, whereas 109 patients did not at the time of P. jirovecii detection. A 638 base-pair fragment of the CYB gene of P. jirovecii was amplified and sequenced. A total of 10 single nucleotide polymorphisms (SNPs) were identified. Both missense mutations C431T (Ala144Val) and C823T (Leu275Phe), located at the Qo active site of the enzyme, were significantly associated with prior atovaquone exposure, these mutations being conversely incidental in the absence of prior atovaquone exposure (P < 0.001). Considering that the aforementioned hospitals may be representative of the national territory, these findings suggest that the overall presence of P. jirovecii CYB mutants remains low in France.

The mutations C431T (Ala144Val) and C823T (Leu275Phe) at the cytochrome b (CYB) active site of Pneumocystis jirovecii are associated with patient prior exposure to atovaquone. Conversely, these mutations are incidental in the absence of exposure. Overall, the presence of P. jirovecii CYB mutants remains low in France.

Using pentamidine to treat cutaneous leishmaniasis in children: a 10-year study in French Guiana.

There are little data on pentamidine as a treatment for paediatric cutaneous leishmaniasis (CL). The objective of this study was to describe the effectiveness and safety of pentamidine over a 10-year period. Every child seen in French Guiana between 2010 and 2020 with proven CL and treated with pentamidine was included. In total, 55 children met the inclusion criteria - 23 girls and 32 boys. There were 38 patients (38/55, 69%) with a > 50% improvement at 1 month after pentamidine treatment and a complete cure at 3 months; 16 children had a < 50% improvement at 1 month and were given a second dose. Of these 16, 8 showed a complete cure at 3 months, 5 were lost to follow-up and 3 showed therapeutic failure at 3 months. The overall cure rate was 84% (46/55) after one or two doses. In terms of the safety of pentamidine, no severe adverse events (grade ≥ 3) were reported.

Pulmonary Histoplasmosis in People Living with Human Immunodeficiency Virus in French Guiana: Clinical Epidemiology, Medical Imaging and Prognostic.

BACKGROUND: Histoplasmosis is mainly described as a disseminated disease in people living with HIV (PLHIV). Compared to historical descriptions in immunocompetent individuals, knowledge is lacking on the detailed clinical and radiological findings and outcomes of pulmonary histoplasmosis (PH). Overlooked or misdiagnosed with other AIDS-defining condition, prognostic of PLHIV may be at risk because of inappropriate care. METHODS: A retrospective multicentric study was conducted in PLHIV from French Guiana between January 1988 and October 2019. Proven PH were documented through mycological direct examination, culture, or histology. Patients with concomitant respiratory infections were excluded. RESULTS: Among 65 patients, sex ratio M:F was 2.4 with a median age of 39 years [IQR 25-75%: 34-44]. Median CD4 count was 24 cells/mm3 [11-71], with histoplasmosis as the AIDS-defining condition in 88% and concomitant AIDS-defining conditions in 29%. Clinical findings were fever (89%), cough (58%), dyspnea (35%), expectoration (14%), and hemoptysis (5%). Sixty-one X-rays and 24 CT-scans were performed. On X-rays, an interstitial lung disease was mainly found (77%). On CT-scans, a nodular pattern was predominant (83%): mostly miliary disease (63%), but also excavated nodules (35%). Consolidations were present in 46%, associated with miliary disease in 21%. Thoracic lymphadenopathies were found in 58%, mainly hilar and symmetric (33%). Despite antifungal treatment, case-fatality rate at one month was 22%. CONCLUSION: When faced with an interstitial lung disease on X-rays or a miliary pattern on CT-scans in advanced PLHIV, physicians in endemic areas, apart from tuberculosis or pneumocystosis, should include histoplasmosis as part of their differential diagnoses.

Risk factors for hypoglycaemia in people with diabetes admitted to the Emergency Department of a Hospital in French Guiana.

