Antibody responses to P. falciparum blood stage antigens and incidence of clinical malaria in children living in endemic area in Burkina Faso.

BACKGROUND: High parasite-specific antibody levels are generally associated with low susceptibility to Plasmodium falciparum malaria. This has been supported by several studies in which clinical malaria cases of P. falciparum malaria were reported to be associated with low antibody avidities. This study was conducted to evaluate the role of age, malaria transmission intensity and incidence of clinical malaria in the induction of protective humoral immune response against P. falciparum malaria in children living in Burkina Faso. METHODS: We combined levels of IgG and IgG subclasses responses to P. falciparum antigens: Merozoite Surface Protein 3 (MSP3), Merozoite Surface Protein 2a (MSP2a), Merozoite Surface Protein 2b (MSP2b), Glutamate Rich Protein R0 (GLURP R0) and Glutamate Rich Protein R2 (GLURP R2) in plasma samples from 325 children under five (05) years with age, malaria transmission season and malaria incidence. RESULTS: We notice higher prevalence of P. falciparum infection in low transmission season compared to high malaria transmission season. While, parasite density was lower in low transmission than high transmission season. IgG against all antigens investigated increased with age. High levels of IgG and IgG subclasses to all tested antigens except for GLURP R2 were associated with the intensity of malaria transmission. IgG to MSP3, MSP2b, GLURP R2 and GLURP R0 were associated with low incidence of malaria. All IgG subclasses were associated with low incidence of P. falciparum malaria, but these associations were stronger for cytophilic IgGs. CONCLUSIONS: On the basis of the data presented in this study, we conclude that the induction of humoral immune response to tested malaria antigens is related to age, transmission season level and incidence of clinical malaria.

Data Management and Data Quality in PERCH, a Large International Case-Control Study of Severe Childhood Pneumonia.

The Pneumonia Etiology Research for Child Health (PERCH) study is the largest multicountry etiology study of pediatric pneumonia undertaken in the past 3 decades. The study enrolled 4232 hospitalized cases and 5325 controls over 2 years across 9 research sites in 7 countries in Africa and Asia. The volume and complexity of data collection in PERCH presented considerable logistical and technical challenges. The project chose an internet-based data entry system to allow real-time access to the data, enabling the project to monitor and clean incoming data and perform preliminary analyses throughout the study. To ensure high-quality data, the project developed comprehensive quality indicator, data query, and monitoring reports. Among the approximately 9000 cases and controls, analyzable laboratory results were available for ≥96% of core specimens collected. Selected approaches to data management in PERCH may be extended to the planning and organization of international studies of similar scope and complexity.

Monitoring the impact of a mebendazole mass drug administration initiative for soil-transmitted helminthiasis (STH) control in the Western Visayas Region of the Philippines from 2007 through 2011.

School-aged children in tropical developing countries carry the highest burden of soil-transmitted helminth (STH) infections in the world. The Western Visayas region of the Philippines continues to struggle with this as a major public health issue in both private and public schools. The War on Worms-Western Visayas approach was launched in 2007 with school-based mass drug administration (MDA) as one of the strategies to control morbidity from STH in support of the Department of Health - Integrated Helminth Control Program. This study aimed to determine trends in prevalence and intensity of STH infections as well as to assess related morbidity and program sustainability through 2011. A cross-sectional parasitologic survey was conducted on three independent samples of Grade 3 students in 2007, 2009, and 2011. Supporting aggregate data were obtained for MDA coverage, National Achievement Test mean percentage scores, and nutritional status. Tests for trend were utilized to detect changes in prevalence over time, with a particular emphasis on trends seen between 2009 and 2011. The initial impact of the program was robust as cumulative prevalence, infection intensities, and parasite densities were all reduced four years following the launch. However, subsequent and significant increases in each were found from 2009 until 2011. These results implicate issues with program sustainability, despite consistent MDA, and existing frameworks for environmental sanitation, hygiene, and education.

Malaria morbidity in high and seasonal malaria transmission area of Burkina Faso.

BACKGROUND: Malariometric parameters are often primary endpoints of efficacy trials of malaria vaccine candidates. This study aims to describe the epidemiology of malaria prior to the conduct of a series of drug and vaccine trials in a rural area of Burkina Faso. METHODS: Malaria incidence was prospectively evaluated over one year follow-up among two cohorts of children aged 0-5 years living in the Saponé health district. The parents of 1089 children comprising a passive case detection cohort were encouraged to seek care from the local health clinic at any time their child felt sick. Among this cohort, 555 children were randomly selected for inclusion in an active surveillance sub-cohort evaluated for clinical malaria during twice weekly home visits. Malaria prevalence was evaluated by cross-sectional survey during the low and high transmission seasons. RESULTS: Number of episodes per child ranged from 0 to 6 per year. Cumulative incidence was 67.4% in the passive and 86.2% in the active cohort and was highest among children 0-1 years. Clinical malaria prevalence was 9.8% in the low and 13.0% in the high season (p>0.05). Median days to first malaria episode ranged from 187 (95% CI 180-193) among children 0-1 years to 228 (95% CI 212, 242) among children 4-5 years. The alternative parasite thresholds for the malaria case definition that achieved optimal sensitivity and specificity (70-80%) were 3150 parasites/µl in the high and 1350 parasites/µl in the low season. CONCLUSION: Clinical malaria burden was highest among the youngest age group children, who may represent the most appropriate target population for malaria vaccine candidate development. The pyrogenic threshold of parasitaemia varied markedly by season, suggesting a value for alternative parasitaemia levels in the malaria case defintion. Regional epidemiology of malaria described, Sapone area field centers are positioned for future conduct of malaria vaccine trials.

