Sexually Transmitted Infections and Foreign Travel

Casual Sexual Activity and Travel

Traditionally, travelers undertaking long and frequent journeys have been recognized to be at risk for STI acquisition during travel. These groups have included long-distance truckers, seafarers, and military troops. However, as more of the population travels for recreational and business purposes, the group at risk for STI acquisition has greatly increased in size and heterogeneity, and risk stratification by occupation or reason for travel becomes less precise. In considering the relationship between international travel and exposure to STIs, the major determinant of risk is the individual's personal behavior.

Estimates of the frequency of sex associated with travel indicate that the practice occurs rather commonly, though the magnitude of such estimates depends on population surveyed and the gender of respondents. A recent meta-analysis reported a pooled prevalence of travel-associated casual sex of 20.4%, with a concomitant three-fold increased risk of acquiring an STI. Factors associated with casual sex while abroad were young age, male sex, and travel without a spouse or partner.

Several studies have examined the likelihood of sexual contacts by people living or employed in foreign or developing countries for long periods, including expatriates, overseas workers, and military personnel. In most of these studies, factors that were highly associated with these sexual contacts included not being accompanied by a partner or spouse, prior experience with purchasing sex, and history of previous STIs.

Despite the efficacy of condoms in preventing STI transmission, several studies have documented low rates of condom use in travelers (likely less than 50% use condoms consistently with casual sex). A recent meta-analysis of studies evaluating the efficacy of pre-travel counseling on incidence of STI found no difference in approaches that used standard counseling versus motivational interviewing. However, randomized trials have not been performed.

Sexual Tourism

Many developing countries have actively fostered the development of tourism as an economic tonic. Particularly before the recognition of the human immunodeficiency virus (HIV) pandemic, sexual tourism was promoted by international tourist agencies, either openly or under the guise of health or “medical treatment” tours. Some of these efforts even underplayed the magnitude of the local emerging HIV epidemic. As fatalities due to acquired immunodeficiency syndrome (AIDS) accrued, the relationship between the commercial sex implied by sexual tourism and HIV acquisition became more difficult to ignore. However, many local tour agencies may still be reluctant to provide, or certainly to stress, relevant information (and attendant caution) regarding local prevalence of HIV and other STIs, for fear of discouraging potential clients.

While specific data on sexual tourism are scarce, many studies have shown that HIV-1 infection is common among commercial sex workers (CSWs): 50-85% of urban CSWs in parts of Africa and Southeast Asia are HIV infected. One tragic consequence of the increased awareness of this risk has been the promotion of child prostitution because of the belief that sex with relatively young persons is safer than with older CSWs. This assumption is false: one survey found that approximately 50% of Thai child sex workers were HIV infected. Young CSWs are quickly exposed to the same STIs and may even be more likely to become infected with STDs during sexual intercourse because of traumatic penetration.

The International Spread of HIV

The initial explosive spread of HIV-1 infection among residents of Africa and rapid spread of HIV-1 through Southeast Asia and South America over the past decades were initially attributed to the high rate of CSWs and genital ulcerative diseases (GUDs) in these areas. Other factors emerged as possible contributors, including chemokine receptors such as CCR-5, which confers relative protection to progression of HIV-1 disease and is less common in blacks relative to whites, and exceedingly high prevalence of genital infection with herpes simplex virus type-2. While HIV transmission in North America, Western Europe, Australia, and New Zealand has been predominantly among homosexual men and intravenous drug users (IDUs), heterosexual transmission accounts for up to 70% of HIV-1 infections in sub-Saharan Africa and parts of the Caribbean and Asia. In Latin America, the epidemic continues to evidence a shift from the homosexual and bisexual population to a pattern of heterosexual transmission. The heterosexual transmission of HIV-1 that is seen in developing countries has followed a consistent trend. Predominantly female CSWs become infected from infected male clients (who include IDUs and international travelers). Male partners of the infected CSWs become infected themselves, and can then infect their female spouses at home. These infected women, many of whom have only one partner—their husbands—then transmit HIV-1 to their children in subsequent pregnancies.

Industrialized countries are presently experiencing a rise in the proportion of HIV-1 transmission occurring within the heterosexual population, particularly in inner cities among IDUs, CSWs, and immigrants from high-risk areas. Men who have sex with men (MSM) continue to be at the highest risk, and many urban areas in the United States have experienced an alarming reversal of the trend toward protected sex among men who have sex with men (many of whom are HIV-1-infected already), which likely continues to sustain an endemic level of HIV-1 transmission within this group. Rates of early syphilis (primary, secondary, and early latent) are presently higher than at any time in the last two decades in many large cities globally as well.