Semi-field assessment of the BG-Malaria trap for monitoring the African malaria vector, Anopheles arabiensis

Odour-baited technologies are increasingly considered for effective monitoring of mosquito populations and for the evaluation of vector control interventions. The BG-Malaria trap (BGM), which is an upside-down variant of the widely used BG-Sentinel trap (BGS), has been demonstrated to be effective to sample the Brazilian malaria vector, Anopheles darlingi. We evaluated the BGM as an improved method for sampling the African malaria vectors, Anopheles arabiensis. Experiments were conducted inside a large semi-field cage to compare trapping efficiencies of BGM and BGS traps, both baited with the synthetic attractant, Ifakara blend, supplemented with CO2. We then compared BGMs baited with either of four synthetic mosquito lures, Ifakara blend, Mbita blend, BG-lure or CO2, and an unbaited BGM. Lastly, we compared BGMs baited with the Ifakara blend dispensed via either nylon strips, BG cartridges (attractant-infused microcapsules encased in cylindrical plastic cartridge) or BG sachets (attractant-infused microcapsules encased in plastic sachets). All tests were conducted between 6P.M. and 7A.M., with 200–600 laboratory-reared An. arabiensis released nightly in the test chamber. The median number of An. arabiensis caught by the BGM per night was 83, IQR:(73.5–97.75), demonstrating clear superiority over BGS (median catch = 32.5 (25.25–37.5)). Compared to unbaited controls, BGMs baited with Mbita blend caught most mosquitoes (45 (29.5–70.25)), followed by BGMs baited with CO2 (42.5 (27.5–64)), Ifakara blend (31 (9.25–41.25)) and BG lure (16 (4–22)). BGM caught 51 (29.5–72.25) mosquitoes/night, when the attractants were dispensed using BG-Cartridges, compared to BG-Sachet (29.5 (24.75–40.5)), and nylon strips (27 (19.25–38.25)), in all cases being significantly superior to unbaited controls (p < 000.1). The findings demonstrate potential of the BGM as a sampling tool for African malaria vectors over the standard BGS trap. Its efficacy can be optimized by selecting appropriate odour baits and odour-dispensing systems

Experience and Challenges from Clinical Trials with Malaria Vaccines in Africa.

Malaria vaccines are considered amongst the most important modalities for potential elimination of malaria disease and transmission. Research and development in this field has been an area of intense effort by many groups over the last few decades. Despite this, there is currently no licensed malaria vaccine. Researchers, clinical trialists and vaccine developers have been working on many approached to make malaria vaccine available.African research institutions have developed and demonstrated a great capacity to undertake clinical trials in accordance to the International Conference on Harmonization-Good Clinical Practice (ICH-GCP) standards in the last decade; particularly in the field of malaria vaccines and anti-malarial drugs. This capacity is a result of networking among African scientists in collaboration with other partners; this has traversed both clinical trials and malaria control programmes as part of the Global Malaria Action Plan (GMAP). GMAP outlined and support global strategies toward the elimination and eradication of malaria in many areas, translating in reduction in public health burden, especially for African children. In the sub-Saharan region the capacity to undertake more clinical trials remains small in comparison to the actual need.However, sustainability of the already developed capacity is essential and crucial for the evaluation of different interventions and diagnostic tools/strategies for other diseases like TB, HIV, neglected tropical diseases and non-communicable diseases. There is urgent need for innovative mechanisms for the sustainability and expansion of the capacity in clinical trials in sub-Saharan Africa as the catalyst for health improvement and maintained

The effect of community groups and mobile phone messages on the prevention and control of diabetes in rural Bangladesh : study protocol for a three-arm cluster randomised controlled trial

BACKGROUND: Increasing rates of type 2 diabetes mellitus place a substantial burden on health care services, communities, families and individuals living with the disease or at risk of developing it. Estimates of the combined prevalence of intermediate hyperglycaemia and diabetes in Bangladesh vary, and can be as high as 30% of the adult population. Despite such high prevalence, awareness and control of diabetes and its risk factors are limited. Prevention and control of diabetes and its complications demand increased awareness and action of individuals and communities, with positive influences on behaviours and lifestyle choices. In this study, we will test the effect of two different interventions on diabetes occurrence and its risk factors in rural Bangladesh. METHODS/DESIGN: A three-arm cluster randomised controlled trial of mobile health (mHealth) and participatory community group interventions will be conducted in four rural upazillas in Faridpur District, Bangladesh. Ninety-six clusters (villages) will be randomised to receive either the mHealth intervention or the participatory community group intervention, or be assigned to the control arm. In the mHealth arm, enrolled individuals will receive twice-weekly voice messages sent to their mobile phone about prevention and control of diabetes. In the participatory community group arm, facilitators will initiate a series of monthly group meetings for men and women, progressing through a Participatory Learning and Action cycle whereby group members and communities identify, prioritise and tackle problems associated with diabetes and the risk of developing diabetes. Both interventions will run for 18 months. The primary outcomes of the combined prevalence of intermediate hyperglycaemia and diabetes and the cumulative 2-year incidence of diabetes among individuals identified as having intermediate hyperglycaemia at baseline will be evaluated through baseline and endline sample surveys of permanent residents aged 30 years or older in each of the study clusters. Data on blood glucose level, blood pressure, body mass index and hip-to-waist ratio will be gathered through physical measurements by trained fieldworkers. Demographic and socioeconomic data, as well as data on knowledge of diabetes, chronic disease risk factor prevalence and quality of life, will be gathered through interviews with sampled respondents. DISCUSSION: This study will increase our understanding of diabetes and other non-communicable disease burdens and risk factors in rural Bangladesh. By documenting and evaluating the delivery, impact and cost-effectiveness of participatory community groups and mobile phone voice messaging, study findings will provide evidence on how population-level strategies of community mobilisation and mHealth can be implemented to prevent and control noncommunicable diseases and risk factors in this population. TRIAL REGISTRATION: ISRCTN41083256 . Registered on 30 Mar 2016 (Retrospectively Registered). TRIAL ACRONYM: D-Magic: Diabetes Mellitus - Action through Groups or mobile Information for better Control

