31 results on '"Julie A. Clennon"'
Search Results
2. Metagenome-wide characterization of shared antimicrobial resistance genes in sympatric people and lemurs in rural Madagascar
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Brooke M. Talbot, Julie A. Clennon, Miarintsoa Fara Nantenaina Rakotoarison, Lydia Rautman, Sarah Durry, Leo J. Ragazzo, Patricia C. Wright, Thomas R. Gillespie, and Timothy D. Read
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Wildlife ecology ,Microbiomes ,Antibiotic resistance genes ,One Health ,Antibiotic stewardship ,Medicine ,Biology (General) ,QH301-705.5 - Abstract
Background Tracking the spread of antibiotic resistant bacteria is critical to reduce global morbidity and mortality associated with human and animal infections. There is a need to understand the role that wild animals in maintenance and transfer of antibiotic resistance genes (ARGs). Methods This study used metagenomics to identify and compare the abundance of bacterial species and ARGs detected in the gut microbiomes from sympatric humans and wild mouse lemurs in a forest-dominated, roadless region of Madagascar near Ranomafana National Park. We examined the contribution of human geographic location toward differences in ARG abundance and compared the genomic similarity of ARGs between host source microbiomes. Results Alpha and beta diversity of species and ARGs between host sources were distinct but maintained a similar number of detectable ARG alleles. Humans were differentially more abundant for four distinct tetracycline resistance-associated genes compared to lemurs. There was no significant difference in human ARG diversity from different locations. Human and lemur microbiomes shared 14 distinct ARGs with highly conserved in nucleotide identity. Synteny of ARG-associated assemblies revealed a distinct multidrug-resistant gene cassette carrying dfrA1 and aadA1 present in human and lemur microbiomes without evidence of geographic overlap, suggesting that these resistance genes could be widespread in this ecosystem. Further investigation into intermediary processes that maintain drug-resistant bacteria in wildlife settings is needed.
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- 2024
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3. Mycobacterium leprae–helminth co-infections and vitamin D deficiency as potential risk factors for leprosy: A case–control study in south-eastern Brazil
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Cori L. Dennison, Lorena B. de Oliveira, Lucia A. de O. Fraga, Rosemary S. e Lima, José A. Ferreira, Julie A. Clennon, Laura de Mondesert, Jessica Stephens, Erica B. Magueta, Alexandre Castelo Branco, Michelle de Carvalho Rezende, Deborah Negrão-Corrêa, Maria Aparecida de Faria Grossi, and Jessica K. Fairley
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Leprosy ,Schistosomiasis ,Hansen’s disease ,Helminth ,Co-infection ,Micronutrient ,Infectious and parasitic diseases ,RC109-216 - Abstract
Background: Evidence suggests that biological mechanisms involved in helminth infections and vitamin deficiencies increase susceptibility to other infections. The aim of this study was to investigate the associations of helminth co-infection and select micronutrient deficiencies with leprosy using a case–control design. Methods: From 2016 to 2018, individuals aged ≥3 years were recruited at clinics in and around Governador Valadares, Minas Gerais, Brazil in three groups: cases of leprosy, household contacts and community-matched (non-contact) controls. Helminths were diagnosed through stool Kato Katz examination and serum reactivity to anti-soluble adult worm antigen preparation IgG4. Serum ferritin, 25-OH vitamin D and retinol concentrations were measured. Multi-variate logistic regression was conducted to identify associations with active leprosy. Results: Seventy-nine cases of leprosy, 96 household contacts and 81 non-contact controls were recruited; 48.1% of participants were male with a median age of 40 years. Helminths were found in 7.1% of participants on Kato Katz test, all but one of which were Schistosoma mansoni, and 32.3% of participants were positive for S. mansoni serology. On multi-variate analysis, cases were more likely to be infected with helminths (diagnosed by stool) than household contacts [adjusted odds ratio (aOR) 8.69, 95% confidence interval (CI) 1.50–50.51]. Vitamin D deficiency was common, and was more likely in cases compared with non-contact controls (aOR 4.66, 95% CI 1.42,–15.33). Iron deficiency was not associated with leprosy, and vitamin A deficiency was not detected. Conclusion: These associations suggest that the immune consequences of schistosomiasis and vitamin D deficiency may increase the risk of active leprosy. Comorbid conditions of poverty deserve further study as addressing co-infections and nutritional deficiencies could be incorporated into programmes to improve leprosy control.
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- 2021
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4. Spatial and temporal patterns of Ross River virus in south east Queensland, Australia: identification of hot spots at the rural-urban interface
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Amanda K. Murphy, Julie A. Clennon, Gonzalo Vazquez-Prokopec, Cassie C. Jansen, Francesca D. Frentiu, Louise M. Hafner, Wenbiao Hu, and Gregor J. Devine
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Ross River virus ,Arbovirus ,Urban ,Spatial ,Epidemic ,Queensland ,Infectious and parasitic diseases ,RC109-216 - Abstract
Abstract Background Ross River virus (RRV) is responsible for the most common vector-borne disease of humans reported in Australia. The virus circulates in enzootic cycles between multiple species of mosquitoes, wildlife reservoir hosts and humans. Public health concern about RRV is increasing due to rising incidence rates in Australian urban centres, along with increased circulation in Pacific Island countries. Australia experienced its largest recorded outbreak of 9544 cases in 2015, with the majority reported from south east Queensland (SEQ). This study examined potential links between disease patterns and transmission pathways of RRV. Methods The spatial and temporal distribution of notified RRV cases, and associated epidemiological features in SEQ, were analysed for the period 2001–2016. This included fine-scale analysis of disease patterns across the suburbs of the capital city of Brisbane, and those of 8 adjacent Local Government Areas, and host spot analyses to identify locations with significantly high incidence. Results The mean annual incidence rate for the region was 41/100,000 with a consistent seasonal peak in cases between February and May. The highest RRV incidence was in adults aged from 30 to 64 years (mean incidence rate: 59/100,000), and females had higher incidence rates than males (mean incidence rates: 44/100,000 and 34/100,000, respectively). Spatial patterns of disease were heterogeneous between years, and there was a wide distribution of disease across both urban and rural areas of SEQ. Overall, the highest incidence rates were reported from predominantly rural suburbs to the north of Brisbane City, with significant hot spots located in peri-urban suburbs where residential, agricultural and conserved natural land use types intersect. Conclusions Although RRV is endemic across all of SEQ, transmission is most concentrated in areas where urban and peri-urban environments intersect. The drivers of RRV transmission across rural-urban landscapes should be prioritised for further investigation, including identification of specific vectors and hosts that mediate human spillover.
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- 2020
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5. Associations between open drain flooding and pediatric enteric infections in the MAL-ED cohort in a low-income, urban neighborhood in Vellore, India
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David M. Berendes, Juan S. Leon, Amy E. Kirby, Julie A. Clennon, Suraja J. Raj, Habib Yakubu, Katharine A. Robb, Arun Kartikeyan, Priya Hemavathy, Annai Gunasekaran, Sheela Roy, Ben Chirag Ghale, J. Senthil Kumar, Venkata Raghava Mohan, Gagandeep Kang, and Christine L. Moe
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Open drains ,Flooding ,Enteric infections ,Urban infrastructure ,Pediatric health ,Environmental contamination ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background Open drains are common methods of transporting solid waste and excreta in low-income urban neighborhoods. Open drains can overflow due to blockages with solid waste and during rainfall, posing exposure risks. The goal of this study was to evaluate whether pediatric enteric infection was associated with open drains and flooding in a dense, low-income, urban neighborhood. Methods As part of the MAL-ED study in Vellore, India, a cohort of 230 children provided stool specimens at 14–17 scheduled home visits and during diarrheal episodes in the first two years of life. All specimens were analyzed for enteric pathogens. Caregivers in 100 households reported on flooding of drains and households and monthly frequency of contact with open drains and flood water. Household GPS points were collected. Monthly rainfall totals for the Vellore district were collected from the Indian Meteorological Department. Clustering of reported drain and house flooding were identified by Kulldorff’s Bernoulli Spatial Scan. Differences in enteric infection were assessed for household responses and spatial clusters, with interactions between reported flooding and rainfall to approximate monthly drain flooding retrospectively, using multivariable, mixed-effects logistic regression models. Results Coverage of household toilets was low (33%), and most toilets (82%) discharged directly into open drains, suggesting poor neighborhood fecal sludge management. Odds of enteric infection increased significantly with total monthly rainfall for children who lived in households that reported that the nearby drain flooded (4% increase per cm of rain: OR: 1.04, 95% CI: 1.00–1.08) and for children in households in a downstream spatial cluster of reported drain flooding (5% increase per cm of rain: OR: 1.05, 95% CI: 1.01–1.09). There was no association between odds of enteric infection and frequency of reported contact with drain or floodwater. Conclusions Children in areas susceptible to open drain flooding had increased odds of enteric infection as rainfall increased. Results suggested that infection increased with rainfall due to neighborhood infrastructure (including poor fecal sludge management) and not frequency of contact. Thus, these exposures may not be mitigated by changes in personal behaviors alone. These results underscore the importance of improving the neighborhood environment to improve children’s health in low-income, urban settings.
