Otranto Domenico, Milillo Piermarino, Capelli Gioia, Colwell Douglas D
Department of Animal Health and Welfare, Faculty of Veterinary Medicine, University of Bari, Valenzano, Bari, Italy.
Vet Parasitol. 2005 Oct 10;133(1):111-8. doi: 10.1016/j.vetpar.2005.05.015.
Horse gastrointestinal myiasis caused by larvae of Gasterophilus spp. (Diptera, Oestridae) flies has a worldwide distribution and, where present, it is primarily caused by larvae of Gasterophilus intestinalis and Gasterophilus nasalis. Other species, i.e., Gasterophilus inermis, Gasterophilus pecorum and Gasterophilus haemorrhoidalis, present in different or in the same regions of the gastrointestinal tract, were only occasionally reported in very limited areas of eastern European Countries and in central Italy. With the aim to contribute data on the species composition of Gasterophilus and on the seasonal variation of the infection pattern in southern Italy, 152 native horses were necropsied from January to December 2003 and Gasterophilus larvae were collected from the stomach, the small intestine and the rectum of each of them. On the whole, 125 (82.2%) horses were infected by larvae of Gasterophilus spp. and 214 second stage larvae (L2) and 13,342 third stage larvae (L3) collected. Five species of Gasterophilus were identified with the following prevalence: G. intestinalis=95.2%, G. nasalis=44.8%, G. inermis=15.2%, G. pecorum=2.6% and G. haemorrhoidalis=0.8%. L3 were retrieved throughout the observation period with the highest mean burdens from January to August 2003 while the lowest mean was registered from September to November 2003. L2 were collected in February-March 2003 and from September to December 2003. The majority of the animals (n=66, 43.4%) were infected with a single Gasterophilus species, however, 45 animals (29.6%) harboured 2 species, 12 animals (7.9%) 3 species and 2 animals (1.3%) 4 species. The trend of abundance in the L3 of G. intestinalis and G. nasalis, the most represented species, was highly concordant (r=0.5, p<0.001). A retrospective comparison of our results and of other data from four seasons of observation (1983-1986) in central Italy showed that the number of G. inermis, G. pecorum and G. haemorrhoidalis have been decreasing relative to G. intestinalis and G. nasalis which may suggest tendency toward the extinction of the three former species of Gasterophilus.
由胃蝇属（双翅目，狂蝇科）蝇类幼虫引起的马胃肠蝇蛆病在全球范围内均有分布，在有该病的地区，主要由肠胃蝇和鼻胃蝇的幼虫引起。其他种类，即无刺胃蝇、马胃蝇和痔胃蝇，存在于胃肠道的不同区域或同一区域，仅在东欧国家的非常有限的地区以及意大利中部偶尔有报道。为了提供有关意大利南部胃蝇物种组成以及感染模式季节变化的数据，2003年1月至12月对152匹本地马进行了尸检，并从每匹马的胃、小肠和直肠中收集胃蝇幼虫。总体而言，125匹（82.2%）马被胃蝇属幼虫感染，共收集到214条二期幼虫（L2）和13342条三期幼虫（L3）。鉴定出五种胃蝇，其感染率如下：肠胃蝇=95.2%，鼻胃蝇=44.8%，无刺胃蝇=15.2%，马胃蝇=2.6%，痔胃蝇=0.8%。在整个观察期内均能检索到三期幼虫，2003年1月至8月平均虫负荷最高，而2003年9月至11月平均虫负荷最低。二期幼虫于2003年2月至3月以及9月至12月收集到。大多数动物（n = 66，43.4%）感染单一胃蝇物种，然而，45只动物（29.6%）感染两种，12只动物（7.9%）感染三种，2只动物（1.3%）感染四种。在数量上占比最大的肠胃蝇和鼻胃蝇的三期幼虫丰度趋势高度一致（r = 0.5，p < 0.001）。将我们的结果与意大利中部四个季节观察期（1983 - 1986年）的其他数据进行回顾性比较，结果显示，相对于肠胃蝇和鼻胃蝇，无刺胃蝇、马胃蝇和痔胃蝇的数量一直在减少，这可能表明前三种胃蝇有灭绝的趋势。
