Since its discovery in 1980, human T-cell lymphotropic virus type-1 (HTLV-1
) has been associated with a number of neurological diseases. The distribution of HTLV-1
-associated neurological disease is worldwide. In endemic areas, up to 30% of the population may be infected with HTLV-1
; however, only a small percentage of infected persons develops neurological disease.
In 1986, HTLV-1
infection was reported in patients of chronic progressive myelopathy of uncertain etiology, and the disease entity was called HTLV-1
-associated myelopathy/tropical spastic paraparesis. Recently, HTLV-1
infection has been associated with polymyositis
. Interestingly, a single patient may display more than one syndrome. Although other neurological syndromes occur in HTLV-1
-infected individuals, there is not enough epidemiologic data that show a strong association. Treatment of HTLV-1
-associated neurological disease is challenging, and well-controlled studies are lacking.
As neurologists and other scientists begin to understand the pathophysiology of HTLV-1
infection, improved therapies should be developed. Randomized trials with longer follow-up are required to understand the effect of treatment on disability and quality of life.