The PreQuine Platform: a novel diagnostic tool for measuring glucose-6-phosphate dehydrogenase (G6PD) activity and hemoglobin concentration

Quantitative diagnosis of glucose-6-phosphate dehydrogenase (G6PD) deficiency is essential for the safe administration of 8-aminoquinoline based radical cure for the treatment of Plasmodium vivax infections. Here, we present the PreQuine Platform (IVDS, USA), a quantitative biosensor that uses a dual-analyte assay for the simultaneous measurement of Hemoglobin (Hgb) levels and G6PD enzyme activity within the same sample. The platform relies on a downloadable mobile application. The device requires 10μl of whole blood and works with a reflectance-based meter. Comparing the G6PD measurement normalized by Hgb of 12 samples from the PreQuine Platform with reference measurements methods (spectrophotometry, Pointe Scientific, USA and hemoglobin meter, HemoCue, Sweden) showed a positive and significant agreement with a slope of 1.0091 and an intercept of -0.0379 under laboratory conditions. Next steps will be to conduct field trials in Bangladesh, Cambodia, and the USA to assess diagnostic performance, user friendliness and acceptance

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

Increased Biting Rate of Insecticide-Resistant Culex Mosquitoes and Community Adherence to IRS for Malaria Control in Urban Malabo, Bioko Island, Equatorial Guinea.

Sustaining high levels of indoor residual spraying (IRS) coverage (≥85%) for community protection against malaria remains a challenge for IRS campaigns. We examined biting rates and insecticide resistance in Culex species and Anopheles gambiae s.l., and their potential effect on community adherence to IRS. The average IRS coverage in urban Malabo between 2015 and 2017 remained at 80%. Culex biting rate increased 6.0-fold (P < 0.001) between 2014 and 2017, reaching 8.08 bites per person per night, whereas that of An. gambiae s.l. remained steady at around 0.68. Although An. gambiae s.l. was susceptible to carbamates and organophosphates insecticides, Culex spp. were phenotypically resistant to all four main classes of WHO-recommended IRS insecticides. Similarly, the residual activity of the organophosphate insecticide used since 2017, ACTELLIC 300CS, was 8 mo for An. gambiae s.l., but was almost absent against Culex for 2 mo post-spray. A survey conducted in 2018 within urban Malabo indicated that 77.0% of respondents related IRS as means of protection against mosquito bites, but only 3.2% knew that only Anopheles mosquitoes transmit malaria. Therefore, the increasing biting rates of culicines in urban Malabo, and their resistance to all IRS insecticides, is raising concern that a growing number of people may refuse to participate in IRS as result of its perceived failure in controlling mosquitoes. Although this is not yet the case on Bioko Island, communication strategies need refining to sensitize communities about the effectiveness of IRS in controlling malaria vectors in the midst of insecticide resistance in nonmalaria vector mosquitoes

Spatial Associations Between Land Use and Infectious Disease: Zika Virus in Colombia

Land use boundaries represent human&ndash;physical interfaces where risk of vector-borne disease transmission is elevated. Land development practices, coupled with rural and urban land fragmentation, increases the likelihood that immunologically na&iuml;ve humans will encounter infectious vectors at land use interfaces. This research consolidated land use classes from the GLC-SHARE dataset; calculated landscape metrics in linear (edge) density, proportion abundance, and patch density; and derived the incidence rate ratios of the Zika virus occurrence in Colombia, South America during 2016. Negative binomial regression was used to evaluate vector-borne disease occurrence counts in relation to Population Density, Average Elevation, Per Capita Gross Domestic Product, and each of three landscape metrics. Each kilometer of border length per square kilometer of area increase in the linear density of the Cropland and Grassland classes is associated with an increase in Zika virus risk. These spatial associations inform a risk reduction approach to rural and urban morphology and land development that emphasizes simple and compact land use geometry that decreases habitat availability for mosquito vectors of Zika virus

Willingness to pay for an Ebola vaccine during the 2014–2016 ebola outbreak in West Africa: Results from a U.S. National sample

The 2014–2016 Ebola virus outbreak in West Africa led to advances in the development of vaccines against Ebola. This study examined factors associated with willingness to pay for an Ebola vaccine among a U.S. national sample during the recent Ebola outbreak. From April 30–May 8, 2015, a national survey was conducted using the GfK Group's KnowlegePanel®. Main outcome measures included willingness to pay at least $1; more than$50; and more than $100 for an Ebola vaccine. Analyses were conducted using weighted multivariable logistic regression. Among participants (N = 1,447), 583 (40.3$1. Among those willing to pay at least $1: 570 (66.0$1–50; 174 (20.1%) would pay $51–100; and 120 (13.9$100. Willingness to pay at least $1 for an Ebola vaccine was associated with international travel; interest in getting an Ebola vaccine; and beliefs that the U.S. government should spend money to control Ebola and assume worldwide leadership in confronting emerging epidemics. Willingness to pay more than$50 was associated with similar variables. Willingness to pay more than $100 was associated with international travel; interest in getting an Ebola vaccine; information seeking; and beliefs that the U.S. government should assume worldwide leadership in confronting emerging epidemics. International travel and interest in an Ebola vaccine were key predictors of willingness to pay across all price points. Understanding willingness to pay for vaccines against emerging infectious diseases remains critical