Browsing by Subject "Epidemiology"
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Item Open Access A Cross-Sectional Study Comparing Torque Teno Virus Infection and Bushmeat Exposure Among Pneumonia Patients: Sarawak, Malaysia(2017) Berkhouse, Hudson TaylorBackground: Torque Teno Virus (TTV) is ubiquitous, possibly zoonotic, and has potential for clinical and global health research application. The goals of the current study were to determine prevalence of TTV among pneumonia patients in two Malaysian hospitals, compare results from qPCR and conventional PCR detection methods, and to compare TTV infection against self-reported exposure to bushmeat products.
Methods: Medical officers obtained plasma, PBMC, and NP swab samples, along with bushmeat exposure information from 34 pneumonia patients in Sibu and Kapit hospitals. Samples were tested for TTV using qPCR. Results were corroborated using conventional PCR. Cornfield’s and McNemar’s exact methods were used to analyze infection by exposure, and agreement between PCR results respectively. Diagnostic abilities of the qPCR test were analyzed using conventional PCR as the gold standard.
Results: Conventional PCR reported 17.65% TTV prevalence, while qPCR reported 91.18%. Household size (OR=0.00, 95% CI=0.00, 0.96) and gender (OR=infinity, 95% CI=1.39, infinity) had statistically significant impacts on odds of infection. The qPCR method showed 100% sensitivity, but 7.69% specificity.
Conclusions: Results suggest low prevalence of TTV within the study population, and reaffirm findings by other researchers that smaller household size and being female are associated with decreased odds of TTV infection. Though statistically insignificant, indications that exposure to bushmeat in general increases odds of TTV infection should be investigated further. Researchers must be aware of differences in diagnostic capabilities between PCR methods for TTV detection when designing their own diagnostic studies or conducting TTV related literature reviews.
Item Open Access A Cross-Sectional Study of Small Mammals for Tickborne Pathogen Infection in Northern Mongolia(2016) Pulscher, Laura AnnIntroduction: Extensive studies on tickborne pathogens (TBPs) have been conducted in developed nations, relatively less has been done in developing nations leaving a large gap of knowledge. Mongolia, a country built upon nomadic culture and pastoralism is an ideal system to study TBPs as the population is at an increased risk due to increased time spent outside herding livestock. Discoveries of TBPs in Mongolia include Babesia spp., Anaplasma spp., Borrelia spp., Rickettsia spp. and tick-borne encephalitis virus. While research has focused on TBPs in humans and ticks in Mongolia, little research has assessed animal reservoirs, specifically small mammal species, as reservoirs for TBPs. This project aimed to 1) identify the role of small mammal species in the ecology of TBPs in Mongolia, specifically Rickettsia spp., Anaplasma spp., and Borrelia spp. using serological and molecular analysis and 2) identify risk factors associated with the prevalence of TBPs in small mammal populations in Mongolia.
Methods: From June to July 2016, rodents were live-trapped, and whole blood, serum and ear biopsy samples were collected. Sixty-four rodents were trapped in three aimags (provinces) in northern Mongolia. Whole blood samples were tested by PCR to detect the presence of Rickettsia spp., Anaplasma spp., and Borrelia spp.. In addition, ear biopsy samples were tested by PCR to detect the presence of Borrelia spp.. All rodents were serologically tested for antibodies to Anaplasma phagocytophilum and Rickettsia rickettsii. A multivariate model was used to assess risk factors for the presence of tickborne pathogens. Risk factors examined included species and sex of animal, location and presence of ticks.
Results: 56.0%, 39.0% and 0.0% of animals were positive by PCR for Borrelia spp., Rickettsia spp. and Anaplasma spp., respectively. 41.9% and 24.2% of animals were seropositive for A. phagocytophilum and Rickettsia rickettsii, respectively. Risk factors found to be important predictors of Borrelia spp. molecular detection included small mammal capture in Tov aimag (OR, 4.1; 95% CI, 1.00 – 16.80), male small mammals (OR, 3.07; 95% CI, 0.99 – 9.51) and ground squirrel species type (OR, 3.24; 95% CI, 0.90 – 11.70). The risk factor found to be an important predictor of Rickettsia spp. molecular detection was Mongolian gerbil species type (OR, 246.5; 95% CI, 20.77 – 2925.88). Presence of ticks on small mammals (OR, 4.62; 95% CI, 0.92 – 23.24) was an important risk factor for A. phagocytophilum antibody detection. No risk factors were identified as being important predictors of antibody detection of R. Rickettsii.
Conclusion: The results of this study provide considerable evidence of TBPs circulating in small mammal populations in Northern Mongolia. Further information on TBPs in ticks, humans, livestock and wildlife reservoirs will be important to address public health interventions for TBPs in Mongolia in the future.
