Summary Background Ivermectin is widely used in mass drug administrations for controlling neglected parasitic diseases, and can be lethal to malaria vectors that bite treated humans. Therefore, it could be a new tool to reduce plasmodium transmission. We tested the hypothesis that frequently repeated mass administrations of ivermectin to village residents would reduce clinical malaria episodes in children and would be well tolerated with minimal harms. Methods We invited villages (clusters) in Burkina Faso to participate in a single-blind (outcomes assessor), parallel-assignment, two-arm, cluster-randomised trial over the 2015 rainy season. Villages were assigned (1:1) by random draw to either the intervention group or the control group. In both groups, all eligible participants who consented to the treatment and were at least 90 cm in height received single oral doses of ivermectin (150–200 μg/kg) and albendazole (400 mg), and those in the intervention group received five further doses of ivermectin alone at 3-week intervals thereafter over the 18-week treatment phase. The primary outcome was cumulative incidence of uncomplicated malaria episodes over 18 weeks (analysed on a cluster intention-to-treat basis) in an active case detection cohort of children aged 5 years or younger living in the study villages. This trial is registered with ClinicalTrials.gov , number NCT02509481 . Findings Eight villages agreed to participate, and four were randomly assigned to each group. 2712 participants (1333 [49%] males and 1379 [51%] females; median age 15 years [IQR 6–34]), including 590 children aged 5 years or younger, provided consent and were enrolled between May 22 and July 20, 2015 (except for 77 participants enrolled after these dates because of unavailability before the first mass drug administration, travel into the village during the trial, or birth), with 1447 enrolled into the intervention group and 1265 into the control group. 330 (23%) participants in the intervention group and 233 (18%) in the control group met the exclusion criteria for mass drug administration. Most children in the active case detection cohort were not treated because of height restrictions. 14 (4%) children in the intervention group and 10 (4%) in the control group were lost to follow-up. Cumulative malaria incidence was reduced in the intervention group (648 episodes among 327 children; estimated mean 2·00 episodes per child) compared with the control group (647 episodes among 263 children; 2·49 episodes per child; risk difference −0·49 [95% CI −0·79 to −0·21], p=0·0009, adjusted for sex and clustering). The risk of adverse events among all participants did not differ between groups (45 events [3%] among 1447 participants in the intervention group vs 24 events [2%] among 1265 in the control group; risk ratio 1·63 [1·01 to 2·67]; risk difference 1·21 [0·04 to 2·38], p=0·060)...

BackgroundOver the past decade, a sharp decline of malaria burden has been observed in several countries. Consequently, the conventional entomological methods have become insufficiently sensitive and probably under-estimate micro-geographical heterogeneity of exposure and subsequent risk of malaria transmission. In this study, we investigated whether the human antibody (Ab) response to Anopheles salivary gSG6-P1 peptide, known as a biomarker of Anopheles exposure, could be a sensitive and reliable tool for discriminating human exposure to Anopheles bites in area of low and seasonal malaria transmission.MethodsA multi-disciplinary survey was performed in Northern Senegal where An. gambiae s.l. is the main malaria vector. Human IgG Ab response to gSG6-P1 salivary peptide was compared according to the season and villages in children from five villages in the middle Senegal River valley, known as a low malaria transmission area.ResultsIgG levels to gSG6-P1 varied considerably according to the villages, discriminating the heterogeneity of Anopheles exposure between villages. Significant increase of IgG levels to gSG6-P1 was observed during the peak of exposure to Anopheles bites, and decreased immediately after the end of the exposure season. In addition, differences in the season-dependent specific IgG levels between villages were observed after the implementation of Long-Lasting Insecticidal Nets by The National Malaria Control Program in this area.ConclusionThe gSG6-P1 salivary peptide seems to be a reliable tool to discriminate the micro-geographical heterogeneity of human exposure to Anopheles bites in areas of very low and seasonal malaria transmission. A biomarker such as this could also be used to monitor and evaluate the possible heterogeneous effectiveness of operational vector control programs in low-exposure areas.

BackgroundThe Northern part of Senegal is characterized by a low and seasonal transmission of malaria. However, some Plasmodium falciparum infections and malaria clinical cases are reported during the dry season. This study aims to assess the relationship between IgG antibody (Ab) responses to gSG6-P1 mosquito salivary peptide and the prevalence of P. falciparum infection in children during the dry season in the Senegal River Valley. The positive association of the Ab response to gSG6-P1, as biomarker of human exposure to Anopheles vector bite, and P. falciparum infectious status (uninfected, infected-asymptomatic or infected-symptomatic) will allow considering this biomarker as a potential indicator of P. falciparum infection risk during the dry season.MethodsMicroscopic examination of thick blood smears was performed in 371 and 310 children at the start (January) and at the end (June) of the dry season, respectively, in order to assess the prevalence of P. falciparum infection. Collected sera were used to evaluate IgG response to gSG6-P1 by ELISA. Association between parasitological and clinical data (infected-asymptomatic or infected-symptomatic) and the anti-gSG6-P1 IgG levels were evaluated during this period.ResultsThe prevalence of P. falciparum infection was very low to moderate according to the studied period and was higher in January (23.5%) compared to June (3.5%). Specific IgG response was also different between uninfected children and asymptomatic carriers of the parasite. Children with P. falciparum infection in the dry season showed higher IgG Ab levels to gSG6-P1 than uninfected children.ConclusionsThe results strengthen the hypothesis that malaria transmission is maintained during the dry season in an area of low and seasonal transmission. The measurement of IgG responses to gSG6-P1 salivary peptide could be a pertinent indicator of human malaria reservoir or infection risk in this particular epidemiological context. This promising immunological marker could be useful for the evaluation of the risk of P. falciparum exposure observed during dry season and, by consequences, could be used for the survey of potential pre-elimination situation.

