Lévesque B, Rochette L, Levallois P, Barthe C, Gauvin D, Chevalier P
Direction régionale de la santé publique de Québec, Canada.
Rev Epidemiol Sante Publique. 1999 Oct;47(5):403-10.
We analyzed data from the notifiable diseases data base in Québec to document the incidence of giardiasis. The objectives were to perform a descriptive analysis of the cases of giardiasis and to verify the relation between their incidence and the quality of drinking water.
The Québec notifiable diseases data-base contained 4273 cases of giardiasis declared between January 1st, 1990 and December 31st, 1995. Incidence rates were adjusted for age and calculated monthly. The sources and kinds of treatment of drinking water permitted to elaborate a vulnerability scale for classifying contamination by Giardia sp. into four categories. Incidence of giardiasis was examined in relation with this vulnerability scale. Other socioeconomic indicators possibly associated with the incidence of giardiasis were also analyzed.
Analysis showed that there were few annual variations in the incidence of giardiasis and that there were no epidemic peaks during the study period. According to age, the incidence follows a bimodal pattern with a peak for young children and young adults. The incidence rates showed an increase of the cases at the end of summer and at the beginning of fall, with a higher relative risk for males. Even if no relation was found between the incidence of giardiasis and the vulnerability of the drinking water source, incidence rates were lower for people living in communities that use the St. Lawrence River as a drinking water source than for those using other sources of surface water.
This study allowed us to obtain a good description of the cases of giardiasis declared in Québec and to formulate hypothesis about their causes. The lower incidence of giardiasis in communities that use the St. Lawrence river as their drinking water source is possibly related to a lower contamination of this source. However, considering the limits of this work, case-control studies should be considered to understand variables, which influence the incidence of giardiasis in Québec.
我们分析了魁北克省法定传染病数据库中的数据，以记录贾第虫病的发病率。目的是对贾第虫病病例进行描述性分析，并验证其发病率与饮用水质量之间的关系。
魁北克省法定传染病数据库包含1990年1月1日至1995年12月31日期间报告的4273例贾第虫病病例。发病率按年龄进行了调整，并按月计算。饮用水的来源和处理方式被用于制定一个脆弱性量表，以便将贾第虫属的污染分为四类。根据这个脆弱性量表对贾第虫病的发病率进行了研究。还分析了其他可能与贾第虫病发病率相关的社会经济指标。
分析表明，贾第虫病的发病率年度变化不大，在研究期间没有出现流行高峰。按年龄划分，发病率呈双峰模式，幼儿和年轻人发病率最高。发病率在夏末和秋初有所上升，男性的相对风险更高。尽管未发现贾第虫病发病率与饮用水源的脆弱性之间存在关联，但以圣劳伦斯河为饮用水源的社区居民的发病率低于使用其他地表水水源的社区居民。
这项研究使我们能够很好地描述魁北克省报告的贾第虫病病例，并对其病因提出假设。以圣劳伦斯河为饮用水源的社区贾第虫病发病率较低，可能与该水源的污染程度较低有关。然而，考虑到这项研究的局限性，应考虑进行病例对照研究，以了解影响魁北克省贾第虫病发病率的变量。
