Diagnosis of liver flukes in cows : a comparison of the findings in the liver, in the feces, and in the bile

Percutaneous ultrasound-guided cholecystocentesis and aspiration of bile were attempted in 176 cows. These same procedures were performed in another 100 cows immediately after slaughter. The bile samples were examined microscopically for large and small liver fluke eggs. In addition, a fecal sample from each cow was examined for liver fluke eggs. The findings of both groups were summarized, and the results of the fecal and bile sample examinations were compared. In all cows the liver was examined for flukes, and the results were used as a reference. Of 41 cows in which adult flukes were found in the liver, 28 had F. hepatica eggs in fecal samples and 40 had F. hepatica eggs in bile samples. Of 204 cows in which no adult flukes were found in the liver, 23 had F. hepatica eggs in fecal samples and 27 had F. hepatica eggs in bile samples. The sensitivity of the determination of F. hepatica eggs in fecal and bile samples was 68 and 98%, respectively. The negative predictive values for fecal and bile examination were 93 and 99%, respectively. Of 49 cows in which adult flukes were observed in the liver, 13 had D. dendriticum eggs in fecal samples and 44 had D. dendriticum eggs in bile samples. Of 176 cows in which no adult flukes were found in the liver, 19 had D. dendriticum eggs in fecal samples and 49 had D. dendriticum eggs in bile samples. The sensitivity of the determination of D. dendriticum eggs in fecal and bile samples was 27 and 90%, respectively. The negative predictive values for fecal and bile examination were 81 and 96%, respectively. The results of this study indicate that the examination of bile is clearly a more reliable method of diagnosing liver fluke infections than microscopic examination of feces.