Arthropod-borne viruses (arboviruses) such as dengue virus (DENV), chikungunya virus (CHIKV), Zika virus (ZIKV), and yellow fever virus (YFV) are the most important ‘emerging pathogens’ because of their geographic spread and their increasing impact on vulnerable human populations. To fight against these arboviruses, vector control strategies (VCS) remain one of the most valuable means. However, their implementation and monitoring are labour intensive and difficult to sustain on large scales, especially when transmission and Aedes mosquito densities are low. To increase the efficacy of VCS, current entomological methods should be improved by new complementary tools which measure the risk of arthropod-borne diseases’ transmission. The study of human–Aedes immunological relationships can provide new promising serological tools, namely antibody-based biomarkers, allowing to accurately estimate the human–Aedes contact and consequently, the risk of transmission of arboviruses and the effectiveness of VCS. This review focuses on studies highlighting the concept, techniques, and methods used to develop and validate specific candidate biomarkers of human exposure to Aedes bites. Potential applications of such antibody-based biomarkers of exposure to Aedes vector bites in the field of operational research are also discussed.

To better understand the influence of periodic mass distribution of Long-Lasting Insecticidal Nets (LLINs) on malaria transmission, a 1-yr entomological survey was conducted in three major districts of Côte d’Ivoire. Mosquitoes were sampled by Human Landing Catches (HLC) in urban and rural areas of San Pedro and Abidjan (coastal), and in Yamoussoukro (central). Mosquitoes were identified morphologically and by molecular methods. The Plasmodium falciparum circumsporozoite (CSP) indices were measured by ELISA, and the Entomological Inoculation Rates (EIR) were calculated for each species and area. Anopheles gambiae s.l. Giles (Diptera: Culicidae) and Anopheles nili Theobald (Diptera: Culicidae) were identified in coastal districts, while An. gambiae s.l. and Anopheles funestus Giles (Diptera: Culicidae) were reported in the central district. In urban areas, malaria vectors showed a low aggressiveness (<10 bites per person per night), except in Yamoussoukro, where up to 18.9 b/p/n were recorded. The annual EIR was higher in the central urban area (138.7 infected bites per person per year) than in coastal ones (10–62 ib/p/n). In rural areas, malaria vectors were highly aggressive with an average 13 b/p/n for An. gambiae s.l, 21.2 b/p/n for An. nili and 12 b/p/n for An. funestus. The annual EIR ranged between 94.9 and 193.4 infected bites per person per year. This work indicates that, despite repeated mass distribution of LLINs, malaria transmission remains high and heterogeneous across Côte d’Ivoire. Malaria transmission was lower in coastal urban areas than in the central one, and remains high rural areas where two additional Anopheles vectors are involved in malaria transmission.

Urban malaria is an underestimated serious health concern in African countries. This study aimed to evaluate the risk of malaria transmission in an urban area by evaluating the level of human exposure to bites using an salivary biomarker ( Salivary Gland Protein-6 peptide 1 [gSG6-P1] peptide). Two multidisciplinary cross-sectional studies were undertaken in five sites of Bouaké city (three urban districts and two surrounding villages, used as control; Côte d'Ivoire) during the rainy season and the dry season. Blood samples were obtained from children 6 months to 14 years of age for immunological tests. The level of anti-gSG6-P1 immunoglobulin G (IgG) antibodies was significantly higher in the rainy season than the dry season in both urban and rural sites ( < 0.0001). Interestingly, children with the highest anti-gSG6-P1 IgG responses in the rainy season were infected by . Surprisingly, no difference of anti-gSG6-P1 IgG level was observed between urban and rural areas, for either season. The current data suggest that children in the urban city of Bouaké could be as highly exposed to bites as children living in surrounding villages. The immunological biomarker of human exposure to bites may be used to accurately assess the potential risk of malaria transmission in African urban settings.

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Les accidents de la vie courante (AcVC) sont fréquents chez l’enfant et peuvent être à l’origine de lésions handicapantes et de décès. L’objectif de notre travail était d’étudier les aspects épidémiologiques et lésionnels des AcVC à Dakar. C’est une étude transversale descriptive menée du 1er Janvier 2013 au 30 juin 2013. Les enfants victimes d’accidents domestiques, d’accidents de sport et de loisirs ou d’accidents scolaires ont été inclus. Nous avons étudié des paramètres généraux et des paramètres ayant trait à chaque type d’AcVC. Deux cent et un enfants ont été inclus, ce qui représentait 27% des consultations aux urgences. Il y avait 148 garçons et 53 filles. Les enfants de moins de 5 ans étaient les plus touchés (37,8%). Le football et le jeu de lutte étaient les grands pourvoyeurs d’AcVC. Les AcVC survenaient principalement à domicile (58,2%) et dans les aires de sport et de loisirs (31,8%). Les fractures prédominaient dans les différents types d’AcVC: 54,9% des accidents domestiques, 68,8% des accidents de sport et de loisirs et 40% des accidents scolaires. Au plan épidémiologique, nos résultats sont superposables à la littérature. Les fractures prédominent à l’opposé de la littérature où les contusions sont prépondérantes. Le jeu de lutte est le plus grand pourvoyeur de ces fractures après le football. La connaissance des aspects épidémiologiques et lésionnels permet de mener des campagnes de prévention des AcVC à Dakar.