2008年5月12日14时28分,四川汶川发生8.0级大地震。地震发生后,多数房屋倒塌或已成危房,垃圾遍地,污水横流,饮用水被大面积污染,蚊蝇孳生,生态遭受严重破坏,腐烂变臭的畜禽尸体更成为各种病菌生长繁殖的理想场所。大批灾民集中在简易房子和帐篷,居住拥挤,人口密度大,极易引发一些传染病 At 14:28 on May 12, 2008, a magnitude 8.0 earthquake hit Wenchuan, Sichuan. After the earthquake, the majority of houses collapsed or became dilapidated buildings, garbage everywhere, sewage cross-flow, drinking water was contaminated by large areas, mosquitoes breeding, ecological damage, rot and smelly livestock and poultry become more ideal for the growth and reproduction of various germs place. A large number of victims concentrated in simple houses and tents, crowded living, population density, can easily lead to some infectious diseases