AIMS/INTRODUCTION: Strict management of glucose levels in elderly people with diabetes or with comorbidities exposes them to the risk of severe hypoglycaemia (capillary or venous glucose ≤3.3 mmol/L) and the associated morbidity and mortality. We aimed to describe the clinical, laboratory, and epidemiological characteristics of people with diabetes admitted to the Emergency Department in Cayenne, French Guiana for severe hypoglycaemia and identify avoidable behaviours in this population. MATERIALS AND METHODS: An observational epidemiological study of adults with diabetes who presented to the Emergency Department with severe hypoglycaemia was conducted between 2015 and 2018. Their medical history, clinical and laboratory data were collected. The primary outcome was the association between therapeutic misuse and age ≥65 years. RESULTS: Overall, 178 admissions were analysed. The main cause of hypoglycaemia was insulin dosing-error or inappropriate glycaemic targets. Among those ≥65 years, 59% had a glycated haemoglobin ≤48 mmol/mol (6.5%), and the median duration of their diabetes was 20 years. Among them, 60% were treated with sulfonylurea, repaglinide, biphasic insulin, or mixed drugs, and 48% were on non-diabetes related treatments that had a hypoglycaemic effect. Furthermore, 23% of the elderly treated with oral antidiabetics had chronic kidney disease. CONCLUSION: Many avoidable risk factors for severe hypoglycaemia have been highlighted, in particular insulin dosing errors or non-compliance with recommendations for participants ≥ 65 years. Primary care physicians and homecare nurses need to provide preventive interventions and undergo training.

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.

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.

Validation of Swab Sampling and SYBR Green-Based Real-Time PCR for the Diagnosis of Cutaneous Leishmaniasis in French Guiana.

Recent studies have highlighted the interest in noninvasive sampling procedures coupled with real-time PCR methods for the detection of Leishmania species in South America. In French Guiana, the sampling method still relied on skin biopsies. Noninvasive protocols should be tested on a large annual cohort to improve routine laboratory diagnosis of cutaneous leishmaniasis. Therefore, we evaluated the performance of a new Leishmania detection and species identification protocol involving cotton swabs and SYBR green-based real-time PCR of the Hsp70 gene, coupled with Sanger sequencing. Between May 2017 and May 2018, 145 patients with ulcerated lesions compatible with cutaneous leishmaniasis were included in the study at the Cayenne Hospital and its remote health centers. Each patient underwent scrapings for a smear, skin biopsies for parasite culture and PCR-restriction fragment length polymorphism (RFLP) (RNA polymerase II), and sampling with a cotton swab for SYBR green-based PCR. The most accurate diagnostic test was the SYBR green-based PCR on swab samples, showing 98% sensitivity. The mean PCR cycle threshold (CT ) was 24.4 (minimum CT , 17; maximum CT , 36) and was <35 in 97.6% of samples. All samples positive by SYBR green-based real-time PCR were successfully identified at the species level by DNA sequencing. This new method should be considered for routine diagnosis of cutaneous leishmaniasis in South America and especially for remote areas, since noninvasive collection tools are easier to use and require fewer precautions for transportation.

Kelch13 mutations in Plasmodium falciparum and risk of spreading in Amazon basin countries.

BACKGROUND: The first potential focus for artemisinin resistance in South America was recently confirmed with the presence of the C580Y mutation in the Plasmodium falciparum kelch 13 gene (pfk13) in Guyana. OBJECTIVES: This study aimed to strengthen pfk13 monitoring in the Amazon basin countries, to compile the available data and to evaluate the risk of spreading of mutations. METHODS: Sanger sequencing was done on 862 samples collected between 1998 and 2019, and a global map of pfk13 genotypes available for this region was constructed. Then, the risk of spreading of mutations based on P. falciparum case importation between 2015 and 2018 within countries of the Amazon basin was evaluated. RESULTS: No additional pfk13 C580Y foci were identified. Few mutations (0.5%, 95% CI = 0.3%-0.8%) in the propeller domain were observed in the general parasite population of this region despite a high proportion of K189T mutations (49.1%, 95% CI = 46.2%-52.0%) in the non-propeller domain. Case information revealed two patterns of intense human migration: Venezuela, Guyana and the Roraima State in Brazil; and French Guiana, Suriname and the Amapá State in Brazil. CONCLUSIONS: There are few pfk13 mutant foci, but a high risk of dispersion in the Amazon basin, mainly from the Guiana Shield, proportionate to mining activities. Therefore, access to prompt diagnosis and treatment, and continuous molecular monitoring is essential in these geographical areas.

Review of diagnostic methods and results for HIV-associated disseminated histoplasmosis: Pathologists are not sufficiently involved.