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- 2019
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6. Upscale or downscale: applications of fine scale remotely sensed data to Chagas disease in Argentina and schistosomiasis in Kenya
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Uriel Kitron, Julie A. Clennon, M. Carla Cecere, Ricardo E. Gürtler, Charles H. King, and Gonzalo Vazquez-Prokopec
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remote sensing, spatial statistics, scale, clustering, Chagas disease, schistosomiasis. ,Geography (General) ,G1-922 - Abstract
Depending on the research question or the public health application, the appropriate resolution of the data varies temporally, spatially, and, for satellite data, spectrally and radiometrically. Regardless of the scale used to address a research or public health question, the temptation is always there to extrapolate from fine-resolution data or to interpolate from coarse resolution studies. In both cases, the relevance of data and analyses conducted on one spatial level to other levels cannot be taken for granted. Spatial heterogeneity on the micro-scale may not be detected using coarse spatial resolution, and conversely, general patterns on the macro-scale may not be detected using fine spatial resolution. Two studies are described where the transmission dynamics and risk of infection was assessed on the micro-scale starting with household level studies in one community, and the study area was extended gradually to consider several communities and sources for vectors or intermediate hosts. In a study of Chagas disease in northwest Argentina, the reinfestation process of communities by the main domestic vector was analyzed using spatial statistics; sources within and outside communities as well as the distance of reinfestation were identified. In a study of urinary schistosomiasis in coastal Kenya, age dependent and directional focal clustering of infections was detected around some aquatic habitats, and a hydrological model was developed to detect least cost dispersal routes that allow snails to reinfest dried-up habitats. Some general aspects of focal statistics are discussed. Several general questions need to be considered in geospatial health studies, including the following: (i) what are the best criteria for selecting the spatial (and temporal) unit of intervention and analysis? (ii) how do the key measures of risk and transmission dynamics vary with scale? (iii) how do we integrate processes occurring at diverse spatial and temporal scales? All of these questions can only be addressed through solid biological, epidemiological and socio-economic understanding of the system in time and space.
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- 2006
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7. COVID‐Clarity demands unification of health and environmental policy
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Thomas R. Gillespie, Julie A. Clennon, Kate E. Jones, Andrew P. Dobson, and Mercedes Pascual
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Conservation of Natural Resources ,Natural resource economics ,Wildlife ,Climate change ,Forests ,law.invention ,Spillover effect ,law ,Tropical climate ,Pandemic ,Humans ,Environmental Chemistry ,Letter to the Editor ,Pandemics ,General Environmental Science ,Tropical Climate ,Global and Planetary Change ,Ecology ,SARS-CoV-2 ,business.industry ,COVID-19 ,Environmental Policy ,Agriculture ,CLARITY ,Business ,Natural capital - Abstract
Spillover of novel pathogens from wildlife to people, such as the virus responsible for the COVID-19 pandemic, is increasing and this trend is most strongly associated with tropical deforestation driven by agricultural expansion. This same process is eroding natural capital, reducing forest-associated health co-benefits, and accelerating climate change. Protecting and promoting tropical forests is one of the most immediate steps we can take to simultaneously mitigate climate change while reducing the risk of future pandemics; however, success in this undertaking will require greater connectivity of policy initiatives from local to global, as well as unification of health and environmental policy.
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- 2021
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8. Hennessee et al. Respond
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Ian Hennessee, Julie A. Clennon, Lance A. Waller, Uriel Kitron, and J. Michael Bryan
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Public Health, Environmental and Occupational Health - Published
- 2022
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9. Mycobacterium leprae-helminth co-infections and vitamin D deficiency as potential risk factors for leprosy: A case-control study in south-eastern Brazil
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Alexandre Castelo Branco, Jose A. Ferreira, Laura de Mondesert, Maria Aparecida de Faria Grossi, Jessica K. Fairley, Jessica Stephens, Michelle de Carvalho Rezende, Julie A. Clennon, Lorena Bruna Pereira de Oliveira, Cori L. Dennison, Rosemary Soares Ker e Lima, Deborah Negrão-Corrêa, Lucia Alves de Oliveira Fraga, and Erica Barbosa Magueta
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0301 basic medicine ,Male ,Infectious and parasitic diseases ,RC109-216 ,chemistry.chemical_compound ,Feces ,0302 clinical medicine ,Risk Factors ,Odds Ratio ,Schistosomiasis ,Micronutrient ,030212 general & internal medicine ,Child ,Coinfection ,General Medicine ,Middle Aged ,Co-infection ,Mycobacterium leprae ,Infectious Diseases ,Child, Preschool ,Female ,Leprosy ,Brazil ,Microbiology (medical) ,Vitamin ,Adult ,medicine.medical_specialty ,Adolescent ,030106 microbiology ,vitamin D deficiency ,03 medical and health sciences ,Internal medicine ,Helminths ,parasitic diseases ,medicine ,Vitamin D and neurology ,Helminth ,Animals ,Humans ,Aged ,business.industry ,Odds ratio ,medicine.disease ,Vitamin D Deficiency ,Vitamin A deficiency ,Hansen’s disease ,Malnutrition ,chemistry ,Case-Control Studies ,business - Abstract
Background Evidence suggests that biological mechanisms involved in helminth infections and vitamin deficiencies increase susceptibility to other infections. The aim of this study was to investigate the associations of helminth co-infection and select micronutrient deficiencies with leprosy using a case–control design. Methods From 2016 to 2018, individuals aged ≥3 years were recruited at clinics in and around Governador Valadares, Minas Gerais, Brazil in three groups: cases of leprosy, household contacts and community-matched (non-contact) controls. Helminths were diagnosed through stool Kato Katz examination and serum reactivity to anti-soluble adult worm antigen preparation IgG4. Serum ferritin, 25-OH vitamin D and retinol concentrations were measured. Multi-variate logistic regression was conducted to identify associations with active leprosy. Results Seventy-nine cases of leprosy, 96 household contacts and 81 non-contact controls were recruited; 48.1% of participants were male with a median age of 40 years. Helminths were found in 7.1% of participants on Kato Katz test, all but one of which were Schistosoma mansoni, and 32.3% of participants were positive for S. mansoni serology. On multi-variate analysis, cases were more likely to be infected with helminths (diagnosed by stool) than household contacts [adjusted odds ratio (aOR) 8.69, 95% confidence interval (CI) 1.50–50.51]. Vitamin D deficiency was common, and was more likely in cases compared with non-contact controls (aOR 4.66, 95% CI 1.42,–15.33). Iron deficiency was not associated with leprosy, and vitamin A deficiency was not detected. Conclusion These associations suggest that the immune consequences of schistosomiasis and vitamin D deficiency may increase the risk of active leprosy. Comorbid conditions of poverty deserve further study as addressing co-infections and nutritional deficiencies could be incorporated into programmes to improve leprosy control.
