parasitic burdens, egg output, hemathologic, and biochemical changes in naturally infected lambs with dicrocoelium dendriticum

background: we investigated the variations of heamathologic and biochemical parameters with different parasitic burdens and the correlation between fecal egg counts and fluke number in livers of sheep naturally infected with dicrocoelium dendriticum . methods: in order to detect excretion of d. dendriticum eggs, fecal samples from 120 sheep of different age groups were collected individually at slaughterhouse in neyshabur county in razavi khorasan province during december 2013 - october 2014. hematologic and blood biochemical values in 120 sheep naturally infected with d. dendriticum were compared with equivalent values in 120 parasite-free sheep from an organically farmed flock. investigated animals were kept in outdoor system, on pastures covered with swamps, which remain flooded after rainy season. results: total numbers of flukes in livers obtained from infected sheep at autopsy varied between 10 and 18,500. a positive relationship was noted (r= 0.94, p < 0.001) between the number of eggs excreted by each sheep and that of total fluke counts in the liver. significantly, lower red blood cell, packed cell volume, neutrophil and albumin were observed in parasitized sheep, when compared to the healthy animals. white blood cells,, lymphocyte and aspartate aminotransferase values were significantly higher in parasitized sheep. no significant correlation was detected between the hematologic and biochemical parameters and the number of d. dendriticum in the liver. conclusion: infection with > 400 d. dendriticum in the liver could be diagnosed by egg per gram. however, there was no relationship between the parasite burden and hematologic and biochemical parameters.