Ivermectin's Impact on Horse Worms: A Danish Study

In Denmark, a recent study looked at how well ivermectin works against strongylid worms in horses. These worms are everywhere and can make horses very sick. One big problem is that these worms are getting resistant to the drugs meant to kill them. Some countries in Europe have made rules to limit how often these drugs can be used. The goal is to slow down the worms' ability to resist the drugs. But, no one has really checked if these rules are working long-term. The study focused on ivermectin, a common worm treatment. It involved 299 horses from 30 different places. The horses were treated with ivermectin, and then scientists checked how many worm eggs were in their poop. They used two different methods to count the eggs. One was the old-fashioned way, and the other was a fancy new system that uses artificial intelligence. The results were a bit mixed. The old-fashioned method showed that ivermectin worked well in most places. But the new system suggested that the drug might not be working as well in some places. This could mean that the worms are starting to resist the drug. The study also found that it takes at least 8 weeks for the worm eggs to show up again after treatment. This is a good sign, as it means the drug is still working for now. Another thing the study looked at was a specific type of worm called Strongylus vulgaris. They found that this worm is still around in Danish horses, but it's not very common. They used two methods to check for this worm. One was growing the worms from poop samples, and the other was using a test called PCR. The PCR test found more cases of the worm than the growing method. The study shows that ivermectin is still working well against strongylid worms in horses. But there are signs that the worms might be starting to resist the drug. This is something to keep an eye on in the future. The two egg-counting methods mostly agreed, but the new system found more low-level infections. This could be because it's more sensitive. The study also shows that Strongylus vulgaris is still a problem in Denmark, even if it's not very common. The study is important because it gives a snapshot of how well ivermectin is working in Denmark. It also shows that the new egg-counting system might be better at finding low-level infections. This could help in the fight against worm resistance. The findings suggest that more monitoring is needed to keep track of how the worms are responding to the drug.