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- 2020
10. Identification of Ross River virus hot spots along urban fringes of South East Queensland, Australia
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Gregor J. Devine, Louise M. Hafner, Francesca D. Frentiu, Wenbiao Hu, Gonzalo M. Vazquez-Prokopec, Amanda Murphy, Cassie C. Jansen, and Julie A. Clennon
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Ross River virus ,Geography ,biology ,South east ,General Earth and Planetary Sciences ,Identification (biology) ,biology.organism_classification ,Archaeology ,General Environmental Science - Published
- 2020
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11. Spatial and temporal patterns of Ross River virus in South East Queensland, Australia: identification of hot spots at the rural-urban interface
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Julie A. Clennon, Francesca D. Frentiu, Wenbiao Hu, Amanda Murphy, Gonzalo M. Vazquez-Prokopec, Cassie C. Jansen, Louise M. Hafner, and Gregor J. Devine
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0301 basic medicine ,Adult ,Male ,030231 tropical medicine ,Wildlife ,Epidemic ,Rural Health ,law.invention ,lcsh:Infectious and parasitic diseases ,03 medical and health sciences ,Ross River virus ,0302 clinical medicine ,law ,Humans ,Urban ,Spatial ,lcsh:RC109-216 ,Socioeconomics ,Arbovirus ,biology ,Alphavirus Infections ,Incidence (epidemiology) ,Incidence ,Urban Health ,Outbreak ,Middle Aged ,biology.organism_classification ,030104 developmental biology ,Infectious Diseases ,Geography ,Transmission (mechanics) ,Spatial ecology ,Enzootic ,Female ,Queensland ,Rural area - Abstract
Background Ross River virus (RRV) is responsible for the most common vector-borne disease of humans reported in Australia. The virus circulates in enzootic cycles between multiple species of mosquitoes, wildlife reservoir hosts and humans. Public health concern about RRV is increasing due to rising incidence rates in Australian urban centres, along with increased circulation in Pacific Island countries. Australia experienced its largest recorded outbreak of 9544 cases in 2015, with the majority reported from south east Queensland (SEQ). This study examined potential links between disease patterns and transmission pathways of RRV. Methods The spatial and temporal distribution of notified RRV cases, and associated epidemiological features in SEQ, were analysed for the period 2001–2016. This included fine-scale analysis of disease patterns across the suburbs of the capital city of Brisbane, and those of 8 adjacent Local Government Areas, and host spot analyses to identify locations with significantly high incidence. Results The mean annual incidence rate for the region was 41/100,000 with a consistent seasonal peak in cases between February and May. The highest RRV incidence was in adults aged from 30 to 64 years (mean incidence rate: 59/100,000), and females had higher incidence rates than males (mean incidence rates: 44/100,000 and 34/100,000, respectively). Spatial patterns of disease were heterogeneous between years, and there was a wide distribution of disease across both urban and rural areas of SEQ. Overall, the highest incidence rates were reported from predominantly rural suburbs to the north of Brisbane City, with significant hot spots located in peri-urban suburbs where residential, agricultural and conserved natural land use types intersect. Conclusions Although RRV is endemic across all of SEQ, transmission is most concentrated in areas where urban and peri-urban environments intersect. The drivers of RRV transmission across rural-urban landscapes should be prioritised for further investigation, including identification of specific vectors and hosts that mediate human spillover.
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- 2020
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12. Invasive Nontypeable Haemophilus influenzae Infection Among Adults With HIV in Metropolitan Atlanta, Georgia, 2008-2018
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Zanthia Wiley, Fiona Havers, Robert A. Petit, Amy Tunali, Tonia Parrott, Lauren F Collins, Sarah W. Satola, Melissa Tobin-D’Angelo, Timothy D. Read, Monica M. Farley, Stephanie Thomas, and Julie A. Clennon
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Adult ,Male ,medicine.medical_specialty ,Georgia ,Haemophilus Infections ,Adolescent ,Population ,Prevalence ,HIV Infections ,01 natural sciences ,Men who have sex with men ,Cohort Studies ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Internal medicine ,Epidemiology ,otorhinolaryngologic diseases ,Medicine ,Humans ,030212 general & internal medicine ,0101 mathematics ,Young adult ,Homosexuality, Male ,Serotyping ,education ,Phylogeny ,Aged ,Original Investigation ,education.field_of_study ,Arthritis, Infectious ,business.industry ,Incidence (epidemiology) ,Incidence ,010102 general mathematics ,General Medicine ,Middle Aged ,Haemophilus influenzae ,Black or African American ,Population Surveillance ,Cohort ,business ,Cohort study - Abstract
IMPORTANCE: Invasive nontypeable Haemophilus influenzae (NTHi) infection among adults is typically associated with bacteremic pneumonia. Nontypeable H influenzae is genetically diverse and clusters of infection are uncommon. OBJECTIVE: To evaluate an increase in invasive NTHi infection from 2017-2018 among HIV-infected men who have sex with men in metropolitan Atlanta, Georgia. DESIGN, SETTING, AND PARTICIPANTS: A population-based surveillance study with a cohort substudy and descriptive epidemiological analysis identified adults aged 18 years or older with invasive NTHi infection (isolation of NTHi from a normally sterile site) between January 1, 2008, and December 31, 2018 (final date of follow-up). EXPOSURES: Time period, HIV status, and genetic relatedness (ie, cluster status) of available NTHi isolates. MAIN OUTCOMES AND MEASURES: The primary outcome was incidence of invasive NTHi infection (from 2008-2016 and 2017-2018) among persons with HIV and compared with NTHi infection from 2008-2018 among those without HIV. The secondary outcomes were assessed among those aged 18 to 55 years with invasive NTHi infection and included epidemiological, clinical, and geographic comparisons by cluster status. RESULTS: Among 553 adults with invasive NTHi infection (median age, 66 years [Q1-Q3, 48-78 years]; 52% male; and 38% black), 60 cases occurred among persons with HIV. Incidence of invasive NTHi infection from 2017-2018 among persons with HIV (41.7 cases per 100 000) was significantly greater than from 2008-2016 among those with HIV (9.6 per 100 000; P
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- 2019
13. Extensively drug-resistant tuberculosis 'hotspots' and sociodemographic associations in Durban, South Africa
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Kristin N. Nelson, James C.M. Brust, Nazir Ahmed Ismail, Julie A. Clennon, Barun Mathema, Angie Campbell, Koleka Mlisana, Pravikrishnen Moodley, Salim Allana, Natashia Morris, Neel R. Gandhi, N S Shah, Sara C. Auld, and M L Peterson
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Pulmonary and Respiratory Medicine ,Adult ,Male ,Cross-sectional study ,Extensively Drug-Resistant Tuberculosis ,Antitubercular Agents ,Article ,03 medical and health sciences ,South Africa ,0302 clinical medicine ,Environmental health ,Tuberculosis, Multidrug-Resistant ,medicine ,Humans ,030212 general & internal medicine ,Cities ,Tuberculosis, Pulmonary ,Demography ,030505 public health ,Poverty ,Extramural ,business.industry ,Incidence ,Spatial mapping ,Extensively drug-resistant tuberculosis ,Census ,medicine.disease ,Educational attainment ,Infectious Diseases ,Cross-Sectional Studies ,Socioeconomic Factors ,Geographic Information Systems ,Female ,0305 other medical science ,business - Abstract
sectitleBACKGROUND/titleIn KwaZulu-Natal, South Africa, the incidence of extensively drug-resistant tuberculosis (XDR-TB) is driven by the transmission of resistant strains. As data suggest that cases may be spatially clustered, we sought to identify 'hotspots' and describe these communities./secsectitleMETHODS/titleWe enrolled XDR-TB patients diagnosed from 2011 to 2014 in eThekwini. Global positioning system (GPS) coordinates for participant homes were collected and hotspots were identified based on population-adjusted XDR-TB incidence. The sociodemographic features of hotspots were characterised using census data. For a subset of participants, we mapped non-home XDR-TB congregate locations and compared these with results including only homes./secsectitleRESULTS/titleAmong 132 participants, 75 (57%) were female and 87 (66%) lived in urban or suburban locations. Fifteen of 197 census tracts were identified as XDR-TB hotspots with ≥95% confidence. Four spatial mapping methods identified one large hotspot in northeastern eThekwini. Hotspot communities had higher proportions of low educational attainment (12% vs. 9%) and unemployment (29.3% vs. 20.4%), and lower proportion of homes with flush toilets (36.4% vs. 68.9%). The case density shifted towards downtown Durban when congregate locations (e.g., workplaces) for 43 (33%) participants were mapped./secsectitleCONCLUSIONS/titleIn eThekwini, XDR-TB case homes were clustered into hotspots with more poverty indicators than non-hotspots. Prevention efforts targeting hotspot communities and congregate settings may be effective in reducing community transmission./sec.