Field evaluation of the BG-Malaria trap for monitoring malaria vectors in rural Tanzanian villages.

BG-Malaria (BGM) trap is a simple adaptation of the widely-used BG-Sentinel trap (BGS). It is proven to be highly effective for trapping the Brazilian malaria vector, Anopheles darlingi, in field conditions, and the African vector, Anopheles arabiensis, under controlled semi-field environments, but has not been field-tested in Africa. Here, we validated the BGM for field sampling of malaria vectors in south-eastern Tanzania. Using a series of Latin-Square experiments conducted nightly (6pm-7am) in rural villages, we compared mosquito catches between BGM, BGS and human landing catches (HLC). We also compared BGMs baited with different attractants (Ifakara-blend, Mbita-blend, BG-Lure and CO2). Lastly, we tested BGMs baited with Ifakara-blend from three odour-dispensing methods (BG-Cartridge, BG-Sachet and Nylon strips). One-tenth of the field-collected female Anopheles gambiae s.l. and Anopheles funestus were dissected to assess parity. BGM captured more An. gambiae s.l. than BGS (p < 0.001), but HLC caught more than either trap (p < 0.001). However, BGM captured more An. funestus than HLC. Proportions of parous An. gambiae s.l. and An. funestus consistently exceeded 50%, with no significant difference between methods. While the dominant species caught by HLC was An. gambiae s.l. (56.0%), followed by Culex spp. (33.1%) and Mansonia spp. (6.0%), the BGM caught mostly Culex (81.6%), followed by An. gambiae s.l. (10.6%) and Mansonia (5.8%). The attractant-baited BGMs were all significantly superior to un-baited controls (p < 0.001), although no difference was found between the specific attractants. The BG-Sachet was the most efficient dispenser for capturing An. gambiae s.l. (14.5(2.75-42.50) mosquitoes/trap/night), followed by BG-Cartridge (7.5(1.75-26.25)). The BGM caught more mosquitoes than BGS in field-settings, but sampled similar species diversity and physiological states as BGS. The physiological states of malaria vectors caught in BGM and BGS were similar to those naturally attempting to bite humans (HLC). The BGM was most efficient when baited with Ifakara blend, dispensed from BG-Sachet. We conclude that though BGM traps have potential for field-sampling of host-seeking African malaria vectors with representative physiological states, both BGM and BGS predominantly caught more culicines than Anopheles, compared to HLC, which caught mostly An. gambiae s.l

Results of pair-wise post hoc comparison using Tukey’s honestly significance tests (Tukey’s HSD).

<p>Howing similarities and differences between number of mosquitoes caught in traps baited with different lures (Panel A) and number of mosquitoes caught in traps baited with different lures dispensed from different media (Panel B).</p

Devices used for dispensing mosquito attractants.

<p>Panels A and B show attractants infused inside microcapsules supplied by Biogents Company encased in a plastic sachet (BG-Sachet) and plastic cartridge (BG-Cartridge), respectively. Panel C shows a batch of nylon strips, each soaked in solution of a different constituent of the synthetic attractant [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0186696#pone.0186696.ref033" target="_blank">33</a>].</p

Distribution and median number of <i>Anopheles arabiensis</i> recaptured per night using different trapping methods in the semi-field system.

<p>BGM = BG-Malaria trap; BGS = BG-Sentinel trap.</p

Schematic diagram of the trap positions and mosquito release points within the semi-field system.

<p>Set ups for experiments 1, 2 and 3, are shown in figure panels A, B and C, respectively. Trap positions are shown in circles, and mosquito release points in triangles. In all experiments, the treatment being tested was rotated between the test locations nightly.</p

Illustration of design and functionality of: (A) BG-Sentinel and (B) BG-Malaria.

<p>IF = Intake funnel; CB = Catch Bag; F = Fan; G = Gauze Cover; T = Tube; RC = Recipient of CO₂; OB = Odour Bait. Arrows indicate the direction of the airflow. Adapted from Kröckel <i>et al</i>., (2006) and Gama <i>et al</i>., (2013).</p