OBJECTIVES: Disseminated histoplasmosis is a major killer of HIV-infected persons in Latin America. Antigen detection, fungal culture and Polymerase Chain Reaction are often not available, but cytology and histology are present in most hospitals and may offer a diagnostic alternative. In this study, we review 34 years of clinical experience to describe the roles of cytology and histology in diagnosing disseminated histoplasmosis. METHODS: Retrospective multicentric study of 349 patients between 1 January 1981 and 1 October 2014 with confirmed disseminated histoplasmosis. RESULTS: Around 32/214 (14.9%) of samples were screened using cytopathology, as were 10/101 (9.9%) bronchoalveolar lavage samples and 5/61 (8.2%) of spinal fluid samples. The samples most commonly sent to pathology were liver biopsies, lower digestive tract and lymphnode biopsies; the greatest proportion of positive results were found in lower digestive tract (43/59 (72.9%) positives), lymph node (39/63 (66.1%)), and liver (38/75 (50.7%)) samples. Overall, 97.2% of bone marrow and 97% of bronchoalveolar lavage samples were directly examined by a mycologist. Positive direct examination was independently associated with death (aHR = 1.5 (95%CI = 1-2.2)). CONCLUSIONS: Opportunities for a rapid diagnosis were regularly missed, notably for bone marrow samples, which could have been examined using staining methods complementary to those of the mycologist.

Accuracy of SD Malaria Ag P.f/Pan® as a rapid diagnostic test in French Amazonia.

BACKGROUND: French Guiana (FG) is a French overseas territory where malaria is endemic. The current incidence rate is 0.74‰ inhabitants, and Plasmodium vivax is widely predominating even though Plasmodium falciparum is still present due to imported cases mainly from Africa. In FG, rapid diagnostic test (SD Malaria Ag P.f/Pan®) is based on the detection of pan-pLDH, PfHRP2, and PfHRP3 antigens, while in South America, the share of deletion of PfHRP2 gene is significantly increasing. Accordingly, the study questions the reliability of RDTs in the Amazonian context. METHODS: The study is retrospective. It is conducted over 4 years and analysed 12,880 rapid diagnostic tests (RDTs) compared to concomitant Blood Film Tests (BFTs) sampled for malaria diagnosis. RESULTS: The global assessment of the accuracy of SD Malaria Ag P.f/Pan® in the diagnostic of malaria shows both Positive and Negative Predictive Values (PPV and NPV) higher than 95%, except for PPV in the diagnosis of malaria to P. falciparum (88%). Overall, the concordance rate between RDT and BFT (positive/positive; negative/negative) was 99.5%. The PPV of the RDT in the follow-up of patients diagnosed with P. falciparum was the lowest during the first 28 days. The PPV of the RDT in the follow-up of patients diagnosed with P. vivax was the lowest during the first 21 days. The global sensitivity of SD Malaria Ag P.f/Pan® test was, on average, 96% (88.2-100) for P. falciparum and 93% (90.6-94.2) for P. vivax. The global specificity was 99.8% (99.5-100) for all included species. CONCLUSION: SD Malaria Ag P.f/Pan® is a reliable rapid test used for the first-line diagnosis in remote healthcare centres. The test results should be interpreted in the light of patient's recent medical history and the date of arrival to FG.

Childhood lead exposure of Amerindian communities in French Guiana: an isotopic approach to tracing sources.

In French Guiana were detected high lead (Pb) levels in blood of Amerindian people. Lead exposure is a serious hazard that can affect the cognitive and behavior development. People can be exposed to Pb through occupational and environmental sources. Fingerprinting based on stable Pb isotopes in environmental media is often used to trace natural and anthropogenic sources but is rarely paired with blood data. The objective of this study was to determine the main factors associated with high Blood Lead Levels (BLL). Soil, manioc tubers, food bowls, beverages, wild games, lead pellets and children blood were sampled in small villages along the Oyapock River. children BLL ranged between 5.7 and 35 µg dL-1, all exceeding 5 µg dL-1, the reference value proposed in epidemiologic studies for lead poisoning. Among the different dietary sources, manioc tubers and large game contained elevated Pb concentrations while manioc-based dishes were diluted. The isotopes ratios (207Pb/206Pb and 208Pb/206Pb) of children blood overlapped these of lead shots and meals. These first results confirm for the first time, the diary consumption of manioc-based food as the main contributor to Amerindian children's BLL in French Guiana, but don't exclude the occasional exposure to lead bullets by hunting activities. This is a specific health concern, since previous studies have shown that these same villagers present high levels of mercury (Hg). These communities are indeed subject to a double exposure to neurotoxic metals, Hg and Pb, both through their diet. The farming activity is based on manioc growing, and explaining that this ancestral practice can induce serious health risks for the child's development may seriously affect their food balance and cultural cohesion.

