The large redworm is not as problematic as it
used to be due to the use of modern equine anthelmintics. However, these are still life-threatening parasites whose migratory larval
stage can cause blockages in blood vessels,
damaging vital organs.

Size/Appearance: The large redworm is
a darker red than the small redworm, and
bigger at up to 5cm long.

Location in Horse: Larvae migrate around
horse’s blood vessels. Adults are found in
the large intestine.

Symptoms: Symptoms of a large redworm infection include colic, sometimes fatal by blocking blood vessels.