Infestation in the dog by the paralysis tick Ixodes holocyclus. 2. Blood-gas and pH, haematological and biochemical findings.

Arterial blood-gas and pH, haematological and biochemical estimations were carried out on 8 dogs infested with Ixodes holocyclus and 2 uninfested controls. The arterial blood-gas and pH measurements did not change significantly until the dogs were recumbent and unable to lift their heads. When affected dogs became moribund, moderate hypoxaemia with acute ventilatory failure was present. The significant haematological and biochemical abnormalities were difficult to interpret individually, but taken together could reflect sympathetic stimulation of the adrenal cortex or medulla.