Which diagnostic test to use for Testing and Treatment strategies in low-transmission settings: a secondary analysis of a longitudinal interventional study.

Background: The lack of sensitive field tests to diagnose blood stages and hypnozoite carriers prevents Testing and Treatment (TAT) strategies to achieve elimination in low-transmission settings, but recent advances in Polymerase Chain Reaction (PCR) and serology position them as promising tools. This study describes a PCR-based TAT strategy (PCRTAT) implemented in Saint Georges (SGO), French Guiana, and explores alternative strategies (seroTAT and seroPCRTAT) to diagnose and treat carriers.

Methods: The PALUSTOP cohort study implemented in SGO (September 2017 to December 2018) screened participants for using PCR tests and treated positive cases.

Seroepidemiology of the Seasonal Human Coronaviruses NL63, 229E, OC43 and HKU1 in France.

Background: The seasonal human coronaviruses (HCoV) NL63, 229E, OC43, and HKU1 are globally endemic, yet the majority of HCoV infections remain undiagnosed.

Methods: In a cross-sectional study, 2389 serum samples were collected from children and adults in France in 2020. In a longitudinal cohort study, 2520 samples were collected from 898 French individuals followed up between 2020 and 2021.

Molecular detection of human Plasmodium species using a multiplex real time PCR.

Molecular detection methods have revealed higher sensitivity and specificity than conventional microscopy or rapid diagnostic tests for malaria diagnosis. In this study, we implemented, evaluated and validated according to the ISO 15,189 requirements, a multiplex real-time PCR assay to detect and identify the five human malaria parasites. DNA samples were extracted from whole blood or dried blood spots drawn from patients.

Estimated protection against COVID-19 based on predicted neutralisation titres from multiple antibody measurements in a longitudinal cohort, France, April 2020 to November 2021.

BackgroundThe risk of SARS-CoV-2 (re-)infection remains present given waning of vaccine-induced and infection-acquired immunity, and ongoing circulation of new variants.AimTo develop a method that predicts virus neutralisation and disease protection based on variant-specific antibody measurements to SARS-CoV-2 antigens.MethodsTo correlate antibody and neutralisation titres, we collected 304 serum samples from individuals with either vaccine-induced or infection-acquired SARS-CoV-2 immunity.

Neutralising antibody responses to SARS-CoV-2 omicron among elderly nursing home residents following a booster dose of BNT162b2 vaccine: A community-based, prospective, longitudinal cohort study.

Background: The protective immunity against omicron following a BNT162b2 Pfizer booster dose among elderly individuals (ie, those aged >65 years) is not well characterised.

Methods: In a community-based, prospective, longitudinal cohort study taking place in France in which 75 residents from three nursing homes were enrolled, we selected 38 residents who had received a two-dose regimen of mRNA vaccine and a booster dose of Pfizer BNT162b2 vaccine. We excluded individuals that did not receive three vaccine doses or did not have available sera samples.

Kinetics of the SARS-CoV-2 Antibody Avidity Response Following Infection and Vaccination.

Serological assays capable of measuring antibody responses induced by previous infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been critical tools in the response to the COVID-19 pandemic. In this study, we use bead-based multiplex assays to measure IgG and IgA antibodies and IgG avidity to five SARS-CoV-2 antigens (Spike (S), receptor-binding domain (RBD), Nucleocapsid (N), S subunit 2, and Membrane-Envelope fusion (ME)). These assays were performed in several cohorts of healthcare workers and nursing home residents, who were followed for up to eleven months after SARS-CoV-2 infection or up to six months after vaccination.

Declines in prevalence alter the optimal level of sexual investment for the malaria parasite .

Successful infectious disease interventions can result in large reductions in parasite prevalence. Such demographic change has fitness implications for individual parasites and may shift the parasite's optimal life history strategy. Here, we explore whether declining infection rates can alter 's investment in sexual versus asexual growth.

Humoral immunity to SARS-CoV-2 and seasonal coronaviruses in children and adults in north-eastern France.

Background: Children are underrepresented in the COVID-19 pandemic and often experience milder disease than adolescents and adults. Reduced severity is possibly due to recent and more frequent seasonal human coronaviruses (HCoV) infections. We assessed the seroprevalence of SARS-CoV-2 and seasonal HCoV specific antibodies in a large cohort in north-eastern France.

Kinetics of the Severe Acute Respiratory Syndrome Coronavirus 2 Antibody Response and Serological Estimation of Time Since Infection.

