Herd R P, Donham J C
Am J Vet Res. 1981 Nov;42(11):1953-5.
Thirty-one horses with naturally occurring summer sores were given a single IM injection of 0.2 mg of ivermectin (22,23-dihydroavermectin B1)/kg during the summer of 1980. Larvae of Draschia and/or Habronema spp were recovered from biopsy samples taken from 21 of 25 horses (84%) on the day of anthelmintic treatment. There was a marked clinical improvement in 26 horses (84%) 7 days after ivermectin was given. The typical summer sore was replaced by healthy pink granulation tissue at 7 days and this healed after 1 to 5 weeks. Biopsy samples were taken from 21 of these horses 1 to 6 weeks after treatment, and the samples in 18 horses (86%) were negative for larvae. Five of the 31 infected horses did not respond to a single dose and appeared to have become reinfected. Biopsy samples taken from 3 of these horses were positive for larvae 2 to 4 weeks after the 1st dose, but became negative and healed 1 to 2 weeks after a 2nd dose with ivermectin. Histopathologic examination of sections from lesions before anthelmintic treatment showed granulation tissue with marked eosinophilic infiltration, multiple eosinophilic abscesses, and transverse sections of nematodes. In sections examined after anthelmintic treatment, there were marked reduction in the number of eosinophils and absence of eosinophilic abscesses or nematodes, and the granulation tissue was more mature, as indicated by the appearance of dense fibrous connective tissue.
1980年夏天，31匹患有自然发生的夏季溃疡的马接受了一次肌肉注射，剂量为0.2毫克伊维菌素（22,23 - 二氢阿维菌素B1）/千克。在驱虫治疗当天，从25匹马中的21匹（84%）的活检样本中发现了德拉什属和/或哈布罗内马属的幼虫。给予伊维菌素7天后，26匹马（84%）有明显的临床改善。典型的夏季溃疡在7天后被健康的粉红色肉芽组织取代，并在1至5周后愈合。在治疗后1至6周从其中21匹马身上采集活检样本，18匹马（86%）的样本中未发现幼虫。31匹受感染的马中有5匹对单剂量治疗无反应，似乎再次感染。从其中3匹马身上采集的活检样本在第一次给药后2至4周幼虫呈阳性，但在第二次给予伊维菌素后1至2周变为阴性并愈合。驱虫治疗前病变切片的组织病理学检查显示肉芽组织有明显的嗜酸性粒细胞浸润、多个嗜酸性脓肿和线虫横切面。在驱虫治疗后检查的切片中，嗜酸性粒细胞数量明显减少，没有嗜酸性脓肿或线虫，肉芽组织更成熟，表现为致密纤维结缔组织的出现。
