Which of the following is NOT a sexually transmitted disease?

Filariasis

The correct answer is Option (3) → Filariasis 

Wuchereria bancrofti and Wuchereria malayi are types of filarial worms that can cause a condition known as elephantiasis or filariasis. These worms live in the lymphatic vessels of the lower limbs, as well as in the genital organs, leading to chronic inflammation and damage over many years.

Infections or diseases which are transmitted through sexual intercourse are collectively called sexually transmitted infections (STI) or venereal diseases (VD) or reproductive tract infections (RTI). Gonorrhoea, syphilis, genital herpes, chlamydiasis, genital warts, trichomoniasis, hepatitis-B and of course, the most discussed infection in the recent years, HIV leading to AIDS are some of the common STIs. Among these, HIV infection is most dangerous. Some of these infections like hepatitis–B and HIV can also be transmitted by sharing of injection needles, surgical instruments, etc., with infected persons, transfusion of blood, or from an infected mother to the foetus too. Except for hepatitis-B, genital herpes and HIV infections, other diseases are completely curable if detected early and treated properly.