Item Open Access A One Health Perspective on Disease Dynamics: Human Monkeypox Transmission in Sankuru District, Democratic Republic of Congo(2015) McMullen, Chelsea LeeBackground: Reports from the first monkeypox (MPX) active surveillance program in the Democratic Republic of Congo (DRC) in the 1980s determined that the disease was not of epidemic potential, with R0<1. However, during an active surveillance period from 2005-2007, researchers found a 20-fold increase during the last 30 years. The purpose of this study was to analyze the contact data from 2005-07 and compare characteristics to those of the 1980s, and toassess the change in R0 of MPX. Methods: Contact tracing information and samples from active lesions were collected. Samples were screened by PCR and positive cases were ranked by generation and grouped into chains of transmission according to date of rash onset, contact tracing, and location. R0 was determined using calculations provided in the 1980s study and chain size distribution was compared. Results: Of 1407 suspected cases of MPX investigated in 2005-07, 287 provided contact information with an average of 6.22 (range, 1-20) contacts each. Among the 703 positive cases, 408 distinct chains of transmission were identified. Average chain size was 1.75 cases (range, 1-12), with the longest reaching six generations. The crude secondary attack rate (AR) was 0.092, with an effective R0 of 0.576. Discussion: Contact characteristics and types of contacts differed from those of the 1980s program. This analysis found a higher crude secondary attack rate and effective R0. This could be the result of a higher proportion of unvaccinated contacts, or that the virus is better able to transmit between humans with a more limited amount of contact.
Item Open Access Air pollution, Fuel Usage and Health Outcomes in Madre de Dios, Peru: a Comparative Cross Sectional Study(2015) Chao, Christina AnnAir pollution is a common problem. Particulate matter generated from air pollution has been tied to adverse health outcomes associated with cardiovascular disease. Biomass fuels are a specific contributor to increased particulate matter and arise as a result of indoor heating, cook stoves and indoor food preparation. This is a two part cross sectional study looking at communities in the Madre de Dios region. Survey data was collected from 9 communities along the Madre de Dios River. Individual level household PM2.5 was also collected as a means to generate average PM data stratified by fuel use. Data collection was affected by a number of outside factors, which resulted in a loss of data. Results from the cross-sectional study indicate that hypertension is not a significant source of morbidity. Obesity is prevalent and significantly associated with kitchen venting method indicating a potential relationship.
Item Open Access Analyzing the Connections Among Water Access, Sanitation, Malaria and Diarrhea Outcomes in Rural Central Uganda(2016-04-22) Hu, MichaelAccess to safe water and sanitation around the world has increased significantly in the past few decades. The United Nations claims that 91% of the world’s population has access to safe water, exceeding the Millennium Development Goal for water access. Yet, some evidence in the literature suggests that safe water and sanitation access is overestimated, as the common indicator used to estimate safe water is infrastructural. The usage of water, behaviors surrounding water acquisition and storage, and possible contamination along the source to point-of-use continuum is poorly understood. This cross-sectional epidemiological study used a combination of surveying, mapping and bacteriological water testing to identify some of the possible factors in water contamination, and relationships with malaria and diarrhea burden, in a parish in Central Uganda. Secondary goals included assessing the burden of malaria and diarrhea in the parish, and assessing the use of mapping and water testing as field research tools. The survey included questions on water acquisition and usage behavior, sanitary conditions, knowledge of diarrhea, and malaria and diarrhea burden. In this parish, 126 households across 9 villages were randomly chosen to be surveyed, mapped and water tested. All water sources in the parish were additionally mapped and water tested. Across all water sources, including piped water, the water quality at the household point-of-use level was drastically worse than quality measured at the source. In fact, among all water sources, piped water recipients showed the highest average bacterial loads, despite the clean quality of the source itself. Possible factors in lowering or raising contamination, as displayed by regression results, include the frequency of obtaining water and distance from the water source respectively. The malaria and diarrhea case sample size proved smaller than expected, and challenges remain in using mapping and water testing in the field. These results support the theories that the amount of people with access to safe water is overestimated, and that contamination exists along the source to point-of-use continuum. More research is needed to investigate the exact points of contamination in the spectrum and possible contaminating factors.Item Open Access Association between Road Traffic Injury and Multimorbidity in Brazil-Results from Pesquisa Nacional de Saude(2019) Pokam Tchuisseu, Yolande BertilleBackground: Globally, road traffic injury (RTI) is predicted to become the fifth leading cause of mortality by 2030. In addition to the burden of RTI, multimorbidity (MM) is increasingly becoming a health concern across all age groups. If MM is left unaddressed, individuals suffering from RTI will most likely experience delayed recovery and poorer health outcomes. Thus, there is a need to examines the association between RTI and MM in order to inform post-injury care practices.
Methods: This study is a cross-sectional analysis of the 2013 Brazilian National Health Survey. 60,202 individuals, aged 18 and above, were included in this study. Univariate and bivariate analyses were used to explore the relationship between demographic variables, chronic diseases, MM and RTI. Network analysis was used to identify multimorbidity patterns.
