Viruses are believed to be a significant cause of recreationally associated water-borne disease. However, they have been difficult to document because of the wide variety of illnesses that they cause and the limitations in previous detection methods. Noroviruses are believed to be the single largest cause of outbreaks, which have been documented in the published literature 45% (n = 25), followed by adenovirus (24%), echovirus (18%), hepatitis A virus (7%) and coxsackieviruses (5%). Just under half of the outbreaks occurred in swimming pools (49%), while the second largest outbreak occurred in lakes or ponds (40%). The number of reported outbreaks associated with noroviruses has increased significantly in recent years probably because of better methods for virus detection. Inadequate disinfection was related to 69% (n = 18) of swimming pool outbreaks. A lack of required reporting and nonuniform water quality and chlorination/disinfection standards continues to contribute to water-borne recreational disease outbreaks.

https://sfamjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2672.2009.04367.x

Viruses in recreational water-borne disease outbreaks: a review.

In May 2004, CDC Kenya, trainees of the CDC-supported Field Epidemiology and Laboratory Training Program (FELTP) in Kenya, the World Health Organization, and CDC were invited by the Kenya Ministry of Health (KMOH) to participate in the investigation of an outbreak of jaundice with a high case-fatality rate (CFR) in the districts of Makueni and Kitui, Eastern Province. Preliminary laboratory testing of food collected from the affected area revealed high levels of aflatoxin, suggesting that the outbreak was caused by aflatoxin poisoning, as was a previous outbreak in the same area in 1981. In the United States, aflatoxin concentrations are limited to 20 parts per billion (ppb), a level also adopted by Kenyan authorities. The 2004 outbreak resulted from widespread aflatoxin contamination of locally grown maize, which occurred during storage of the maize under damp conditions. Urgent replacement of the aflatoxin-contaminated maize with noncontaminated maize proved to be a critical intervention; however, as of July 21, a limited number of new cases continued to be detected. This report summarizes the preliminary results of the outbreak investigation. Aflatoxin poisoning likely will continue to be a public health problem until culturally appropriate storage methods for dry maize are implemented by the local population. In addition, enhanced surveillance for human aflatoxin poisoning and testing of commercially sold maize for aflatoxin levels will lead to long-term improvements in public health.

/pdf/outbreak-of-aflatoxin-poisoning-eastern-and-central-1tdeuaekmm.pdf

Outbreak of Aflatoxin Poisoning - Eastern and Central Provinces, Kenya, January - July 2004

http://www.watermicro.gr/wp-content/uploads/papadopoulou.pdf

Microbiological quality of indoor and outdoor swimming pools in Greece: Investigation of the antibiotic resistance of the bacterial isolates

In spite of the importance and popularity of swimming pools in summer, they have been identified as posing some public health risks to users due to either chemical or microbiological contamination. This study was carried out aiming at assessing the quality of water for some Alexandria's swimming pools in order to determine its compliance with the Egyptian standards no. 418/1995. Five swimming pools were selected randomly from different districts. Physical and chemical parameters, as well as biological examination of a total of 30 samples, were carried out using standard analytical methods. Water samples were collected from the studied swimming pools monthly over 6 months and pool water monitoring was carried out during afternoon of the weekends when the pools were most heavily used. The results indicated overall poor compliance with the standards. Compliance of the pool water to the microbial parameters, residual chlorine, pH, and turbidity were 56.7% (17 samples), 20% (6 samples), 46.7% (14 samples), and 46.7% (14 samples), respectively. Statistical analysis showed significant association between water contamination with microbial indicators and physical–chemical aspects such as residual chlorine, temperature, turbidity, and load of swimmers. Furthermore, Cryptosporidium oocysts and Giardia lamblia cysts has been found in 10% of samples. It was concluded that there is a need to improve disinfection and cleaning procedures, with consideration given to safety, and size of the pool in relation to bathing load. There is also a need to monitor swimming pool water quality continuously, and to increase bather hygienic practices and awareness of the risks as well as training of governmental inspectors.

/pdf/assessment-of-water-quality-of-some-swimming-pools-a-case-4wqaovil4z.pdf

Assessment of water quality of some swimming pools: a case study in Alexandria, Egypt

Characterization of microbial populations associated with natural swimming pools.

John Snow's historic investigation of a severe epidemic of cholera traced the cause of infection to a common water source. Today, 150 years later, waterborne diseases remain a public health problem, and similar investigations are used to identify the source of infection. On February 3, 2004, the Vermont Department of Health (VDH) was notified of an outbreak of acute gastroenteritis among children whose only common exposure was attendance at a swimming club the previous weekend (January 31-February 1). This report summarizes the results of an investigation conducted by VDH and CDC, which determined the cause of the outbreak to be a combination of stool contamination, a blocked chlorine feed tube, and multiple lapses of pool-maintenance procedures. The findings underscore the importance of correct pool maintenance for rapid identification of water-quality problems to prevent outbreaks of swimming pool-associated illness.

W. Knight

Papers

An outbreak of norovirus gastroenteritis at a swimming club - Vermont, 2004.