8Life Cycle Larvae develop to infective stage within one week Larvae crawl up blades of grass and are ingested by the horseOnce ingested, larvae travel through the digestive system to the large intestineS. vulgaris migrate to the anterior mesenteric artery
9Life CycleS. endentatus to the liver and flank areaS. equinus migrate to the liver and pancreasAdult large strongyles live in the cecum and large intestineEggs are laid in the cecum and large intestine and passed through the fecesSuperior mesenteric artery
10Adult Strongyle Damage These worms are aggressive feedersAfter feeding, move to a fresh site leaving a bleeding craterCraters ulcerate and heals, leaving scar
11Large Strongyles in Mesenteric Artery Large strongyles can live in mesenteric artery, which supplies blood to the intestineInflame artery wallCreate blood clots that interfere with oxygen and nutrients to/from the intestineLeads to severe and often fatal colic
12Small Strongyles Also called cyathostomes Cause under-performance Loss of conditionFeed inefficiencyPredisposition to secondary diseasesAre extremely prolificEmerge from lining of intestines and leave an ulcerated gut wall
13Roundworms Adult roundworms are visible to the eye Roundworm larvae migration through the lungs and liver is most dangerousOften causes foal pneumonia – potentially fatal
15Large Roundworms Most common in young horses Intestinal infections may show no clinical signsCan decrease gut motilityIntestinal impactions from clustered roundworms may cause rupture to the intestine and produce peritonitis
16Roundworm Life CycleHost foal ingests infected eggs from contaminated environment and/or feed. Eggs pass through oral cavity to the stomach and into the small intestine. (Solid Arrows)Eggs hatch in intestine and migrate through the liver to the lungs via the circulatory system. Larvae then travel to the pharynx and are swallowed (tracheal migration shown by the interrupted arrows). Larvae mature to adult state in the small intestine
17Roundworm Life Cycle Adult roundworms in small intestine Eggs are laid in the small intestineEggs are excreted in fecesLarvae develop to infective 2nd state eggs within two weeksEmaciated infected foalAdult roundworms clustered in ruptured small intestine
19Bots Eggs are yellow in color Eggs are difficult to remove Each female bot fly may lay as many as 1,000 eggsRemoval of eggs on hair coat when present is essentialUse lvermectin or Moxidectin 1 month after first frost and in spring to eliminate larvae in stomach
20Bot life Cycle Pupae form in loose soil Adult bot fly emerges from pupa in 3-10 weeks. Female posterior is long and pointed to deposit eggs.Common bot fly (G. intestinalis) lays eggs on leg hairs. Eggs must be licked to hatch larvae. After ingestion, larvae tunnel in epithelium of tongue and form pockets between upper molars. One month later, larvae migrate to stomach or duodenum
21Bot life CycleThroat bot fly (G. nasalis) lays eggs on hairs around side and back of mouth. Eggs are ingested with food and water.Nose bot fly (G. hemorroidalis) lays eggs around nose and mouth. Eggs ingested with food and water.Larvae of bot fly cluster on linings of stomach and proximal duodenum
22Bot life Cycle Larvae passed in feces Common bot fly larva Throat bot fly larva
24PinwormsMajor sign is horse rubbing his tail or rear quarters on any available surfaceCaused by females depositing eggsEggs are pale yellow to cream coloredContain fluidNeed a microscope or hand lens to view themCleanliness is essential prevention
25Pinworm Life CycleSticky eggs will adhere to walls, fences, bedding, and will be found in water or feedLarvae develop into infective stage within the eggsInfective larvae are ingested by the host. Larvae travel through digestive system to the cecum and large intestine where they mature in four or five months.
26Pinworm Life CycleAdult pinworms reside in the lumen of the cecum and large intestineAdult female crawls to the skin around the anal area to deposit eggs in clusters
28TapewormsTapeworms have a head (known as the scolex) and a segmented body. There are three known species of pathogenic tapeworm, with Anoplocephala perfoliata being the most common. Other species reported are rare and rarely cause disease.Tapeworms do not have separate sexes, the segments (proglotids) contain eggs which develop and mature. These mature segments detach and are passed out in the horse's faeces where they disintegrate, releasing the eggs.
29TapewormsTapeworms can be up to 20cm in length, although normally average around 4-5cm; rarer species can be up to 80cm long. They are white in colour.Looks like riceFound at the narrow junction between the small and large intestine, tapeworm use the four suckers on their head to attach to the lining of the digestive tract to avoid being swept away from the intestine by peristalsis.
30Tapeworm Life CycleThe tapeworm life cycle is about 6 months long and has an intermediate host called the oribatid (forage) mite found on the pasture, as well as in food and bedding. The mite consumes the egg passed in the feces, and the immature tapeworm (cysticercoid) then develops inside the mite before it itself is ingested by the horse.
33Fenbendazoletreatment of large strongyles, small strongyles, pinworms, and ascarids
34Moxidectinkills bots, small strongyle larvae encysted in the intestinal wall. These larvae are responsible for many of the late winter/early spring colics when they emerge from the intestinal wall
35Pyrantel PomoateKills large strongyles, pinworms, large roundworms, and small strongylesCan kill tapeworms if a “double dose” is given.(Off label)
36Praziquantel Excellent at killing tapeworms Only comes combined with either Ivermectin or Moxidectin.
37Ivermectinsmall strongyles, large strongyles, pinworms, ascarids, hairworms, large-mouth stomach worms, bots, lungworms, summer sores, and intestinal threadworms
38Oxibendazoleroundworms, strongyles, threadworms, pinworms and lungworm
39January:Broad Spectrum de-wormer such as fenbendazole (Panacur, Safe-Guard); oxibendazole (Anthelcide EQ)March:Ivermectin 1.87% (Equell, Equimectrin, Eqvalen, Ivercare, Zimectrin), for general de-worming.April:Moxidectin plus praziquantel (Quest Plus or Combo Care), to treat encysted strongyles and tapeworms.June:Either double dose pyrantel pamoate (Strongid, Strongyle Care) OR single dose praziquantel combination product with either ivermectin or moxidectin (Equimax, ComboCare, Quest Plus, Zimectrin Gold), to treat tapeworms.August:Ivermectin 1.87% (Equell, Equimectrin, Eqvalen, Ivercare, Zimectrin) for bots; first dose.October:Ivermectin 1.87% (Equell, Equimectrin, Eqvalen, Ivercare, Zimectrin) for bots; second dose.November: