Publications Directory

Publications Directory

Hands and Water as Vectors of Diarrheal Pathogens in Bagamoyo, Tanzania
Mia Catharine Mattioli, Amy Pickering, Rebecca Gilsdorf, Jenna Davis, Ali Boehm

Using molecular methods, this study examines the relative importance of different exposure routes by measuring enteric bacteria (pathogenic Escherichia coli) and viruses (rotavirus, enterovirus, adenovirus) in hand rinses, stored water, and source waters in Bagamoyo, Tanzania.

Water, Sanitation and Health Sub-Saharan Africa Monday, November 26, 2012 Visit Website
The impact of urbanization on water vulnerability: A coupled human-environment system approach for Chennai, India
Veena Srinivasana, Karen C. Setob, Ruth Emerson, Steve Gorelick

This paper examines the relationship between urbanization and water vulnerability for a fast-growing city, Chennai, India, using a coupled human–environment systems (CHES) modeling approach. The result of the study suggest that in order to reduce vulnerability to water shortages, there is a need for new forms of urban governance and planning institutions that are capable of managing both centralized actions by utilities and decentralized actions by millions of households.

Sustainable Service Models South Asia Thursday, November 15, 2012 Visit Website
Scenarios of transmission risk of foot-and-mouth with climatic, social and landscape changes in southern Africa
Elise Diona, Eric Lambin

Part of southern Africa is endemic to foot-and-mouth disease. African buffaloes (Syncerus caffer) living in the Kruger National Park act as virus reservoirs and spread the infection to domestic cattle by close contacts. This study explores potential factors influencing the spatial and temporal risk of disease transmission, based on a spatially-explicit multi-agent simulation that represents the dynamics of buffalo-cattle contacts. The knowledge gained through model simulation experiments is useful to prevent disease transmission and improve the management of disease risk.

Water, Sanitation and Health Sub-Saharan Africa Thursday, November 1, 2012 Visit Website
The nature and causes of the global water crisis: Syndromes from a meta-analysis of coupled human-water studies
V. Srinivasan, Eric Lambin, Steve Gorelick, B. H. Thompson, S. Rozelle

Freshwater scarcity has been cited as the major crisis of the 21st century, but it is surprisingly hard to describe the nature of the global water crisis. This study conducted a meta-analysis of 22 coupled human–water system case studies, using qualitative comparison analysis (QCA) to identify water resource system outcomes and the factors that drive them.

Expanding Access Other Friday, October 5, 2012 Visit Website
Mechanisms for Photoinactivation of Enterococcus faecalis in Seawater
Lauren M. Sassoubre, Kara L. Nelson, Ali Boehm

We investigated sunlight inactivation of Enterococcus faecalis to gain insight into photoinactivation mechanisms and cellular responses to photostress. E. faecalis bacteria were exposed to natural sunlight in clear, filtered seawater under both oxic and anoxic conditions to test the relative importance of oxygen-mediated and non-oxygen-mediated photoinactivation mechanisms. Photoinactivation, based on numbers of cultivable cells, was faster in oxic than in anoxic microcosms exposed to sunlight, suggesting that oxygen-mediated photoinactivation dominated. This research furthers our understanding of photoinactivation mechanisms and the conditions under which diel fluctuations in enterococci can be expected in natural and engineered systems.

Water, Sanitation and Health Other Friday, August 31, 2012 Visit Website
Fecal contamination and diarrheal pathogens on surfaces and in soils among Tanzanian households with and without improved sanitation
Amy Pickering, T. Julian, S. Marks, Mia Catharine Mattioli, Ali Boehm, K. Schwab, Jenna Davis

Little is known about the extent or pattern of environmental fecal contamination among households using low-cost, on-site sanitation facilities, or what role environmental contamination plays in the transmission of diarrheal disease. A microbial survey...

WASH and Development Sub-Saharan Africa Tuesday, June 5, 2012 Visit Website
Salt marsh ecohydrological zonation due to heterogeneous vegetation-groundwater-surface water interactions
Kevan B. Moffett, Steve Gorelick, Robert G. McLaren, Edward A. Sudicky

Vegetation zonation and tidal hydrology are basic attributes of intertidal salt marshes, but specific links among vegetation zonation, plant water use, and spatiotemporally dynamic hydrology have eluded thorough characterization. This study developed a quantitative model of an intensively studied salt marsh field site, integrating coupled 2-D surface water and 3-D groundwater flow and zonal plant water use.

WASH and Development Other Wednesday, February 15, 2012 Visit Website
Freshwater Availability and Water Fetching Distance Affect Child Health in Sub-Saharan Africa
Amy Pickering, Jenna Davis

A 15-min decrease in one-way walk time to water source is associated with a 41% average relative reduction in diarrhea prevalence, improved anthropometric indicators of child nutritional status, and a 11% relative reduction in under-five child mortality. These results suggest that reducing the time cost of fetching water should be a priority for water infrastructure investments in Africa.

