Maize pollen diet enhances malaria mosquito longevity and infectivity to Plasmodium parasites in Ethiopia.

Although larval diet quality may affect adult mosquito fitness, its impact on parasite development is scarce. Plant pollen from Zea mays, Typha latifolia, and Prosopis juliflora was ultraviolet-sterilized and examined for effects on larval development, pupation rate, adult mosquito longevity, survival and infectivity. The control larvae were fed Tetramin fish food as a comparator food. Four treatment and two control groups were used for each pollen diet, and each experimental tray had 25 larvae. Female An. arabiensis were starved overnight and exposed to infectious blood using a membrane-feeding system. The Kaplan-Meier curves and log-rank test were used for analysis. The Z. mays pollen diet increased malaria mosquito survival and pupation rate (91.3%) and adult emergence (85%). Zea mays and Tetramin fish food had comparable adulthood development times. Adults who emerged from larvae fed Z. mays pollen had the longest average wing length (3.72 mm) and were more permissive to P. vivax (45%) and P. falciparum (27.5%). They also survived longer after feeding on infectious blood and had the highest number of P. vivax oocysts. Zea mays pollen improved larval development, adult mosquito longevity, survival and infectivity to Plasmodium. Our findings suggest that malaria transmission in Z. mays growing villages should be monitored.

Implementation of a malaria prevention education intervention in Southern Ethiopia: a qualitative evaluation.

BACKGROUND: Though school-aged children (SAC) are at high risk of malaria, they are the ones that benefit the least from malaria prevention measures. A cluster randomized controlled trial was conducted to evaluate the effect of malaria prevention education (MPE) on insecticide-treated bed net (ITN) utilization and prompt diagnosis, reported incidence and treatment (PDAT) of malaria. Qualitative evaluation of the implementation of such interventions is vital to explain its effectiveness and will serve as guidance for future interventions. Therefore, this study aimed to evaluate the implementation of the MPE in southern Ethiopia.  METHODS: The trial was registered in Pan African Clinical Trials Registry (PACTR202001837195738) on 21/01/2020. A descriptive qualitative study using semi-structured interview with participants of the MPE was conducted in January 2020 and January 2021. The collected data were transcribed verbatim and analyzed thematically. The analysis of the data was supported by NVivo. RESULTS: The four themes identified after evaluation of MPE training were the setup of the training, challenges for the success of the training, anticipated challenges for practice as per the protocol and experienced immediate influences of the training. Participants appreciated the training: content covered, way of delivery and the mix of the participants. The context specific facilitators to bed net use were the collateral benefits of ITN and perceived at high risk of malaria while its barriers were quality and quantity of the bed nets, bed net associated discomforts, malaria health literacy and housing condition. Severeness of malaria symptoms and malaria health literacy were reported as both barriers and facilitators of the PDAT of malaria. The identified facilitators of PDAT of malaria were health professionals' attitude and exposure to MPE while its barriers were poverty, use of traditional medicine, health facility problems and Coronavirus Disease 2019 (COVID-19) pandemic. CONCLUSION: Low attendance of parents in the training was the major challenge for the success of MPE. National malaria program should ensure the access to malaria prevention measures; and future studies using increased frequency of the intervention embedded with monitoring adherence to the intervention protocol shall be conducted to improve the gains from existing malaria interventions.

An evaluation of repellency and feeding inhibition of ethno-medicinal plants against major malaria vectors in southern Ethiopia.

BACKGROUND: Plant-based mosquito control methods may use as a supplementary malaria vector control strategy. This study aimed to evaluate the effect of smoking ethno-medicinal plants on indoor density and feeding activity of malaria vectors at early hours of the night and its residual effect after midnight in southern Ethiopia. METHODS: Both field and tent trials were conducted to evaluate the impact of smoking Juniperus procera leaves, Eucalyptus globulus seeds and Olea europaea leaves in Kolla Shara Village from July 2016 to February 2017. For the field trial, five grass-thatched traditional huts (three for ethno-medicinal plants and two as control [only charcoal smoking and non-charcoal smoking]) were used. Indoor host-seeking mosquitoes were collected by CDC light traps. A Latin square design was employed to minimize the bias due to the variation in house location and different sampling nights. For the tent experiment, 25 3-5-day-old starved wild female Anopheles mosquitoes reared from the larvae were released into the tents where a calf was tethered at the mid-point of each tent. RESULTS: A total of 614 Anopheles mosquitoes belonging to 5 species were collected from 5 huts, of which 93.4% was An. arabiensis; O. europaea, E. globulus and J. procera reduced the indoor density of An. arabiensis, with the mean percentage drop of 80%, 73% and 70%, respectively. In the tent trial, smoking of these plants had significant knockdown effects and inhibited feeding on the calves (F = 383.5, DF = 3, P < 0.01). The mean knockdown effect due to O. europaea was relatively high (17.7 ± 0.54; 95% CI 16.8-18.6), while it was only 0.9 ± 0.1 (95% CI 0.29-1.52) in the control tents. All the test plants used in the tent trial caused significantly inhibited feeding activity of An. arabiensis on the host (F = 383.5, DF = 3, P < 0.01). About 94.5%, 89.5% and 86% of mosquitoes were unfed because of the smoking effect of O. europaea, E. globulus and J. procera, respectively, whereas only 19.5% were unfed in the control tent. CONCLUSIONS: Smoking ethno-medicinal plant materials reduced indoor density of malaria vectors and inhibited feeding on calves inside the tents. Thus, plant-based mosquito control methods may play a vital role in reducing mosquito bites in the early hours of the night and thereby reduce residual malaria transmission.