The Hygiene Hypothesis and Old Friends Hypothesis focus attention on the coevolutionary relationship between humans and pathogens, positing that reduced pathogen exposure in economically developed nations is responsible for immune dysregulation and associated increases in chronic inflammation, allergy, and autoimmunity. Despite progress in testing these ideas, few studies have examined these relationships among populations undergoing the transition from traditional to more market-based lifestyles. The present study tests relationships between economic development and social change, altered infectious disease exposure, and immune function among the Shuar forager-horticulturalists of Amazonian Ecuador, a population undergoing rapid economic change associated with increased market participation. Using stool samples to assess soil-transmitted helminth (STHs; parasitic intestinal worms) burden, dried blood spot measurement of the inflammatory marker C-reactive protein (CRP), and interviews to evaluate level of market integration (MI; the suite of social and cultural changes associated with rapid economic development) and disgust sensitivity, this dissertation tests the Hygiene and Old Friends Hypotheses. The first study tests relationships between STH exposure and MI, using geographic location in relation to the regional market center as a proxy for MI. This study documents lower rates of STHs in people living in more market integrated regions. The second study tests the coevolutionary role that STHs and other pathogens have played in shaping human psychology and behavior. Findings suggest that pathogen exposure has acted as a selective pressure, resulting in evolved disgust sensitivity toward pathogen related stimuli. This study provides evidence that disgust sensitivity is calibrated to local environments, acting to decrease STH exposure. The third study tests the role of STHs in immune function. CRP was positively related to age in uninfected individuals. No relationships existed for more traditionally living or infected individuals. These findings suggest that STH exposure may decrease the risk of developing chronic inflammation and associated diseases with advancing age. These studies provide support for the idea that STHs provide stimuli that decrease chronic inflammation, suggesting that altered intestinal microflora in developed nations may be partially responsible for the development of chronic inflammatory disorders like allergy and autoimmunity. This dissertation includes previously published and unpublished coauthored material.

MSc (Microbiology) / Department of Microbiology / Introduction: Intestinal infections caused by soil transmitted helminth and diarhoegenic Escherichia coli (E. coli) are a major threat to the health and socio-economic wellbeing of children in developing countries. Soil-transmitted helminthes (STH), Ascaris lumbricoides (A. lumbricoides), Trichuris tricuria (T. trichuris ), Hookworms and diarhogenic E coli are transmitted through the faecal-oral route and enter the body through the ingestion of eggs (STH) or E. coli pathogens following contact with contaminated hands, food, soil or the deliberate act of eating contaminated soil. Aim: This study aim to determine the prevalence of intestinal parasitic infection and diarhoegenic E. coli on the hands of school children in the Vhembe district of South Africa. Methods: The study was conducted among school children aged 5 to15 years, attending grades 0(R) to 8 at the primary and secondary school levels in the Vhembe district region of the Limpopo province. A total of 358 hand washing samples was collected from the hands of school children using hand anionic (7X 1% quadrafos, glycol ether and dioctyl sulfoccinate sodium salt) soap solution. The Microscopic McMaster slide technique was used for the identification of intestinal parasitic eggs and the Colilert Quanti-Tray®/2000 technique was used for the enumeration of E. coli. A standardised Multiplex PCR protocol was utilized to characterize the positive pathogenic E. coli strains obtained from the Colilert Quanti-Tray®/2000. A structural questionnaire was used to associate the positive results with selected socio-demographic variables. The raw data was organized and analysed by the use of SPSS version 24 software. Results: A prevalence of 2.6% intestinal parasite was found among the study population with hookworm and Enterobius vermicularis having detection rate of 0.6% and 2.0% respectively. However there were no Ascaris lumbricoides and Trichuris trichiura detected in the study population. A prevalence of 13.4% of the samples was positive for E. coli and 4.7% were identified as pathogenic E. coli strains: Enteroaggregative Escherichia coli (EAEC), Atypical Enteropathogenic Escherichia coli (APEC), Typical Enteropathogenic Escherichia Coli (TPEC) and Enterotoxigenic Escherichia coli (ETEC) distributed with prevalence percentage of 2%, 0.3%, 1.1% and 0.3% respectively. The study also revealed a significant association between hand child hygiene with the prevalence of E. coli. Conclusion: Environmental sanitation conditions like type of toilets and lack of safe drinking water is closely associated with the prevalence of E. coli among the school going children. / NRF

