Sheep and goats also serve as the intermediate host for several other species of tapeworms. Echinoccus granulosus causes hydatid disease in livestock and humans. Taenia ovis causes “sheep measles” (ovine cysticercosis). Both have life cycles involving dogs as definitive hosts and sheep and goats as intermediate hosts.
The adult worms cause few symptoms in the dog, but the cystic stages can cause considerable damage to the intermediate host. Hydatid disease can be life threatening to humans and is the result of accidental ingestion of hydatid eggs from dogs. Though not considered a human health risk, cysts caused by T. ovis can get in the meat and organis and cause a carcasses to be condemned.
The best way to prevent these problems is to keep dogs (domestic and wild) from eating carrion or other raw meat. Scientists have developed an effective vaccine for sheep against. T. ovis and E. granulosus; however the vaccine is currently not available in the U.S.
Lungworms
Lungworm larvae are passed in the feces, but travel to the respiratory system once they enter the sheep system. The symptoms of lung worm infection are not obvious unless the problem is severe. Lungworm infestations are most commonly diagnosed at necropsy or slaughter. The same anthelmintics that are effective against stomach worms are also effective against lung worms.
Liver flukes (Fasciola hepatica)
Liver flukes can be problematic in wet areas. They are spread by snails and slugs. As the name would suggest, liver flukes damage the liver of the host animal. They cause blood loss, diarrhea, weight loss, and death. The only drugs that are effective against liver flukes (the adult form) are clorsulon (contained in Ivomec® Plus) and albendazole (Valbazan®).
Meningeal worm
(Paralaphostrongylus tenius, deer worm, brain worm)
The meningeal worm is a parasite of the White Tail deer. Sheep, goats, llamas, alpacas, and horses are abnormal hosts for the parasite. After they ingest the larvae, the larvae travel to the spinal cord causing gait abnormalities and eventually paralysis. When the parasite reaches the sheep’s brain, it will kill them.
Meningeal worm infection cannot be detected in the live animal. When meningeal worm is suspected, high doses of anthelmintics and anti-inflammatory drugs are recommended. Infections can be prevented by limiting exposure to deer or by controlling snail populations, since the parasite requires snails to complete its life cycle.