Which parasite causes Morgellons disease?

Morgellons disease (MD) is a rare disease in which fibres remain present beneath the skin or emerge out of unbroken skin or delayed sores. This disease also affects the mental status of the patients and they experience crawling and stinging sensations on the skin, akin to that of insect or parasite infestation.

The condition is controversial and poorly understood owing to the uncertainty of the cause of symptoms. Several medical practitioners consider it as a purely psychiatric condition, while rigorous experimental investigation suggests that this condition arises as a psychological response to an existing infectious agent.