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EALTH TEAM REPORT
Know your Enemy – Strongyles - Part 1
remain encysted in the intestinal wall for up to 3 years, Certain parasites can cause severe and sometimes fatal making it important to use a dewormer that is effective damage to our four-legged friends, making it a very against both adult worms and encysted larvae. If a horse important part of equine management. It can also be one has been heavily infected with small strongyles they can of the most confusing. To better protect our horses we suffer from diarrhea and even colic. It has recently been need to understand the different parasites that can infect discovered that small strongyles have developed a our horses, which dewormers are affective against them, resistance to some dewormers that have been used in and at which part of their life cycle are they effective. the past, this resistance is believed to have developed from deworming horses too frequently. Small strongyles The most common parasites affecting horses are have shown resistance to bezimindazole as well as strongyles and also one of the most potentially pyrantel. Ivermectin and moxidectin are the preferred damaging. There are over 100 different species of drugs of choice for eliminating small strongyles but there strongyles that can be divided into two groups; large strongyles or “bloodworms”, and small strongyles. is concern that resistance to these two drugs could also develop. It is important to consult with a veterinarian to develop an effective deworming program for reducing Horses become infected with large strongyles by grazing on pasture contaminated with strongyle larvae. Those larvae penetrate the intestinal wall and migrate through In Part 2 I'll cover some of the other parasites; tapeworm, the blood vessels supplying the intestines. This migration can damage those blood vessels leading to blood clots, ruptured blood vessels and even death. Some species of large strongyles migrate to other internal organs such as the liver or pancreas. Eventually large strongyles return to the intestines forming nodules which eventually rupture, releasing adult worms. These adult worms feed off the mucosal lining of the intestinal wall, causing ulcers and anemia. Male and female large strongyles mate and the female releases eggs into the lumen of the intestines which are shed in the horse's manure and molt into larvae. The typical life cycle of the large strongyle is approximately 6 months. Large strongyles are susceptible to ivermectin and moxidectin and are rarely seen in horses that have been dewormed on a regular basis. Because of the average 6 month life cycle of the large strongyle, it is wise to deworm horses every 6 months with a dewormer containing either ivermectin or moxidectin such as Eqvalan or Quest. Small strongyles are the most common parasites seen in horses. Heavily infested horses can have up to 2000 eggs per gram of manure. Small strongyles have a similar life cycle to large strongyles but do not migrate. Instead small strongyles burrow into the intestinal lining forming cysts. Those encysted larvae eventually release adult worms into the intestine. The life cycle of the small strongyle is quite varied in length as some worms can Jack with “his girls” India & Jessie

Source: http://www.circlef.ca/Newsletters/PDF/HealthTeamReportMarch.pdf