Larvae washed from manure pats into the soil by rain may overwinter in earthworms that carry them from deeper in the soil to the surface in the spring. Here, they may be eaten by cattle. Some researchers feel that parasite development stops during the winter months in some infected animals. When development begins again in the spring, these carrier animals may contaminate pastures and thereby pass the infection to other animals in the herd. Have a veterinarian examine the cattle as soon as a herd coughing problem is noticed.
Diagnosis is made by physical examination of the animal.
If the examination suggests lungworm, then diagnosis is confirmed by microscopic examination of a fresh manure sample taken from the rectum. Lungworms may also be diagnosed on postmortem examination by your veterinarian. All pasture deaths should be routinely submitted for post mortem examinations. Preventive measures Young animals slowly develop immunity to lung-worms if they are not overwhelmed by the initial exposure. Pasture management measures should be designed to minimize early exposure.