Soil-transmitted helminth (STH) (A. lumbricoides, T. trichiura and hookworm) infections are a significant public health concern in Honduras. These infections are treatable using inexpensive anthelmintic medications, however long-term control and eradication will require large investments in public and private sanitation infrastructure. Importantly, both types of interventions are targeted towards high-risk populations and regions rather than individuals. The goal of this thesis is to contribute to improving the efficiency of soil-transmitted helminth control efforts in Honduras. In our first study, we use multiple regression analyses to identify determinants of STH infections and generate estimates of A. lumbricoides, T. trichiura and hookworm infection prevalence, as well as recommended deworming frequencies, for each of Honduras’ 298 municipalities. Our estimates suggest that prevalence of all three infections has declined over time, however 75% of municipalities still require annual or semi-annual deworming. In our second study, we quantify how the type of region used for measuring prevalence and allocating resources can impact the success and efficiency of public health programs. More specifically, we compare administrative regions to alternative zoning schemes at the same geographic scale. Our findings suggest that regions designed to be homogeneous with respect to prevalence can be more efficient than existing municipalities (at the same scale) for distributing resources. This research has implications on future control efforts. / Thesis / Master of Science (MSc)

The sex hormone testosterone supports male reproduction. However, testosterone is hypothesized to suppress immune activity, resulting in a tradeoff between energetic investment in reproductive effort and immune function. The Immunocompetence Handicap Hypothesis (ICHH) therefore argues that testosterone-linked masculine traits honestly signal health status to prospective mates, as only uninfected males should be able to maintain high testosterone levels. Still, this proposed tradeoff remains poorly tested among human men, especially among natural fertility populations experiencing high infectious disease burdens. This dissertation therefore tested the ICHH among indigenous Shuar men of Amazonian Ecuador. Specifically, this project examined testosterone variation patterns and assessed how male investment in reproductive effort is associated with reproductive success and immune function. The first study tested testosterone level variation among Shuar men in relation to body composition, age, and style of life factors. This study demonstrated that age and BMI interactions shape testosterone levels in complex ways, such that the relationship between body composition and testosterone profile varies throughout the life course. The second study investigated whether individual reproductive success was significantly influenced by masculine trait development and parasite load. These results failed to support the hypotheses that masculine traits increased reproductive success or honestly signaled lack of parasitic disease. Instead, a significant positive association was observed between a composite score of masculine traits and Ascaris lumbricoides infection load; suggesting that male investment in reproductive effort may increase parasitic infection risk. The final study assessed whether testosterone levels were negatively associated with four measures of immune function (parasite load, C-Reactive Protein [CRP], Immunoglobulin-G [IgG], and Immunoglobulin-E [IgE]). Testosterone levels were inversely associated with CRP levels and a positive relationship between testosterone levels and Trichuris trichiura infection load was documented, suggesting increased investment in reproductive effort may suppress some aspects of immune function and increase parasite burden. Overall, these studies fail to support the ICHH, but do indicate a context-dependent tradeoff between energetic investment in male reproductive effort and some aspects of immune function; thereby demonstrating complex interactions between physical characteristics, physiological processes, and immune activity in human men. This dissertation includes unpublished, co-authored material.

