The most common venereal diseases are mycoplasma, chlamydia and ureaplasma, unusual types of bacteria that live inside cells and do not have their own cell walls. Practicing physicians do not have an effective way to diagnose these bacteria.

Mycoplasma can infect any lining in your body: your eyes, throat, nose, lungs, vagina, bladder, urinary tube, prostate, colon and joints. You can get it in your lungs when an infected person coughs in your face or in your genitals and urinary tract when an infected person has sexual relations with you. When you have a genital infection, you may feel like there is a hair in your urinary tube, you may have terrible burning on urination, absolute misery when your bladder is full, spotting between periods, a feeling that you have to urinate all the time, pain on intercourse or you may have no symptoms at all.

The only way to diagnose mycoplasma infections is to order a special test called PCR which is not available to practicing physicians.

Your doctor can suspect mycoplasma when women have a fishy odor and an alkaline vaginal discharge and bacteria stuck on vaginal cells. These are the same signs of a common vaginal infection called bacterial vaginosis (1). Women with mycoplasma infections usually are infected with ureaplasma also. Doctors used to prescribe tetracyclines, but they do not eradicate ureaplasmas, so most doctors now treat the patient and all partners with mycoplasma, ureaplasma and chlamydia with long-acting erythromycins, such as azithromycin 250 mg once a day for at least 9 days.

By Gabe Mirkin, M.D., for CBS Radio News

PA Mardh, S Elshibly, I Kallings, D Hellberg. Vaginal flora changes associated with Mycoplasma hominis. American Journal of Obstetrics and Gynecology. 176: 1 Part 1 (JAN 1997): 173-178. Women who harbored Mycoplasma hominis had significantly more often complained of a fishy odor, had a positive amine test, a vaginal pH >4.7, and clue cells than did the comparison group; Ureaplasma urealyticum occurred in 75% of the Mycoplasma hominis-positive women.