Tehran University of Medical Sciences Iranian Journal of Parasitology 1735-7020 11 1 2016 03 14 30 34 Mohammad YAKHCHALI Dep. of Pathobiology, Parasitology Division, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran Kia BAHRAMNEJAD Dep. of Pathobiology, Parasitology Division, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran 2016 03 14 2016 03 14 Background: Fasciolosis, caused by the liver flukes of the genus Fasciola, is one of the most prevalent diseases of domestic livestock and human throughout the world, imposing considerable economic losses. The present study was aimed to assess the effects of different pH values on hatching rate of Fasciola miracidia. Methods: The flukes were isolated from the infected livers of the slaughtered ruminants at the abattoir of Urmia City, Iran, crushed thoroughly and sieved for isola­tion of the Fasciola eggs. The eggs were washed up several times by PBS (0.01N, pH 7.2). They were incubated at different pH values of 7±0.1 (control) and 3-9.5 (treatments) at 28°C for 16 days. Results: The maximum hatching rate was observed at pH 7 (14.93±0.65%), while no miracidia were hatched at pH 3 and/or pH 9-9.5. There were significant differences between the hatching rate of the treatments and that of the control group. Conclusion: Water pH is proven to be a crucial factor affecting the life cycle of Fasciola and its epidemiology. https://ijpa.tums.ac.ir/index.php/ijpa/article/view/807 https://ijpa.tums.ac.ir/index.php/ijpa/article/download/807/650