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- 2019
14. Associations between open drain flooding and pediatric enteric infections in the MAL-ED cohort in a low-income, urban neighborhood in Vellore, India
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Katharine Robb, J. Senthil Kumar, Christine L. Moe, Arun Kartikeyan, Suraja Raj, Julie A. Clennon, Amy E. Kirby, Venkata Raghava Mohan, Ben Chirag Ghale, Gagandeep Kang, David Berendes, Priya Hemavathy, Annai Gunasekaran, Sheela Roy, Habib Yakubu, and Juan S. Leon
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Enteric infections ,medicine.medical_specialty ,Urban Population ,Open drains ,Environmental contamination ,Rain ,Open collector ,Urban infrastructure ,India ,030209 endocrinology & metabolism ,Disease cluster ,Logistic regression ,Odds ,Cohort Studies ,Feces ,03 medical and health sciences ,0302 clinical medicine ,Residence Characteristics ,Flooding ,Poverty Areas ,Environmental health ,Epidemiology ,medicine ,Humans ,030212 general & internal medicine ,Sanitation ,Child ,Pediatric health ,Sewage ,business.industry ,lcsh:Public aspects of medicine ,Flooding (psychology) ,Public Health, Environmental and Occupational Health ,lcsh:RA1-1270 ,Bacterial Infections ,Floods ,Cohort ,Biostatistics ,business ,Research Article - Abstract
Background Open drains are common methods of transporting solid waste and excreta in low-income urban neighborhoods. Open drains can overflow due to blockages with solid waste and during rainfall, posing exposure risks. The goal of this study was to evaluate whether pediatric enteric infection was associated with open drains and flooding in a dense, low-income, urban neighborhood. Methods As part of the MAL-ED study in Vellore, India, a cohort of 230 children provided stool specimens at 14–17 scheduled home visits and during diarrheal episodes in the first two years of life. All specimens were analyzed for enteric pathogens. Caregivers in 100 households reported on flooding of drains and households and monthly frequency of contact with open drains and flood water. Household GPS points were collected. Monthly rainfall totals for the Vellore district were collected from the Indian Meteorological Department. Clustering of reported drain and house flooding were identified by Kulldorff’s Bernoulli Spatial Scan. Differences in enteric infection were assessed for household responses and spatial clusters, with interactions between reported flooding and rainfall to approximate monthly drain flooding retrospectively, using multivariable, mixed-effects logistic regression models. Results Coverage of household toilets was low (33%), and most toilets (82%) discharged directly into open drains, suggesting poor neighborhood fecal sludge management. Odds of enteric infection increased significantly with total monthly rainfall for children who lived in households that reported that the nearby drain flooded (4% increase per cm of rain: OR: 1.04, 95% CI: 1.00–1.08) and for children in households in a downstream spatial cluster of reported drain flooding (5% increase per cm of rain: OR: 1.05, 95% CI: 1.01–1.09). There was no association between odds of enteric infection and frequency of reported contact with drain or floodwater. Conclusions Children in areas susceptible to open drain flooding had increased odds of enteric infection as rainfall increased. Results suggested that infection increased with rainfall due to neighborhood infrastructure (including poor fecal sludge management) and not frequency of contact. Thus, these exposures may not be mitigated by changes in personal behaviors alone. These results underscore the importance of improving the neighborhood environment to improve children’s health in low-income, urban settings. Electronic supplementary material The online version of this article (10.1186/s12889-019-7268-1) contains supplementary material, which is available to authorized users.
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- 2019
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15. 33. Concerning Trends of Pediatric Leprosy in Minas Gerais, Brazil and Associations with Number of Municipality Medical Facilities
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Jessica K. Fairley, Taylor Landay, Maria Aparecida de Faria Grossi, Julie A Clennon, Jose A. Ferreira, and Lucia Alves de Oliveira Fraga
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medicine.medical_specialty ,AcademicSubjects/MED00290 ,Infectious Diseases ,Oral Abstracts ,Oncology ,business.industry ,Family medicine ,Epidemiology ,Disease Notification ,medicine ,Leprosy ,business ,medicine.disease - Abstract
Background Leprosy in children under 15 years of age, and in particular, the presence of leprosy grade 2 disability (G2D) in children, signifies ongoing transmission and the need for improved surveillance. Our objective was to describe the epidemiology of pediatric leprosy in Minas Gerais, Brazil and to explore associations with access to medical facilities. Methods A cross-sectional study was conducted using data from the Brazilian Notifiable Diseases Surveillance System (SINAN) from 2002–2017. Incident cases were included if they resided in a municipality with both adult and pediatric cases. Municipalities were divided by the number of medical facilities per municipality: < 5, 5–17, and 18 or higher. Analyses compared pediatric cases across two time periods (2002–2009 and 2010–2017) and number of medical facilities / municipality using chi-square, t-tests, and logistic regression. Results A total of 27,725 cases were reported with 1,611 under 15 years of age. Overall incidence declined from 34.8 per 100,000 to 13.6 per 100,000 during the study period with pediatric incidence declining from 2.6 per 100,000 to 0.8 per 100,000. Time period 2 (TP2) showed an increase in the proportion of pediatric G2D (2.58% vs 1.91%, p < 0.0001) when compared to time period 1 (TP1). Mean age of diagnosis in children was younger in TP2 then in TP1 (10.06 vs 10.43, p=0.02). In 2017, the pediatric incidence in municipalities with the fewest medical facilities was 0.95 per 100,000 compared to 0.23 per 100,000 in municipalities with > 5 facilities (p=0.009). There was significantly higher odds of disability at diagnosis (grades 1 and 2) in pediatric cases residing in municipalities with < 5 medical facilities (aOR 1.88; 95% CI 1.37–2.59), adjusted for age and sex. See map (Fig 1). Figure 1. Cases of Pediatric Disability By Number of Municipality Medical Facilities from 2002–2017 (White areas without reported pediatric leprosy) Conclusion The increasing proportion of G2D in children in the second half of the study period despite declining incidence suggest occult infections among children and adults alike in Minas Gerais. Furthermore, the average age of diagnosis in children should increase, not decrease, if M. leprae transmission was truly declining. Lastly, the association between fewer municipality health facilities and increased disability suggest barriers to timely diagnosis and a critical area of focus for research into access to healthcare and leprosy risk. Disclosures All Authors: No reported disclosures
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- 2020
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16. The Influence of Household- and Community-Level Sanitation and Fecal Sludge Management on Urban Fecal Contamination in Households and Drains and Enteric Infection in Children
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David, Berendes, Amy, Kirby, Julie A, Clennon, Suraja, Raj, Habib, Yakubu, Juan, Leon, Katharine, Robb, Arun, Kartikeyan, Priya, Hemavathy, Annai, Gunasekaran, Ben, Ghale, J Senthil, Kumar, Venkata Raghava, Mohan, Gagandeep, Kang, and Christine, Moe
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Sewage ,education ,India ,Campylobacter ,Hygiene ,Articles ,digestive system diseases ,Feces ,fluids and secretions ,Water Supply ,Child, Preschool ,Escherichia coli ,Linear Models ,Prevalence ,Humans ,Sanitation ,Toilet Facilities ,Water Microbiology ,Environmental Monitoring ,Hand Disinfection - Abstract
Urban sanitation necessitates management of fecal sludge inside and outside the household. This study examined associations between household sanitation, fecal contamination, and enteric infection in two low-income neighborhoods in Vellore, India. Surveys and spatial analysis assessed the presence and clustering of toilets and fecal sludge management (FSM) practices in 200 households. Fecal contamination was measured in environmental samples from 50 households and household drains. Enteric infection was assessed from stool specimens from children under 5 years of age in these households. The two neighborhoods differed significantly in toilet coverage (78% versus 33%) and spatial clustering. Overall, 49% of toilets discharged directly into open drains ("poor FSM"). Children in households with poor FSM had 3.78 times higher prevalence of enteric infection when compared with children in other households, even those without toilets. In the neighborhood with high coverage of household toilets, children in households with poor FSM had 10 times higher prevalence of enteric infection than other children in the neighborhood and drains in poor FSM clusters who had significantly higher concentrations of genogroup II norovirus. Conversely, children in households with a toilet that contained excreta in a tank onsite had 55% lower prevalence of enteric infection compared with the rest of the study area. Notably, households with a toilet in the neighborhood with low toilet coverage had more fecal contamination on floors where children played compared with those without a toilet. Overall, both toilet coverage levels and FSM were associated with environmental fecal contamination and, subsequently, enteric infection prevalence in this urban setting.
