Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.
PLoS Negl Trop Dis. 2012;6(2):e1481. doi: 10.1371/journal.pntd.0001481. Epub 2012 Feb 14.
Opisthorchis viverrini is a food-borne trematode species that might give rise to biliary diseases and the fatal cholangiocarcinoma. In Lao PDR, an estimated 2.5 million individuals are infected with O. viverrini, but epidemiological studies are scarce and the spatial distribution of infection remains to be determined. Our aim was to map the distribution of O. viverrini in southern Lao PDR, identify underlying risk factors, and predict the prevalence of O. viverrini at non-surveyed locations.
A cross-sectional parasitological and questionnaire survey was carried out in 51 villages in Champasack province in the first half of 2007. Data on demography, socioeconomic status, water supply, sanitation, and behavior were combined with remotely sensed environmental data and fed into a geographical information system. Bayesian geostatistical models were employed to identify risk factors and to investigate the spatial pattern of O. viverrini infection. Bayesian kriging was utilized to predict infection risk at non-surveyed locations.
The prevalence of O. viverrini among 3,371 study participants with complete data records was 61.1%. Geostatistical models identified age, Lao Loum ethnic group, educational attainment, occupation (i.e., rice farmer, fisherman, and animal breeder), and unsafe drinking water source as risk factors for infection. History of praziquantel treatment, access to sanitation, and distance to freshwater bodies were found to be protective factors. Spatial patterns of O. viverrini were mainly governed by environmental factors with predictive modeling identifying two different risk profiles: low risk of O. viverrini in the mountains and high risk in the Mekong corridor.
CONCLUSIONS/SIGNIFICANCE: We present the first risk map of O. viverrini infection in Champasack province, which is important for spatial targeting of control efforts. Infection with O. viverrini appears to be strongly associated with exposure to the second intermediate host fish, human behavior and culture, whereas high transmission is sustained by the lack of sanitation.
华支睾吸虫是一种食源性吸虫，可能导致胆道疾病和致命的胆管癌。在老挝人民民主共和国，估计有 250 万人感染了华支睾吸虫，但流行病学研究很少，感染的空间分布仍有待确定。我们的目的是绘制老挝南部华支睾吸虫的分布地图，确定潜在的危险因素，并预测未调查地点的华支睾吸虫感染率。
2007 年上半年，在占巴塞省的 51 个村庄进行了横断面寄生虫学和问卷调查。将人口统计学、社会经济状况、供水、卫生和行为数据与遥感环境数据相结合，并输入地理信息系统。采用贝叶斯地质统计学模型来确定危险因素，并研究华支睾吸虫感染的空间模式。利用贝叶斯克里金法来预测未调查地点的感染风险。
在 3371 名有完整数据记录的研究参与者中，华支睾吸虫的患病率为 61.1%。地质统计学模型确定了年龄、老挝娄姆族、教育程度、职业（即水稻种植者、渔民和动物饲养者）以及不安全的饮用水源为感染的危险因素。使用过吡喹酮治疗、使用卫生设施以及与淡水体的距离是保护性因素。华支睾吸虫的空间模式主要由环境因素控制，预测模型确定了两种不同的风险概况：山区华支睾吸虫的风险较低，而湄公河走廊的风险较高。
结论/意义：我们首次绘制了占巴塞省华支睾吸虫感染的风险图，这对于有针对性地开展控制工作具有重要意义。华支睾吸虫感染似乎与接触第二中间宿主鱼类、人类行为和文化密切相关，而卫生条件差则维持了高传播率。