Incidence and Trends in Immune Reconstitution Inflammatory Syndrome Associated With Histoplasma capsulatum Among People Living With Human Immunodeficiency Virus: A 20-Year Case Series and Literature Review.

BACKGROUND: Histoplasmosis is among the main acquired immunodeficiency syndrome (AIDS)-defining conditions in endemic areas. Although histoplasmosis has a worldwide distribution, histoplasmosis-associated immune reconstitution inflammatory syndrome (IRIS) in people living with human immunodeficiency virus (PLHIV) is rarely reported.This study aimed to describe the incidence and features of histoplasmosis-associated IRIS in a cohort of PLHIV. METHODS: A retrospective multicenter study was conducted in French Guiana from 1 January 1997 to 30 September 2017. The target population was represented by PLHIV who presented an episode of histoplasmosis within 6 months after antiretroviral therapy initiation. We used a consensual IRIS case definition, submitted to the agreement of 2 experts. Each case was described using a standardized questionnaire, and all patients gave informed consent. RESULTS: Twenty-two cases of histoplasmosis-associated IRIS were included (14 infectious/unmasking and 8 paradoxical), with an overall incidence rate of 0.74 cases per 1000 HIV-infected person-years (95% confidence interval, 0.43-1.05). Mean age was 40.5 years. The ratio of males to females was 1:4. Median time to IRIS was 11 days (interquartile range 7-40 days) after antiretroviral therapy initiation. The main clinical presentation was fever, without any specific pattern, and disseminated disease. We reported 2 severe cases and partial or complete recovery at 1 month was the rule. Twenty-two cases were identified in the literature with similar characteristics. CONCLUSIONS: Histoplasmosis-associated IRIS incidence was low but generated significant morbidity in PLHIV. In endemic areas, screening for latent or subclinical histoplasmosis should be implemented before antiretroviral therapy initiation.

Resurgence risk for malaria, and the characterization of a recent outbreak in an Amazonian border area between French Guiana and Brazil.

BACKGROUND: In 2017, inhabitants along the border between French Guiana and Brazil were affected by a malaria outbreak primarily due to Plasmodium vivax (Pv). While malaria cases have steadily declined between 2005 and 2016 in this Amazonian region, a resurgence was observed in 2017. METHODS: Two investigations were performed according to different spatial scales and information details: (1) a local study on the French Guiana border, which enabled a thorough investigation of malaria cases treated at a local village health center and the entomological circumstances in the most affected neighborhood, and (2) a regional and cross-border study, which enabled exploration of the regional spatiotemporal epidemic dynamic. Number and location of malaria cases were estimated using French and Brazilian surveillance systems. RESULTS: On the French Guianese side of the border in Saint-Georges de l'Oyapock, the attack rate was 5.5% (n = 4000), reaching 51.4% (n = 175) in one Indigenous neighborhood. Entomological findings suggest a peak of Anopheles darlingi density in August and September. Two female An. darlingi (n = 1104, 0.18%) were found to be Pv-positive during this peak. During the same period, aggregated data from passive surveillance conducted by Brazilian and French Guianese border health centers identified 1566 cases of Pv infection. Temporal distribution during the 2007-2018 period displayed seasonal patterns with a peak in November 2017. Four clusters were identified among epidemic profiles of cross-border area localities. All localities of the first two clusters were Brazilian. The localization of the first cluster suggests an onset of the outbreak in an Indigenous reservation, subsequently expanding to French Indigenous neighborhoods and non-Native communities. CONCLUSIONS: The current findings demonstrate a potential increase in malaria cases in an area with otherwise declining numbers. This is a transborder region where human mobility and remote populations challenge malaria control programs. This investigation illustrates the importance of international border surveillance and collaboration for malaria control, particularly in Indigenous villages and mobile populations.

