HIV/AIDS and other sexually transmitted infections
Sexually-transmitted infections have been known since ancient times; they remain, worldwide, a major public health problem, compounded by the appearance of HIV/AIDS around 1980. The most important sexually transmitted infections and infectious agents are:
Some countries have adopted entry and visa restrictions for people living with HIV/AIDS. Travellers who are infected with HIV should consult their personal physician for a detailed assessment and advice before travel. WHO has taken the position that there is no public health justification for entry restrictions that discriminate solely on the basis of an individual’s HIV status.
Sexual infections are transmitted during unprotected sexual intercourse (both heterosexual and homosexual – anal, vaginal or oral). Some of the infectious agents, such as HIV, hepatitis B and syphilis, can also be passed on from an infected mother to her unborn or newborn baby and can be transmitted via blood transfusions. Hepatitis B and HIV infections may also be transmitted through contaminated blood products, syringes and needles used for injection, and potentially by unsterilized instruments used for acupuncture, piercing and tattooing.
Nature of the disease
A number of the most common sexually transmitted infections could be included in the following syndromes: genital ulcer, pelvic inflammatory disease, urethral discharge and vaginal discharge. However, many infections are asymptomatic.
Sexually transmitted infections may cause acute and chronic illness, infertility, long-term disability and death, with severe medical and psychological consequences for millions of men, women and children.
Apart from being serious diseases in their own right, sexually transmitted infections increase the risk of contracting or transmitting HIV infection. Other viral infections, such as herpes simplex virus type 2 (causing genital ulcer) or human papillomavirus (causing cervical cancer) are becoming more prevalent. The presence of an untreated disease (ulcerative or non-ulcerative) can increase by a factor of up to 10 the risk of becoming infected with HIV. Individuals with HIV infection are also more likely to transmit the infection to their sexual partner if either of them already has a sexually transmitted infection. Early diagnosis and treatment of all sexually transmitted infections are therefore important.
Importance and geographical distribution
An estimated 340 million episodes of curable sexually transmitted infections (chlamydial infections, gonorrhoea, syphilis, trichomoniasis) occur throughout the world every year. Regional differences in the prevalence of HIV infection are shown on the map. In high-risk groups, however, such as injecting drug users and sex workers, prevalence rates may be very high in countries where the prevalence in the general population is low.
Risk for travellers
Some travellers may be at an increased risk of infection. Lack of information about risk and preventive measures and the fact that travel and tourism may enhance the probability of having sex with casual partners increase the risk of contracting sexually transmitted infections. In some countries, a large proportion of sexually transmitted infections now occur as a result of unprotected sexual intercourse during international travel.
There is no risk of acquiring any sexually transmitted infection from casual day-to-day contact at home, at work or socially. People run no risk of infection when sharing any means of communal transport (e.g. aircraft, boat, bus, car, train) with infected individuals. There is no evidence that HIV or other sexually transmitted infections can be acquired from insect bites.
Appropriate information about safe sex, risks and preventive measures, and provision of adequate means of prevention, such as condoms, are considered to be the best prophylaxis. Vaccination against hepatitis B is to be considered (Chapter 6). Preventive vaccines against oncogenic types of human papillomavirus are now available in some countries. When accidental exposure occurs, post-exposure prophylaxis may be available for hepatitis B and HIV (Chapter 8).
The risk of acquiring a sexually transmitted infection can be prevented by abstinence from sex with occasional or casual partners during travel or reduced by safer sexual practices such as non-penetrative sex and correct and consistent use of male or female condoms. Condoms also reduce the risk of unwanted pregnancy. Latex rubber condoms are relatively inexpensive, are highly reliable and have virtually no side-effects. Studies on serodiscordant couples (only one of whom is HIV-positive) have shown that, with regular sexual intercourse over a period of two years, partners who consistently use condoms have a near-zero risk of HIV infection.
A man should always use a condom during sexual intercourse, each time, from start to finish, and a woman should make sure that her partner uses one. A woman can also protect herself from sexually transmitted infections by using a female condom – essentially, a vaginal pouch – which is now commercially available in some countries.
To reduce the risk of acquiring hepatitis B and HIV infections, it is essential to avoid injecting drugs for non-medical purposes, and particularly to avoid any type of needle-sharing. Blood transfusions should be given only on the basis of strong (or “clear”) medical indications, to minimize the risk of transmitting infections such as syphilis, HIV and hepatitis B.
Medical injections, dental care and piercing and tattooing using unsterilized needles or blades are also possible sources of infection and should be avoided. If an injection is needed, the traveller should try to ensure that single-use needles and syringes come from a sterile package Patients under medical care who require frequent injections, e.g. diabetics, should carry sufficient sterile needles and syringes for the duration of their trip and a doctor’s authorization for their use.