Expanding Access Sub-Saharan Africa Thursday, February 9, 2012 Visit Website
Comparison of enterovirus and adenovirus concentration and enumeration methods in seawater from Southern California, USA and Baja Malibu, Mexico
Lauren M. Sassoubre, David C. Love, Andrea I. Silverman, Kara L. Nelson, Ali Boehm

This study examines enterovirus and adenovirus concentrations in coastal water samples collected from four beaches impacted by microbial pollution: (1) Malibu Lagoon, Malibu; (2) Tijuana River, Imperial Beach; (3) Baja Malibu, Baja California; and (4) Punta Bandera, Baja California. The detection of viruses by MF and (RT)QPCR was positively correlated with the presence of infectious viruses. Further research is needed to determine if detection of viruses by rapid methods such as (RT)QPCR can be a useful water quality monitoring tool to assess health risks in recreational waters.

Water, Sanitation and Health North America Sunday, January 1, 2012 Visit Website
Smallholder irrigation as a poverty alleviation tool in sub-Saharan Africa
Jennifer A. Burney, Rosamond Naylor

Burney and Naylor evaluate three important sub-components of irrigation technology--access, distribution, and use-- and the ways in which the design of the technology can either bridge, or succumb to, institutional gaps as they apply to a solar-powered drip irrigation project in rural, northern Benin. The combined evidence highlights the technical and institutional requirements for project success and points to two important areas of research in the scale-up of any small-scale irrigation strategy: the risk behavior of water users, and the evolution of institutions that either support or obstruct project replication over space and time.

WASH and Development Sub-Saharan Africa Sunday, January 1, 2012 Visit Website
Solar inactivation of four Salmonella serovars in fresh and marine waters
Ali Boehm, Cherrie Soetjipto, Dan Wang

This study sought to document the photo-inactivation of environmental isolates of Salmonella in filter-sterilized natural seawater and freshwater and to test the hypothesis that diverse Salmonella serovars decay at similar rates both within and between water matrices. The inactivation of Salmonella enterica Typhimurium LT2, Typhimurium ST19, Heidelberg, and Mbandaka was examined in sunlit and dark microcosms. The results document intra-species variation in photo-inactivation, likely owing to differences in intracellular concentrations of photo-sensitizing molecules or molecules that quench reactive species.

Water, Sanitation and Health Other Sunday, January 1, 2012 Visit Website
Climate trends and global crop production since 1980
David Lobell, Wolfram Schlenker, Justin Costa-Roberts

A study of how trends in climate have affected crop productivity in different regions, and the relevant importance of temperature and rainfall.

Sustainable Service Models, WASH and Development Other Friday, July 29, 2011 Visit Website
Understanding Household Behavioral Risk Factors for Diarrheal Disease in Dar es Salaam: A Photovoice Community Assessment
Natalie Badowski, Cynthia M. Castro, Maggie Montgomery, Amy Pickering, Simon Mamuya, Jenna Davis

This study utilized a qualitative, cross-sectional, modified Photovoice method to capture daily activities of Dar es Salaam mothers. The photographs and interviews revealed insufficient hand washing procedures, unsafe disposal of wastewater, uncovered household drinking water containers, a lack of water treatment prior to consumption, and inappropriate toilets for use by small children. The results draw attention to the real economic and behavioral challenges faced in reducing the spread of disease.

Water, Sanitation and Health Sub-Saharan Africa Wednesday, July 27, 2011 Visit Website
Swimmer risk of gastrointestinal illness from exposure to tropical coastal waters contaminated with terrestrial runoff
Emily J. Viau, Debbie Lee, Ali Boehm

This study used molecular methods to measure concentrations of four enteric viruses (adenovirus, enterovirus, norovirus GI, and norovirus GII) and fecal source tracking markers (human, ruminant, and pig Bacteroidales) in land-based runoff from 22 tropical streams on O’ahu, Hawai’i. Virus concentrations and culturable Salmonella and Campylobacter were used as inputs to a quantitative microbial risk assessment model to estimate the risk of acquiring gastrointestinal illness from swimming in tropical marine waters adjacent to discharging streams. The results of the study suggest land-based runoff in the tropics as a potential source of GI illness risk, with pathogens coming from both human and nonhuman nonpoint sources including septic tanks.

Water, Sanitation and Health North America Friday, July 22, 2011 Visit Website
The landscape epidemiology of foot-and-mouth disease in South Africa: A spatially-explicit multi-agent simulation
Elise Diona, Louis VanSchalkwyk, Eric Lambin

This study aimed at understanding how landscape heterogeneity influences outbreaks of contagious diseases in southern Africa. A multi-agent simulation was developed to represent the spatial and temporal dynamics of pathogens between human-livestock and wildlife interfaces at the fringe of large wildlife conservation areas. Results show that cattle–buffalo contacts mostly depend on the range of displacements of cattle and buffaloes, as influenced by the landscape configuration, and on the number of fence breakages multiplied by the time between breakage and repair.

Water, Sanitation and Health Sub-Saharan Africa Sunday, July 10, 2011 Visit Website