STD Diagnostic Testing Overview Sexually transmitted diseases (STDs) are a major global cause of acute illness, infertility, long-term disability and death, with serious medical and psychological consequences to millions of men, women and infants. Today, over 30 bacterial, viral and parasitic pathogens have been identified that can be transmitted sexually.
STDs are generally acquired by sexual contact specifically through blood, semen, or vaginal and other bodily fluids. Many STDs (chlamydia, gonorrhea, hepatitis, HIV, papillomavirus, herpes and syphilis) can also be transmitted non-sexually such as from mother to infant during pregnancy or childbirth, or through blood transfusions, or shared needles. Many STDs cause no symptoms, therefore an infection may go unnoticed until complications occur. Worldwide, more than 1 million people acquire a STD every day which has a profound impact on sexual and reproductive health globally. STDs rank among the top five disease categories for which adults seek health care. There are more than 30 known pathogens that cause STDs which include bacteria (gonorrhea, syphilis, chlamydia), parasites (trichomoniasis), and viruses
ESTIMATED NEW CASES OF CURABLE SEXUALLY TRANSMITTED INFECTIONS (GONORRHEA, CHLAMYDIA, SYPHILIS AND TRICHOMONIASIS) BY WHO REGION, 2008
(HPV, herpes, HIV). Each year, an estimated 500 million people become infected with one of the four “classic” STDs (chlamydia, gonorrhea, syphilis and trichomoniasis). In addition, more than 530 million people are infected with genital herpes (HSV-2) and more than 290 million women have a human papillomavirus (HPV) infection. One of the major concerns regarding the control of STDs is that the majority of infections remain asymptotic and infected individuals can unknowingly pass on the infection for several years. In addition, without proper diagnosis and treatment, STDs can have serious consequences beyond the immediate impact of the infection itself, such as: • An increased risk (more than 3x) of acquiring HIV • Stillbirth, neonatal death, low-birth-weight and prematurity, sepsis, pneumonia, neonatal conjunctivitis, and congenital deformities in infected pregnant woman • Cervical cancer in women • Infertility
Sexually Transmitted Disease (STD) Diagnostic Assays
Early and rapid diagnosis of STDs increases the chance to limit effects of the disease. Since many people infected by an STD have little or no symptoms of their infection, they put others (including unborn children for pregnant mothers) at risk. There are five main methods for the diagnosis of STDs which include (1) culture (2) microscopy (3) detection of antigens or enzymes (4) detection of nucleic acid sequences (NAAT) and (5) detection of antibodies. Of the five approaches, the assays that provide the most rapid diagnosis have gained the most acceptance. As a result, this has largely limited the traditional use of culture and increased development efforts on rapid tests using microscopy, detection of antibodies by rapid serologic methods, and specific detection of cellular components, including antigens, enzymes, or nucleic acid sequences (especially with amplification).
Sexually Transmitted Diseases (STDs)- Reagents for Assay Development 5
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