Christopher D. Heaney

Concentration and Detection of Cryptosporidium Oocysts in Surface Water Samples by Method 1622 Using Ultrafiltration and Capsule Filtration

ABSTRACT The protozoan parasite Cryptosporidium parvumis known to occur widely in both source and drinking water and has caused waterborne outbreaks of gastroenteritis. To improve monitoring, the U.S. Environmental Protection Agency developed method 1622 for isolation and detection of Cryptosporidium oocysts in water. Method 1622 is performance based and involves filtration, concentration, immunomagnetic separation, fluorescent-antibody staining and 4′,6-diamidino-2-phenylindole (DAPI) counterstaining, and microscopic evaluation. The capsule filter system currently recommended for method 1622 was compared to a hollow-fiber ultrafilter system for primary concentration of C. parvum oocysts in seeded reagent water and untreated surface waters. Samples were otherwise processed according to method 1622. Rates of C. parvumoocyst recovery from seeded 10-liter volumes of reagent water in precision and recovery experiments with filter pairs were 42% (standard deviation [SD], 24%) and 46% (SD, 18%) for hollow-fiber ultrafilters and capsule filters, respectively. Mean oocyst recovery rates in experiments testing both filters on seeded surface water samples were 42% (SD, 27%) and 15% (SD, 12%) for hollow-fiber ultrafilters and capsule filters, respectively. Although C. parvum oocysts were recovered from surface waters by using the approved filter of method 1622, the recovery rates were significantly lower and more variable than those from reagent grade water. In contrast, the disposable hollow-fiber ultrafilter system was compatible with subsequent method 1622 processing steps, and it recovered C. parvum oocysts from seeded surface waters with significantly greater efficiency and reliability than the filter suggested for use in the version of method 1622 tested.

Contact with beach sand among beachgoers and risk of illness.

Recent studies of beach sand fecal contamination have triggered interest among scientists and in the media. Although evidence shows that beach sand can harbor high concentrations of fecal indicator organisms, as well as fecal pathogens, illness risk associated with beach sand contact is not well understood. Beach visitors at 7 US beaches were enrolled in the National Epidemiological and Environmental Assessment of Recreational Water (NEEAR) Study during 2003-2005 and 2007 and asked about sand contact on the day of their visit to the beach (digging in the sand, body buried in the sand). Then, 10-12 days after their visit, participants were telephoned to answer questions about any health symptoms experienced since the visit. The authors completed 27,365 interviews. Digging in the sand was positively associated with gastrointestinal illness (adjusted incidence proportion ratio (aIPR) = 1.13, 95% confidence interval (CI): 1.02, 1.25) and diarrhea (aIPR = 1.20, 95% CI: 1.05, 1.36). The association was stronger between those buried in the sand and gastrointestinal illness (aIPR = 1.23, 95% CI: 1.05, 1.43) and diarrhea (aIPR = 1.24, 95% CI: 1.01, 1.52). Nonenteric illnesses did not show a consistent association with sand contact activities. Sand contact activities were associated with enteric illness at beach sites. Variation in beach-specific results suggests that site-specific factors may be important in the risk of illness following sand exposure.

Livestock-Associated Methicillin and Multidrug Resistant Staphylococcus aureus Is Present among Industrial, Not Antibiotic-Free Livestock Operation Workers in North Carolina