Results: Out of those who had experienced RTI (n=1910), 16.50% have reported having a multimorbid condition. Age, gender, risky alcohol use and regions were key predictors of RTI. Risky alcohol use was one of the direct nodes that connected RTI to other morbidities. Within the road traffic injured population, seven multimorbid communities were identified, with two communities being the most central: the cardio-metabolic morbidities and physical-mental morbidities.
Conclusions: Risky use of alcohol was a key predictor of RTI and a potential mediator in the association between RTI and other morbidities. Given that the temporal association between RTI and MM could not be established in this study, additional studies are needed to further assess the direction of the association between RTI and MM.
Item Embargo Association of Alcohol Use with Risk of Malnutrition Among Injury Patients in Moshi, Tanzania: A Mixed-Method Study(2023) Yuan, YunBackground: Alcohol consumption is a major risk factor for several adverse health effects globally and is associated with a high disease burden of malnutrition in Tanzania. This study aims to: 1) assess the practicality and effectiveness of mid-upper arm circumference (MUAC) as a feasible bedside measure to detect malnutrition among adult and pediatric patients, 2) evaluate the association between alcohol use and nutritional status among adult injury patients and 3) qualitatively identify social determinants of malnutrition in Tanzania. Methods: This mixed-method study was conducted in Kilimanjaro Christian Medical Centre. Receiver Operating Characteristic (ROC) curves and logistic regression were used for quantitative data on alcohol use, body mass index (BMI), MUAC. Thematic approach was used for qualitative data on perspectives on alcohol use and its interactions with malnutrition. Results: MUAC cut-offs were determined at < 25.5 cm (BMI < 16 kg/m2) for severely underweight, < 28 cm (BMI < 18.5 kg/m2) for underweight, ≥ 30.5 cm (BMI ≥ 25 kg/m2) for overweight, ≥ 33 cm (BMI ≥ 30 kg/m2) for obese. The association between alcohol use and malnutrition (MUAC < 25.5 cm) was statistically significant. Qualitative results helped explain the association between alcohol use and malnutrition. Conclusions: MUAC is an effective tool to detect adult malnutrition to inform clinical practice in Tanzania. Polarizing attitudes towards drinking revealed by qualitative data suggested the need for alcohol awareness campaigns. Food assistance programs are needed to reduce the risk of malnutrition among vulnerable populations.
Item Open Access Associations between Family Functioning, Social Support, and Sarcopenia among Community-Dwelling Older Adults in China: A Cross-Sectional Study(2024) Hu, XinwenIntroductionSarcopenia, an age-associated disorder characterized by the loss of skeletal muscle mass and function, is becoming increasingly prevalent among older adults in China. High levels of family and social support have been reported to be associated with enhanced health outcomes among the elderly. However, the evidence regarding the protective impact of these factors on sarcopenia remains limited and controversial. Furthermore, only a limited number of studies have examined the prevalence of possible sarcopenia in China. The current study aimed to (1) estimate the prevalence of possible sarcopenia, (2) evaluate the perceived family functioning and social support, and (3) examine the associations between family functioning, social support, and sarcopenia.
MethodsCross-sectional data from 624 community-dwelling older participants aged 60 years and older in Suzhou, China were collected via structured interviews. Possible sarcopenias were defined in accordance with the criteria of the 2019 Asian Working Group for Sarcopenia. Family functioning was assessed using six positive items from the McMaster Family Assessment Device – General Functioning Subscale (GF6+). Social support was evaluated based on the Social Support Rating Scale (SSRS). Univariable and multivariable logistic regression was conducted to examine the association between family functioning, social support, and sarcopenia.
ResultsThe prevalence of possible sarcopenia was 10.58%. Females with sarcopenia were more likely to report depression (P<0.05). The mean scores of GF6+ and the total scores were 1.36 ± 0.61 and 32.96 ± 8.47, respectively. Female participants exhibited higher mean scores for GF6+ (P<0.05) and higher total scores for SSRS compared to male participants (P<0.05). No statistically significant associations between family functioning, social support, and sarcopenia were detected.
ConclusionOur study revealed sex differences in the perception of family functioning and social support among Chinese older adults. However, we did not find statistically significant associations between family functioning, social support, and sarcopenia. More research should be conducted in this novel field to facilitate the early screening and prevention of sarcopenia in China.
Item Open Access Bungoma County Woman’s Study: A Pilot Randomized Evaluation To Estimate The Impact Of A Screening and Referral Service On Contraceptive Use(2018) Augustine, Arun MathewBackground: An estimated 225 million women globally have an unmet family planning need, three-quarters of whom live in low and middle-income countries. Addressing this need requires new and innovative approaches, such as digital health solutions. We examined the impact of a new phone-based screening and referral service on the take-up of family planning as part of a pilot study to prepare for a full trial of the intervention.
Methods: This pilot study tested the procedures for a randomized encouragement trial. We recruited 112 women with an unmet need for family planning from local markets in Western Kenya, conducted an eligibility screening, and randomized half of the women to receive an encouragement to try the investigational intervention. Four months after sending an encouraging to the treatment group, we attempted to conduct a follow-up survey with all enrolled participants.
