Human T lymphotrophic virus-I (HTLV-I) is a pathogenic virus and the cause of adult T cell leukaemia/lymphoma (ATLL), and tropical spastic paresis (TSP). It is endemic in Japan, the Caribbean islands, and Africa. It has also been reported from some places in India (few cases mainly in south India - Kerala), from select populations in Israel, and other countries in the West. This virus is mainly spread vertically through the sexual route, through blood transfusions and sharing of needles. HTLV-I has also been associated with clinical conditions like infective dermatitis. In countries with a high prevalence of HTLV-I in the general population, the prevalence of HTLV-I infection in these conditions is higher than in countries with a lower prevalence. This infection can be diagnosed by immunological and molecular techniques but these are not available as routine tests since it is very rare in India. You are lucky not to have acquired HIV or any other infection, and should stop worrying and ensure that you do not indulge in unsafe sex in future. Weakness is a non-specific symptom and not indicative of any sexually transmitted infection.