Objectives Administration of antibiotics to food animals may select for drug-resistant pathogens of clinical significance, such as methicillin-resistant Staphylococcus aureus (MRSA). In the United States, studies have examined prevalence of MRSA carriage among individuals exposed to livestock, but prevalence of multidrug-resistant S. aureus (MDRSA) carriage and the association with livestock raised with versus without antibiotic selective pressure remains unclear. We aimed to examine prevalence, antibiotic susceptibility, and molecular characteristics of S. aureus among industrial livestock operation (ILO) and antibiotic-free livestock operation (AFLO) workers and household members in North Carolina. Methods Participants in this cross-sectional study were interviewed and provided a nasal swab for S. aureus analysis. Resulting S. aureus isolates were assessed for antibiotic susceptibility, multi-locus sequence type, and absence of the scn gene (a marker of livestock association). Results Among 99 ILO and 105 AFLO participants, S. aureus nasal carriage prevalence was 41% and 40%, respectively. Among ILO and AFLO S. aureus carriers, MRSA was detected in 7% (3/41) and 7% (3/42), respectively. Thirty seven percent of 41 ILO versus 19% of 42 AFLO S. aureus-positive participants carried MDRSA. S. aureus clonal complex (CC) 398 was observed only among workers and predominated among ILO (13/34) compared with AFLO (1/35) S. aureus-positive workers. Only ILO workers carried scn-negative MRSA CC398 (2/34) and scn-negative MDRSA CC398 (6/34), and all of these isolates were tetracycline resistant. Conclusions Despite similar S. aureus and MRSA prevalence among ILO and AFLO-exposed individuals, livestock-associated MRSA and MDRSA (tetracycline-resistant, CC398, scn-negative) were only present among ILO-exposed individuals. These findings support growing concern about antibiotics use and confinement in livestock production, raising questions about the potential for occupational exposure to an opportunistic and drug-resistant pathogen, which in other settings including hospitals and the community is of broad public health importance.

Relation between malodor, ambient hydrogen sulfide, and health in a community bordering a landfill ☆

BACKGROUND Municipal solid waste landfills are sources of air pollution that may affect the health and quality of life of neighboring communities. OBJECTIVES To investigate health and quality of life concerns of neighbors related to landfill air pollution. METHODS Landfill neighbors were enrolled and kept twice-daily diaries for 14d about odor intensity, alteration of daily activities, mood states, and irritant and other physical symptoms between January and November 2009. Concurrently, hydrogen sulfide (H(2)S) air measurements were recorded every 15-min. Relationships between H(2)S, odor, and health outcomes were evaluated using conditional fixed effects regression models. RESULTS Twenty-three participants enrolled and completed 878 twice-daily diary entries. H(2)S measurements were recorded over a period of 80d and 1-h average H(2)S=0.22ppb (SD=0.27; range: 0-2.30ppb). Landfill odor increased 0.63 points (on 5-point Likert-type scale) for every 1ppb increase in hourly average H(2)S when the wind was blowing from the landfill towards the community (95% confidence interval (CI): 0.29, 0.91). Odor was strongly associated with reports of alteration of daily activities (odds ratio (OR)=9.0; 95% CI: 3.5, 23.5), negative mood states (OR=5.2; 95% CI: 2.8, 9.6), mucosal irritation (OR=3.7; 95% CI=2.0, 7.1) and upper respiratory symptoms (OR=3.9; 95% CI: 2.2, 7.0), but not positive mood states (OR=0.6; 95% CI: 0.2, 1.5) and gastrointestinal (GI) symptoms (OR=1.0; 95% CI: 0.4, 2.6). CONCLUSIONS Results suggest air pollutants from a regional landfill negatively impact the health and quality of life of neighbors.

The West End Revitalization Association's community-owned and -managed research model: development, implementation, and action.

Background: Principal investigators (PIs) of community-based projects are predominantly university faculty who partner with community-based organizations (CBOs) to find a place to conduct research in communities that will cooperate with their research objectives. University-managed research models (UMRMs) are not always beneficial for CBOs because the university usually manages the study, collects and owns the data, and leverages control at each stage of research, without priority to resolution of problems impacting the quality of life of participating communities. Objectives: We present the principles of community-owned and -managed research (COMR), as a new community-driven research model developed by the West End Revitalization Association (WERA), a CBO in Mebane, North Carolina. Methods: We describe WERAs development of COMR, compare the power hierarchies of COMR with traditional UMRMs, distinguish COMR partnerships from UMRM partnerships, discuss disbursement of funds, and control/ownership of data. As the PI of research activities, WERA drafted Memoranda of Agreement (MOAs) for all partners, including academic researchers, implemented quality assurance and control procedures, submitted community research protocols for institutional review, and retained data ownership for action, activism, and problem solving. COMR methods encouraged corrective action of environmental justice (EJ) problems in affected communities, including provision of public, regulated drinking water and sewer services. Conclusions: COMR promotes CBOs with demonstrated organizational capacity to PI and project manager. The COMR model goes beyond UMRMs and CBPR because it emphasized the credibility and capacity of CBOs to develop, own, manage, foster, and sustain viable research agendas to address ongoing environmental hazards and related threats to health and quality of life.