Results: The encouragement sent via text message to the treatment group led to differential rates of intervention uptake between the treatment and control groups, but take-up among the group was lower than anticipated (33.9% vs 1.8% in the control group). Study attrition was also substantial. We obtained follow-up data from 44.6% of enrolled participants. Among those in the treatment group who tried the intervention, however, the instrumental variables estimate of the Local Average Treatment Effect was an increase of 41 percentage points in the probability of contraceptive take-up.
Conclusion: This randomized encouragement design and study protocol is feasible but requires modifications to the encouragement and follow-up data collection procedures. The investigational intervention appears to have a positive impact on contraceptive take-up among women with an unmet need despite a number of contextual challenges.
Item Open Access Causes of Childhood Blindness in North Ghana: Results From a School for the Blind in Wa, Upper West Region(2016) Huh, Grace JeakyungBackground: Because most developing countries lack sufficient resources and infrastructure to conduct population-based studies on childhood blindness, it can be difficult to obtain epidemiologically reliable data available for planning public health strategies to effectively address the major determinants of childhood blindness. The major etiologies of blindness can differ regionally and intra-regionally. The objective of this retrospective study was to determine (1) the major causes of childhood blindness (BL) and severe visual impairment (SVI) in students who attend Wa Methodist School for the Blind in Upper West Region, North Ghana, and (2) any potential temporal trends in the causes of blindness for this region.
Methods: In this retrospective study, demographic data and clinical information from an eye screening at Wa Methodist School for the Blind were coded according to the World Health Organization/Prevention of Blindness standardized reporting methodology. Causes of BL and SVI were categorized anatomically and etiologically. We determined the major causes of BL/SVI over time using information provided about the age at onset of visual loss for each student.
Results: The major anatomical causes of BL/SVI among the 190 students screened were corneal opacity and phthisis bulbi (n=28, 15%), optic atrophy (n=23, 13%), glaucoma (n=18, 9%), microphthalmos (n=18, 9%), and cataract (n=18, 9%). Within the first year of life, students became blind mainly due to whole globe causes (n=23, 26%), cataract (n=15, 17%), and optic atrophy (n=11, 13%). Those who became blind after age one year had whole globe causes (n=26, 26%), corneal opacity (n=24, 24%), and optic atrophy (n=13, 13%).
Conclusion: At the Wa Methodist School for the Blind, the major anatomical causes of BL/SVI were corneal opacity and phthisis bulbi. About half of all students became blind within the first year of life, and were disproportionately affected by cataract and retinal causes in comparison to the other students who became blind after age one year. While research in blind schools has a number of implicit disadvantages and limitations, considering the temporal trends and other epidemiological factors of blindness may increase the usefulness and/or implications of the data that come from blind school studies in order to improve screening methods for newborns in hospitals and primary care centers, and to help tailor preventative and treatment programs to reduce avoidable childhood blindness in neonates and schoolchildren.
Item Open Access Characterization of Risk Factors for Inter- and Intraspecies Transmission of Respiratory Illness at Lola Ya, Democratic Republic of Congo(2023) Hanberry, Daniel AustinZoonotic disease poses one of the greatest threats to both human and animal health in our world today. Recent pandemics such as Ebola, SARS-CoV2, and highly pathogenic Avian Influenza have shown the devastating consequences of infectious disease on both human and animal populations. Few studies have characterized the risk of interspecies pathogen transmission with one of our closest living relatives, Pan paniscus. This endangered species of great apes inhabits only rainforests of the Congo River Basin. Due to human encroachment, bushmeat trade, illegal pet trade, and deforestation, only 15,000-20,000 wild bonobos remain. The Lola Ya Bonobo Sanctuary (LYB) serves as the world’s only haven for orphaned and injured bonobos and presents a valuable opportunity to study the epidemiology of respiratory pathogens in a habituated population. This study aimed to characterize the risk factors for transmission of respiratory illness between bonobos and humans at LYB. Between 2014-2017 a cohort of 77 bonobos and 44 human staff were observed for signs of clinical illness and had their upper respiratory tract routinely sampled. We used a multiplex nucleic acid amplification assay to detect the presence of 18 viral and 3 bacterial respiratory pathogens. Of 282 total bonobo testing events, 93 (33%) returned positive results, primarily RSV-A (n = 41, 44.1%) and Rhinovirus/Enterovirus (n = 37, 39.8%). Although the point of entry into LYB could not be determined, RSV-A initially appeared in the infant and juvenile enclosures and spread serially through the older bonobo enclosures. Rhinovirus/Enterovirus appeared in diffuse clusters throughout the sanctuary. Although new bonobos are subject to a prolonged quarantine, current policy allows for relocation of bonobos between enclosures and frequent and sustained contact with human staff. Active surveillance for respiratory and other pathogens and additional infection control measures may benefit bonobo and human health.