Emergence of Plasmodium vivax Resistance to Chloroquine in French Guiana.

In South America, Plasmodium vivax resistance to chloroquine was recently reported in Brazil and Bolivia. The objective of this study was to collect data on chloroquine resistance in French Guiana by associating a retrospective evaluation of therapeutic efficacy with an analysis of recurrent parasitemia from any patients. Patients with P. vivax infection, confirmed by microscopy and a body temperature of ≥37.5°C, were retrospectively identified at Cayenne Hospital between 2009 and 2015. Follow-up and treatment responses were performed according to the World Health Organization protocol. Parasite resistance was confirmed after dosage of a plasma concentration of chloroquine and microsatellite characterization. The pvmdr1 and pvcrt-o genes were analyzed for sequence and gene copy number variation. Among the 172 patients followed for 28 days, 164 presented adequate clinical and parasitological responses. Eight cases of treatment failures were identified (4.7%; n = 8/172), all after 14 days. The therapeutic efficacy of chloroquine was estimated at 95.3% (95% confidence interval [CI], 92.5 to 98.1%; n = 164/172). Among the eight failures, five were characterized: two cases were true P. vivax chloroquine resistance (1.2%; 95% CI, 0 to 2.6%; n = 2/172), and three cases were found with subtherapeutic concentrations of chloroquine. No particular polymorphism in the Plasmodium vivaxpvmdr1 and pvcrt-o genes was identified in the resistant parasites. This identified level of resistance of P. vivax to chloroquine in French Guiana does not require a change in therapeutic recommendations. However, primaquine should be administered more frequently to limit the spread of resistance, and there is still a need for a reliable molecular marker to facilitate the monitoring of P. vivax resistance to chloroquine.

Angiostrongylus cantonensis Infection of Central Nervous System, Guiana Shield.

We report a case of eosinophilic meningitis complicated by transverse myelitis caused by Angiostrongylus cantonensis in a 10-year-old boy from Brazil who had traveled to Suriname. We confirmed diagnosis by serology and real-time PCR in the cerebrospinal fluid. The medical community should be aware of angiostrongyliasis in the Guiana Shield.

Primaquine 30 mg/day versus 15 mg/day during 14 days for the prevention of Plasmodium vivax relapses in adults in French Guiana: a historical comparison.

BACKGROUND: The preventive treatment of Plasmodium vivax relapse recommended by the World Health Organization is primaquine at a dose of 15 mg/day for 14 days, except for malaria cases from Asia and Oceania. Since 2006, CDC recommends the use of primaquine at 30 mg/day for 14 days. In France, all cases of malaria due to P. vivax are treated with 30 mg of primaquine. This systematically increased dosage needs to be evaluated according to epidemiological context. The aim of the study was to compare relapses after 14 days of primaquine at 15 or 30 mg/day. METHODS: All patients treated with primaquine after a vivax malaria episode in French Guiana, between 1 January, 2007 and 1 August, 2016, were studied. Based on the compulsory hospital pharmacy forms for primaquine delivery, adult patients who received 15 or 30 mg of primaquine during 14 days for hypnozoite eradication were included. The recommended dose was initially 15 mg and was changed to 30 mg in 2011. Vivax malaria recurrences within 2 months after primaquine treatment, and vivax malaria recurrences 2-6 months after primaquine in each treatment group were analysed using survival analysis at 2, 3 and 6 months. RESULTS: Out of 544 patients included, 283 received 15 mg/day and 261 received 30 mg/day of primaquine. At 2 and 3 months after primaquine treatment, the number of recurrences was 7 (2.5%) and 19 (7.3%), and 9 (3.4%) and 15 (5.3%), in the 15 and 30 mg groups (p = 0.51 respectively 0.35), respectively. Within 3 months, the median time to recurrence was 2.05 months in the 15 and 30 mg groups. At 6 months after primaquine treatment, the number of recurrences was 25 (8.8%) and 31 (11.9%) at 15 and 30 mg, respectively (p = 0.24). The median time to recurrence was 2.38 months at 15 mg/day and of 2.64 months at 30 mg/day. CONCLUSIONS: There were no significant differences between primaquine at 15 or 30 mg/day for 14 days in the prevention of P. vivax relapses at 2, 3 and 6 months after primaquine treatment in French Guiana.