Water cooler common source in Norovirus outbreak in China

Posted on August 7, 2016 by Douglas Powell

Noroviruses are a common cause of acute gastroenteritis around the world; however, reports of outbreaks caused by GII.17 norovirus are rare. An outbreak caused by GII.17 norovirus in a senior high school in Wuxi, Jiangsu Province, China is reported here.

An epidemiological investigation, pathogen detection, and case–control study were performed. Epidemiological data combined with the epidemic curve indicated that this outbreak was a point source type initially, followed by secondary transmission. The first case was identified as most likely the source of the outbreak.

Risk analysis showed exposure to patients and sharing a communal water cooler to be associated with the spread of infection. Sequence analysis of GII-positive samples confirmed that the norovirus GII.17 variant was the etiological agent of this outbreak.

An acute gastroenteritis outbreak caused by GII.17 norovirus in Jiangsu Province, China

Chao Shi1, Wei-Hong Feng1, Ping Shi1, Jing Ai, Hong-Xia Guan, Dan Sha, Qian Geng, Jun Mei, Shan-hui Chen, Yong Xiao, Yan-Hua Qian

1Chao Shi, Ping Shi, and Wei-Hong Feng contributed equally to this study.

International Journal of Infectious Diseases, August 2016, Volume 49, Pages 30-32, DOI: http://dx.doi.org/10.1016/j.ijid.2016.05.004

http://www.ijidonline.com/article/S1201-9712(16)31047-5/fulltext

19 sick with crypto in Arizona

Posted on August 6, 2016 by Douglas Powell

Maricopa County Department of Public Health officials are investigating an outbreak of Cryptosporidium, a diarrheal illness caused by a parasite Cryptosporidium parvum, and are advising the public to take precautions to further prevent the spread of this disease.

Public health officials said 19 cases were reported in July. Five of those initial cases have been linked to recreational water facilities.

While officials said some people with Crytosporidium show no symptoms, the most common symptom to be on the lookout for is watery diarrhea usually beginning 2-10 days from infection.

Some other symptoms include stomach cramps, dehydration, nausea, vomiting, fever and weight loss.

While chlorine typically kills most germs in swimming pools, this disease can survive even in properly chlorinated waters for long periods of time.

Olympic advice: Sailors, keep your mouth closed

Posted on July 28, 2016 by Douglas Powell

Andrew Jacobs of The New York Times reports health experts in Brazil have a word of advice for the Olympic marathon swimmers, sailors and windsurfers competing in Rio de Janeiro’s picture-postcard waters next month: Keep your mouth closed.

Despite the government’s promises seven years ago to stem the waste that fouls Rio’s expansive Guanabara Bay and the city’s fabled ocean beaches, officials acknowledge that their efforts to treat raw sewage and scoop up household garbage have fallen far short.

In fact, environmentalists and scientists say Rio’s waters are much more contaminated than previously thought.

Recent tests by government and independent scientists revealed a veritable petri dish of pathogens in many of the city’s waters, from rotaviruses that can cause diarrhea and vomiting to drug-resistant “super bacteria” that can be fatal to people with weakened immune systems.

Researchers at the Federal University of Rio also found serious contamination at the upscale beaches of Ipanema and Leblon, where many of the half-million Olympic spectators are expected to frolic between sporting events.

“Foreign athletes will literally be swimming in human crap, and they risk getting sick from all those microorganisms,” said Dr. Daniel Becker, a local pediatrician who works in poor neighborhoods. “It’s sad, but also worrisome.”

Government officials and the International Olympic Committee acknowledge that, in many places, the city’s waters are filthy. But they say the areas where athletes will compete — like the waters off Copacabana Beach, where swimmers will race — meet World Health Organization safety standards.

Even some venues with higher levels of human waste, like Guanabara Bay, present only minimal risk because athletes sailing or windsurfing in them will have limited contact with potential contamination, they add.

Still, Olympic officials concede that their efforts have not addressed a fundamental problem: Much of the sewage and trash produced by the region’s 12 million inhabitants continues to flow untreated into Rio’s waters.

“Our biggest plague, our biggest environmental problem, is basic sanitation,” said Andrea Correa, the top environmental official in the state of Rio de Janeiro. “The Olympics has woken people up to the problem.”

“A giant pipe running from downtown churns human waste into the marina [on Guanabara Bay] at certain times each day. Rats roam around in the waste. The stench makes uninitiated visitors feel like vomiting or fainting,” USA Today’s Martin Rogers reported Tuesday, less than two weeks before the Games kick off on Aug. 5.

739 sickened in 2007: Cryptosporidium outbreak cost Ireland €19m

Posted on July 12, 2016 by Douglas Powell

Paul Melia of the Irish Independent reports a Cryptosporidium outbreak that resulted in 120,000 people being forced to boil their water for five months cost €19m, a new study shows.