Item Open Access Characterizing Epilepsy Treatment and Patient Outcomes in Uganda: A Prospective Hospital-Based Cohort Study(2018) Chakraborty, PayalBackground: Epilepsy is one of the most common neurological disorders globally, and an overwhelmingly high number of people who suffer from epilepsy reside in low- and middle-income countries (LMICs), where access to care is a significant challenge. Stigma associated with epilepsy and poor knowledge of the disease further hamper access to appropriate care. According to the World Health Organization (WHO) treatment guidelines, epilepsy can be treated cost-effectively in low-resource settings. However, in many LMIC settings, capacity for epilepsy treatment is inadequate. In Uganda specifically, there is a significant treatment gap in epilepsy care, and the magnitude of and reasons for this gap are not well characterized. In addition to suffering caused by disease in people with epilepsy (PWE), there are severe social ramifications of disease due to stigma. Therefore, access to adequate treatment is imperative for PWE in Uganda.
Purpose: The general objective of the overall project is to characterize epilepsy treatment and patient outcomes in public hospital-based care in Uganda, specifically in Mulago National Referral Hospital (MNRH), Butabika National Mental Hospital (BNMH), and Mbarara Regional Referral Hospital (MRRH). Outcomes from this study can inform specific targets of future interventions, and can provide insight towards improving the provision of epilepsy care in Uganda. The present thesis focuses on a narrower objective of the overall project, and involves validating outcome measures for PWE in Uganda, as well as using these measures in a preliminary analysis to identify predictors that most influence health outcomes.
Methods: The present study is nested in a larger prospective cohort study that recruits patients of all ages seeking care for epilepsy at MNRH, BNMH, and MRRH, and conducts follow-up over the phone at three weeks, three months and six months. At the hospital baseline visit, patients and/or caregivers were interviewed in either English, Luganda, or Runyankole to obtain demographic and clinical information and the Personal Impact of Epilepsy Scale (PIES), among other measures conducted as a part of a longer one- to two-hour interview. Reliability, internal consistency specifically, was assessed using three parameters: Cronbach’s alpha, McDonald’s Omega, and composite reliability for the PIES. Construct validity (internal structure) was evaluated with principal components analysis (PCA) and confirmatory factor analysis (CFA). Based on the validation results, the PIES questionnaire was treated as three outcome measures, from three subscales of the PIES. Possible predictors of the subscale scores were assessed using bivariate and multivariable linear regression.
Results: 626 patients seeking care for epilepsy and/or their caregivers were interviewed at baseline. The three-factor model of the PIES had excellent reliability. The PCA and CFA models for the scale demonstrated adequate fit with the TLI, CFI and RMSEA indices, but the model demonstrated inadequate fit with the Chi-square indicator. Several demographic and clinical indicators were associated with the three subscale scores of the PIES, Seizures, Adverse Effects of Medications, and Mood and Social Situation, in the multivariable regression models. Of these indicators, for the PIES Seizures Subscale Score, recruitment site and experience of confusion or tiredness after seizures were negatively associated with outcome scores, while taking one anti-epileptic drug (AED), education, and employment were positively associated with outcome scores. For the PIES Adverse Effects of Medications Subscale Score, taking AEDs, recruitment at MRRH, experience of isolated repetitive movements, auras, learning difficulties, and fevers were negatively associated with outcome scores, while employment status was positively associated with outcome scores. Finally, for the PIES Mood and Social Situation Subscale, recruitment at MRRH, experience of confusion and tiredness after seizures, learning difficulties, and phenytoin use were negatively associated with outcome scores, while education and employment were positively associated with outcome scores.
Conclusions: This thesis presents the first Luganda and Runyankole versions of the PIES, and the first validation of this scale with epilepsy patients in Uganda. The PIES has demonstrated adequate reliability and validity, and can be used to assess epilepsy related health outcomes, which is especially important in low-resource settings, where diagnostic equipment and specialist providers for epilepsy are not readily accessible. Furthermore, this thesis presents some preliminary results from the overall cohort study that use the PIES scale to identify some potential predictors of epilepsy-related health outcomes. Among the variables that showed associations with the PIES subscale scores, education and employment were associated with all three scores, highlighting the importance of community- and policy-based interventions for PWE, in addition to the possible identification of epilepsy subpopulations that may be at higher risk for poorer outcomes during clinical interventions.
Item Open Access Chikungunya as an Emerging Cause of Acute Febrile Illness in Southern Sri Lanka(2012) Akoroda, UfuomaAbstract
Objective: The aim of this study was to determine the epidemiology of Chikungunya as an etiology of acute febrile illness in southern Sri Lanka.
MethodAs part of the Duke-Ruhuna post-Tsunami response, a joint research team established a prospective study of acute febrile illness. Between February and November 2007, the investigators enrolled 1079 patients > 2 years of age who presented with fever (>38°C tympanic) to the acute care clinics and emergency department of Teaching Hospital Karapitiya, Sri Lanka. We obtained paired sera from participants for Chikungunya diagnosis including IgG Indirect immunofluorescent assay (IFA), PCR, virus isolation, and sequencing.
