IgG Ab response to Nterm-34kDa salivary peptide from individuals exposed to <i>Ae</i>. <i>albopictus</i> bites, after vector control implementation and according to the initial level.

<p>IgG Ab response before and after vector control was presented for “lower responders” (3A), “medium responders” (3B) and “higher responders” (3C) groups defined according to tertile values of individual ΔOD before vector control (= initial level). Statistical differences of the level of IgG response between two time-points are indicated by P-values estimated by a Wilconxon matched pair test. Vertical solid grey line indicates timing of VCI.</p

Median of IgG Ab response to Nterm-34kDa salivary peptide from individuals exposed to <i>Ae</i>. <i>albopictus</i> bites according to adult mosquito density.

<p>Evolution of IgG Ab response to Nterm-34kDa salivary peptide (median values) is represented (dotted grey line with circle) with the average density of <i>Ae</i>. <i>albopictus</i> adult population as estimated every two days during the follow-up (solid black line with circles). The timing of vector control implementation (vertical solid grey line) is represented.</p

IgG Ab response to <i>Ae</i>. <i>aegypti</i> Nterm-34kDa salivary peptide in individuals exposed to <i>Ae</i>. <i>albopictus</i> bites at La Reunion Island and in non-exposed individuals.

<p>Black points indicate individual IgG response (ΔOD) and bars represent the median value in each group. Dotted line represents the cut-off of specific Ab response (ΔOD>0.181) and p-value was calculated using the Mann-Whitney U test.</p

IgG Ab response to Nterm-34kDa salivary peptide from individuals exposed to <i>Ae</i>. <i>albopictus</i> bites before and after vector control implementation.

<p>Individual IgG Ab response (ΔOD) is presented just before (T0) and then 15, 30 and 45 days after vector control implementation. Bars indicated the median value in the population at each time point and dotted line represents the cut-off of immune response. P-values indicating differences in IgG response level at the overall time points (Kruskal-Wallis test) or between two different time points (Wilconxon matched pair test) are presented. Vertical solid grey line indicates timing of VCI.</p

Human IgG Antibody Response to <i>Aedes</i> Nterm-34kDa Salivary Peptide, an Epidemiological Tool to Assess Vector Control in Chikungunya and Dengue Transmission Area

<div><p>Background</p><p>Arboviral diseases are an important public health concerns. Vector control remains the sole strategy to fight against these diseases. Because of the important limits of methods currently used to assess human exposure to <i>Aedes</i> mosquito bites, much effort is being devoted to develop new indicators. Recent studies have reported that human antibody (Ab) responses to <i>Aedes aegypti</i> Nterm-34kDa salivary peptide represent a promising biomarker tool to evaluate the human-<i>Aedes</i> contact. The present study aims investigate whether such biomarker could be used for assessing the efficacy of vector control against <i>Aedes</i>.</p><p>Methodology/Principal findings</p><p>Specific human IgG response to the Nterm-34kDa peptide was assessed from 102 individuals living in urban area of Saint-Denis at La Reunion Island, Indian Ocean, before and after the implementation of vector control against <i>Aedes</i> mosquitoes. IgG response decreased after 2 weeks (P < 0.0001), and remained low for 4 weeks post-intervention (P = 0.0002). The specific IgG decrease was associated with the decline of <i>Aedes</i> mosquito density, as estimated by entomological parameters and closely correlated to vector control implementation and was not associated with the use of individual protection, daily commuting outside of the house, sex and age. Our findings indicate a probable short-term decrease of human exposure to <i>Aedes</i> bites just after vector control implementation.</p><p>Conclusion/Significance</p><p>Results provided in the present study indicate that IgG Ab response to <i>Aedes aegypti</i> Nterm-34kDa salivary peptide could be a relevant short-time indicator for evaluating the efficacy of vector control interventions against <i>Aedes</i> species.</p></div

Proportion of use of vector control measures in the populations of 45 districts of Dakar urban region.

<p>The proportion of use in the total population (children and adults), children or adults was calculated for each type of vector control measure listed. The standard error of each proportion is indicated in brackets. “n” represents the effectiveness of individuals in each group. “Others” means simultaneous use of two or more of the listed vector control tools by populations.</p

IgG responses to gSG6-P1 according to adult perception of mosquito bites.

<p>Anti-gSG6-P1 IgG responses represented according to the degree of perception of mosquito bites (Fig. 3a) and taking into account the use of bed nets (Fig. 3b). Boxes indicate the middle 50% of the data; horizontal lines in the boxes indicate medians of the individual data; lengths of boxes correspond to the inter-quartile ranges. In Fig. 3B, bed net and non-bed net users are represented white and grey boxes, respectively. The horizontal black dotted line represents the cut-off of IgG responder. Statistical significant differences of specific IgG between bed net and non-bed net users are indicated.</p

Factors influencing specific IgG response to gSG6-P1 peptide.

<p>Intercept = when the values of all independent variables are zero (e.g. the value of median IgG response in someone with no risk factors). The estimated coefficient and the degree of significance (p-value) are indicated. A positive coefficient means that the explanatory variable increases the probability of IgG response to gSG6-P1, while a negative coefficient means that the variable decreases the probability of IgG response to gSG6-P1.</p

Localization of the studied sites in Dakar.

<p>The 50 blood spot-sampling (in yellow) sites are proportionally localized on the map. Enclosed asterisks represent the 5 prosperous residential districts of the Dakar department in which the collected blood samples were not enough for several reasons. The 45 remaining districts in which sufficient blood spot-samples were collected for immunological assays are numbered from 1 to 45 on the map. DK, PK, GUE and RF are, respectively, Dakar, Pikine, Guediawaye and Rufisque, the four departments of Dakar region. The brown base of the map represents the area not inhabited by humans. The darker areas correlate with the presence of vegetation.</p

Relationship between use of bed net and other vector control tools in the study population.

<p>Relationship between use of bed net and other vector control tools in the study population.</p