Between 5% and 10% of those with the virus will develop a rapidly fatal form of leukaemia
Human T-lymphotropic virus type 1 is spread through contaminated blood, unprotected sex and breastmilk. Like HIV, there is no cure. Like HIV, the virus causes potentially fatal complications but unlike HIV it takes much longer for symptoms to appear. Some people may carry the virus for 30 years before chronic complications appear.