Results: Of the 797 patients with available paired sera, 109 (13.7%) screened positive for Chikungunya IgG using IFA. Using a 4-fold rise in acute and convalescent sera, we identified 28(3.5%) acute infections. Additionally, we identified 12 past infections based on the presence of antibodies in both acute and convalescent sera. Among the 28 seroconversions, 10 were isolated by culture and 18 by PCR. Those with acute infections were older (40 years compared to 30 years, p=0.07), more likely males (82% compared to 60%, p=0.02) and were more often admitted to the hospital (93% vs 71%, p=0.001) compared to those without acute Chikungunya infection. Participants with acute Chikungunya infection were more likely to have joint pain (RR: 3.12, CI: 1.39, 7.00, p=0.004), muscle pain (RR: 4.86, CI: 1.87, 12.67, p=<0.001), rash (RR: 5.49, CI: 1.83, 16.45, p=0.001) and conjunctival injection (RR: 3.36, CI: 1.59, 7.10, p=0.001) than those without acute Chikungunya infection. Furthermore, viral Sequencing data confirmed the presence of epidemic African strain throughout the study.
Conclusion:Chikungunya virus was present in southern Sri Lanka and should be considered in the differential diagnosis of acute febrile illnesses. Our limited data suggest infection with the recently identified epidemic strain.
Item Open Access Determinants of Insecticide Treated Nets (ITNs) Ownership and Use in Ghana(2011) Adeyeri, OluwakemiMalaria is hyper-endemic in Ghana, and remains one of the leading causes of morbidity and mortality, especially in pregnant women and children under the age of five. The use of insecticide-treated nets is an effective intervention for malaria control; however, despite known evidence of its efficacy, there is still a low rate of implementation and usage. Considering the significant public health impact to be gained from proper use of ITNs, it is worthwhile to study factors that determine ownership of ITNs in Ghana. Cross-sectional data from the Demographic and Health Surveys (DHS) for Ghana in 2008 was analyzed to determine which variables were predictors of ITN ownership. Additional semi-structured interviews were also conducted to explore these variables. Approximately 33% of Ghanaian households own at least one ITN. The strongest positive predictors of ITN ownership were number of children <5 years (52%) and residence in a rural area (47%). Marital status and birth in the last five years were also positive predictors, 48% and 56% respectively Electricity in the household was found to be a negative predictor (28%), while wealth was not a significant predictor. Consequently, there is the need for increased targeted government interventions towards groups that are less likely to own bed nets - urban areas, low level of education. It is also paramount that already existing interventions that target risk groups - young children and pregnant women are continued to ensure continued reduction in the global burden of malaria.
Item Open Access Determinants of Treatment Seeking Behavior Following Injury in Maringá, Brazil(2015) Toomey, NicoleBackground: Injury currently accounts for 6% of all disability adjusted life years (DALYS) lost. As the global incidence of injuries increases, so does the need for care. Current research on access to care and injury does not always account for injury severity or focus on the overall effects of injury. Our project focused on a medium-sized city in Brazil to determine what barriers to care after injury arise in Brazil’s universal health care system.
Methods: Households were randomly selected for survey in the 561 populated districts of the city of Maringa between May 2015 and September 2015. Demographic information was collected for the entire household; one individual from the household was then randomly selected to provide injury history. A chi-square analysis was used to determine the association between care seeking and demographics. A preliminary significance level of α = 0.20 was selected for inclusion of variables into the multivariate logistic regression. A full multivariate logistic regression model using injury as the primary exposure and seeking care as the outcome was run. Thirty reduced models were run; mean squared estimate (MSE) and Akaike Information Criterion (AIC) were calculated to find the best predictive model.
Results: 2678 households and individuals participated, 30.3% individuals reported an injury in their lifetime. The bivariate analysis found that gender (p = 0.034), cause of injury (p = 0.000), race (p = 0.051), severity (p = 0.103) and insurance status (p = 0.026) were potential predictors of seeking care. Education (p = 0.62), income (p = 0.343) and age (p = 0.838) were included in the multivariate model due to past significance in the literature. The reduced multivariate model that eliminated education level and race (MSE = 0.0274, AIC = 0.7689) was chosen as the best representative model and showed gender, age, socioeconomic status, and cause of injury as all strong predictors of care seeking.
Conclusions: Cause of injury is a major predictor for seeking care, as are factors related to socioeconomic status such as insurance and income. Injury cause potentially masked the effects of gender on care seeking. More research needs to be done on specific causes of injuries, the role of gender, and why socioeconomic status is still a barrier to care in a universal access system.
