monitor pathogens?
Disease-causing organisms, known as pathogens, exist as bacteria, viruses or parasites. Monitoring for these pathogens is expensive and difficult. Large volumes of water are needed to monitor for pathogens because they are present in such small numbers. Many different types of pathogens exist and testing for a single pathogen may not accurately assess the health risk present due to other pathogens. Because indicator bacteria occur in greater numbers than pathogens and are easier to isolate in a laboratory, monitoring for them is more cost-effective.