p. 1-112 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-04-24T21:04:41Z No. of bitstreams: 1 11111111111.pdf: 829006 bytes, checksum: d72adf5912d3d4a5a6ab9659a04a516d (MD5) / Approved for entry into archive by Maria Creuza Silva(mariakreuza@yahoo.com.br) on 2013-05-04T17:26:41Z (GMT) No. of bitstreams: 1 11111111111.pdf: 829006 bytes, checksum: d72adf5912d3d4a5a6ab9659a04a516d (MD5) / Made available in DSpace on 2013-05-04T17:26:41Z (GMT). No. of bitstreams: 1 11111111111.pdf: 829006 bytes, checksum: d72adf5912d3d4a5a6ab9659a04a516d (MD5) Previous issue date: 2008 / Introducción: El control de las infecciones causadas por geohelmintos está basado en la administración periódica de drogas antihelmínticas a los grupos de alto riesgo, particularmente a niños en edad escolar que viven en áreas endémicas. Existen datos limitados sobre la efectividad de tratamientos antihelmínticos periódicos a largo plazo en la prevalencia de infecciones por geohelmintos particularmente desde programas operacionales. Objetivo: El presente estudio investigó el impacto de 17 años de tratamiento en masa con un antihelmíntico de amplio espectro, la ivermectina, usada para el control de la oncocercosis, en la parevalencia e intensidad de infección por geohelmintos en niños escolares. Métodos: Un estudio transversal fue conducido en comunidades que han recibido tratamientos anuales o bianuales y comunidades adyacentes que no han recibido dicho tratamiento en dos cantones de la Provincia de Esmeraldas en Ecuador. Una única muestra de heces fue colectada de cada niño y fue examinada usando las técnicas de Kato Katz y por concentración con formol-éter. Datos sobre los factores de riesgo para las infecciones por geohelmintos fueron colectadas por medio de cuestionarios aplicados a los padres. Resultados: Un total de 3563 niños en edad escolar (6-16 años) de 31 comunidades tratadas y 27 comunidades no tratadas fueron investigados. El tratamiento con ivermectina tuvo un efecto significante en la prevalencia (ORadj= 0,06; IC 95%: 0,03-0,14) y en la intensidad de la infección (RPadj=0,28; IC 95%: 0,11-0,70) por Trichuris trichiura pero no se observó dicho efecto en la infección por Ascaris lumbricoides o uncinarias. Conclusión: Tratamientos con ivermectina anuales y bianuales por un periodo de alrededor de 17 años tuvieron un efecto significante en la infección por T. trichiura pero no sobre otras infecciones por geohelmintos. La adición de una segunda droga antihelmíntica, tal como el albendazol, sería necesaria para obtener un efecto a largo plazo en la infección por A. lumbricoides en áreas altamente endémicas. / Salvador

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-10-04T12:34:05Z No. of bitstreams: 1 izabelladeoliveirapinheiro.pdf: 2789735 bytes, checksum: 88fd51d57fe8e1982bbacbad4e1341dc (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2016-10-04T12:39:56Z (GMT) No. of bitstreams: 1 izabelladeoliveirapinheiro.pdf: 2789735 bytes, checksum: 88fd51d57fe8e1982bbacbad4e1341dc (MD5) / Made available in DSpace on 2016-10-04T12:39:56Z (GMT). No. of bitstreams: 1 izabelladeoliveirapinheiro.pdf: 2789735 bytes, checksum: 88fd51d57fe8e1982bbacbad4e1341dc (MD5) Previous issue date: 2010-07-13 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Doenças tropicais negligenciadas (DTNs), assim classificadas pela Organização Mundial de Saúde, constituem um grupo de infecções praticamente eliminadas no mundo desenvolvido, mas que persistem em áreas pobres de países de baixa renda. Dentre elas estão a ascaridíase, a tricuríase e a ancilostomíase, cujos agentes etiológicos têm parte de seu ciclo evolutivo passando pelo solo, e são, por isso, denominadas de geohelmintoses. Recentemente, a giardíase também foi incluída como DTN, uma vez que sua forma de transmissão pode ser associada com falta de saneamento. Este estudo transversal de base populacional visou à investigação da ocorrência dessas parasitoses em três municípios do sudeste de