Citizen science for monitoring the spatial and temporal dynamics of malaria vectors in relation to environmental risk factors in Ruhuha, Rwanda

Background As part of malaria prevention and control efforts, the distribution and density of malaria mosquitoes requires continuous monitoring. Resources for long-term surveillance of malaria vectors, however, are often limited. The aim of the research was to evaluate the value of citizen science in providing insight into potential malaria vector hotspots and other malaria relevant information, and to determine predictors of malaria vector abundance in a region where routine mosquito monitoring has not been established to support vector surveillance. Methods A 1-year citizen science programme for malaria mosquito surveillance was implemented in five villages of the Ruhuha sector in Bugesera district, Rwanda. In total, 112 volunteer citizens were enrolled and reported monthly data on mosquitoes collected in their peridomestic environment using handmade carbon-dioxide baited traps. Additionally, they reported mosquito nuisance experienced as well as the number of confirmed malaria cases in their household. Results In total, 3793 female mosquitoes were collected, of which 10.8% were anophelines. For the entire period, 16% of the volunteers reported having at least one confirmed malaria case per month, but this varied by village and month. During the study year 66% of the households reported at least one malaria case. From a sector perspective, a higher mosquito and malaria vector abundance was observed in the two villages in the south of the study area. The findings revealed significant positive correlations among nuisance reported and confirmed malaria cases, and also between total number of Culicidae and confirmed malaria cases, but not between the numbers of the malaria vector Anopheles gambiae and malaria cases. At the sector level, of thirteen geographical risk factors considered for inclusion in multiple regression, distance to the river network and elevation played a role in explaining mosquito and malaria mosquito abundance. Conclusions The study demonstrates that a citizen science approach can contribute to mosquito monitoring, and can help to identify areas that, in view of limited resources for control, are at higher risk of malaria.

EVALUATION OF DYNATRAP® DT160 AS AN INEXPENSIVE ALTERNATIVE TO CDC TRAPS FOR ADULT MOSQUITO MONITORING IN MALI, WEST AFRICA

Mosquito monitoring traps (i.e., CDC light traps) are crucial tools for basic vector ecology research, risk assessment, and vector control programs. Unfortunately, they are expensive which is often an issue in projects conducted in developing countries. Therefore, it would be desirable to have reliable but inexpensive alternatives based on existing consumer products. We compared an off-the-shelf DynaTrap (model DT160, CCFL tube 365 ± 3 nm UV) modified to fit a CDC trap collection bag and to use a 12V power supply, with two commonly used CDC traps: CDC Miniature Light Trap Model 512 (incandescent light, 6 Volt) and CDC Miniature Downdraft Blacklight (UV) Trap Model 912 (4-Watt blue-black-light tube, 12 Volt), in different ecological settings in southwest (Kenieroba) and northwest (Nioro du Sahel) Mali, West Africa. In northwest Mali, the modified DynaTrap caught a mean of 20.67 ± 2.8 females and 5.38 ± 1.0 male Aedes aegypti which was 16.55% and 10.78% more, respectively, than the CDC incandescent trap (control). The DynaTrap caught a mean of 29.75 ± 2.8 female and 17.92 ± 3.5 male Culex quinquefasciatus. which was 47.76% and 20.70% more than the control CDC incandescent trap. The DynaTrap caught a mean of 2.46 ± 0.5 females and 1.63 ± 0.6 males and 10.16% and 2.45% more female and male An. gambiae s.l., respectively, than the CDC incandescent trap. Trap and catch means were lower at the southwest Mali site. However, trap catch proportions by sex were similar to those in the northwest. The modified DynaTrap outperformed both CDC monitoring traps for less than one third of the cost including the cost of the DynaTrap modifications.

Efficient Monitoring of Adult and Immature Mosquitoes Through Metabarcoding of Bulk Samples: A Case Study for Non-Model Culicids With Unique Ecologies

The rapid and economical monitoring of mosquitos is imperative to understanding the dynamics of both disease vectors and nuisance species. In light of technological advances in mosquito sampling and DNA sequencing, health agencies can now utilize the full potential of metabarcoding pipelines for rapid and standardizable surveillance. Here, we describe mosquito spatial and temporal variation, with particular focus on Mansonia Blanchard species, in the Madeira (Rondônia State) and the Ribeira (São Paulo) watersheds, Brazil using metabarcoding of the D2 rDNA marker. Sampling and molecular pipelines were used to evaluate the taxonomic contribution of mosquitos in pools of culicids collected en masse from macrophyte-roots (immatures) and from Mosquito Magnet traps and protected human landings (adults). Results for adult captures are comparable to morphological diagnoses and clarify previously unknown temporal and spatial species turnover. Metabarcoding of immature stages also confirmed the extent of the geographical distribution of some species and each taxon’s association with macrophyte species. Given the benefits of metabarcoding, such as taxonomic acuity, high throughput processing, and objectivity, we suggest such techniques should be more fully incorporated into culicid monitoring schemes. The metabarcoding protocol described herein paired with standardized field sampling schemes, when used by mosquito monitoring professionals, offers substantial improvements in terms of practicality, speed and cost.

