The parasite, identified as Thelazia gulosa, is normally spread between cattle by flies landing on or near the eyes. This particular eye worm species has never been documented in humans ...

Calves under one year of age are more susceptible than older cattle. Older cattle frequently have been exposed to the parasites and developed a degree of immunity. Adult worms in the gut of cattle ...

Stomach worms must complete several life-cycle stages both inside the gastrointestinal tract of cattle and on the pasture. The cows can only be infected by consuming grass from infected pastures ...