Humoral immunity to Plasmodium falciparum is acquired after repeated infections, and can lead to clinical protection. This study aimed to evaluate how human-, parasite-, and environment-related determinants can modulate the dynamics of IgG responses to Plasmodium falciparum after an infection. Individuals (n = 68, average age = 8.2 years) with uncomplicated malaria were treated with ACT and followed up for 42 days. IgG responses to P. falciparum merozoite antigens (PfMSP1, PfMSP3, PfAMA1, PfGLURP-R0), to whole schizont extract (PfSchz), and to Anopheles gSG6-P1 and Aedes Nterm–34 kDa salivary peptides were measured. Regression analyses were used to identify factors that influence the dynamics of IgG response to P. falciparum antigen between D0 and D42, including demographic and biological factors and the level of exposure to mosquito bites. The dynamics of IgG response to P. falciparum differed according to the antigen. According to multivariate analysis, IgG responses to PfSchz and to PfGLURP-R0 appear to be affected by exposure to Aedes saliva and are associated with age, parasite density, and anti-Plasmodium pre-existing immune response at study inclusion. The present work shows that human exposure to Aedes saliva may contribute, in addition to other factors, to the regulation of anti-Plasmodium immune responses during a natural infection.

Since its outbreak in December 2019 in Wuhan Province (China), the Coronavirus (COVID-19) disease quickly spread around the world in such a way that most response plans were outdated. There was an urgent need to change and adapt response strategies as the virus globally spread. Entire firms and economies were brought to a standstill in order to reduce the virus' capacity to spread and to limit some of the short-term impacts in order to save time and find out solutions to come back to a more or less normal way of life. Thus, most of the countries that closed their air, sea and land borders had to reopen them progressively, with travel restrictions submitted to rigid controls. In Côte d'Ivoire, as in all other countries, air travellers leaving the territory were required to provide a certificate for a negative COVID-19 test, valid for 24 to 72 hours depending on the country of destination. However, the national system implemented could not provide a result before 48 hours. The objective of this work was to develop an alternative strategy to the system for air travellers who were in a hurry and those who had a computer bug in ob-

Effective chemotherapy is an essential component in the fight against malaria. Thus, in the face of the emergence and rapid spread of resistance to artemisinin derivatives, a molecule used as first-line treatment for malaria, it is important to search for new antimalarial molecules. The eradication of malaria requires the research of antimalarial drugs with gametocytocidal effects. The objective of this work was to set up cultures propagating Plasmodium falciparum gametocytes from clinical isolates and to evaluate the gametocytocidal and schizonticidal activity of Entandrophragma angolense extracts. Gametocytes were produced with asexual forms of clinical isolates in culture. The gametocytocidal activity of the extracts was evaluated by microscopy. Schizonticidal activity was evaluated using the SYBR Green method. The formation of gametocytes until maturation was observed. Gametocytocidal activity was evaluated by the percentage of gametocyte inhibition. It ranged from 95.69% to 82.76% and from 93.1% to 63.83% respectively for the hydroethanolic and methanolic extract of Entandrophragma angolense. The inhibitory concentration 50 percent of the extracts was determined. It ranges from 05.73 to 14.76 µg/mL. Generally, the extracts showed significant gametocytocidal and schizonticidal activity. This work is a precursor for the research of gametocytocidal molecules, a source of antimalarial molecules blocking malaria transmission.

Background Culex mosquitoes are vectors for a variety of pathogens of public health concern. New indicators of exposure to Culex bites are needed to evaluate the risk of transmission of associated pathogens and to assess the efficacy of vector control strategies. An alternative to entomological indices is the serological measure of antibodies specific to mosquito salivary antigens. This study investigated whether the human IgG response to both the salivary gland extract and the 30 kDa salivary protein of Culex quinquefasciatus may represent a proxy of human exposure to Culex bites. Methodology/Principal findings A multidisciplinary survey was conducted with children aged 1 to 14 years living in neighborhoods with varying exposure to Culex quinquefasciatus in the city of Bouaké, Côte d’Ivoire. Children living in sites with high exposure to Cx quinquefasciatus had a significantly higher IgG response to both salivary antigens compared with children living in the control site where only very few Culex were recorded. Moreover, children from any Culex-high exposed sites had significantly higher IgG responses only to the salivary gland extract compared with children from the control village, whereas no difference was noted in the anti-30 kDa IgG response. No significant differences were noted in the specific IgG responses between age and gender. Sites and the use of a bed net were associated with the level of IgG response to the salivary gland extract and to the 30 kDa antigen, respectively. Conclusions/Significance These findings suggest that the IgG response to Culex salivary gland extracts is suitable as proxy of exposure; however, the specificity to the Culex genus needs further investigation. The lower antigenicity of the 30 kDa recombinant protein represents a limitation to its use. The high specificity of this protein to the Culex genus makes it an attractive candidate and other specific antibody responses might be more relevant as a biomarker of exposure. These epidemiological observations may form a starting point for additional work on developing serological biomarkers of Culex exposure.