Discipline: Veterinary Medicine
The freshwater Asiatic clam (Corbicula fluminea O. F. Müller, 1774) or locally called “tulya” collected from freshwater bodies and sold in wet markets in the municipalities of Baler, San Luis and Maria Aurora in the province of Aurora, Philippines (from December 2010 to February 2011) were examined for the presence of Cryptosporidium oocyts. Ten clams were pooled as one sample where their tissues and hemolymph were processed by homogenization and concentration technique, stained with Kinyoun acid fast stain and examined by microscopy. Prevalence of Cryptosporidium spp. oocyst in pooled clam samples from freshwaters bodies was 87.5% (35/40) in Baler, 83.33% (40/48) in Maria Aurora and 66.67% (28/42) in San Luis. The prevalence of oocysts in pooled samples of clams sold in wet markets was 55% (11/20) in Baler, 50% (10/20) in Maria Aurora and 45% (9/20) in San Luis. The average oocyst density per ml of homogenized tissues from clams collected in water bodies was 234, 84, and 42 in Maria Aurora, Baler and San Luis, respectively. Similarly, the average oocyst density in clams sold by vendors was 81, 77 and 25 in Maria Aurora, Baler and San Luis, respectively. The presence of Cryptosporidium oocyst in the freshwater Asiatic clams suggests that this bivalve could be a source of human infection as this is eaten as human food in the province of Aurora and at the same time it can serve as bioindicator of the contamination of the water environment with oocyst of Cryptosporidium.