Background: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces a complex antibody response that varies by orders of magnitude between individuals and over time.

Methods: We developed a multiplex serological test for measuring antibodies to 5 SARS-CoV-2 antigens and the spike proteins of seasonal coronaviruses. We measured antibody responses in cohorts of hospitalized patients and healthcare workers followed for up to 11 months after symptoms.

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.

Asymptomatic and symptomatic SARS-CoV-2 infections elicit polyfunctional antibodies.

Many SARS-CoV-2-infected individuals remain asymptomatic. Little is known about the extent and quality of their antiviral humoral response. Here, we analyze antibody functions in 52 asymptomatic infected individuals, 119 mildly symptomatic, and 21 hospitalized patients with COVID-19.

Multiplex assays for the identification of serological signatures of SARS-CoV-2 infection: an antibody-based diagnostic and machine learning study.

Background: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces an antibody response targeting multiple antigens that changes over time. This study aims to take advantage of this complexity to develop more accurate serological diagnostics.

Methods: A multiplex serological assay was developed to measure IgG and IgM antibody responses to seven SARS-CoV-2 spike or nucleoprotein antigens, two antigens for the nucleoproteins of the 229E and NL63 seasonal coronaviruses, and three non-coronavirus antigens.

Predictors of antimalarial self-medication in illegal gold miners in French Guiana: a pathway towards artemisinin resistance.

Background: Malaria is endemic in French Guiana (FG), South America. Despite the decrease in cases in the local population, illegal gold miners are very affected by malaria (22.3% of them carried Plasmodium spp.

Asymptomatic Plasmodium falciparum and vivax infection in the neighborhood of Blondin, Saint-Georges-de-l'Oyapock District, French Guiana.

Optimized elimination strategies are needed to control transmission of malaria. As part of an elimination campaign, active detection of asymptomatic Plasmodium carriers by highly sensitive methods is deemed necessary. Asymptomatic carriage leads to complex scientific, ethical, and operational issues regarding individual or collective detection and treatment.

Antiplasmodial activities of dyes against Plasmodium falciparum asexual and sexual stages: Contrasted uptakes of triarylmethanes Brilliant green, Green S (E142), and Patent Blue V (E131) by erythrocytes.

The search for safe antimalarial compounds acting against asexual symptom-responsible stages and sexual transmission-responsible forms of Plasmodium species is one of the major challenges in malaria elimination programs. So far, among current drugs approved for human use, only primaquine has transmission-blocking activity. The discovery of small molecules targeting different Plasmodium falciparum life stages remains a priority in antimalarial drug research.

Plasmodium vivax multidrug resistance-1 gene polymorphism in French Guiana.

Background: Plasmodium vivax malaria is a major public health problem in French Guiana. Some cases of resistance to chloroquine, the first-line treatment used against P. vivax malaria, have been described in the Brazilian Amazon region.

Prevalence of Plasmodium spp. in illegal gold miners in French Guiana in 2015: a hidden but critical malaria reservoir.

Background: Malaria is endemic in French Guiana, an overseas territory of France on the Guiana Shield. Since 2005, notified malaria cases are decreasing. However, new data show that malaria affects many Brazilian gold miners working illegally in French Guiana, the majority of whom are not counted in official data.

Malaria Hyperendemicity and Risk for Artemisinin Resistance among Illegal Gold Miners, French Guiana.

To assess the prevalence of malaria among illegal gold miners in the French Guiana rainforest, we screened 205 miners during May-June 2014. Malaria prevalence was 48.3%; 48.

Adaptive evolution of malaria parasites in French Guiana: Reversal of chloroquine resistance by acquisition of a mutation in pfcrt.

In regions with high malaria endemicity, the withdrawal of chloroquine (CQ) as first-line treatment of Plasmodium falciparum infections has typically led to the restoration of CQ susceptibility through the reexpansion of the wild-type (WT) allele K76 of the chloroquine resistance transporter gene (pfcrt) at the expense of less fit mutant alleles carrying the CQ resistance (CQR) marker K76T. In low-transmission settings, such as South America, drug resistance mutations can attain 100% prevalence, thereby precluding the return of WT parasites after the complete removal of drug pressure. In French Guiana, despite the fixation of the K76T allele, the prevalence of CQR isolates progressively dropped from >90% to <30% during 17 y after CQ withdrawal in 1995.