An intestinal parasite that feeds on the blood of sheep, cattle and other ruminant animals could become its own worst enemy. That's if ARS researchers can exploit important biochemicals in the parasite's own gut that help it digest red blood cells. Currently, anthelmintic drugs are the weapon of choice against the parasite, the nematode Haemonchus contortus. Also called the barberpole worm, H. contortus belongs to a genus that costs cattle and sheep producers millions of dollars in losses and control measures. The barberpole causes bleeding in its host's stomach walls, then feeds on the blood.
Severe infections can kill an animal or cause poor milk, meat, hide or wool production.
The worm mainly derives its nutrition from hemoglobin in red blood cells it ingests. Scientists recently found several key proteins and enzymes that help the barberpole utilize these nutrients. One protein group, called hemolytic factors, ruptures the red blood cells. This causes hemoglobin to seep out into the barberpole's digestive system. In test tube studies, the hemolytic proteins completely destroyed sheep red blood cells within 90 minutes after exposure.