The 2007 outbreak in Galway cost each household €95 and resulted in one in eight hotel and guesthouse bookings being cancelled.

One in five people in the city refuse to drink the tap water today due to concerns about its safety, the study says.

It found that had the water supply to the city and surrounding areas been subjected to an adequate treatment process costing just €1.6m, it would have resulted in an €11 saving for every €1 invested.

The ‘Economic Assessment of the Waterborne Outbreak of Cryptosporidium Hominis in Galway 2007’ study, which was funded by the Environmental Protection Agency (EPA), says the outbreak lasted for 158 days and resulted in 242 confirmed cases of cryptosporidiosis, “although it was likely the actual number affected was far higher”.

– There were 242 notified cases of cryptosporidiosis, with another 497 non-reported cases.

– 45,160 households were affected, and around 120,000 people.

– There was an 80pc increase in bottled water consumption during the outbreak, with a spend of €3.5m. Another €400,000 was spent boiling water.

– Hotels and guesthouses were obliged to provide 4.2 litres of water per day to guests, and the hospitality industry bore costs of €50,000 per day.

Cryptosporidium remains a problem across the country, with the latest data showing that 17 water supplies require upgrades to remove the threat.

The report, compiled by researchers at NUI Galway with an official from the HSE, found that households bore costs totalling €3.9m, the hospitality sector another €8m, while the local authorities spent almost €6m.

Possums, birds and tank water in Queensland: A microbial risk

Posted on July 4, 2016 by Douglas Powell

As Australians begin the workweek with a hung parliament after yet another federal election, I aptly turn my attention to the politicians of the rodent world: possums.

The Australian climate can be harsh, in a No-Country-for-Old-Men sorta way, with temperature extremes, flooding, followed by five years of drought.

So we have new-fangled rain barrels that my grandparents used to have in Ontario (ours, right, exactly as shown and I know there’s possums wandering around there at night because possum poop accumulates).

The rainwater is supposed to be used for toilets, dishes, laundry and other non-potable uses, but is there a risk (no drinking from the garden hose here)?

Here’s the most recent from researchers:

Avian and possum fecal droppings may negatively impact roof-harvested rainwater (RHRW) water quality due to the presence of zoonotic pathogens. This study was aimed at evaluating the performance characteristics of a possum feces-associated (PSM) marker by screening 210 fecal and wastewater samples from possums (n = 20) and a range of nonpossum hosts (n = 190) in Southeast Queensland, Australia.

The host sensitivity and specificity of the PSM marker were 0.90 and 0.95 (maximum value, 1.00), respectively. The mean concentrations of the GFD marker in possum fecal DNA samples (8.8 × 107 gene copies per g of feces) were two orders of magnitude higher than those in the nonpossum fecal DNA samples (5.0 × 105 gene copies per g of feces). The host sensitivity, specificity, and concentrations of the avian feces-associated GFD marker were reported in our recent study (W. Ahmed, V. J. Harwood, K. Nguyen, S. Young, K. Hamilton, and S. Toze, Water Res 88:613–622, 2016, http://dx.doi.org/10.1016/j.watres.2015.10.050). The utility of the GFD and PSM markers was evaluated by testing a large number of tank water samples (n = 134) from the Brisbane and Currumbin areas. GFD and PSM markers were detected in 39 of 134 (29%) and 11 of 134 (8%) tank water samples, respectively. The GFD marker concentrations in PCR-positive samples ranged from 3.7 × 102 to 8.5 × 105 gene copies per liter, whereas the concentrations of the PSM marker ranged from 2.0 × 103 to 6.8 × 103 gene copies per liter of water. The results of this study suggest the presence of fecal contamination in tank water samples from avian and possum hosts.

This study has established an association between the degradation of microbial tank water quality and avian and possum feces. Based on the results, we recommend disinfection of tank water, especially for tanks designated for potable use.

Importance

The use of roof-harvested rainwater (RHRW) for domestic purposes is a globally accepted practice. The presence of pathogens in rainwater tanks has been reported by several studies, supporting the necessity for the management of potential health risks. The sources of fecal pollution in rainwater tanks are unknown. However, the application of microbial source tracking (MST) markers has the potential to identify the sources of fecal contamination in a rainwater tank. In this study, we provide evidence of avian and possum fecal contamination in tank water samples using molecular markers. This study established a potential link between the degradation of the microbial quality of tank water and avian and possum feces.

Evidence of avian and possum fecal contamination in rainwater tanks as determined by microbial source tracking approaches

Ahmed a, K. A. Hamilton a,b, P. Gyawali a,c, S. Toze a,c and C. N. Haas b

A CSIRO Land and Water, Ecosciences Precinct, Brisbane, Queensland, Australia

B Drexel University, Philadelphia, Pennsylvania, USA

C School of Public Health, University of Queensland, Herston, Queensland, Australia

Applied and Environmental Microbiology, Volume 82, Number 14, Pages 4379-4386, doi:10.1128/AEM.00892-16

http://aem.asm.org/content/82/14/4379.abstract?etoc

Irrigation water safety in Penn.