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- 2017
17. Combining contact tracing with targeted indoor residual spraying significantly reduces dengue transmission
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Brian L. Montgomery, Gonzalo M. Vazquez-Prokopec, Scott A. Ritchie, Peter Horne, and Julie A. Clennon
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Male ,0301 basic medicine ,Insecticides ,transmission heterogeneity ,030231 tropical medicine ,Indoor residual spraying ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Zika virus ,law.invention ,Dengue fever ,Dengue ,03 medical and health sciences ,Aedes aegypti ,0302 clinical medicine ,Aedes ,Pregnancy ,law ,Environmental health ,medicine ,Dengue transmission ,Animals ,Humans ,human mobility ,Health and Medicine ,Pregnancy Complications, Infectious ,Research Articles ,Multidisciplinary ,biology ,Population size ,fungi ,transmission chain ,insecticide ,Australia ,food and beverages ,SciAdv r-articles ,biology.organism_classification ,medicine.disease ,Virology ,Vector control ,030104 developmental biology ,Geography ,Transmission (mechanics) ,Communicable Disease Control ,Female ,Pest Control ,Contact tracing ,Research Article - Abstract
Pairing location-based contact tracing and targeted indoor insecticide applications can effectively prevent dengue transmission., The widespread transmission of dengue viruses (DENV), coupled with the alarming increase of birth defects and neurological disorders associated with Zika virus, has put the world in dire need of more efficacious tools for Aedes aegypti–borne disease mitigation. We quantitatively investigated the epidemiological value of location-based contact tracing (identifying potential out-of-home exposure locations by phone interviews) to infer transmission foci where high-quality insecticide applications can be targeted. Space-time statistical modeling of data from a large epidemic affecting Cairns, Australia, in 2008–2009 revealed a complex pattern of transmission driven primarily by human mobility (Cairns accounted for ~60% of virus transmission to and from residents of satellite towns, and 57% of all potential exposure locations were nonresidential). Targeted indoor residual spraying with insecticides in potential exposure locations reduced the probability of future DENV transmission by 86 to 96%, compared to unsprayed premises. Our findings provide strong evidence for the effectiveness of combining contact tracing with residual spraying within a developed urban center, and should be directly applicable to areas with similar characteristics (for example, southern USA, Europe, or Caribbean countries) that need to control localized Aedes-borne virus transmission or to protect pregnant women’s homes in areas with active Zika transmission. Future theoretical and empirical research should focus on evaluation of the applicability and scalability of this approach to endemic areas with variable population size and force of DENV infection.
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- 2017
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18. Geographical variations in the risk of adverse birth outcomes in Spain
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Julie A. Clennon, Gonzalo López-Abente, María Sandín-Vázquez, Adela Castelló, Pablo Fernández-Navarro, Javier García-Pérez, Francisco Bolumar, Isabel Río, Lance A. Waller, Instituto de Salud Carlos III, and Ministerio de Ciencia e Innovación (España)
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Pregnancy ,Environmental Engineering ,Specific risk ,Vulnerability ,Preterm birth ,Spatial distribution ,medicine.disease ,Adverse birth outcomes ,Low birth weight ,Geography ,Relative risk ,Environmental health ,Maps ,medicine ,Environmental Chemistry ,medicine.symptom ,General Agricultural and Biological Sciences ,Geographical variation ,Observation unit - Abstract
The objective of this study was to describe the spatial risk-patterns of prematurity and low birth weight in Spain. A descriptive spatial analysis of births registered in the Spanish Vital Statistics during 2004–2008 using municipalities as the observation unit was carried out. Besag-York-Mollié autoregressive spatial models were adjusted using the Integrated Nested Laplace approximation to calculate relative risks and posterior probabilities of having very and moderate preterm or low weight newborns. Results were represented in maps to assess geographic risk-patterns. Spatial analysis shows geographical variations in the risk of adverse reproductive outcomes in Spain highlighting three main high-risk zones, namely, municipalities in Asturias, Madrid City and Murcia. The specific risk patterns identified on each zone suggests some differences regarding the potential underlying risk factors and specific areas for future research. A differential exposure during pregnancy to some risks potentially related to industry or agriculture and other contextual factors could underlie an unequal vulnerability to adverse reproductive outcomes in some Spanish regions. Fondo de Investigación Sanitaria (PI081330); Spanish Ministry of Science and Innovation (SEJ 2005/07679); CIBER en Epidemiología y Salud Pública (CIBERESP), Spain. Sí
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- 2013
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19. Landscape and environmental influences on Mycobacterium ulcerans distribution among aquatic sites in Ghana
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Julie A. Clennon, Heather R. Jordan, Charles Quaye, Shannon M. Pileggi, Ryan Kimbirauskas, Lance A. Waller, Ellen A. Whitney, Lindsay P. Campbell, Jiaguo Qi, Daniel A. Boakye, Pamela L. C. Small, Jenni Gronseth, William Opare, M. Eric Benbow, Mollie D. McIntosh, Edwin Ampadu, and Richard W. Merritt
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0301 basic medicine ,Buruli ulcer ,Bacterial Diseases ,Statistical methods ,lcsh:Medicine ,Distribution (economics) ,Wetland ,Pathology and Laboratory Medicine ,Ghana ,West africa ,Geographical Locations ,0302 clinical medicine ,Environmental Geography ,Medicine and Health Sciences ,lcsh:Science ,Buruli Ulcer ,Multidisciplinary ,geography.geographical_feature_category ,Ecology ,Actinobacteria ,Monte Carlo method ,Physical sciences ,Infectious Diseases ,Mycobacterium ulcerans ,Pathogens ,Research Article ,Neglected Tropical Diseases ,Infectious Disease Control ,030231 tropical medicine ,030106 microbiology ,Statistics (mathematics) ,Biology ,Environment ,Spatial distribution ,03 medical and health sciences ,Rivers ,Water Supply ,Surface Water ,medicine ,Humans ,Ponds ,Ecological niche ,geography ,Bacteria ,business.industry ,lcsh:R ,Ecology and Environmental Sciences ,Organisms ,Biology and Life Sciences ,15. Life on land ,biology.organism_classification ,medicine.disease ,Tropical Diseases ,Research and analysis methods ,Causal association ,Wetlands ,People and Places ,Africa ,Earth Sciences ,Mathematical and statistical techniques ,lcsh:Q ,Hydrology ,business ,Mathematics - Abstract
Buruli ulcer, caused by Mycobacterium ulcerans, is highly endemic in West Africa. While the mode of transmission is unknown, many studies associate Buruli ulcer with different types of water exposure. We present results from the largest study to date to test for M. ulcerans in aquatic sites and identify environmental attributes associated with its presence. Environmental samples from 98 aquatic sites in the Greater Accra, Ashanti, and Volta regions of Ghana were tested for the presence of M. ulcerans DNA by polymerase chain reaction. The proportion of aquatic sites positive for M. ulcerans varied by region: Ashanti 66% (N = 39), Greater Accra 34% (N = 29), and Volta 0% (N = 30). We explored the spatial distribution of M. ulcerans positive and negative water bodies and found no significant clusters. We also determined both highly localized water attributes and broad scale remotely sensed land cover and terrain environmental characteristics associated with M. ulcerans presence through logistic regression. Our results concur with published results regarding conditions suitable for M. ulcerans growth and associations with Buruli ulcer disease burden with regards to water characteristics and disturbed environments, but differ from others with regards to spatial associations and topographic effects such as elevation and wetness. While our results suggest M. ulcerans is an environmental organism existing in a specific ecological niche, they also reveal variation in the elements defining this niche across the sites considered. In addition, despite the causal association between Buruli ulcer and M. ulcerans, we observed no significant statistical association between case reports of Buruli ulcer and presence of M. ulcerans in nearby waterbodies.
