Cephalopina titillator is a common parasite that infest camels all over the world and causes nasal myiasis. The infestation is diagnosed only on post-mortem examination of the animal after slaughtering. The goal of the present study was to isolate and characterize a special protein fraction extracted from the larvae of the parasite, which can be used for sensitive and specific diagnosis of early infestation in living camels in Saudi Arabia. Four soluble antigens were extracted from the proximal and distal ends, the surface tegument, and the excretory-secretory (ES) products of living first-, second- and third-stage larvae. Fractionation of the antigens using SDS-PAGE revealed seven protein fractions from the anterior-end antigens with molecular weights (MWs) of 76-85 kD, 58 kD, 47-49 kD, 37-45 kD, 35 kD, 30-32 kD and 23-25 kD. We used a Western blot technique to identify the protein fractions extracted from different larval stages in the sera of infested camels and non-infested camels. The protein fraction with a MW of 58 kD had the highest sensitivity, specificity and validity among all of the protein fractions. This protein is present in large enough quantities in the anterior end of larvae, particularly in the third-stage of development, that the antigenic fractions may be used for diagnosis of parasitic infestation in living camels.
