Guillot F S, Cole N A
Vet Parasitol. 1984 Oct;16(1-2):127-35. doi: 10.1016/0304-4017(84)90014-1.
A test was begun in November 1982 to evaluate the development of Psoroptes ovis, the severity of psoroptic mange of cattle, and the incidence of transfer of P. ovis from artificially infested cattle to non-infested cattle held in feed lots in either an endemic (Bushland, TX) or non-endemic region (Kerrville, TX). The 2 herds each consisted of 24 Hereford steers. The 24 steers were randomly assigned to 3 pens of 8 steers per pen. Two steers from each pen that were randomly selected were artificially exposed to ca. 1000 P. ovis (AINF). The development of mange on these 6 AINF steers and the incidence of transfer to the other steers (INF) were monitored approximately every 3 weeks for 17 weeks. The 6 AINF steers at Bushland (endemic region) developed significantly more lesions than the 6 AINF steers at Kerrville. Three AINF steers in Bushland died from hypothermia and mange while no deaths were recorded at Kerrville. The numbers of mites sampled from affected skin areas of AINF steers from both regions were not significantly different. All 18 of the naturally exposed steers (INF) in Bushland contracted mange; whereas, only 9 INF steers in Kerrville did. The severity (% lesions) and number of mites per sample from affected skin were significantly greater on the INF steers in Bushland. These differences among INF steers in Bushland and Kerrville may be attributed to the higher level of parasitism attained in Bushland on the AINF steers. We propose that the extremely cold weather in Bushland contributed to the greater level of parasitism attained on AINF steers in Bushland by stressing the host steers.
1982年11月开始了一项试验，以评估绵羊痒螨的发育情况、牛痒螨病的严重程度，以及绵羊痒螨从人工感染的牛转移到位于地方病流行区（得克萨斯州布什兰）或非地方病流行区（得克萨斯州克尔维尔）的饲养场中未感染牛的发生率。两个牛群各由24头赫里福德阉牛组成。将这24头阉牛随机分配到3个围栏中，每个围栏8头阉牛。从每个围栏中随机挑选出的2头阉牛被人工暴露于约1000只绵羊痒螨（AINF）。对这6头AINF阉牛的螨病发展情况以及向其他阉牛（INF）的传播发生率进行了约17周的监测，大约每3周监测一次。布什兰（地方病流行区）的6头AINF阉牛比克尔维尔的6头AINF阉牛出现了明显更多的损伤。布什兰的3头AINF阉牛死于体温过低和螨病，而克尔维尔没有死亡记录。从两个地区的AINF阉牛受影响皮肤区域采集的螨的数量没有显著差异。布什兰所有18头自然暴露的阉牛（INF）都感染了螨病；而在克尔维尔，只有9头INF阉牛感染。布什兰的INF阉牛受影响皮肤的严重程度（损伤百分比）和每个样本中的螨数量明显更高。布什兰和克尔维尔的INF阉牛之间的这些差异可能归因于布什兰的AINF阉牛达到了更高的寄生虫感染水平。我们认为，布什兰极端寒冷的天气通过使宿主阉牛处于应激状态，导致布什兰的AINF阉牛达到了更高的寄生虫感染水平。
