The histopathology of Capillaria hepatica were studied in Meshkin-Shahr district, Ardabile province, northwest Iran. One hundred seventy three Meriones persicus were trapped between end of July till October 1996, ten out of 173 (5.8%) Meriones persicus had been infected with C. hepatica. One of the highly infected rodents revealed the worm and masses of eggs in the liver and many pseudo tubercle in the lung as well. The histopathology of lung characterized by granulomatous lesion around the C. hepatica eggs within the interstitial tissue of the lung, hyperplasia of epithelial cells lining alveoli and terminal branchioles and inflammatory cells around the C. hepatica eggs. The predominant cells were macrophages and plasma cells.
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