I had the worms sticking to the inside of my cloths for months. I now use this as an indicator of how bad the infection is. I thnk that most times these are a type of round worm referred to as filaria.
As "Buggered" posted permethrin is the only thing that will kill these larvae.
I put all my cloths in 1 once of permethrin to 5 gallons of hat water.
I take my cloths off in the bathroom and put them in a garbage bag to keep the larvae from blowing around. They go from the garbage bag into the hot water/permethrin solution. After 12 hours they get washed. Always check the inside of you cloths when you take them out of the dryer. If they are still there they are not dead. Start over.
When I first started taking Valbazen I took off my cloths one day and there were hundreds of 1/2 inch long thin white worms sticking out of my body.