Thanks for your query.
STD which stands for sexually transmitted diseases includes diseases like gonorrhea, Chlamydia, herpes etc. these disease are transmitted by means of sexual contact with someone who is suffering from these diseases. HIV is one of these STDs that are transmitted by sexual contact and also by other means.
Both STD and HIV are closely related as people who are suffering from sexually transmitted diseases are more susceptible to HIV. This is because HIV virus is more readily passed on through the genitals of one who is suffering from STDs. various studies have proved that person having any sort of STD is more prone to getting affected by HIV virus. There are 2 reasons behind this. The STDs cause cancers in genital organs and these in turn create cracks on the surface of the sex organs. The cracks in turn produce exposed points from where the AIDS virus can enter easily. The STDs also cause inflammation that causes the cells of the genital part to be more vulnerable to HIV.