You could maintain them using a dog and the animal's feces will be a long-term source

Hi Sarit

For culturing stool samples contain eggs and larvae of Strongyloides stercoralis, I recommend you to use filter paper technique, by this method you can harvest high numbers of infective filariform larvae can then be used to maintain new generation in only two hosts either in dog or gerbil. All the best

from doges fecal samples by contain egg or larvae of this parasite by flotation test or Berman techniques or by fecal culture 

may be this link help you 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4557157/