Honolulu Civil Beat has an article on efforts to treat RLW, with this important information about diagnosis via lumbar puncture (aka spinal taps):
For example, lumbar punctures, commonly known as spinal taps, have been misrepresented as an invasive, painful procedure. Information obtained from a lumbar puncture provides priceless information that helps physicians make very important decisions regarding diagnosis and treatment of patients.
In fact, it is a common, very safe procedure that is typically a critical part of the work up for rat lungworm disease. Local anesthetic makes it relatively painless and, as an added benefit, a spinal tap will usually dramatically relieve the headaches, which typically accompany an infection.