- Published
- 2016
20. Quantification of exposure to fecal contamination in open drains in four neighborhoods in Accra, Ghana
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Dorothy Peprah, Katharine Robb, Julie A. Clennon, Peter Teunis, Habib Yakubu, Christine L. Moe, Nii Wellington, Stephanie R. Gretsch, Joseph A. Ampofo, Kelly K. Baker, Clair Null, and Heather Reese
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Microbiology (medical) ,Sanitation ,Adolescent ,030231 tropical medicine ,Stormwater ,010501 environmental sciences ,01 natural sciences ,Coliphages ,Ghana ,03 medical and health sciences ,Feces ,0302 clinical medicine ,Environmental health ,Water Quality ,Environmental monitoring ,Escherichia coli ,Humans ,Coliphage ,Drainage ,Child ,Waste Management and Disposal ,0105 earth and related environmental sciences ,Water Science and Technology ,biology ,Public Health, Environmental and Occupational Health ,Environmental engineering ,Infant ,Environmental exposure ,Environmental Exposure ,biology.organism_classification ,Fecal coliform ,Infectious Diseases ,Child, Preschool ,Environmental science ,Water quality ,Water Microbiology ,Environmental Monitoring - Abstract
In low-income countries, rapid urbanization adds pressure to already stressed water and sanitation systems that are critical to the health of communities. Drainage networks, designed for stormwater but commonly used for disposing of waste, are rarely covered completely, allowing residents to easily come into contact with their contents. This study used spatial mapping, documentation of physical drain characteristics, microbiological analysis of drain samples, and behavioral observation to comprehensively examine drains as a route of exposure to fecal contamination in four low-income neighborhoods in Accra, Ghana. A stochastic model of six likely exposure scenarios was constructed to estimate children's exposure to drain water. Regardless of the age of the child, any exposure scenario considered resulted in exposure to a high level of fecal contamination. Fecal contamination levels in drains were high (Escherichia coli: geometric mean (GM), 8.60 cfu log10/100 mL; coliphage: GM, 5.56 pfu log10/100 mL), and did not differ by neighborhood or physical drain characteristics, indicating that frequency of contact with drains, and not drain type or location, drives exposure risk. To mitigate health risks associated with this exposure, drains should be covered, with priority given to large concrete and small to medium dirt-lined drains that children were most commonly observed entering.
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- 2016
21. SPATIAL AND TEMPORAL VARIATIONS IN LOCAL TRANSMISSION OF SCHISTOSOMA HAEMATOBIUM IN MSAMBWENI, KENYA
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Julie A. Clennon, Charles H. King, Eric M. Muchiri, Uriel Kitron, and Peter Mungai
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Schistosoma haematobium ,biology ,Ecology ,Intermediate host ,Zoology ,Schistosomiasis ,biology.organism_classification ,medicine.disease ,law.invention ,Infectious Diseases ,Transmission (mechanics) ,law ,Virology ,parasitic diseases ,medicine ,Spatial ecology ,Common spatial pattern ,Parasitology ,Bulinus ,Spatial variability - Abstract
As part of an extensive study of the eco-epidemiology of urinary schistosomiasis along the southern coast of Kenya, spatial and temporal transmission patterns were associated with various ponds infested with Bulinus snails. The household-level spatial pattern of infection for children of various age groups in 2000 was contrasted with historical data from 1984. Significant local clustering of high and low infection levels among school age children was detected, and the spatial extent of clusters and their direction from specific water sources were measured. High infection levels were clustered around ponds known to contain Bulinus nasutus snails that shed Schistosoma haematobium cercariae, and low infection levels were concentrated near a river where intermediate host snails were rarely found. The spatial patterns of infection varied between 2000 and 1984 and between age groups. High levels of infection were clustered around different transmission foci in the two study periods, and, for younger children in 2000, were clustered nearer to the transmission foci than for the older children. Simultaneous consideration of the effects of different foci on transmission will allow for targeted application of control measures aimed at interrupting S. haematobium transmission at a local level.
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- 2006
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22. SPATIAL PATTERNS OF URINARY SCHISTOSOMIASIS INFECTION IN A HIGHLY ENDEMIC AREA OF COASTAL KENYA
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Peter Mungai, John H. Ouma, H. Curtis Kariuki, Julie A. Clennon, Eric M. Muchiri, Charles H. King, and Uriel Kitron
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Schistosoma haematobium ,biology ,Ecology ,Schistosomiasis ,Snail ,biology.organism_classification ,medicine.disease ,law.invention ,Infectious Diseases ,Transmission (mechanics) ,law ,Virology ,Environmental health ,biology.animal ,parasitic diseases ,Spatial ecology ,medicine ,Parasitology ,Trematoda ,Spatial analysis ,Disease burden - Abstract
Urinary schistosomiasis remains a major contributor to the disease burden along the southern coast of Kenya. Selective identification of transmission hot spots offers the potential for more effective, highly-focal snail control and human chemotherapy to reduce Schistosoma haematobium transmission. In the present study, a geographic information system was used to integrate demographic, parasitologic, and household location data for an endemic village and neighboring households with the biotic, abiotic, and location data for snail collection/water contact sites. A global spatial statistic was used to detect area-wide trends of clustering for human infection at the household level. Local spatial statistics were then applied to detect specific household clusters of infection, and, as a focal spatial statistic, to evaluate clustering of infection around a putative transmission site. High infection intensities were clustered significantly around a water contact site with high numbers of snails shedding S. haematobium cercariae. When age was considered, clustering was found to be significant at different distances for different age groups.
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- 2004
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23. Use of remote sensing to identify spatial risk factors for malaria in a region of declining transmission: a cross-sectional and longitudinal community survey
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Timothy Shields, Aniset Kamanga, Harry Hamapumbu, William J. Moss, Julie A. Clennon, Tamaki Kobayashi, Philip E. Thuma, Sungano Mharakurwa, and Gregory E. Glass
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Adult ,Wet season ,lcsh:Arctic medicine. Tropical medicine ,Adolescent ,lcsh:RC955-962 ,Cross-sectional study ,Psychological intervention ,Zambia ,Shuttle Radar Topography Mission ,Parasitemia ,lcsh:Infectious and parasitic diseases ,law.invention ,Young Adult ,Risk Factors ,law ,parasitic diseases ,medicine ,Humans ,lcsh:RC109-216 ,Longitudinal Studies ,Child ,Sampling frame ,Remote sensing ,Rapid diagnostic test ,Geography ,Data Collection ,Research ,medicine.disease ,Malaria ,Cross-Sectional Studies ,Infectious Diseases ,Transmission (mechanics) ,Child, Preschool ,Remote Sensing Technology ,Parasitology - Abstract
Background The burden of malaria has decreased dramatically within the past several years in parts of sub-Saharan Africa. Further malaria control will require targeted control strategies based on evidence of risk. The objective of this study was to identify environmental risk factors for malaria transmission using remote sensing technologies to guide malaria control interventions in a region of declining burden of malaria. Methods Satellite images were used to construct a sampling frame for the random selection of households enrolled in prospective longitudinal and cross-sectional surveys of malaria parasitaemia in Southern Province, Zambia. A digital elevation model (DEM) was derived from the Shuttle Radar Topography Mission version 3 DEM and used for landscape characterization, including landforms, elevation, aspect, slope, topographic wetness, topographic position index and hydrological models of stream networks. Results A total of 768 individuals from 128 randomly selected households were enrolled over 21 months, from the end of the rainy season in April 2007 through December 2008. Of the 768 individuals tested, 117 (15.2%) were positive by malaria rapid diagnostic test (RDT). Individuals residing within 3.75 km of a third order stream were at increased risk of malaria. Households at elevations above the baseline elevation for the region were at decreasing risk of having RDT-positive residents. Households where new infections occurred were overlaid on a risk map of RDT positive households and incident infections were more likely to be located in high-risk areas derived from prevalence data. Based on the spatial risk map, targeting households in the top 80th percentile of malaria risk would require malaria control interventions directed to only 24% of the households. Conclusions Remote sensing technologies can be used to target malaria control interventions in a region of declining malaria transmission in southern Zambia, enabling a more efficient use of resources for malaria elimination.
