一次伤寒的食物型暴发

<正> 伤寒是个很古老的疾病,伤寒的发病率随着城市卫生措施的改进,特别是饮水的改进而大大降低。解放以来,伤寒发病在全国均大幅度下降,尤以大城市下降更为明显。但近几年,有些传染病包括伤寒又有所抬头,甚至引起局部暴发流行。因此,目前对伤寒的防治工

A Food-Borne Outbreak of Typhoid Fever

1. In June-July, 1977, a 246 cases outbreak of typhoid fever happenediu Xian xx College. All the cases were surely diagnosed by clinical, labora-tory and epidemiological methods. The attack rate was 19. 9% of the wholepopulation of the college, but the exposed population was as high as 48. 4%,the relaps rate 40%. Only one case was complicated with hemorrhage of theintestine. There wasn't any fatal case in this outbreak. The incubationperiods ranged from 2-20 days with a mean (G) 10. 6 days. 2. According to the distribution of time it seems mostly of normaldistribution. The secondary infection rate in this outbreak is very low sothat personal contact can't be the source of infection. It is more likely thatthe common source may be the cause of this outbreak. 3. Almost all the cases occured in a cafeteria, where all students tookfoods. By investigation, it was proved that water-borne infection was impo-ssible, thus indicating that the main cause of transmission is food. 4. The exposure date was estimated by many methods. It is sure onJune 8 th. The foods were not contaminated from inside of the cafeteria;the contamination might be caused by vegetables, especially cucumber, becauseit can be eaten raw. During the exposure date, it was often eaten raw. 5. When the prophylactic measures were made on June 20th, the outbreakhad already been, weakened so that it was useless to control this outbreak.But owing to the measures, not only the secondary infection was controlled,but the infection no longer spreaded widely.