Hi thanks for asking question in HCM. In the demyelinating disease,myeline sheath got damaged. It could be because of congenital genetic cause, trauma or inflammation or infection of brain or spinal cord. During house flea treatment mere inhalation will not lead to demyleniting disease.So it could not be the cause. The common etiological disease associated with causing demyelination is multiple sclerosis. I hope i have solve your query.