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- 2011
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24. Hydrological modelling of snail dispersal patterns in Msambweni, Kenya and potential resurgence of Schistosoma haematobium transmission
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Charles H. King, Eric M. Muchiri, Julie A. Clennon, and Uriel Kitron
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Schistosoma haematobium ,biology ,Ecology ,Snails ,Intermediate host ,Water ,Snail ,biology.organism_classification ,Kenya ,Models, Biological ,Human morbidity ,Schistosomiasis haematobia ,Infectious Diseases ,Habitat ,biology.animal ,Gastropoda ,Biological dispersal ,Animals ,Humans ,Animal Science and Zoology ,Parasitology ,Bulinus ,Ecosystem ,Demography - Abstract
SUMMARYUrinary schistosomiasis is an important source of human morbidity in Msambweni, Kenya, where the intermediate host snail,Bulinus nasutusis found in ponds and water pools. In the past, aquatic habitats in the area have been studied separately; however, recent collections ofB. nasutussnails and shells indicated that many of these ponds are in fact connected during and following sufficient rains. Satellite imagery and a geographical information system (GIS) were used to survey the main water courses and potential drainage routes, to locate potential source populations of snails and to determine probable snail dispersal routes. The 2 water bodies implicated as being the most importantSchistosoma haematobiumtransmission foci in the area were found to differ in their degree of connectivity to otherB. nasutussource habitats. One pond becomes connected even after normal rains, while the other pond requires prolonged rains or flooding to become connected with source habitats. Consequently, the transmission foci differ in their susceptibility to snail population control measures. Spatially explicit dispersal models that consider the spatial and temporal patterns of connectivity between aquatic habitats will contribute to improved snail surveillance and more focused control for urinary schistosomiasis at a local level.
- Published
- 2006
25. Upscale or downscale: applications of fine scale remotely sensed data to Chagas disease in Argentina and schistosomiasis in Kenya
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M. Carla Cecere, Uriel Kitron, Julie A. Clennon, Gonzalo M. Vazquez-Prokopec, Charles H. King, and Ricardo E. Gürtler
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Health (social science) ,Geospatial analysis ,Geography, Planning and Development ,Argentina ,Medicine (miscellaneous) ,lcsh:G1-922 ,Disease Vectors ,computer.software_genre ,Risk Assessment ,Article ,Unit (housing) ,remote sensing, spatial statistics, scale, clustering, Chagas disease, schistosomiasis ,Animals ,Humans ,Schistosomiasis ,Chagas Disease ,Spacecraft ,Temporal scales ,Spatial analysis ,Ecology ,Health Policy ,Kenya ,Spatial heterogeneity ,Geography ,Population Surveillance ,Epidemiological Monitoring ,Biological dispersal ,Public Health ,Scale (map) ,computer ,Cartography ,lcsh:Geography (General) ,Environmental Monitoring - Abstract
Depending on the research question or the public health application, the appropriate resolution of the data varies temporally, spatially, and, for satellite data, spectrally and radiometrically. Regardless of the scale used to address a research or public health question, the temptation is always there to extrapolate from fine-resolution data or to interpolate from coarse resolution studies. In both cases, the relevance of data and analyses conducted on one spatial level to other levels cannot be taken for granted. Spatial heterogeneity on the micro-scale may not be detected using coarse spatial resolution, and conversely, general patterns on the macro-scale may not be detected using fine spatial resolution. Two studies are described where the transmission dynamics and risk of infection was assessed on the micro-scale starting with household level studies in one community, and the study area was extended gradually to consider several communities and sources for vectors or intermediate hosts. In a study of Chagas disease in northwest Argentina, the reinfestation process of communities by the main domestic vector was analyzed using spatial statistics; sources within and outside communities as well as the distance of reinfestation were identified. In a study of urinary schistosomiasis in coastal Kenya, age dependent and directional focal clustering of infections was detected around some aquatic habitats, and a hydrological model was developed to detect least cost dispersal routes that allow snails to reinfest dried-up habitats. Some general aspects of focal statistics are discussed. Several general questions need to be considered in geospatial health studies, including the following: (i) what are the best criteria for selecting the spatial (and temporal) unit of intervention and analysis? (ii) how do the key measures of risk and transmission dynamics vary with scale? (iii) how do we integrate processes occurring at diverse spatial and temporal scales? All of these questions can only be addressed through solid biological, epidemiological and socio-economic understanding of the system in time and space.
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- 2006
26. Distribution patterns and cercarial shedding of Bulinus nasutus and other snails in the Msambweni area, Coast Province, Kenya
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H Curtis, Kariuki, Julie A, Clennon, Melinda S, Brady, Uriel, Kitron, Robert F, Sturrock, John H, Ouma, Saidi Tosha Malick, Ndzovu, Peter, Mungai, Orit, Hoffman, Joseph, Hamburger, Cara, Pellegrini, Eric M, Muchiri, and Charles H, King
- Subjects
Schistosomiasis haematobia ,Bulinus ,Schistosoma haematobium ,Animals ,Cluster Analysis ,Humans ,Water ,Disease Vectors ,Hydrogen-Ion Concentration ,Satellite Communications ,Kenya - Abstract
In the Msambweni area of the Kwale District in Kenya, an area endemic for Schistosoma haematobium, potential intermediate-host snails were systematically surveyed in water bodies associated with human contact that were previously surveyed in the 1980s. Bulinus (africanus) nasutus, which accounted for 67% of the snails collected, was the only snail shedding S. haematobium cercariae. Lanistes purpureus was the second most common snail (25%); lower numbers of Bulinus forskalii and Melanoides tuberculata were also recovered. Infection with non-S. haematobium trematodes was found among all snail species. Rainfall was significantly associated with the temporal distribution of all snail species: high numbers of Bulinus nasutus developed after extensive rainfall, followed, in turn, by increased S. haematobium shedding. Spatial distribution of snails was significantly clustered over a range of up to 1 km, with peak clustering observed at a distance of 400 meters. Water lily (Nymphaea spp.) and several aquatic grass species appeared necessary for local colonization by B. nasutus or L. purpureus.
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- 2004
27. Distribution patterns and cercarial shedding of Bulinus nasutus and other snails in the Msambweni area, Coast Province, Kenya
- Author
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Cara Pellegrini, John H. Ouma, Julie A. Clennon, Orit Hoffman, Joseph Hamburger, Robert F. Sturrock, Melinda S. Brady, Peter Mungai, Uriel Kitron, Charles H. King, Eric M. Muchiri, Saidi Tosha Malick Ndzovu, and H. Curtis Kariuki
- Subjects
Lanistes ,Schistosoma haematobium ,0303 health sciences ,biology ,Ecology ,030231 tropical medicine ,Zoology ,Snail ,biology.organism_classification ,Melanoides ,Pulmonata ,030308 mycology & parasitology ,03 medical and health sciences ,0302 clinical medicine ,Infectious Diseases ,Bulinus forskalii ,Virology ,biology.animal ,Gastropoda ,Parasitology ,Bulinus - Abstract
In the Msambweni area of the Kwale District in Kenya, an area endemic for Schistosoma haematobium, potential intermediate-host snails were systematically surveyed in water bodies associated with human contact that were previously surveyed in the 1980s. Bulinus (africanus) nasutus, which accounted for 67% of the snails collected, was the only snail shedding S. haematobium cercariae. Lanistes purpureus was the second most common snail (25%); lower numbers of Bulinus forskalii and Melanoides tuberculata were also recovered. Infection with non-S. haematobium trematodes was found among all snail species. Rainfall was significantly associated with the temporal distribution of all snail species: high numbers of Bulinus nasutus developed after extensive rainfall, followed, in turn, by increased S. haematobium shedding. Spatial distribution of snails was significantly clustered over a range of up to 1 km, with peak clustering observed at a distance of 400 meters. Water lily (Nymphaea spp.) and several aquatic grass species appeared necessary for local colonization by B. nasutus or L. purpureus.