Posted on June 19, 2016 by Douglas Powell

Recent produce-associated foodborne illness outbreaks have been attributed to contaminated irrigation water. This study examined microbial levels in Pennsylvania surface waters used for irrigation, relationships between microbial indicator organisms and water physicochemical characteristics, and the potential use of indicators for predicting the presence of human pathogens.

A total of 153 samples taken from surface water sources used for irrigation in southeastern Pennsylvania were collected from 39 farms over a 2-year period. Samples were analyzed for six microbial indicator organisms (aerobic plate count, Enterobacteriaceae, coliform, fecal coliforms, Escherichia coli, and enterococci), two human pathogens (Salmonella and E. coli O157), and seven physical and environmental characteristics (pH, conductivity, turbidity, air and water temperature, and sampling day and 3-day-accumulated precipitation levels).

Indicator populations were highly variable and not predicted by water and environmental characteristics. Only five samples were confirmed positive for Salmonella, and no E. coli O157 was detected in any samples. Predictive relationships between microbial indicators and the occurrence of pathogens could therefore not be determined.

Microbial survey of Pennsylvania surface water used for irrigating produce crops

Journal of Food Protection®, Number 6, June 2016, pp. 896-1055, pp. 902-912(11)

Draper, Audrey D.; Doores, Stephanie; Gourama, Hassan; LaBorde, Luke F.

http://www.ingentaconnect.com/contentone/iafp/jfp/2016/00000079/00000006/art00002

Hepatitis A is endemic in Tunisia wastewater

Posted on June 19, 2016 by Douglas Powell

Hepatitis A virus (HAV) is the main causative agent of hepatitis infection associated with waterborne outbreaks worldwide. In Tunisia, there is no specific surveillance system for HAV and current secondary wastewater treatment processes are unable to remove viral particles, which present a potential public health problem.

Qualitative and quantitative analysis of HAV in 271 raw and treated wastewater samples from five sewage treatment plants (STPs) during 13 months was performed. Moreover, the efficiency of three secondary wastewater treatment processes (conventional activated sludge, extended aeration, and oxidation ditch activated sludge) was evaluated.

Data obtained demonstrated that HAV is endemic in Tunisia and circulates with high prevalence in both raw (66.9%) and treated (40.7%) wastewater. HAV circulates throughout the year in the coastal areas, with the highest rates found during summer and autumn, whereas in central Tunisia, high levels were shown in autumn and winter. Total virus removal was not achieved, since no difference in mean HAV loads was observed in effluents (6.0 × 103 genome copies [GC]/ml) and influents (2.7 × 103 GC/ml). The comparison of the HAV removal values of the three different wastewater treatment methods indicates that extended aeration and oxidation ditch activated sludge had better efficiency in removing viruses than conventional activated sludge did.

Molecular characterization revealed that the vast majority of HAV strains belonged to subgenotype IA, with the cocirculation of subgenotype IB in wastewater treatment plants that collect tourism wastewater.

Detection and molecular characterization of Hepatitis A virus from Tunisian wastewater treatment plants with different secondary treatments

Appl. Environ. Microbiol. July 2016 vol. 82 no. 13 3834-3845, DOI: 10.1128/AEM.00619-16

Imen Ouardani, Syrine Turki, Mahjoub Aouni, and Jesús L. Romalde

http://aem.asm.org/content/82/13/3834.abstract?etoc

Norovirus: Best way to assess risk?

Posted on June 13, 2016 by Douglas Powell

The application of quantitative microbial risk assessments (QMRAs) to understand and mitigate risks associated with norovirus is increasingly common as there is a high frequency of outbreaks worldwide.

A key component of QMRA is the dose–response analysis, which is the mathematical characterization of the association between dose and outcome. For Norovirus, multiple dose–response models are available that assume either a disaggregated or an aggregated intake dose. This work reviewed the dose–response models currently used in QMRA, and compared predicted risks from waterborne exposures (recreational and drinking) using all available dose–response models.

The results found that the majority of published QMRAs of norovirus use the 1F1hypergeometric dose–response model with α = 0.04, β = 0.055. This dose–response model predicted relatively high risk estimates compared to other dose–response models for doses in the range of 1–1,000 genomic equivalent copies. The difference in predicted risk among dose–response models was largest for small doses, which has implications for drinking water QMRAs where the concentration of norovirus is low.

Based on the review, a set of best practices was proposed to encourage the careful consideration and reporting of important assumptions in the selection and use of dose–response models in QMRA of norovirus.

