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Malaria is a vector-borne parasitic disease affecting tropical and subtropical regions. Regardless control efforts, malaria incidence is still incredible high with 219 million clinical cases and an estimated 660,000 related deaths (WHO, 2012). In this project, different population genetic approaches were explored to characterize parasite populations. The goal was to

Malaria is a vector-borne parasitic disease affecting tropical and subtropical regions. Regardless control efforts, malaria incidence is still incredible high with 219 million clinical cases and an estimated 660,000 related deaths (WHO, 2012). In this project, different population genetic approaches were explored to characterize parasite populations. The goal was to create a framework that considered temporal and spatial changes of Plasmodium populations in malaria surveillance. This is critical in a vector borne disease in areas of low transmission where there is not accurate information of when and where a patient was infected. In this study, fragment analysis data and single nucleotide polymorphism (SNPs) from South American samples were used to characterize Plasmodium population structure, patterns of migration and gene flow, and discuss approaches to differentiate reinfection vs. recrudescence cases in clinical trials. A Bayesian approach was also applied to analyze the Plasmodium population history by inferring genealogies using microsatellites data. Specifically, fluctuations in the parasite population and the age of different parasite lineages were evaluated through time in order to relate them with the malaria control plan in force. These studies are important to understand the turnover or persistence of "clones" circulating in a specific area through time and consider them in drug efficacy studies. Moreover, this methodology is useful for assessing changes in malaria transmission and for more efficiently manage resources to deploy control measures in locations that act as parasite "sources" for other regions. Overall, these results stress the importance of monitoring malaria demographic changes when assessing the success of elimination programs in areas of low transmission.
ContributorsChenet, Stella M (Author) / Escalante, Ananias A (Thesis advisor) / Clark-Curtiss, Josephine (Committee member) / Rosenberg, Michael (Committee member) / Taylor, Jesse E (Committee member) / Arizona State University (Publisher)
Created2014
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Description
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

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.
ContributorsWright, Mia Christina (Author) / Jacobs, Bertram (Thesis director) / Salamone, Damien (Committee member) / Ayers, Stephanie (Committee member) / Barrett, The Honors College (Contributor) / Department of Psychology (Contributor) / School of Life Sciences (Contributor)
Created2014-05
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Description

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

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.

ContributorsPhillips, Keeley Isabella (Author) / Huijben, Silvie (Thesis director) / Gile, Gillian (Committee member) / Young, Steven (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05