Fenbendazole by Safeguard, buy it at Tractor Supply stores or online at Jeffers, TS has it on sale for 7bucks, you'll not regret the decision to use it, probably 6 months to 2 years, one can pulse the treatments, for advanced cases, use the mix of Equimax and Pyrantel pamoate, strong stuff, use with caution, use 2 turns on the threaded limiter, if blindness gets bad stop until sight returns, many sufferers have worm larva in their eyes, same stuff as the filarial fibers in the above pics.