Taye A, Alemayehu W, Melese M, Geyid A, Mekonnen Y, Tilahun D, Asfaw T
Department of Infectious and Non-infectious Diseases Research, Ethiopian Health and Nutrition Research Institute, PO Box 1242, Addis Ababa, Ethiopia.
Ann Trop Med Parasitol. 2007 Jul;101(5):441-8. doi: 10.1179/136485907X176544.
In the Gurage zone of central Ethiopia, the association between fly density and the occurrence of trachoma has been investigated across varying altitudes. The seasonal pattern of fly density in the area was also explored. When, over short sampling periods (10 min/child indoors and 10 min/child outdoors), hand nets were used to collect flies from the eyes of children aged 2-8 years, only Musca sorbens and M. domestica were caught. Almost all of the 13,147 'eye-seeking' flies collected came from villages at low (<2000 m; 40.7%) or mid altitudes (2200-2500 m; 58.6%) with only 0.7% of them caught in the high-altitude villages investigated (at >3000 m). Musca sorbens predominated outdoors and M. domestica indoors. Almost all (99.3%) of the eye-seeking M. sorbens collected were caught outdoors whereas most (76.7%) of the M. domestica were caught indoors (P<0.0001 for each). The median numbers of flies caught, per child, per 10-min collection, in the low-, mid- and high-altitude villages were 9.5, six and zero, respectively, for M. sorbens, and eight, three and zero, respectively, for M. domestica. The altitudinal trends in these numbers of 'eye-seeking' flies matched those in the prevalences of active trachoma among children aged 1-10 years, which were high in the villages at low (81.6%) and mid altitude (78.7%) but much lower (1.7%) in the high-altitude villages. In conclusion, trachoma is a common disease of public-health importance only in the low- and mid-altitude villages in the Gurage zone, where there are large numbers of eye-seeking flies, and not in the villages that lie >3000 m above sea level, where there is a dearth of such flies.
在埃塞俄比亚中部的古拉格地区，研究人员在不同海拔高度对苍蝇密度与沙眼发病情况之间的关联进行了调查。同时还探究了该地区苍蝇密度的季节性模式。在较短的采样时间段内（室内每个孩子10分钟，室外每个孩子10分钟），研究人员使用捕虫网从2至8岁儿童的眼睛上捕捉苍蝇，结果只捕获到了厩螫蝇和家蝇。在收集到的13147只“嗜眼”苍蝇中，几乎所有苍蝇都来自低海拔（<2000米；40.7%）或中海拔（2200 - 2500米；58.6%）的村庄，在被调查的高海拔村庄（>3000米）中捕获的仅占0.7%。厩螫蝇在室外占主导，家蝇在室内占主导。收集到的嗜眼厩螫蝇几乎全部（99.3%）是在室外捕获的，而大多数（76.7%）家蝇是在室内捕获的（每种情况P<0.0001）。在低海拔、中海拔和高海拔村庄，每10分钟收集时间内每个孩子捕获的厩螫蝇中位数分别为9.5只、6只和0只，家蝇分别为8只、3只和0只。这些“嗜眼”苍蝇数量的海拔趋势与1至10岁儿童活动性沙眼患病率的海拔趋势相匹配，低海拔村庄（81.6%）和中海拔村庄（78.7%）的患病率较高，而高海拔村庄（1.7%）的患病率则低得多。总之，沙眼仅在古拉格地区低海拔和中海拔村庄是具有公共卫生重要性的常见疾病，这些村庄有大量嗜眼苍蝇，而在海拔高于3000米的村庄并非如此，那里这类苍蝇数量稀少。