Persistence of livestock-associated antibiotic-resistant Staphylococcus aureus among industrial hog operation workers in North Carolina over 14 days

Objectives This study aimed to evaluate the persistence of nasal carriage of Staphylococcus aureus, methicillin-resistant S. aureus and multidrug-resistant S. aureus over 14 days of follow-up among industrial hog operation workers in North Carolina. Methods Workers anticipating at least 24 h away from work were enrolled June–August 2012. Participants self-collected a nasal swab and completed a study journal on the evening of day 1, and each morning and evening on days 2–7 and 14 of the study. S. aureus isolated from nasal swabs were assessed for antibiotic susceptibility, spa type and absence of the scn gene. Livestock association was defined by absence of scn. Results Twenty-two workers provided 327 samples. S. aureus carriage end points did not change with time away from work (mean 49 h; range >0–96 h). Ten workers were persistent and six were intermittent carriers of livestock-associated S. aureus. Six workers were persistent and three intermittent carriers of livestock-associated multidrug-resistant S. aureus. One worker persistently carried livestock-associated methicillin-resistant S. aureus. Six workers were non-carriers of livestock-associated S. aureus. Eighty-two per cent of livestock-associated S. aureus demonstrated resistance to tetracycline. A majority of livestock-associated S. aureus isolates (n=169) were CC398 (68%) while 31% were CC9. No CC398 and one CC9 isolate was detected among scn-positive isolates. Conclusions Nasal carriage of livestock-associated S. aureus, multidrug-resistant S. aureus and methicillin-resistant S. aureus can persist among industrial hog operation workers over a 14-day period, which included up to 96 h away from work.

Hepatitis E virus seroprevalence in three hyperendemic areas: Nepal, Bangladesh and southwest France

BACKGROUND Hepatitis E causes a significant burden of disease in developing countries and has recently been increasingly recognized in developed countries. Comparing population anti-hepatitis E virus (HEV) seroprevalence across populations has been difficult. OBJECTIVES The aim of this study was to compare the anti-HEV IgG seroprevalence in both adults and children in three hyper-endemic areas (Nepal, Bangladesh and southwest France) using a sensitive, commercial anti-HEV IgG assay. STUDY DESIGN Serum or plasma from adults and children in Nepal (n=498), Bangladesh (n=1,009) and Southwest France (n=1031) were tested for anti-HEV IgG using the Wantai assay. RESULTS After age-standardization, anti-HEV IgG seroprevalence was 47.1%, 49.8% and 34.0% in Nepal, Bangladesh and southwest France, respectively. There was no difference in seroprevalence by gender in any of the countries. A paucity of infections in children 1-10 years-old was consistently observed (less than 15%) at all 3 locations. CONCLUSIONS Surprisingly similar high rates of anti-HEV antibodies were detected using a common, sensitive assay. Despite differences in the epidemiology and circulating genotype of HEV in Nepal, Bangladesh and southwest France, this study found more similarities in population seroprevalence than expected.

Source tracking swine fecal waste in surface water proximal to swine concentrated animal feeding operations

