Improving the performance of spray operators through monitoring and evaluation of insecticide concentrationsof pirimiphos-methyl during indoor residual spraying for malaria control on Bioko Island

Background: Quality control of indoor residual spraying (IRS) is necessary to ensure that spray operators (SOs) deposit the correct concentration of insecticide on sprayed structures, while also confrming that spray records are not being falsifed. Methods: Using high-performance liquid chromatography (HPLC), this study conducted quality control of the organophosphate insecticide pirimiphos-methyl (Actellic 300CS), during the 2018 IRS round on Bioko Island, Equatorial Guinea. Approximately 60 SOs sprayed a total of 67,721 structures in 16,653 houses during the round. Houses that were reportedly sprayed were randomly selected for quality control testing. The SOs were monitored twice in 2018, an initial screening in March followed by sharing of results with the IRS management team and identifcation of SOs to be re-trained, and a second screening in June to monitor the efectiveness of training. Insecticide samples were adhesive-lifted from wooden and cement structures and analysed using HPLC. Results: The study suggests that with adequate quality control measures and refresher training, suboptimal spraying was curtailed, with a signifcant increased concentration delivered to the bedroom (diference=0.36, P<0.001) and wooden surfaces (diference 0.41, P=0.001). Additionally, an increase in efective coverage by SOs was observed, improving from 80.7% in March to 94.7% in June after re-training (McNemar’s test; P=0.03). Conclusions: The ability to randomly select, locate, and test houses reportedly sprayed within a week via HPLC has led to improvements in the performance of SOs on Bioko Island, enabling the project to better evaluate its own performance. Keywords: Malaria, Indoor residual spraying, Vector control, Quality control, Bioko Islan

Experimentelle Untersuchungen zum Verhalten von Randschichten keramischer Werkstoffe und Schichtsystemen unter mechanischer Beanspruchung durch Eindruckversuche

SIGLEAvailable from TIB Hannover: RN 1909(1996,3) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Optimization of tissue sampling for Borrelia burgdorferi in white-footed mice (Peromyscus leucopus).

Peromyscus leucopus (the white-footed mouse) is a known reservoir of the Lyme disease spirochete Borrelia burgdorferi. Sampling of white-footed mice allows for year-round B. burgdorferi surveillance as well as opportunities to establish the diversity of the different variants in a geographic region. This study explores the prevalence of B. burgdorferi infections in the tissues of white-footed mice, investigates the correlations between B. burgdorferi infected tissues, and determines the optimum field methods for surveillance of B. burgdorferi in P. leucopus. A total of 90 mice and 573 tissues (spleen, liver, ear, tongue, tail, heart, and kidney) were screened via nested PCR for B. burgdorferi infections. A large number of infections were found in the 90 mice as well as multiple infections within individual mice. Infections in a single mouse tissue (spleen, liver, ear, tongue and tail) were predictive of concurrent infection in other tissues of the same mouse at a statistically significant level. Ear tissue accounted for 68.4% of detected infections, which increased to 78.9% of the infected mice with the inclusion of tail samples. The use of ear punch or tail snip samples (used individually or in tandem) have multiple advantages over current Lyme disease ecological studies and surveillance methodologies, including lower associated costs, minimization of delays, year-round B. burgdorferi testing opportunities, as well as longitudinal monitoring of B. burgdorferi in defined geographic regions. In the absence of an effective vaccine, personal prevention measures are currently the most effective way to reduce Lyme disease transmission to humans. Thus, the identification and monitoring of environmental reservoirs to inform at-risk populations remains a priority. The sampling methods proposed in this study provide a reasonable estimate of B. burgdorferi in white-footed mice in a timely and cost-effective manner