Abo-Shehada M N, Arab B, Mekbel R, Williams D, Torgerson P R
Parasitology Research Laboratory, Faculty of Veterinary Medicine, Jordan University of Science and Technology, Irbid, Jordan.
Prev Vet Med. 2000 Nov 16;47(3):205-12. doi: 10.1016/s0167-5877(00)00160-4.
During the period March 1996-July 1997, 417 heads of Awassi sheep slaughtered at the Irbid Abattoir (northern Jordan) were examined for the three larval instars (L1, L2 and L3) of Oestrus ovis. Of the 417 heads, 242 (58%) were infested with O. ovis larvae. Larval numbers were highly aggregated. The lowest number of larvae and the lower quartile were both zero, whilst the median was two and the upper quartile was 12. The highest number of larvae recovered from one head was 151. All three larval instars were observed in each month of the year. July and October had the highest proportions of L1, 75 and 78%, respectively, among infected animals (adjusted for age). The number of larvae increased with age. Infestation with live larvae was associated with inflammatory responses in the upper respiratory tract and with catarrhal or purulent discharge. The percentage of infested sheep and the mean monthly total number of larvae/sheep peaked in the warmer part of the year. Most larvae were L1 except during the spring when L2 and L3 predominated. Distribution analysis demonstrates that the numbers of larvae recovered in the sheep population followed a negative-binomial distribution. Furthermore, the negative-binomial constant k for each month correlated with the monthly prevalence.
在1996年3月至1997年7月期间，对在伊尔比德屠宰场（约旦北部）宰杀的417头阿瓦西羊的头部进行了检查，以查找羊狂蝇的三个幼虫龄期（L1、L2和L3）。在这417头羊中，有242头（58%）感染了羊狂蝇幼虫。幼虫数量高度聚集。幼虫数量的最低值和下四分位数均为零，中位数为2，上四分位数为12。从一头羊身上回收的幼虫数量最多为151条。一年中的每个月都观察到了所有三个幼虫龄期。在受感染动物中（按年龄调整），7月和10月的L1比例最高，分别为75%和78%。幼虫数量随年龄增长而增加。活幼虫感染与上呼吸道的炎症反应以及卡他性或脓性分泌物有关。受感染绵羊的百分比和每月每只羊的幼虫平均总数在一年中较温暖的时期达到峰值。除了在L2和L3占主导的春季外，大多数幼虫为L1。分布分析表明，绵羊群体中回收的幼虫数量呈负二项分布。此外，每个月的负二项常数k与每月患病率相关。