Haemoglobin variants and Plasmodium falciparum malaria in children under five years of age living in a high and seasonal malaria transmission area of Burkina Faso.

BACKGROUND: Genetic factors play a key role in determining resistance/susceptibility to infectious disease. Susceptibility of the human host to malaria infection has been reported to be influenced by genetic factors, which could be confounders if not taken into account in the assessment of the efficacy of interventions against malaria. This study aimed to assess the relationship between haemoglobin genotypes and malaria in children under five years in a site being characterized for future malaria vaccine trials. METHODS: The study population consisted of 452 children living in four rural villages. Hb genotype was determined at enrolment. Clinical malaria incidence was evaluated over a one-year period using combined active and passive surveillance. Prevalence of infection was evaluated via bi-annual cross-sectional surveys. At each follow-up visit, children received a brief clinical examination and thick and thin blood films were prepared for malaria diagnosis. A clinical malaria was defined as Plasmodium falciparum parasitaemia >2,500 parasites/µl and axillary temperature ≥37.5°C or reported fever over the previous 24 hours. RESULTS: Frequencies of Hb genotypes were 73.2% AA; 15.0% AC; 8.2% AS; 2.2% CC; 1.1% CS and 0.2% SS. Prevalence of infection at enrolment ranged from 61.9%-54.1% among AA, AC and AS children. After one year follow-up, clinical malaria incidence (95% CI) (episodes per person-year) was 1.9 (1.7-2.0) in AA, 1.6 (1.4-2.1) in AC, and 1.7 (1.4-2.0) in AS children. AC genotype was associated with lower incidence of clinical malaria relative to AA genotype among children aged 1-2 years [rate ratio (95% CI) 0.66 (0.42-1.05)] and 2-3 years [rate ratio (95% CI) 0.37 (0.18-0.75)]; an association of opposite direction was however apparent among children aged 3-4 years. AS genotype was associated with lower incidence of clinical malaria relative to AA genotype among children aged 2-3 years [rate ratio (95% CI) 0.63 (0.40-1.01)]. CONCLUSIONS: In this cohort of children, AC or AS genotype was associated with lower risk of clinical malaria relative to AA genotype only among children aged one to three years. It would be advisable for clinical studies of malaria in endemic regions to consider haemoglobin gene differences as a potentially important confounder, particularly among younger children.

H1N1 preventive health behaviors in a university setting.

BACKGROUND: When H1N1 emerged in 2009, institutions of higher education were immediately faced with questions about how best to protect their community from the virus, yet limited information existed to help predict student preventive behaviors. METHODS: The authors surveyed students at a large urban university in November 2009 to better understand how students perceived their susceptibility to and the severity of H1N1, which preventive behaviors they engaged in, and if policies impacted their preventive health decisions. RESULTS: Preventive health behavior messaging had a mixed impact on students. Students made simple behavior changes to protect themselves from H1N1, especially if they perceived a high personal risk of contracting H1N1. Although policies were instituted to enable students to avoid classes when ill, almost no student self-isolated for the entire duration of their illness. CONCLUSIONS: These findings can help inform future decision making in a university setting to best influence preventive health behaviors.

Assessing physicians' in training attitudes and behaviors during the 2009 H1N1 influenza season: a cross-sectional survey of medical students and residents in an urban academic setting.

BACKGROUND: Despite concern for hospital-based transmission of influenza, little research has been carried out on perceptions and behaviors of physicians in training with regard to influenza-like illness (ILI), especially in light of the recent H1N1 pandemic. OBJECTIVES: We aimed to evaluate self-reported episodes of ILI among medical students and residents to determine the impact of ILI on school and clinical performance, absenteeism, and patterns of preventive measures used by this population both in and out of the healthcare setting. METHODS: We anonymously surveyed medical students and residents at an urban institution between November 3 and December 11, 2009. Data were analyzed separately for medical students and residents for frequency of close-ended responses. Open-ended answers were analyzed thematically. Our Institutional Review Board exempted this study from review. RESULTS: Forty-five percent of medical students and 53% of resident respondents perceived the risk of acquiring H1N1 at school or work as high, and although 43% of medical students and 66% of resident respondents had received the influenza vaccination and most reported increasing non-pharmaceutical preventive measures, 9% of medical students and 61% of residents with one or more episodes of ILI chose to continue to attend class or work when ill. CONCLUSIONS: Although students and residents report high risk of infection because of work- or school-related activities, many involved in patient care activities do not comply with recommended infection control precautions. Educational campaigns should be developed and infection control guidelines should be included in routine medical student and resident curricular activities.