Minas Gerais. Para tanto, 2367 indivíduos foram selecionados aleatoriamente. Os dados foram obtidos por meio de um questionário estruturado acerca das condições socioeconômicas, ambientais e culturais da população amostral e do exame de uma única amostra fecal de cada participante, pelo método de sedimentação espontânea (HPJ). Para cada amostra fecal foram examinadas cinco lâminas, e concluiu-se que o exame de três lâminas por amostra expressou a melhor relação custo-benefício para o SUS. A análise dos resultados mostrou que 6,1% (n=145) da população amostral estava infectada com uma ou duas DTNs. Dentre os indivíduos infectados, as prevalências observadas para ancilostomídeos, G. lamblia, T. trichiura e A. lumbricoides foram 47,3%, 27,3%, 16,0% e 9,3%, respectivamente. Na análise bivariada dos dados (p<0,05; IC 95%), o teste do Qui-quadrado de Pearson foi usado para avaliar a força das possíveis associações entre as variáveis independentes e o desfecho. Na análise de regressão logística, quatro variáveis permaneceram estatisticamente significantes, sugerindo serem os possíveis fatores de risco para as DTNs nos municípios: o destino inadequado do esgoto (p<0,001), o hábito de beber água não potável (p<0,001), a falta de instalação sanitária adequada (p=0,015) e pertencer ao sexo masculino (p<0,001). Os resultados encontrados neste estudo nos permitem concluir que DTNs estão presentes mesmo em regiões mais desenvolvidas do Brasil. O número de pessoas parasitadas confirma a área como de baixa endemicidade para geohelmintoses e giardíase em relação a outras regiões do Estado, e justifica estudos que avancem no conhecimento do perfil epidemiológico da região e subsidiem o desenvolvimento de políticas públicas locais. / Neglected tropical diseases (NTDs), so classified by the World Health Organization, are a group of infections that have been eliminated in the developed world, but still persist in poor areas of low-income countries. Among them, ascariasis, trichuriasis, and hookworm infection are soil-transmitted helminthiasis. Recently, and despite its worldwide distribution, giardiasis was also included in the WHO list, due to its way of transmission, which can be associated with lack of sanitation. This population-based cross-sectional survey aimed at investigating the occurrence of such infections in three municipalities of southeastern Minas Gerais state. A total of 2,367 individuals randomly chosen provided one single fecal sample. The baseline data consisted of a questionnaire and parasitological coproscopy using the HPJ method. Five slides were examined from each fecal sample, allowing us to conclude that, regarding this method, the examination of three slides per sample presented a satisfactory sensitivity and the best cost-effectiveness for the SUS. The results showed that 6.1% (n=145) of the population sample was infected with either one or two NTDs, of which the prevalences observed for hookworms, G. lamblia, T. trichiura, and A. lumbricoides were 47.3%, 27.3%, 16.0% e 9.3%, respectively. In the bivariate analysis (p<0.05; CI 95%), Pearson Qui-square tests were used to assess the strength of the associations. Multivariate analysis was run with all significant variables. Four variables remained significant in the logistic regression, as the possible risk factors for the installation and spread of the infections in the municipalities: inadequate sewage discharge (p<0.001), the habit of drinking unsafe water (p<0.001), lack of adequate sanitary infrastructure in the household (p=0.015), and masculine sex of the individual (p<0.001). Our findings allow us to conclude that NTDs occur even in more developed areas of Brazil. Our numbers confirm the study area as low endemic for giardiasis and soil-transmitted helminthiasis, and justify surveys in order to get more information on the epidemiological profile of the Zona da Mata Mineira region, aiming at giving support to the development of local health policies.

