Haematology, weight and condition of captive red grouse (Lagopus lagopus scoticus) infected with caecal threadworm (Trichostrongylus tenuis).

Red grouse infected with the caecal threadworm Trichostrongylus tenuis developed a mild anaemia. Haemoglobin and albumin levels in the blood fell but there were no significant changes in the number of red blood cells or their size. In infected birds the numbers of circulating eosinophils and heterophils increase, as did the concentration of alpha, beta and gamma globulin. Body weights did not change but muscle masses shrank. Birds that subsequently died had the lowest concentration of haemoglobin and packed cell volumes and the highest counts of eosinophils. The survivors were affected little by worms and their haematology showed small deviations from normal.