Myiasis in sheep farms in Riyadh Region, Saudi Arabia.

During a survey for myiasis in Riyadh Region, 3712 sheep were examined. 73 animals (2%) were infested with different dipterous larvae. Out of the 115 larvae recovered, 100 larvae (87%) were Chrysomya bezziana, 10 (8.7%) were C. albiceps, and 5 (4.3%) were Wohlfahrtia nuba. The prevalence rate of larval myiasis among young sheep was 60%, and 40% among adults. The myiasis incidences were highest during Mar-May (60%) and Sept-Nov (31.5%) where temperature and R.H. are optimum. In the dry hot season (Jun-August) and cold season (Dec-Feb) infestation incidences were low (5%&1.5% respectively). Temperature and R.H. are conducive in controlling myiasis in other regions of the Kingdom.