In many states it is a criminal offense to intentionally or recklessly transmit a sexually transmitted disease (STD or venereal disease) to another person. Examples of such diseases include HIV/AIDS, syphilis, gonorrhea, chlamydia, genital herpes, human papillomavirus (HPV), genital warts, and hepatitis B.

Laws vary from state to state, and in some states these laws include other infectious or communicable diseases. In some states there is a specific criminal offense for transmission of sexually transmitted or communicable diseases, and in other states criminal prosecutors charge the defendant with a more general crime like assault.

Laws regarding criminal liability for the intentional or reckless transmission of sexual or other infectious or communicable diseases are generally located in a state’s statutes—often in the penal or criminal code, or the health and safety code.

A person who negligently transmits a sexually transmitted disease to another person through sexual contact—without informing the other person of the offender’s infection before the sexual contact—may also be subject to civil liability for money damages in a lawsuit.

In Illinois, the transmission of HIV is specifically addressed under the Illinois Criminal Code. According to 720 ILCS 5/12-5.01, it is a Class 2 felony for an individual who knows that they are infected with HIV to engage in unprotected sexual activity with another without informing that person of their HIV status prior to any engagement in sexual activity. The law requires the infected individual to disclose their HIV-positive status to their partner, regardless of whether the virus is actually transmitted. For other STDs like syphilis, gonorrhea, chlamydia, genital herpes, HPV, genital warts, and hepatitis B, Illinois does not have specific criminal statutes addressing the transmission. However, individuals may still face criminal charges under general criminal offenses such as assault or battery if they intentionally or recklessly transmit an STD to another person. Additionally, civil liability may arise if a person negligently transmits an STD to a partner, potentially resulting in a lawsuit for monetary damages.