Effect of different carbon dioxide (CO2) flows on trapping Aedes albopictus with BG traps in the field in Zhejiang Province, China

Carbon dioxide (CO2) attracts host-seeking adult mosquitoes; this fact is exploited for mosquito monitoring, which is important for evaluating the effects of mosquito-control operations. A field experiment was designed to explore the relationship between the CO2 flow rate and the trapping effect of BG traps. The aim was to select an appropriate flow rate for monitoring Aedes albopictus. Six sampling sites were selected for field experiments in Hangzhou city, Zhejiang Province, China. A total of six CO2 flow rates (0.00 L/min, 0.075 L/min, 0.15 L/min, 0.30 L/min, 0.60 L/min and 1.20 L/min) were tested to compare their effects on mosquito trapping. The catches were performed in six trapping periods between 15:30 and 18:30, and each catch period lasted 0.5 h. A total of 3068 adult mosquitoes were captured at six sampling sites in six days using BG traps (with BG-Sweetscent), among which 86.96% were Ae. albopictus. The total number of Ae. albopictus (males and females) captured at a flow rate of 0.00 L/min was significantly lower than the numbers captured at 0.075 L/min, 0.15 L/min, 0.30 L/min, 0.60 L/min and 1.20 L/min (P<0.001, P<0.001, P<0.001, P<0.001, and P<0.001 respectively). The total number of Ae. albopictus captured and the number of Ae. albopictus females captured increased with increasing CO2 flow and peaked at 0.3 L/min, above which these capture numbers did not increase significantly. In conclusion, the appropriate CO2 flow rate for monitoring Ae. albopictus with BG traps was 0.3 L/min.

Comparative Analysis Between Sampling Methods for Immature Mosquitoes in an Atlantic Forest Fragment in Brazil

ABSTRACT In this study, traps were set out to improve mosquito monitoring, study their viability, and determine the most suitable traps for female mosquito species of epidemiological importance during oviposition. The effectiveness of 3 types of traps (bamboo traps, tire traps, and ovitraps) were compared at 2 sampling sites. A total of 24 traps were installed on the ground at elevations of 3 m, 6 m, and 9 m in a fragment of the Atlantic Forest in the municipality of Nova Iguaçu, Rio de Janeiro State, Brazil. The samplings took place every 2 wk from July 2017 to June 2018. A total of 1,854 mosquitoes belonging to 16 different species were identified, of which 2 species are involved in the transmission of arbovirus: Haemagogus leucocelaenus (Dyar and Shannon) and Aedes albopictus Skuse. Larval tire traps were the most effective at trapping females laying eggs, followed by ovitraps. The results were consistent with the usual habitats of certain species that were found in tire traps, which are artificial objects commonly found in human environments.

Correction to: Application of smart mosquito monitoring traps for the mosquito forecast systems by Seoul Metropolitan city

An amendment to this paper has been published and can be accessed via the original article.

New Records of the Asian Tiger Mosquito (Aedes albopictus) in North Macedonia

Aedes albopictus is an invasive mosquito species spreading throughout Europe and its presence in North Macedonia was recorded in 2016. Following the first detection in September 2018, we conducted a two-week mosquito monitoring by ovitraps in order to determine if there were established populations of Aedes albopictus in Skopje, the capital of North Macedonia. Ninety-four Ae. albopictus eggs (0 to 18 eggs per ovitrap per week) were collected from 7 (14%) ovitraps in 3 (30%) municipalities. Thirty-eight eggs (40.4%) successfully hatched and the adult mosquitoes were identified by morphology and PCR. No other potentially invasive species were identified during the monitoring period. Ae. albopictus distribution is expanding and poses a risk for an Aedes-borne disease transmission in North Macedonia. The available data highlight the need for a regular monitoring for tiger mosquitoes to plan adequate control measures.