广西某中学甲型副伤寒暴发的流行特征及原因

The Epidemiological Feature and Potential Risk Factor of an Outbreak Caused by S. paratyphi A in A Middle School of Guangxi Province

目的 调查甲型副伤寒暴发疫情的流行特征及原因。 方法 对发热病人进行个案调查、采样和疫点环境卫生学调查 ,运用描述性流行病学和卫生统计学方法对现场调查资料和实验室结果进行统计和分析。 结果 本起疫情共发生甲型副伤寒病例 3 2 2例 ,罹患率 9.2 1%。其中学生 3 2 1例 ,食堂从业人员 1例 ;内宿罹患率 (14 .3 8% )高于外宿(0 .2 9% ) (P <0 .0 1) ;男性罹患率 (12 .45 % )高于女性 (6.0 2 % ) (P <0 .0 1) ;流行时间为 3 6d ,流行过程有两个波峰 ;共分离出甲型副伤寒沙门氏菌 41株 ,其中发热病人血和粪便培养分别为 2 0株和 2株 ,无症状学生肛拭培养为 19株 ;2 3株菌株对 18种常用抗生素均敏感。流行原因为无安全饮用水、食堂卫生状况不良、学生有饮生水等不良卫生习惯等 ;传播途径流行前期极可能为水型传播所致 ,后期则为生活接触传播。 结论 加强学校水源及食堂卫生的管理和监督、改善学生卫生习惯是防止甲型副伤寒疫情暴发的关键措施 ;流行早期及时采取严格、有效的措施和保证资金投入是短期内疫情得到有效控制的保证。

Objective To study the prevalence of an outbreak caused by S. paratyphi A, and analyze the epidemiological feature and potential risk factors. Methods Epidemiological survey and sample collection were performed by epidemiologist among febrile patients. Environmental investigation was conducted at the site of outbreak. Data collected from the filed site and laboratory has been analyzed using methods of descriptive epidemiology and hygienic statistics. Results A total of 322 cases of paratyphoid fever A have been found in this outbreak, with an attack rate of 9.21%. 321 were student cases, and 1 was food handler. The attack rate was significantly higher in boarders( 14.38%), compared to day students( 0.29%)(P<0.01). A higher attack rate has been also found in male (12.45%), compared to female(6.02%)(P< 0.01). The outbreak with two peaks has lasted 36 days' duration. Among 41 S. paratyphi. A isolated in this outbdreak, 20 were from blood and 2 from stool samples of febrile patients, and 19 from rectal swabs of the students without signs and symptoms of paratyphoid fever. 23 out of 41 isolates were sensitive to 18 classes of common antimicrobial agents. The occurrence of the epidemic was due to lacking safe water supply, poor sanitation at school refectory and poor personal hygiene, such as unboiled-water drinking. The transmission was likely to occur via contaminated water at early outbreak, whereas to occur at late outbreak by contacting patients or carriers. Conclusion The most important interventions to prevent outbreak of paratyphoid include strengthening management of both sources of water supply and hygiene systems at refectory, monitoring and improving personal hygiene of students. Strict and effective measures taking place at early epidemic and funds investment are considered as the assurance of prompt outbreak control.