Việc đánh giá rủi ro trong quần thể người phụ thuộc rất nhiều vào khoa học về dịch tễ học. Dịch tễ học là chi nhánh của thuốc bao gồm các nghiên cứu của tỷ lệ mắc và lây truyền bệnh trong dân số. Do đó, trọng tâm của nghiên cứu là nhóm người chứ không phải là cá nhân. Có, như được nêu ra, không có dịch tễ học các nghiên cứu đã đặc biệt điều tra tầm quan trọng sức khỏe cộng đồng của các màng sinh học trong các hệ thống nước uống | 2 Epidemiology CONTENTS Epidemiological Methods and Waterborne Preparation for the Detection of an Outbreak Outbreak Hypothesis Remedial Control Hypothesis Testing Analytical Epidemiology . 23 Control Measures. 26 Formal Report. 26 Further Reading . 26 References. 26 INTRODUCTION The assessment of risk in human populations relies heavily on the science of epidemiology. Epidemiology is that branch of medicine covering the study of the incidence and transmission of disease in populations. Thus the focus of study is groups of people rather than the individual. There are as yet no epidemiological studies that have specifically investigated the public health importance of biofilms in potable water systems. Nevertheless epidemiological investigation is essential to the understanding of waterborne disease. In 1854 John Snow simultaneously invented the science of epidemiology and proved that drinking water was capable of spreading disease. Since then epidemiological studies have been important in elucidating the role of water in many infectious diseases. In particular epidemiological methods are central to the investigation of outbreaks of waterborne disease. Furthermore as will be seen in a subsequent chapter the results from epidemiological studies are essential in defining several of the input variables for various risk assessment models which are finding important roles in assessing the risks of waterborne disease. By itself epidemiology does not offer proof of the causation of disease. Instead epidemiological investigations identify associations between disease and possible risk factors. At best we are left with the demonstration of statistically significant associations between environmental factors and disease. Those factors found to be associated with disease may be causative but other
