Why STIs/RTIs are important - Sexually transmitted and other reproductive tract infections

STI/RTI basics
Chapter 1. Infections of the male and female reproductive tract and their consequences

Why STIs/RTIs are important

STIs/RTIs are common

STIs/RTIs cause a large proportion of the global burden of ill-health. WHO estimates that over 340 million new cases of four curable STIs (gonorrhoea, chlamydia, syphilis and trichomoniasis) occurred in 1999. If viral STIs such as human papilloma virus (HPV), herpes simplex virus (HSV) and human immunodeficiency virus (HIV) infections are included, the number of new cases may be three times higher. Among women, non-sexually transmitted RTIs are even more common.

Box 1.1. Where STIs/RTIs occur

STIs/RTIs are found worldwide but are more common in some areas. Transmission and prevalence (how common they are) are influenced by social and economic factors as well as by biology and behaviour. The burden of STIs/RTIs thus varies greatly from region to region, and from community to community. Where STIs/RTIs are common, so are their complications.

STIs such as syphilis, gonorrhoea and chancroid spread more rapidly in places where communities are disrupted, migrant labour is common and commercial sex networks are active.
Iatrogenic infections are more common where there are many STIs, and where health care providers do not have the training or supplies to perform procedures safely. Postpartum and postabortion infections are more common where safe services and follow-up care are not available.
Endogenous infections, such as yeast infection and bacterial vaginosis, are common worldwide and are influenced by environmental, hygienic, hormonal and other factors.

Differences between STIs/RTIs are important

Table 1.2 lists some common syndromes caused by infections that primarily affect the reproductive tract. Some are sexually transmitted, others not. Some can be easily cured using antibiotics or other agents, while others are incurable. An understanding of these differences is essential in order to provide effective care and good advice to patients with reproductive tract complaints. The table does not include STIs such as HIV and hepatitis B which are not clearly linked to one distinct syndrome.

Syndrome	STI/RTI	Organism	Type	Sexually transmitted	Curable
Genital ulcer	Syphilis	Treponema pallidum	bacterial	yes	yes
	Chancroid	Haemophilus ducreyi	bacterial	yes	yes
	Herpes	Herpes simplex virus (HSV2)	viral	yes	no
	Granuloma inguinale (donovanosis)	Klebsiella granulomatis	bacterial	yes	yes
	Lymphogranuloma venereum	Chlamydia trachomatis	bacterial	yes	yes
Discharge	Bacterial vaginosis	multiple	bacterial	no	yes
	Yeast infection	Candida albicans	fungal	no	yes
	Gonorrhoea	Neisseria gonorrhoeae	bacterial	yes	yes
	Chlamydia	Chlamydia trachomatis	bacterial	yes	yes
	Trichomoniasis	Trichomonas vaginalis	protozoal	yes	yes
Other	Genital warts	Human papilloma virus (HPV)	virus	yes	no

STIs/RTIs cause serious health problems

The consequences of STIs/RTIs for reproductive health can be severe and life-threatening. They include pelvic inflammatory disease (PID), infertility (in women and men), ectopic pregnancy, and adverse pregnancy outcomes including miscarriage, stillbirth, preterm birth, and congenital infection. STIs/RTIs also increase the risk of HIV transmission (see Annex 5 for a more complete list of RTI complications).

Most STIs/RTIs can affect both men and women, although the consequences for women are more common and more severe than for men (Box 1.2). In fact, STIs/RTIs and their complications are among the most important causes of illness and death for women in poor regions of the world. Infectious complications of pregnancy (postabortion and postpartum infections) alone are estimated to cause about one-third of the 500 000 maternal deaths that occur each year. Most of this preventable burden of disease is concentrated in low-income populations (Table 1.3).

STIs/RTIs also cause poor pregnancy outcomes. Infection within the placenta or amniotic sac (chorioamnionitis) due to endogenous or sexually transmitted organisms is a major cause of late spontaneous abortion and stillbirth. Infection may lead to prelabour rupture of membranes and preterm delivery. Congenital infection due to syphilis, gonorrhoea, chlamydia, herpes simplex virus, hepatitis B and HIV can cause blindness, disability and death of the newborn.