Swine farming has gone through many changes in the last few decades, resulting in operations with a high animal density known as confined animal feeding operations (CAFOs). These operations produce a large quantity of fecal waste whose environmental impacts are not well understood. The purpose of this study was to investigate microbial water quality in surface waters proximal to swine CAFOs including microbial source tracking of fecal microbes specific to swine. For one year, surface water samples at up- and downstream sites proximal to swine CAFO lagoon waste land application sites were tested for fecal indicator bacteria (fecal coliforms, Escherichia coli and Enterococcus) and candidate swine-specific microbial source-tracking (MST) markers (Bacteroidales Pig-1-Bac, Pig-2-Bac, and Pig-Bac-2, and methanogen P23-2). Testing of 187 samples showed high fecal indicator bacteria concentrations at both up- and downstream sites. Overall, 40%, 23%, and 61% of samples exceeded state and federal recreational water quality guidelines for fecal coliforms, E. coli, and Enterococcus, respectively. Pig-1-Bac and Pig-2-Bac showed the highest specificity to swine fecal wastes and were 2.47 (95% confidence interval [CI]=1.03, 5.94) and 2.30 times (95% CI=0.90, 5.88) as prevalent proximal down- than proximal upstream of swine CAFOs, respectively. Pig-1-Bac and Pig-2-Bac were also 2.87 (95% CI=1.21, 6.80) and 3.36 (95% CI=1.34, 8.41) times as prevalent when 48 hour antecedent rainfall was greater than versus less than the mean, respectively. Results suggest diffuse and overall poor sanitary quality of surface waters where swine CAFO density is high. Pig-1-Bac and Pig-2-Bac are useful for tracking off-site conveyance of swine fecal wastes into surface waters proximal to and downstream of swine CAFOs and during rain events.

Two Generations of “Gold Standards”: The Impact of a Decade in Hepatitis E Virus Testing Innovation on Population Seroprevalence

Hepatitis E virus (HEV) is a global pathogen responsible for approximately 20 million infections every year in developing countries, yet remains under-recognized. In this population-based cohort study, 1,025 randomly selected participants were enrolled from Matlab, Bangladesh (2004–2005). All participants were tested for HEV antibodies and total immunoglobulin (Ig), using an in-house enzyme immunoassay developed by Walter Reed Army Institute of Research (WRAIR). In 2014, we retested the banked sera of 1,009 of those participants using the Wantai anti-HEV IgG enzyme-linked immunosorbent assay (ELISA). The WRAIR assay estimated the overall population seroprevalence as 26.6% (95% confidence interval [CI]: 24.0, 29.5), whereas the Wantai assay produced significantly higher estimated seroprevalence, 46.7% (95% CI: 43.5–49.8) (P < 0.001). However, the two tests give nearly identical findings in those 5 years and under (N = 94) with a 98% agreement between the tests. Retesting populations with modern assays is necessary to establish better population-level estimates of disease burden.

Water quality, weather and environmental factors associated with fecal indicator organism density in beach sand at two recreational marine beaches

Recent studies showing an association between fecal indicator organisms (FIOs) in sand and gastrointestinal (GI) illness among beachgoers with sand contact have important public health implications because of the large numbers of people who recreate at beaches and engage in sand contact activities. Yet, factors that influence fecal pollution in beach sand remain unclear. During the 2007 National Epidemiological and Environmental Assessment of Recreational (NEEAR) Water Study, sand samples were collected at three locations (60 m apart) on weekend days (Sat, Sun) and holidays between June and September at two marine beaches - Fairhope Beach, AL and Goddard Beach, RI - with nearby publicly-owned treatment works (POTWs) outfalls. F(+) coliphage, enterococci, Bacteroidales, fecal Bacteroides spp., and Clostridium spp. were measured in sand using culture and qPCR-based calibrator-cell equivalent methods. Water samples were also collected on the same days, times and transects as the 144 sand samples and were assayed using the same FIO measurements. Weather and environmental data were collected at the time of sample collection. Mean FIO concentrations in sand varied over time, but not space. Enterococci CFU and CCE densities in sand were not correlated, although other FIOs in sand were. The strongest correlation between FIO density in sand and water was fecal Bacteroides CCE, followed by enterococci CFU, Clostridium spp. CCE, and Bacteroidales CCE. Overall, the factors associated with FIO concentrations in sand were related to the sand-water interface (i.e., sand-wetting) and included daily average densities of FIOs in water, rainfall, and wave height. Targeted monitoring that focuses on daily trends of sand FIO variability, combined with information about specific water quality, weather, and environmental factors may inform beach monitoring and management decisions to reduce microbial burdens in beach sand. The views expressed in this paper are those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency.