Sometimes refered to as Blood Worms because of their colour. Large Redworms mature in the gut, feeding on the lining of the gut wall, larvae then burrow into the arteries which can cause blood clots, weaking of the artery walls, anaemia, weight loss, severe colic and in very severe cases death.
The adult Large redworm produces eggs which are passed in the droppings, which then hatch into larvae in warm weather and contaminate the pasture, the larvae is then eaten while the pony is grazing and the cycle continues.
Small Redworm are the most common of the equine worms.The life cycle of the Small Redworm follows the same pattern as the Large Redworm. There is some evidence to suggest that the worm is beginning to develop some resistance to conventional wormers such as Fenbendazole and Ivermectin. Larve living in the gut at the onset of winter hibernate until spring, they then re-emerge in large numbers when the weather is warmer. Treatment should be in November/December as a routine. In a survey carried out (2016) only 68% of those asked had used an effective product. Initially symptoms may not be obvious, later they can cause diarrhoea, severe weight loss and colic, even fatalities when severe encysted larval infections are present.
Roundworms are named due to the shape of their eggs The adults resemble large white earthworms. The adult Roundworms live in the small intestine. The eggs are passed in droppings, which hatch and are then eaten while the pony is grazing, the larvae then migrates to the liver and lungs, then back to the intestine via the windpipe and throat where they mature.
The adult Roundworm in the intestine could cause colic, pot-belly, weight loss, and in the event of a blockage of the intestine death. The larvae whilst migrating through the body can cause coughing, nasal discharge, lung & liver damage, and damage possibly permanent damage to the digestive system.
Threadworms are fine worms that infest the intestines of foals. The foals become infected by Threadworm larvae in mares milk. Eggs are passed through the droppings, the foal is then re-infected while grazing. Diarrhoea, poor growth or weight loss, loss of appetite are all symptoms. Foals usually develop immunity to this worm after about six months.
Tapeworms are often called Flatworms. The adult Tapeworms live in the intestine at the junction between the large and small intestine ( Illeocaecal Junction ). The Tapeworm eggs are passed through droppings which are eaten by Forage Mites ( Orbatid Mites ) which can be found on grass, hay or straw they are then eaten by the pony when grazing, the Tapeworm then develop within a small region of the gut and fully mature three to five months after the pony has eaten the mites.
Tapeworm can cause ulceration of the intestine wall, colic, irritation, digestive problems, and possible obstruction or rupture of the intestine.
Pinworms are small white worms that live in the large intestine, they crawl out to lay masses of yellowish grey gelatinous eggs around the anus. This causes severe itching trauma in which ponies may rub their tails and hind quarters bare, this may cause open sores which could then lead to infection.
Bots are not worms, they are the larvae of a species of fly. It is the larvae that are refered to as Bots. The adult flies lay their eggs on the ponies coat, as the pony grooms itself, or other ponies, the eggs are ingested, The eggs hatch int larvae while inside the ponies mouth, then migrate to the stomach where they attach to the gastric lining until maturity, when they then pass in the feces. If left untreated it could result in stomach ulcers, colic or in severe cases perforation of the stomach.
For further information on equine paraistic worms :- www.bhsscotland.org.uk