Do we all face the same risk when bathing in the estuary?

Abstract

With the development of coastal areas, microbial water quality is an emerging public health issue though few studies have focused on risks according to age. A survey was undertaken of faecal contamination in relation to recreational activities in the Peel Harvey estuarine system, Western Australia. Levels of exposure to contaminated water were estimated though social surveys. Follow-up was also conducted to estimate the incidence of disease associated with bathing in the estuary. Pathogen levels exceeded the guideline values recommended by the World Health Organisation (WHO) at most locations throughout the year. The social survey provided information about exposure of the population in age groups. Only 31% of the recreational users belonged to the healthy adult group upon which the WHO quantitative microbial risk assessment model is based. A correlation was established between microbial water quality and incidence of respiratory diseases for children as well as for adults. Exposure to recreational water increased the incidence of respiratory illnesses for the whole population almost by a factor 2. Behaviours which resulted in increased exposures were associated with increased incidence of illnesses were observed, particularly among children aged 11-15 yr, who exhibited the highest odd ratio (OR 4.23 [2.44-6.01], CI 95%, p=0.05). There is a need for combining epidemiology studies with risk assessment processes and complementing them with social surveys for understanding the risk of recreational activities to public health.

Importance of public information and perception for managing recreational activities in the Peel-Harvey estuary, Western Australia

“…Faecal contamination of the water was evident most of the year with faecal streptococci levels ranging from 61 CFU/100 ml in April to 645 CFU/100 ml in December (Lepesteur et al, 2006). Levels outside the bathing season (April-October) averaged 186 CFU/100 ml despite an increase during the period of high rainfall and river discharge (June), in accordance with the significant increase of microbial concentration following rainfall observed by Crowther et al (2001).…”

“…Risk is usually perceived when visible, palatable, or when water clarity is restricted to 1.2 m (Smith et al, 1991). However, high faecal contamination in the PeelHarvey estuary (Western Australia) as suggested by bacterial indicator level exceeding Australian guidelines by almost a factor of 10 (Lepesteur et al, 2003(Lepesteur et al, , 2006 may not create a risk perception amongst beach users (Pendleton et al, 2001). The aim of this study was to identify the information available to recreationists, their perception, in regard to water quality in the estuary, and their consequent behaviour.…”

Quantifying the variability in Escherichia coli (E. coli) throughout storm events at a karst spring in northwestern Arkansas, United States

“…5), and visitors who purposefully or inadvertently ingest water may be at risk of E. coli exposure, which correlates to increased risk of gastro- (Prüss 1998). This is especially true of children, who are more likely to inadvertently swallow water and tend to be in the water for longer (Lepesteur et al 2006).…”

The association between marine bathing and infectious diseases– a review

“…Breaches of innate defences (e.g. skin ulcers and penetrating trauma) increase the risk of bathing-related infection (Vignier et al , 2013; Janda & Abbott, 2014); subsequent disease risk depends on age (Lepesteur et al , 2006; Wade et al , 2008); co-morbid conditions such as diabetes mellitus and impaired immunity (Frank et al , 2006; Vignier et al , 2013); and the presence of immunity from previous infection (Prieto et al , 2001) or vaccination. The ability of an organism to cause disease, and the subsequent severity, is termed ‘virulence’; some pathogens, such as noroviruses, generally cause mild self-limiting illness, whereas ingestion of a limited number of Verotoxin-producing E. coli can lead to severe illness and even death.…”