Prevalence and molecular detection of Sarcocystis spp. infection in the dromedary camel (Camelus dromedarius) in Riyadh city, Saudi Arabia

This study was conducted to investigate the prevalence of Sarcocystis infections in camels slaughtered using different detection methods. Tissues from the oesophagus, tongue, skeletal muscle, diaphragm and heart were collected from 80 camels (60 males and 20 females) slaughtered. Pepsin-digestion and histological methods were used in the study. Bradyzoites were purified using Percoll density gradient centrifugation and molecular detection was attempted from the DNA extracted from purified bradyzoites. The prevalence of Sarcocystis infections in camels in Riyadh city was 50% using the pepsindigestion method and 41.3% using microscopic method. Males revealed 24 (40%) Sarcocystis infection following the pepsin digestion method while 13 (21.7%) showed microscopic cysts in histological sections (Chi square=4.7281 and p<0.05). While females revealed 80% and 45% prevalence using the pepsindigestion and the microscopic methods, respectively (Chi square=5.2267 and p<0.05). The skeletal muscle showed the highest bradyzoites count in the 5 minutes count (606 ± 74) while the heart showed the lowest count (101 ± 18). The highest prevalence on histological sections was reported from the tongue while the skeletal muscle revealed the lowest. Attempts to amplify the 18S rDNA from purified bradyzoites DNA revealed successful amplification of the expected DNA fragment for Sarcocystis spp