- Published
- 2004
28. Identifying malaria vector breeding habitats with remote sensing data and terrain-based landscape indices in Zambia
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Clive Shiff, Aniset Kamanga, Julie A. Clennon, Gregory E. Glass, and Mulenga Musapa
- Subjects
Wet season ,General Computer Science ,030231 tropical medicine ,Business, Management and Accounting(all) ,Plasmodium falciparum ,Zambia ,Terrain ,Shuttle Radar Topography Mission ,lcsh:Computer applications to medicine. Medical informatics ,03 medical and health sciences ,0302 clinical medicine ,Dry season ,parasitic diseases ,Anopheles ,Animals ,Humans ,Satellite imagery ,030212 general & internal medicine ,Malaria, Falciparum ,Digital elevation model ,Ecosystem ,biology ,Research ,fungi ,Public Health, Environmental and Occupational Health ,15. Life on land ,biology.organism_classification ,General Business, Management and Accounting ,3. Good health ,Insect Vectors ,Geography ,Logistic Models ,Habitat ,Population Surveillance ,Multivariate Analysis ,lcsh:R858-859.7 ,Cartography ,Computer Science(all) - Abstract
Background Malaria, caused by the parasite Plasmodium falciparum, is a significant source of morbidity and mortality in southern Zambia. In the Mapanza Chiefdom, where transmission is seasonal, Anopheles arabiensis is the dominant malaria vector. The ability to predict larval habitats can help focus control measures. Methods A survey was conducted in March-April 2007, at the end of the rainy season, to identify and map locations of water pooling and the occurrence anopheline larval habitats; this was repeated in October 2007 at the end of the dry season and in March-April 2008 during the next rainy season. Logistic regression and generalized linear mixed modeling were applied to assess the predictive value of terrain-based landscape indices along with LandSat imagery to identify aquatic habitats and, especially, those with anopheline mosquito larvae. Results Approximately two hundred aquatic habitat sites were identified with 69 percent positive for anopheline mosquitoes. Nine species of anopheline mosquitoes were identified, of which, 19% were An. arabiensis. Terrain-based landscape indices combined with LandSat predicted sites with water, sites with anopheline mosquitoes and sites specifically with An. arabiensis. These models were especially successful at ruling out potential locations, but had limited ability in predicting which anopheline species inhabited aquatic sites. Terrain indices derived from 90 meter Shuttle Radar Topography Mission (SRTM) digital elevation data (DEM) were better at predicting water drainage patterns and characterizing the landscape than those derived from 30 m Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) DEM. Conclusions The low number of aquatic habitats available and the ability to locate the limited number of aquatic habitat locations for surveillance, especially those containing anopheline larvae, suggest that larval control maybe a cost-effective control measure in the fight against malaria in Zambia and other regions with seasonal transmission. This work shows that, in areas of seasonal malaria transmission, incorporating terrain-based landscape models to the planning stages of vector control allows for the exclusion of significant portions of landscape that would be unsuitable for water to accumulate and for mosquito larvae occupation. With increasing free availability of satellite imagery such as SRTM and LandSat, the development of satellite imagery-based prediction models is becoming more accessible to vector management coordinators.
- Published
- 2010
29. Urban sanitation coverage and environmental fecal contamination: Links between the household and public environments of Accra, Ghana.
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David M Berendes, Amy E Kirby, Julie A Clennon, Chantal Agbemabiese, Joseph A Ampofo, George E Armah, Kelly K Baker, Pengbo Liu, Heather E Reese, Katharine A Robb, Nii Wellington, Habib Yakubu, and Christine L Moe
- Subjects
Medicine ,Science - Abstract
Exposure to fecal contamination in public areas, especially in dense, urban environments, may significantly contribute to enteric infection risk. This study examined associations between sanitation and fecal contamination in public environments in four low-income neighborhoods in Accra, Ghana. Soil (n = 72) and open drain (n = 90) samples were tested for E. coli, adenovirus, and norovirus. Sanitation facilities in surveyed households (n = 793) were categorized by onsite fecal sludge containment ("contained" vs. "uncontained") using previous Joint Monitoring Program infrastructure guidelines. Most sanitation facilities were shared by multiple households. Associations between spatial clustering of household sanitation coverage and fecal contamination were examined, controlling for neighborhood and population density (measured as enumeration areas in the 2010 census and spatially matched to sample locations). E. coli concentrations in drains within 50m of clusters of contained household sanitation were more than 3 log-units lower than those outside of clusters. Further, although results were not always statistically significant, E. coli concentrations in drains showed consistent trends with household sanitation coverage clusters: concentrations were lower in or near clusters of high coverage of household sanitation facilities-especially contained facilities-and vice versa. Virus detection in drains and E. coli concentrations in soil were not significantly associated with clustering of any type of household sanitation and did not exhibit consistent trends. Population density alone was not significantly associated with any of the fecal contamination outcomes by itself and was a significant, yet inconsistent, effect modifier of the association between sanitation clusters and E. coli concentrations. These findings suggest clustering of contained household sanitation, even when shared, may be associated with lower levels of fecal contamination within drains in the immediate public domain. Further research is needed to better quantify these relationships and examine impacts on health.
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- 2018
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30. Landscape and environmental influences on Mycobacterium ulcerans distribution among aquatic sites in Ghana.
- Author
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Shannon M Pileggi, Heather Jordan, Julie A Clennon, Ellen Whitney, M Eric Benbow, Richard Merritt, Mollie McIntosh, Ryan Kimbirauskas, Pamela Small, Daniel Boakye, Charles Quaye, Jiaguo Qi, Lindsay Campbell, Jenni Gronseth, Edwin Ampadu, William Opare, and Lance A Waller
- Subjects
Medicine ,Science - Abstract
Buruli ulcer, caused by Mycobacterium ulcerans, is highly endemic in West Africa. While the mode of transmission is unknown, many studies associate Buruli ulcer with different types of water exposure. We present results from the largest study to date to test for M. ulcerans in aquatic sites and identify environmental attributes associated with its presence. Environmental samples from 98 aquatic sites in the Greater Accra, Ashanti, and Volta regions of Ghana were tested for the presence of M. ulcerans DNA by polymerase chain reaction. The proportion of aquatic sites positive for M. ulcerans varied by region: Ashanti 66% (N = 39), Greater Accra 34% (N = 29), and Volta 0% (N = 30). We explored the spatial distribution of M. ulcerans positive and negative water bodies and found no significant clusters. We also determined both highly localized water attributes and broad scale remotely sensed land cover and terrain environmental characteristics associated with M. ulcerans presence through logistic regression. Our results concur with published results regarding conditions suitable for M. ulcerans growth and associations with Buruli ulcer disease burden with regards to water characteristics and disturbed environments, but differ from others with regards to spatial associations and topographic effects such as elevation and wetness. While our results suggest M. ulcerans is an environmental organism existing in a specific ecological niche, they also reveal variation in the elements defining this niche across the sites considered. In addition, despite the causal association between Buruli ulcer and M. ulcerans, we observed no significant statistical association between case reports of Buruli ulcer and presence of M. ulcerans in nearby waterbodies.
- Published
- 2017
- Full Text
- View/download PDF
31. Hennessee et al. Respond.
- Author
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Hennessee I, Clennon JA, Waller LA, Kitron U, and Michael Bryan J
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- Humans, COVID-19
- Published
- 2022
- Full Text
- View/download PDF
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