As shown in Table 1, overall mean age was low 13

As shown in Table 1, overall mean age was low 13.5 (median = 11; 1C68 years) with variable ranges from 2010 to 2013. of Cote dIvoire. Antibody responses to recombinant proteins or BSA-peptides, 8 (PfAMA1, PfMSP4, PfMSP1, PfEMP1-DBL11-PF13, PfLSA1-41, PfLSA3-NR2, PfGLURP and PfCSP), one (PmCSP) and one salivary (gSG6-P1) antigens were measured using magnetic bead-based multiplex immunoassay (MBA). Total anti- IgG responses against schizont lysate from african 07/03 strain (adapted to culture) and 3D7 strain was measured by ELISA. Results High prevalence (7C93%) and levels of antibody responses to most of the antigens were evidenced. However, analysis showed only marginal decreasing trend of Ab responses from 2010 to 2013 that did not parallel the reduction of clinical malaria prevalence following the implementation of intervention in this area. There was a significant inverse correlation between Ab responses and parasitaemia (P<10?3, rho = 0.3). The particular recruitment of asymptomatic individuals in 2011 underlined a high background level of immunity almost equivalent to symptomatic patients, possibly obscuring observable yearly variations. Conclusion The use of cross-sectional clinical malaria surveys and MBA can help to identify endemic sites where control measures have unequal impact providing relevant information about population immunity and possible decrease of transmission. However, when immunity is substantially boosted despite observable clinical decline, a larger cohort including asymptomatic recruitment is needed to monitor the impact of control measures on level of immunity. SR1078 Introduction malaria remains a major threat in tropical and sub-tropical regions, with nearly 50% of the world population exposed to infective bites by Anopheles mosquitoes and almost half million deaths annually [1]. Scaling up of integrated interventions strategies including artemisinin-based combination therapy (ACT), universal coverage with long-lasting insecticide-impregnated bed nets (LLINs), systematic diagnosis using rapid tests (RDTs) and intermittent preventive treatment in vulnerable target groups have considerably reduced the SR1078 burden of malaria in many countries and saved more than a million lives since the year 2000, most of them among children under 5 years of age [2]. Presently, the number of malaria cases is still very high (more than 214 million malaria cases) as well as the number of deaths (236 000C635 000 according to the WHO 2015). Furthermore, in addition to the threats associated with the emergence of resistance to artemisinin in Southeast Asia and insecticides in Africa, malaria rebound in some countries like Rwanda, Sao Tome, Principe and Zambia that were the leaders in the early upgrade of fighting efforts [2]. Monitoring changes in malaria transmission intensity and disease prevalence through surveillance allows health authorities to evaluate health services and plan control programs. Sero-surveillance is based on the use of species-specific antibodies as indicators for exposure, transmission, and immunity. Such tool has a significant potential for contributing to the effectiveness of malaria control and elimination program. Antibodies are very sensitive marker of malaria exposure in low-transmission settings and reflect cumulative exposure over a period of time, which is useful in areas with highly seasonal transmission [3,4]. Although this approach was used historically as part of malaria control programs, its use was not developed in part because of the lack of standardized antigens and methodology [4]. Of more than 5,000 proteins expressed by the Plasmodium species, few have been examined in any detail, and there is a trend towards further development of sero-epidemiological analysis for monitoring malaria control and elimination. A comprehensive evaluation of candidate antigens as biomarkers is required to identify those antibody responses that are most sensitive for detecting changes in transmission. Studies employing protein microarrays [5] or expanded repertoires of purified antigens [6] are beginning to address this knowledge VLA3a gap, and it SR1078 is likely that multiple antigens will need to be included in serologic assays [4,5,6,7]. Several teams use sero-epidemiology analysis in low transmission settings focusing investigations on change of seroprevalence levels. They use results from cross-sectional studies to build mathematical seroconversion rate models and predict decline of malaria transmission [8]. In addition, few analyses were SR1078 focused on symptomatic cases. Parasite invasion and multiplication in human strongly stimulates immune responses leading to possible higher individual antibody responses in more exposed persons that thereby possess a higher degree of acquired immunity [9,10]. Thus, Ab responses measured during symptomatic episode rather represent surrogates of an effective immune background depending upon duration and intensity of parasitemia before.