付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院 / 京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第21616号 / 理博第4523号 / 新制||理||1649(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 岡本 宗裕, 准教授 Andrew MacIntosh, 教授 髙井 正成 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Malaria is one of the most prevalent vector-borne infectious diseases with major morbidity and mortality in sub-Saharan Africa and Southeast Asia. Recent epidemiological studies have shown that co-occurrence of soil-transmitted helminth (STH) infections, or infection caused by parasitic worms, are associated with increased risk of malaria infection. However, studies of the association between STH and malaria, and the effect of antihelminth (deworming) treatments that are more commonly used in areas with high STH infection rates, are sparse. Therefore, we explored the relationship between STH and malaria infection in an Indonesian community (N=1997) with high prevalence of both STH and malaria while controlling for covariates and evaluating the role of deworming treatment as a covariate. Participants with STH infection and/or malaria infection were categorized as either infected or uninfected using PCR testing (cycle threshold count) at both baseline and end of study. Self-report, blood, and stool samples were used to assess overall STH and malaria infection from September 2008 to July 2010. Descriptive statistics were used to assess the impact of STH infection on malaria outcomes. To quantify these associations, robust Poisson regression models were used to assess the impact of baseline infections including STH infection on malaria while adjusting for age, sex, and the use of deworming treatment. Approximately 39.5% and 19.1% of all participants were infected with Plasmodium vivax and P. falciparum, respectively, at the start, while 18.0% and 9.96%, respectively, were infected at the end. A positive association was observed between Ascaris lumbricoides and P. vivax, and between Necator americanus and P. falciparum (PR = 1.04, 95% CI = 0.53 to 2.04; PR = 2.07, 95% CI = 1.00 to 4.29, respectively). While a negative association was observed between N. americanus and P. vivax, and between A. lumbricoides and P. falciparum (PR = 0.91, 95% CI = 0.44 to 1.89; PR = 0.66, 95% CI = 0.27 to 1.65, respectively). Overall, two of these models were significant (p = 0.062; p = 0.008; p = 0.030; p = 0.062, respectively). Similarly, there was a positive association observed between the use of albendazole treatment and STH and malaria outcomes.

The United Nations Millennium Development Goals have prioritized improving access to sanitation, but unfortunately about a third of the global population is still without an improved sanitation source and one billion still practice open defecation. Lack of access to adequate and safe sanitation means the proliferation of dangerous pathogens in the environment, especially soil-transmitted helminths (STHs). In the Bocas del Toro Province of Panama (and similar locations in the world), composting latrines have been built in many of the indigenous communities in the area. They are a form of dry or ecological sanitation and are designed to produce an end product that can be used as a soil amendment for agricultural purposes. The issue is that many of these latrines are not working as designed and do not go through the composting process. Instead, they may act as incubators for harmful pathogens, such as Ascaris lumbricoides (roundworm). This research 1) provides an extensive literature review of the health situation of Panama, focusing on indigenous populations; soil-transmitted helminths and helminthiasis; Ascaris lumbricoides and its implications for wastewater reuse and land application of biosolids/sewage sludge; and inactivation of Ascaris in composting latrines; and 2) develops and proposes an experimental plan, with field-based methods, to assess the inactivation of Ascaris, by urea and solar heat (increased temperature), in composting latrines in Panama. Various experiments have been conducted in the laboratory using urea and increased temperature to inactive Ascaris; however few have been carried out in dry toilet technologies in the field. The contribution of this thesis is the field-based experimental design developed for inactivating Ascaris in composting latrines. The methods build upon previous research carried out both in the laboratory and in the field.

Introduction Schistosomiasis is one of the most important and widespread diseases of rural poverty. Worldwide, approximately 779 million people are at risk of infection, with 207 million already infected. Infections with Ascaris lumbricoides, hookworms and Trichuris trichiura, collectively known as the soil-transmitted helminths (STHs), are also highly endemic throughout the tropics, particularly in resource-poor settings. An estimated 1 billion people worldwide are estimated to be infected with STHs. Schistosomes and STHs often co-exist in the same epidemiological settings and, given the high prevalence of concurrent multiple species infections (multiparasitism), a combined approach to prevention and control could lead to significant improvements, including reducing costs associated with single-species control programmes. In China, rigorous national schistosomiasis control efforts over the past 60 years have decreased the prevalence by over 90%; however, since 2000 the number of infected individuals has been