Item Embargo Developing a Machine Learning Based Clinical Decision-Making Tool for Traumatic Brain Injury Patients in Moshi, Tanzania(2023) Huo, LilyBackground: Traumatic brain injury (TBI) has a disproportionate burden on low- and middle-income countries (LMICs) and cost-effective and culturally relevant measures are necessary to improve TBI care. This study aims to characterize emergency healthcare providers’ decision making when treating TBI patients, develop a machine learning-based model to predict TBI patient outcome, and conduct a decision curve analysis (DCA) to evaluate model clinical applicability. Methods: This study is twofold: 1) a secondary analysis of a TBI data registry with 4142 patients and 2) a survey examining physicians decision-making in treating 50 TBI patients in real time. Results: Five machine learning models were developed with AUCs ranging from 70.86% (Single C5.0 Ruleset) to 85.67% (Ensemble Model). DCA showed that all models exhibited a greater net benefit over ranges of clinical thresholds. The survey collected information on 50 patients providing insight on tools used by physicians in real-time when treating TBI patients as well as the unmet need patients at KCMC faced. Conclusions: This study is the first to use machine learning modeling and DCA in the context of TBI prognosis in Sub-Saharan Africa. Prognostic models have great potential within the decision-making process for treating TBI patients in LMIC health systems and such utility can be expanded through determining different threshold probabilities for various interventions.
Item Open Access Disclosure of HIV Status to Sexual Partners Among People with HIV in Singida Regional Referral Hospital of Tanzania(2023) Alexander, Alex GabagambiBackground: Human immunodeficiency virus (HIV) status nondisclosure to sexual partners remains a major challenge in Tanzania because it is still self-avoided among heterosexual partners with HIV. Voluntary HIV disclosure among sexual partners has both advantages and disadvantages. The advantages are such as helping people with HIV to ask for and receive social support, have safer sex, and assistance to access HIV treatment among sexual partners while disadvantages are such as being blamed, discriminated against, depressed, divorced, and verbally abused after voluntary disclosure. This study assessed voluntary HIV status disclosure to sexual partners, its associated factors, and outcomes among people with HIV (PWH) in the Singida region of Tanzania. Methods: A hospital-based descriptive, cross-sectional study design, 380 persons with HIV were recruited from the Care and Treatment Clinic (CTC) at Singida Hospital -- located in Central Tanzania between June and August 2022. A Swahili questionnaire was used to obtain demographic and HIV disclosure information. Results: About 78 % (n=297) of the study participants reported they disclosed their HIV status. Adjusted multivariable logistic revealed that HIV status disclosure to sexual partners was significantly associated with living with a sexual partner (AOR = 3.91, 95%, CI = 1.43-10.72), knowledge of HIV disclosure (AOR = 11.71, 95% CI = 2.88-47.63), known serostatus of the sexual partner (AOR =40.20, 95% CI, = 15.31-105.56) and HIV disclosure related stigma (AOR = 0.92, 95% CI = 0.85-0.99). Ninety percent (n=267) of respondents’ sexual partners tested for HIV after disclosure. Conclusion: These findings suggest that there is a significant number of people with HIV who have not disclosed their HIV status to their sexual partners in Singida region of Tanzania, and more interventions should be adopted or designed to scale-up disclosure to sexual partners by addressing the significant factors.
Item Open Access Drug Development in Dengue Virus and Molecular Epidemiology of Malaria in Western Kenya(2017) Levitt, Brandt E.Dengue viruses (DENV) and other mosquito-borne flaviviruses are rapidly emerging human pathogens that threaten nearly half of the world’s population. There is currently no effective vaccine or antiviral therapeutics for the prophylaxis or treatment of DENV. While traditional drug development efforts have focused on inhibitors of viral enzymes, an alternative approach is to target host proteins that support virus replication. In an effort to identify novel human enzymes important for the DENV-2 life-cycle, we conducted a genome-wide RNAi screen and identified ERI3, a putative 3′-5′ exonuclease, as a novel DENV-2 host factor. Cell-free assays confirmed that purified ERI3 is capable of degrading single-stranded RNA in a 3′ to 5′ direction. We conducted a screen for compounds that inhibit ERI3 in vitro and identified small molecules that antagonized both exonuclease activity. In summary, we identified a host exonuclease that is important for DENV-2 replication and is a potential therapeutic target. Our approach illustrates the utility of identifying host enzymatic functions for development of anti-viral drugs.
Large-scale molecular epidemiologic studies of Plasmodium falciparum parasites have provided insights into parasite biology and transmission, can identify the spread of drug resistance, and are useful in assessing vaccine targets. The polyclonal nature infections in high transmission settings is problematic for traditional genotyping approaches. Next-generation sequencing approaches to parasite genotyping allow sensitive detection of minority variants, disaggregation of complex parasite mixtures, and scalable processing of large samples sets. Therefore, we designed, validated, and applied to field parasites a new approach that leverages sequencing of individually barcoded samples in a multiplex manner. We utilize variant barcodes, invariant linker sequences and modular template-specific primers to allow for the simultaneous generation of high-dimensional sequencing data of multiple gene targets. This modularity permits a cost-effective and reproducible way to query many genes at once. In mixtures of reference parasite genomes, we quantitatively detected unique haplotypes comprising as little as 2% of a polyclonal infection. We applied this genotyping approach to field-collected parasites collected in Western Kenya in order to simultaneously obtain parasites genotypes at three unlinked loci. In summary, we present a rapid, scalable, and flexible method for genotyping individual parasites that enables molecular epidemiologic studies of parasite evolution, population structure and transmission.
