1、BASIC PRINCIPLES IN OCCUPATIONAL HYGIENE职业卫生基本原则Day 3第3天12 - BIOLOGICAL HAZARDS 12-生物危害BIOLOGICAL HAZARDS生物危害 Biological Hazards - bacteria, viruses or moulds have the ability in the right conditions to rapidly replicate themselves. 生物危害细菌、病毒或霉菌在适当的条件均能够快速复制自己。 Focus on control is not only avoidance
2、 of contact with the agent but also on ensuring that conditions favourable for growth of the organism are prevented. 加强控制不仅能够避免与生物因素的接触，还能够抑制微生物生长的有利条件。 BIOLOGICAL HAZARDS生物危害The three main categories of biological agents:生物危害可分为三大类： Bacteria - single celled micro organisms that live in soil, water
3、and air. 细菌单细胞微生物，生活在土壤、水和空气中。 Viruses tiny parasitic organisms that can only reproduce within living cells. 病毒微小的寄生生物，只能在活细胞体内繁殖。 Fungi simple plants lacking chlorophyll and normal plant structures (e.g. leaves, stems etc). 真菌简单的植物，没有叶绿素和植物正常结构（如叶，茎等）。 Dividing Escherichia coli bacteria大肠杆菌细菌 Sourc
4、e: Wikimedia Commons 资料来源：维基共享资源 Exposure to micro-organisms微生物的风险 Individual to exposure to micro-organisms depends on state of immunity:微生物对个人的影响取决于个人的免疫能力： whether the individual has already experienced a particular illness 个人是否已患过相关疾病； immunisation levels 免疫程 individual resistance 个人 力 Fatigue 体
5、 age. Legionella pneumophila multiplying inside a cultured human lung fibroblast 菌在人 维细胞中繁殖 Source: Wikimedia Commons资料来源：维基共享资源 CONTROL DEPENDANT ON RISK GROUP微生物的危害等 Risk Group 1 - (low individual and community risk). An organism that is unlikely to cause human or animal disease. 危害等 1 （ 个体危害， 体危害
6、） ：不 人类和 物生病的有 体。 Risk Group 2 - (moderate individual risk, limited community risk). A pathogen that may cause human or animal disease and which might be a hazard to laboratory workers, but is unlikely to spread to the community, livestock or the environment. 危害等 2 （中等个体危害，有 体危害） ：可能 人类和物生病，对 人 生危险，
7、 不可能在 体、 或中的病原体。 Risk Group 3 - (high individual risk, low community risk). A pathogen that can cause serious human disease but does not ordinarily spread from one individual to another. 危害等 3 （个体危害， 体危害）：currency1人类或 物“疾病， 常不 在个体的病原体。 Risk Group 4 - (high individual and community risk). A pathogen
8、that usually produces serious human or animal disease and may be readily transmitted from one individual to another, directly or indirectly. 危害等 4 （个体危害， 体危害）：currency1人类或 物“疾病，可能 在个体fi或接的病原体。 Biosafety levels (1)生物fl (1) Four Biosafety levels which give the containment precautions:， 生物”分个生物fl ： Bio
9、safety Level 1 Little containment or segregation, precautions such as separation and labelling of waste materials. 生物fl 1生物”或 ” ，取如物 和的”。 Biosafety Level 2 Staff have specific training in handling pathogenic agents, restricted access, sharps protection, biological cabinets for certain activities 生物f
10、l 2对 有关 病原体的，取 ，加强 ，生物fl 分类的 。 Biosafety levels (2)生物fl (2) Four Biosafety levels which give the containment precautions:， 生物”分个生物fl ： Biosafety Level 3 Biological safety cabinets or other physical containment devices, personal protective clothing and equipment. Double-door access zones. 生物fl 3生物fl
11、或 、个人 物和 。“ 。 Biosafety Level 4 Separate building/ controlled are. Controlled ventilation maintaining it under negative pressure. All activities are carried out in Class III biological safety cabinets, or Class II biological safety cabinets with one-piece positive pressure personnel suits ventilated
12、 by a life support system. 生物fl 4 /控制 。控制 风， 于条件。 有活 均 在生物fl 3或生物fl 2的生物fl 中 ”， 还 为 人 体 正 ， 生 风。 Legionella菌 X5000 Magnification of a large grouping of Gram-negative Legionella pneumophila bacteria X5000 的 氏阴性 菌 Source: Wikimedia Commons资料来源：维基共享资源 Legionella菌 1976 - an outbreak occurred among deleg
13、ates attending an American Legion convention. 1976 在美国退伍 人大 与 代表中爆发。 Two patterns of disease in humans; 该种疾病在人体中有两种型 ： Pontiac Fever (a mild flu-like illness) 庞蒂亚克热（ 种流感样温和疾病） Legionnaires Disease. (pneumonia and flu-like symptoms. It is fatal in about 10 - 15% of cases). 菌病（ 炎和流感样症 ， 大约为10 - 15）。 It enters into the body when fine droplets of contaminated water are inhaled. The bacterium is not transmitted from person to person. 饮 污染水滴 ，细菌就 入人体。 般不 在个体。 Legionella are widespread in natural fresh water including rivers, lakes, streams and ponds. 菌广泛存在于天然淡水，包括河流，湖泊，溪流和池塘。