rising, possibly indicative of a re-emergence. Fishermen, migrant communities and poor households in rural areas may be most at risk of single and multiple-species parasitic infections and the associated morbidity. Objectives This Ph.D. thesis is structured according to four main goals and a number of specific objectives: Firstly, to update estimates of S. japonicum prevalence, intensity and associated morbidity levels in Hunan province, China, according to the third national PES carried out in 2004; Secondly, to investigate existing barriers in access to preventive, diagnostic and treatment services for advanced schistosomiasis; Thirdly, to compare and evaluate direct and proxy methods of measuring household socio-economic position, according to data on income, savings and asset-based estimations of wealth; and Finally, to explore and identify behavioural, demographic, economic, environmental and social risk factors associated with the distribution of S. japonicum, STHs and multiple species infections, in two villages of the Dongting Lake region, Hunan province, China. Methods Firstly, we used data from the third national schistosomiasis periodic epidemiological survey (PES) of 2004. In Hunan province, the PES was carried out in 47 villages of the endemic Dongting lake area. A total of 47144 human serological, 7205 stool, and 3893 clinical examinations were performed. For the reservoir hosts, stools from 874 buffaloes and other domestic animals were examined for schistosomiasis by the miracidial hatching test. Secondly, we conducted an in-depth study involving interviews with 66 schistosomiasis control staff and 79 advanced schistosomiasis patient, and six focus group discussions (FGDs), in the Dongting lake region, between August 2002 and February 2003. Using the Health-Access Livelihood framework we examined availability, accessibility, affordability, adequacy and acceptability of schistosomiasis control in the Dongting lake area. Lastly, we carried out two village-wide parasitological, clinical and questionnaire-based investigations between October and December 2006. Parasitological examinations for the prevalence of S. japonicum and the STHs were performed by the Kato-Katz thick smear method, with repeated sampling of each individual. We took fingerprick blood samples to assess haemoglobin levels, using a B-haemoglobin HemoCue photometer. The household-based questionnaire focused on direct and proxy measurements of household wealth, while the individual-based questionnaire focused on demographic and behavioural factors, treatment history and self-perceived symptoms. Results Human sero-prevalence was 11.9% (range: 1.3-34.9% at village level), and the rate of egg-positive stools was 1.9% (0-10.9%) for the same population. The prevalence of infection among buffaloes was 9.5% (0-66.7%). Extrapolating to the entire population of the Dongting Lake region, an estimated 73225 people and 13973 buffaloes were infected. Most frequently reported symptoms were abdominal pain (6.2%) and bloody stools (2.7%). Accessibility and affordability were major barriers in access to schistosomiasis control. Many of staff interviewed indicated that a majority of patients who develop advanced schistosomiasis resided in mildly-endemic or non-endemic settings. None of the patients interviewed had any form of health insurance, and most of their health expenses were out-of-pocket payments. Exploratory factor analysis generated internally robust proxy wealth indices, however these were not complementary to direct measures of household wealth, as indicated by low correlation co-efficients. We found wide disparities in household ownership of durable assets, utility and sanitation, within both settings. Pooled data from the rural and peri-urban settings highlighted structural differences in socioeconomic position (SEP), more likely a result of localised urbanization and modernization. We found higher infection prevalences in rural settings, than in peri-urban settings, for schistosomiasis (6.3% and 6.7% respectively), ascariasis (8.3% and 2.2%, respectively) and trichuriasis (5.1% and 0.5%, respectively), but lower for hookworms (0.1% and 1.5% respectively). Multiple species infections (2.6% and 0.2%, respectively) were less prevalent than single species infections (14.5% and 10.4%). There were significant disparities in the prevalence of parasitic infections between poorest and least poor quintiles of the cohort population. Anaemia and other symptoms, especially headache, stomach ache and swollen stomach, were common in both rural and peri-urban village settings. Conclusion The studies conducted within the framework of this Ph.D. thesis document the current situation pertaining to schistosomiasis and the STHs in Hunan province, China. Our findings highlight the need for increased surveillance, monitoring and health education, with relation to schistosomiasis and STHs, in non-endemic or post-transmission control settings. Based upon these results, we call for improved diagnostic tools, particularly in the case of low intensity infections and for hookworm, and propose an extension of the use of available infrastructure, human resources, knowledge and technology by integrating prevention and control of schistosomiasis with that of other intestinal helminths, particularly STHs. In the future, our studies may form a base from which to further examine local needs and priorities for parasitic disease control in the area.