Box 1.2. Complications of upper genital tract infection in women

1. Pelvic inflammatory disease. Some of the most serious consequences of RTIs in women occur when an infection of the lower genital tract (cervix or vagina) or outside organisms reach the upper genital tract (uterus, fallopian tubes, ovaries and surrounding structures). Infection may become generalized and life-threatening, and resulting tissue damage and scarring may cause infertility, chronic pelvic pain and increased risk of ectopic pregnancy.

3. Infertility often follows untreated pelvic inflammatory disease in women, and epididymitis and urethral scarring in men. In fact, complications of RTI are the most important preventable causes of infertility in regions where childlessness is most common. Repeated spontaneous abortion and stillbirth�often due to RTI such as syphilis�are other important reasons why couples are unable to have children.

2. Upper genital tract infection can develop at any time, but women are more vulnerable immediately following childbirth or abortion. Infectious complications of abortion and postpartum infection are major causes of maternal mortality and are largely preventable.

4. The tubal scarring and blockage that often follow PID may be total or partial. Fertilization can still occur with partial tubal blockage but risk of implantation in the fallopian tubes or other site outside the uterus � ectopic pregnancy � is high. Ruptured ectopic pregnancy, along with complications of abortion and postpartum infection, is a common preventable cause of maternal death in places with high prevalence of STIs/RTIs and PID.

Table 1.3. Risks and burden of upper genital tract infection and complications

Disease or complication	Risk	Situation in low-resource communities
Cervical infection	Gonorrhoea or chlamydia in the cervix can ascend to the upper genital tract. Transcervical procedures increase risk of ascending infection.	Gonorrhoea and chlamydial infection may be 10 to 100 times more common in low-income communities than high-income communities.
PID	Estimated 8�10% of chlamydia and 8�20% of gonorrhoea infections progress to PID.	Estimated gynaecology admissions related to pelvic infection: 17�40% in Africa; 15�37% in South-East Asia.
Postabortion infection	Estimated 10�23% of women with chlamydia and 15% with gonorrhoea develop upper genital tract infection after unsafe abortion.	Accounts for 7�29% of maternal deaths in developing regions when abortion is performed unsafely.
Postpartum infection	Rare with normal delivery if nothing introduced into vagina during labour.	Infection following vaginal delivery up to 10 times more common in developing countries; accounts for up to 30% of maternal deaths.
Infertility	Risk of infertility 15�25% after one episode of PID, 50�60% after third episode. Rates higher where antibiotic treatment is not available.	Most infertility related to infection.
Ectopic pregnancy	6�10 times greater risk in women who have had PID.	Up to 32 ectopic pregnancies per 1000 live births in Africa.

Other STIs/RTIs may also have serious or fatal consequences. Some types of human papilloma virus greatly increase the risk of cervical cancer, a leading cause of cancer death in women. AIDS is a consequence of HIV infection. HIV is much more easily transmitted and acquired sexually when other STIs/RTIs are present (Box 1.3). Many regions with high HIV prevalence also have high rates of curable STI/RTI.

Box 1.3. STIs/RTIs and sexually transmitted HIV

HIV is transmitted in the same way as other STIs; prevention of STIs also prevents sexual transmission of HIV infection

Effective treatment of STIs decreases the amount of HIV in genital secretions and makes HIV transmission less likely

Many STIs/RTIs increase the risk of acquiring HIV infection as well as the chances of transmitting it to others�by as much as 50�300 times per contact when a genital ulcer is present, for example. HIV transmission is more likely when STIs/RTIs are present for several reasons:

HIV can easily pass through breaks in the skin or mucous membranes caused by genital ulcers.
HIV can attach to the many white blood cells that are present in genital discharges.
Large amounts of HIV are found in ulcers and genital fluid (semen, cervical secretions) of people with certain STIs.

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	Department of Reproductive Health and Research (RHR), World Health Organization Sexually transmitted and other reproductive tract infections A guide to essential practice	Preface/Full text PDF About the guide Abbreviations Glossary