Finally, in the absence of one best norovirus dose–response model, multiple models should be used to provide a range of predicted outcomes for probability of infection.

Comparison of risk predicted by multiple norovirus dose–response models and implications for quantitative microbial risk assessment

Nicole Van Abel, Mary E. Schoen, John C. Kissel, J. Scott Meschke

Risk Analysis, June 2016, DOI: 10.1111/risa.12616

http://onlinelibrary.wiley.com/doi/10.1111/risa.12616/abstract

Better environmental control, less Legionnaires’ disease

Posted on June 13, 2016 by Douglas Powell

Background: The number of reported cases of Legionnaires’ disease, a severe pneumonia caused by the bacterium Legionella, is increasing in the United States. During 2000–2014, the rate of reported legionellosis cases increased from 0.42 to 1.62 per 100,000 persons; 4% of reported cases were outbreak-associated. Legionella is transmitted through aerosolization of contaminated water. A new industry standard for prevention of Legionella growth and transmission in water systems in buildings was published in 2015. CDC investigated outbreaks of Legionnaires’ disease to identify gaps in building water system maintenance and guide prevention efforts.

Methods: Information from summaries of CDC Legionnaires’ disease outbreak investigations during 2000–2014 was systematically abstracted, and water system maintenance deficiencies from land-based investigations were categorized as process failures, human errors, equipment failures, or unmanaged external changes.

Results: During 2000–2014, CDC participated in 38 field investigations of Legionnaires’ disease. Among 27 land-based outbreaks, the median number of cases was 10 (range = 3–82) and median outbreak case fatality rate was 7% (range = 0%–80%). Sufficient information to evaluate maintenance deficiencies was available for 23 (85%) investigations. Of these, all had at least one deficiency; 11 (48%) had deficiencies in ≥2 categories. Fifteen cases (65%) were linked to process failures, 12 (52%) to human errors, eight (35%) to equipment failures, and eight (35%) to unmanaged external changes.

Conclusions and Implications for Public Health Practice: Multiple common preventable maintenance deficiencies were identified in association with disease outbreaks, highlighting the importance of comprehensive water management programs for water systems in buildings. Properly implemented programs, as described in the new industry standard, could reduce Legionella growth and transmission, preventing Legionnaires’ disease outbreaks and reducing disease.

Deficiencies in environmental control identified in outbreaks of Legionnaires’ disease — North America, 2000–2014

L.E. Garrison, J.M. Kunz, L.A. Cooley, M.R. Moore, C. Lucas, S. Schrag, J. Sarisky, C.G. Whitney

http://www.cdc.gov/mmwr/volumes/65/wr/mm6522e1.htm?s_cid=mm6522e1_e

Exposure to Norovirus at the beach

Posted on June 12, 2016 by Douglas Powell

Swimming in fecally-contaminated natural waterbodies can result in gastrointestinal (GI) infections and associated symptoms. However, the pathogenic microorganisms responsible are often unidentified because studies nearly always rely on self-reported symptoms. Noroviruses have been considered a likely cause because they are relatively resistant to conventional wastewater treatment and can survive in the environment.

Symptoms among swimmers usually occur within a few days of exposure, consistent with a short incubation period characteristic of noroviruses.

In the summer of 2009, we conducted an epidemiology study at a beach in Puerto Rico. We previously reported no association between swimming and self-reported GI symptoms at this beach. As part of this study, we also collected saliva samples from a subset of participants (N=1300) using an Oracol oral swab: on the day of the beach visit (S1); after 10-12 days (S2); and after approximately three weeks (S3), and tested them for IgG antibody responses to two common noroviruses (Norwalk and VA387) using a Luminex platform and a previously published method. An immunoconversion, indicating a potential new infection, was defined as at least a fourfold increase in norovirus-specific median fluorescence intensity (MFI) from the S1 to the S2 sample with the S3 sample remaining at least two times above the baseline (S1) MFI.

Approximately 4.7% (N=61) immunoconverted to at least one of the noroviruses. Swimmers who immersed their head in water had a higher rate of immunoconversion (5.5%) compared to non-swimmers (2.0%) (OR=3.32, 95% CI 1.2-9.5). Immunoconversion to norovirus was not associated with increased self-reported GI symptoms, indicating these infections were largely asymptomatic.

To our knowledge, this is the first epidemiology study to show an association between norovirus infection and swimming exposure. This abstract does not reflect EPA policy.

Evidence for asymptomatic norovirus infection transmission associated with swimming at a tropical beach

Soceity for Epidemiology Research, Miami, FL, June 07 – 16, 2016

Wade, Tim, S. Augustine, S. Griffin, K. Simmons, T. Eason, K. Oshima, E. Sams, A. Egorov, AND A. Dufour

https://cfpub.epa.gov/si/si_public_record_Report.cfm?dirEntryId=318202

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