Prevalence and public health implications of mycotoxigenic fungi in treated drinking water systems

Abstract

Insufficient potable water resources and poorly treated drinking water quality are the world's number one cause for preventable morbidity and mortality from water-related pathogenic microorganisms. Pathogenic microorganisms, including mycotoxigenic fungi, have been identified in treated drinking water. This paper presents a review of mycotoxigenic fungi as a health risk to the public as these fungi are responsible for allergies, cancers and opportunistic infections mainly to immunocompromised patients. The exacerbating factors contributing to fungal presence in water distribution systems, factors that lead to fungi being resistant to water treatment and treated drinking water quality legislations are also discussed. This paper provides a review on the prevalence of mycotoxigenic fungi and their implications to public health in treated drinking water, and the need for inclusion in treated drinking water quality regulations.

Occurrence of Fungi in the Potable Water of Hospitals: A Public Health Threat

“…Biofilm formation also affects the quality of water by reducing the effectiveness of residual chlorine, raising the costs of maintenance of potable water distribution networks [ 24 ]. This increased resistance to chlorine disinfection is likely due to the consumption of disinfectants by the biofilm, reduced disinfectant penetration into the biofilm, and composition of the microbial community in the biofilm itself [ 41 ].…”

“…One of the main problems related to the presence of fungi in drinking water is the poor effectiveness of disinfection treatments of the water network on some fungal genera. Dematiaceous fungi, like Alternaria , secreting melanin or melanin-like pigment in their thick cell walls, have hydrophobic spores, which make them resistant to water treatments [ 24 , 30 , 42 , 43 ].…”

“…According to the European Commission, water intended for human consumption should be "free from any microorganisms and parasites, and any substances which, in numbers or concentrations, constitute a potential danger to human health" [38]. However, as the concentration of fungi in water was not considered quantitatively relevant as that of bacteria and other microbial contaminants, it has led to the omission of detecting the occurrence of fungi in routine potable water quality monitoring tests, resulting in a lack of information on the possible impacts on human health [24,39].…”

“…Although literature data about mold behavior in the network are limited, and guidelines regarding acceptable mold values do not exist, it is important to note that health problems linked to fungi in water are also due to the production of secondary metabolites such as mycotoxins. Some molds such as, Penicillium spp., Fusarium spp., Aspergillus spp., can produce toxic secondary metabolites that prejudice water quality and become a threat to humans and animals [24,43,49]. Some of these products are carcinogenic and have the ability to impair the immune system [43,50,51].…”

“…Until a few years ago, the occurrence of fungi in water was rarely considered, because attention was directed towards occurrence of bacteria and viruses [ 19 , 20 , 21 ]. These microorganisms unlike fungi cause acute diseases when they contaminate potable water, and are now regarded as emerging causes of chronic water quality problems [ 22 , 23 , 24 ].…”