Genetic Resistance to Common Goats’ Worms Is Widespread in Poland

A recent survey examined 81 goat herds across Poland to see how many worms inside these animals can ignore a common drug called benzimidazole. The researchers first grew the worms from poop samples in a lab and used a DNA test to confirm they were dealing with Haemonchus contortus, the main parasite. They then looked for two tiny DNA changes, called E198A and F200Y, that make the worms immune to the drug. These changes were measured with a technique called pyrosequencing, and the scientists calculated how common each form was in the whole worm population. Almost every herd had at least one of the resistance markers: 79 out of 81 herds showed F200Y and 80 out of 81 had E198A.The median percentage of worms carrying F200Y was high, about 86 %, while only around 8 % carried E198A. When all the herds were pooled, about 89 % of the worms in Poland had at least one resistance gene. The study also linked higher resistance levels to several herd practices. Buying goats from abroad, keeping more than 100 animals, using the drug levamisole for deworming, and giving multiple treatments each year all raised the odds of finding resistant worms. Because resistance is so common, the researchers advise farmers to rethink relying on benzimidazole alone. They suggest mixing different drugs and adopting longer‑term parasite control plans that are more sustainable.