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Analyzing Uncertainties Around Gene Drives: A Case Study of Mosquitos in Sub-Saharan Africa

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Malaria is a disease that has plagued human populations throughout history. Malaria is cause by the parasite Plasmodium, which uses mosquitoes as a vector for transfer. Current methods for controlling malaria include issuing bed nets to citizens, spraying home with

Malaria is a disease that has plagued human populations throughout history. Malaria is cause by the parasite Plasmodium, which uses mosquitoes as a vector for transfer. Current methods for controlling malaria include issuing bed nets to citizens, spraying home with insecticides, and reactive medical care. However, using Clustered Regularly Interspaced Short Palindromic repeats (CRISPR) in conjunction with the Cas9 protein found in bacteria, the genomes of mosquitoes can be edited to remove the ability of mosquitoes to host Plasmodium or to create sex bias in which the birth rate of males is increased so as to make reproduction near impossible. Using CRISPR, this genome edit can be ‘driven’ through a population by increasing the likelihood of that gene being passed onto subsequent generations until the entire population possesses that gene; a gene drive can theoretically be used to eliminate malaria around the world. This paper identifies uncertainties concerning scientific, environmental, governance, economic ,and social aspects of researching and implementing gene drives and makes recommendations concerning these areas for the emerging technology of gene drives concerning the eradication of malaria using Sub-Saharan Africa as a case study

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2017-05

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An Evaluation of HEAL International's Health Education Program in Tanzania, Africa

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This study investigated the potential efficacy of HEAL International's prevention education program in inducing health behavior change in HIV/AIDS, malaria, and communicable disease to children in grade levels ranging from primary school to secondary school. The health education program was

This study investigated the potential efficacy of HEAL International's prevention education program in inducing health behavior change in HIV/AIDS, malaria, and communicable disease to children in grade levels ranging from primary school to secondary school. The health education program was aimed at changing health behavior by increasing knowledge. This increase in knowledge was analyzed as a modifying factor in the Health Belief Model suggesting that knowledge, along with five other modifying factors, are directly responsible for an individual's health perceptions. These health perceptions ultimately result in an individual's health behavior. As a result, it is argued that an increase in knowledge can lead to health behavior change so long as it is coupled with a strong theoretical framework. Administering pre-evaluations at the beginning of the program, post evaluations at the end of the program, and a second post evaluation again two months later completed the evaluation. It was hypothesized that if there was a significant difference between the percent of correct answers at the pre-evaluation compared the second post-evaluation then there is evidence that HEAL's health education program is, or at least has the potential to, create sustainable health behavior change. A paired samples t-test was completed on the data and showed a statistically significant difference between the percent of correct answers at pre-evaluation and the percent of correct answers at second post-evaluation. These results indicated that the number of students with a comprehensive knowledge of the subjects that HEAL taught during the program had increased. It was concluded that the results of the study indicate evidence that HEAL's program has the potential to deliver sustainable health behavior change but that it will be more quantifiable once HEAL is able to adopt a theoretical framework on which to base future programs.

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2014-05

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Plasmodium Cost of Resistance and Life Stage Development within the Mosquito Vector

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Hundreds of thousands of people die annually from malaria; a protozoan of the genus Plasmodium is responsible for this mortality. The Plasmodium parasite undergoes several life stages within the mosquito vector, the transition between which require passage across the lumen

Hundreds of thousands of people die annually from malaria; a protozoan of the genus Plasmodium is responsible for this mortality. The Plasmodium parasite undergoes several life stages within the mosquito vector, the transition between which require passage across the lumen of the mosquito midgut. It has been observed that in about 15% of parasites that develop ookinetes in the mosquito abdomen, sporozoites never develop in the salivary glands, indicating that passage across the midgut lumen is a significant barrier in parasite development (Gamage-Mendis et al., 1993). We aim to investigate a possible correlation between passage through the midgut lumen and drug-resistance trends in Plasmodium falciparum parasites. This study contains a total of 1024 Anopheles mosquitoes: 187 Anopheles gambiae and 837 Anopheles funestus samples collected in high malaria transmission areas of Mozambique between March and June of 2016. Sanger sequencing will be used to determine the prevalence of known resistance alleles for anti-malarial drugs: chloroquine resistance transporter (pfcrt), multidrug resistance (pfmdr1) gene, dihydropteroate synthase (pfdhps) and dihydrofolate reductase (pfdhfr). We compare prevalence of resistance between abdomen and head/thorax in order to determine whether drug resistant parasites are disproportionately hindered during their passage through the midgut lumen. A statistically significant difference between resistance alleles in the two studied body sections supports the efficacy of new anti-malarial gene surveillance strategies in areas of high malaria transmission.

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2021-05

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Aedes aegypti Thermal Choice Experiment

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The non-native mosquito Aedes aegypti has become a common nuisance in Maricopa county. Associated with human settlement, Ae. aegypti is known to reproduce in standing water sources both indoors and outdoors, within vessels such as tires, flowerpots, and neglected swimming

The non-native mosquito Aedes aegypti has become a common nuisance in Maricopa county. Associated with human settlement, Ae. aegypti is known to reproduce in standing water sources both indoors and outdoors, within vessels such as tires, flowerpots, and neglected swimming pools (Jansen & Beebe, 2010). Ae. aegypti and the related Ae. albopictus are the primary vectors of the arboviral diseases chikungunya, Zika, yellow fever and dengue. Ae. aegypti tends to blood feed multiple times per gonotrophic cycle (cycle of feeding and egg laying) which, alongside a preference for human blood and close association with human habitation, contributes to an increased risk of Ae. aegypti borne virus transmission (Scott & Takken, 2012). Between 2010-2017, 153 travel-associated cases of dengue were reported in the whole of Arizona (Rivera et al., 2020); while there have been no documented locally transmitted cases of Aedes borne diseases in Maricopa county, there are no apparent reasons why local transmission can’t occur in the future via local Aedes aegypti mosquitoes infected after feeding from travelling viremic hosts. Incidents of local dengue transmission in New York (Rivera et al., 2020) and Barcelona (European Center for Disease Control [ECDC], 2019) suggest that outbreaks of Aedes borne arbovirus’ can occur in regions more temperate than the current endemic range of Aedes borne diseases. Further, while the fact that Ae. aegypti eggs have a high mortality rate when exposed to cold temperatures limits the ability for Ae aegypti to establish stable breeding populations in temperate climates (Thomas, Obermayr, Fischer, Kreyling, & Beierkuhnlein, 2012), global increases in temperature will expand the possible ranges of Ae aegypti and Aedes borne diseases.

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2020-05