Pasley J N, Daly J J, McCullough D, McChesney T, Daly E B, Tank S K
Department of Physiology, University of Arkansas for Medical Sciences, Little Rock 72205.
Chronobiol Int. 1989;6(2):185-9. doi: 10.3109/07420528909064629.
A circannual rhythm of Giardia lamblia positive stools was found by examination of records from three clinical laboratories in central Arkansas for the period 1980-1986. Cosinor analysis of monthly Giardia incidence based on stool specimen records from approximately 12,000 patients over the 7-year period revealed a circannual rhythm (P less than 0.001) on the basis of percent positive patients/month, with a computive acrophase occurring in late summer and minimum values in the winter. Patients involved in the study were primarily from the central Arkansas metropolitan areas, southern delta regions and northern mountainous regions of the state. Analysis of the data on the basis of total positive Giardia patients/month also revealed a circannual rhythm with the acrophase again occurring in late summer. The overall mean for percent positive stool specimens for the 7-year period was 5.3%, compared with the national average of 3.8% for G. lamblia positive stools. The data indicate that there may be a "Giardia season" in Arkansas since they could not be explained on the basis of day-care age distribution, or geographic origin. Awareness by epidemiologists, public health officials and other health care professionals of this circannual incidence of giardiasis is important for the prevention, diagnosis and treatment of this infectious disorder.
通过对阿肯色州中部三个临床实验室1980 - 1986年期间的记录进行检查，发现了兰氏贾第鞭毛虫阳性粪便的年周期节律。基于7年期间约12,000名患者的粪便标本记录，对每月贾第虫发病率进行余弦分析，结果显示以每月阳性患者百分比为基础存在年周期节律（P < 0.001），计算得出的高峰期出现在夏末，冬季为最低值。参与研究的患者主要来自该州阿肯色州中部大都市地区、南部三角洲地区和北部山区。以每月贾第虫阳性患者总数为基础对数据进行分析，也显示出年周期节律，高峰期同样出现在夏末。7年期间粪便标本阳性百分比的总体平均值为5.3%，而兰氏贾第鞭毛虫阳性粪便的全国平均水平为3.8%。这些数据表明，阿肯色州可能存在一个“贾第虫季节”，因为这些数据无法根据日托年龄分布或地理来源来解释。流行病学家、公共卫生官员和其他医疗保健专业人员了解贾第虫病的这种年周期发病率，对于预防、诊断和治疗这种传染病很重要。
