Nationally notifiable diseases are diseases that doctors are required to report to the CDC so that their incidence can be monitored and tracked. Disease reporting allows the government to efficiently become aware of outbreaks so they can improve the likelihood of an early intervention.
There are several sexually transmitted diseases on the nationally notifiable diseases reporting list. As of January 1, 2011, the reportable STDs are:
- Chlamydia - confirmed cases
- Chancroid - confirmed and probable cases
- Gonorrhea - confirmed and probable cases
- Hepatitis B - confirmed acute cases; both confirmed and probable chronic cases
- HIV - confirmed cases and possible perinatal exposures
- Syphilis - confirmed and probable cases
STDs are not nationally notifiable diseases because the government wants to invade your privacy. They're nationally notifiable diseases because the government has a vested interest in protecting the public health, and it is theoretically possible to reduce the spread of STDs with regular screening, prompt treatment, and efficient contact tracing.
Source:
CDC. Nationally Notifiable Conditions. Accessed 2/3/2011. http://www.cdc.gov/ncphi/disss/nndss/phs/files/NNC_2011_Notification_Requirements_By_Category.pdf