Item Open Access Effectiveness of Respondent Driven Sampling in Engaging Methamphetamine Users in HIV Prevention Research in Cape Town, South Africa(2014) Kimani, Stephen MburuSouth Africa has a substantial HIV epidemic as well as a rising methamphetamine use problem, particularly in Cape Town. Respondent driven sampling (RDS) may be a useful tool for engaging vulnerable and hard-to-reach populations in HIV research, although its effectiveness has not yet been examined among South African methamphetamine users. The aim of the current study was to describe the effectiveness of RDS as a method for engaging methamphetamine users in Cape Town into a HIV behavioral research study. RDS procedures were used to screen 374 potential participants from a peri-urban township in Cape Town. Measures of homophily, equilibrium and RDS-1 estimators were computed for key demographic and social variables.
Beginning with 8 seeds, 345 methamphetamine users were enrolled over a 6 month period, with a coupon return rate of 67%. The sample included 197 men and 148 women who were ethnically diverse (73% Coloured, 27% Black African) and had a mean age of 28.8 years (SD=7.2). Social networks were adequate (mean network size >5) and mainly comprised of close social ties. Equilibrium on race was reached after 11 waves of recruitment, and after ≤3 waves for all other variables of interest. There was little to moderate preference for either in- or out-group recruiting in all subgroups.
Results suggest that RDS is an effective method for engaging methamphetamine users into HIV prevention research in South Africa. RDS may be a useful strategy for seeking high risk methamphetamine users for HIV testing and linkage to HIV care in this and other low resource settings. We also discuss future directions for RDS studies.
Item Open Access Effects of Toxic Metal Exposures and Their Mixtures on Adverse Health Outcomes in the Peruvian Amazon(2022) Berky, AxelNon-essential trace metals (lead, mercury, arsenic, and cadmium) are ubiquitous in our environment and have overlapping routes of exposure, yet mixed trace metal exposures are rarely considered in epidemiological studies. Instead, research often follows a single research question that focuses on a single trace metal of concern and does not incorporate potential co-exposures. The published literature of artisanal small-scale mining in the Amazon is a prime example as it has predominantly focused on mercury exposure, due to its use in the mining process. Once exposures of concern are identified, further studies evaluate health outcomes; however, the health effects cannot be accurately determined without accounting for co-exposures. This verification is becoming more important as there is a growing recognition that mixed trace metal exposures are more common than previously believed.To address the prevalence of mixed trace metal exposures and their health effects in the Peruvian Amazon region of Madre de Dios, I use epidemiological data from the COhorte de NAcimiento de MAdre de Dios (CONAMAD) birth cohort study (2018-Present), and two cross-sectional epidemiological studies (Amarakaeri Communal Reserve study (ACR, 2015), and Etiology and Toxic Metals study (EATM, 2018)). CONAMAD collected survey data along with maternal and cord blood samples at birth, which were processed for minerals and trace metals. The cross-sectional studies collected venous blood for trace metal analysis and hair samples for total hair mercury. Blood samples from the ACR were also processed for amino acids. In-depth demographic and health survey data were collected in all three studies. Structural equation models and random mixed effect models were used to evaluate research questions. The cross-sectional studies demonstrate a high correlation of lead and mercury exposure in communities that rely on wild fish and wild game as protein sources, which is prevalent throughout the Amazon. Consuming a meal of wild game resulted in an estimated lead dose of 500 µg, with those who eat wild game (Yes/No) associated with 1.41 µg/dL (95% CI: 1.20 – 1.70) higher blood lead levels compared to those who do not. This furthers the notion that mixed exposures are likely more common than previously believed. Mixed exposures target the same toxicological pathway, which may lead to synergistic or antagonistic effects. My research found that lead disrupts the arginine pathway and is associated with increased blood pressure. Mercury exposure was a modifier of the arginine pathway, with high blood mercury levels changing the effect of global arginine bioavailability from 17.16 (95% CI: 9.09 – 25.84) to -14.17 (95% CI: -31.88 - -0.33) on systolic blood pressure. Interestingly, mercury was not directly associated with the arginine pathway. Results from the birth cohort demonstrate the importance of nutrition and prenatal care for fetal development, which had a large positive effect on birthweight and gestational age. However, even low maternal lead exposure had detrimental effects on fetal health. A 1% increase in maternal blood lead was associated with a shorter gestational age of 0.05 days (β: -0.75, 95% CI: -1.51 - -0.13), even with the CONAMAD birth cohort having lower blood lead levels than other birth cohorts. There is a need for an integrated approach of nutritional and exposure assessments to better understand neonatal health outcomes.