Statement on travellers and sexually transmitted diseases

Canadian Medical Association Journal 1995; 152: 1826-1828
Health Canada, 1994
Reproduced with permission of the Minister of Supply and Services Canada, 1996
Copies of the original report (Canada Communicable Disease Report 1994; 20: 204-207) can be obtained from Eleanor Paulson, editor, CCDR, Bureau of Communicable Disease Epidemiology, Laboratory Centre for Disease Control, Tunney's Pasture, Ottawa, ON K1A 0L2.
Overseas workers, tourists and business people appear to be groups at high risk for sexually transmitted diseases (STDs). The anonymity of travel, the sense of isolation brought on by an unfamiliar environment and the desire for unique experiences all tend to encourage travellers to shed their social and sexual inhibitions. The risk of STDs for travellers may be enhanced by an ignorance of the global epidemiology of STDs and by cultural taboos against condom use. Furthermore, some infections that may be acquired abroad are rare in North America and, therefore, may go undiagnosed or be treated inappropriately by physicians who are unfamiliar with them. The price of sexual freedom for a traveller to areas of the world with a high prevalence of STDs may be a variety of acute or chronic medical problems, such as infertility or ectopic pregnancy due to pelvic inflammatory disease, genital ulcers or urethritis; chronic liver disease caused by hepatitis B or C virus; genital cancer caused by papillomavirus; and premature death from human immunodeficiency virus (HIV) infection. In light of this situation, health care professionals who give advice on international travel must counsel their patients on the risk of STDs and ways to prevent them.

Sexual behaviour of travellers

Few studies have assessed the prevalence of casual sexual contacts among overseas travellers. A recent study by Hättich and associates showed that of the 30% of returning Swiss travellers who responded to a questionnaire, 5% to 10% admitted to having had sexual intercourse, primarily with local female prostitutes. In an intention-to-have-sex study of young Australians travelling alone to Thailand, only 34% of the sample reported a definite intention not to have sex.

Long-term overseas workers appear, with some exceptions, to be more likely than other types of travellers to engage in sexual activity while abroad. Among a sample of Belgian men working in Central Africa, 51% and 31% reported having had extramarital sex with a local woman or with a prostitute, respectively. In a study involving 1968 Dutch expatriates working in sub-Saharan Africa, 31% of men and 13% of women reported having had casual sex with African partners; regular condom use was reported by less than 25% of the participants. Several studies have shown that although men are more likely than women to be sexually active while abroad, they are also more likely to use condoms.

Seamen and military personnel are reported to have very high rates of sexual contact with overseas nationals. Among 1744 US Navy and Marine corps personnel deployed abroad for 6 months, 49% reported having had sexual contact with a prostitute. Of those who reported having had sexual contact during deployment, 70% reported that they had had multiple partners, and almost all of those who used condoms reported that they had used them inconsistently. In a Spanish study involving 7848 seamen travelling to sub-Saharan Africa, 54.8% reported that they had had contact with prostitutes and only 25% that they had used a condom.

Risk of STDs during international travel

STDs are hyperendemic in many developing countries; over 20 pathogens are known to be spread by sexual contact. Prevalence data from ad hoc surveys provide useful estimates but must be interpreted with caution because they may not be representative of the total population. Surveys in antenatal clinics in Africa have noted an STD point prevalence of 3.4% to 11.2%. Surveys carried out in populations of commercial sex workers have found rates of 5% to 65% in Africa, 20.9% in Brazil, and 0% to 13.6% in Southeast Asia. Specifically, studies have indicated that gonorrhea occurs in 4% to 40% of pregnant women attending antenatal clinics in Africa and in 11% to 45% of commercial sex workers worldwide. In Africa, rates of Chlamydia trachomatis infection range from 6.7% to 19.7% among pregnant women to 13% to 32% among commercial sex workers. In several studies, lymphogranuloma venereum immunotypes were found to be responsible for 7% to 19% of cases of genital ulceration in Africa and for up to 9% in Asia. Serologic studies for syphilis in a variety of populations showed positivity rates ranging from 5% to 55% in Africa and from 5% to 6% in Latin America.

Sexual transmission of hepatitis B and C is well documented in both developed and developing countries. The antibody prevalence rate for hepatitis B is over 50% in some countries in Africa and Asia, and surface antigen (HBsAg) carriage rates are as high as 25%. In a study involving commercial sex workers in Asia, 6.1% to 17.9% were found to be HBsAg carriers.

Infection with HIV has now been reported in more than 160 countries. Sexual transmission has been implicated in almost 75% of the 16 million infections worldwide. Unlike in developed countries, where acquisition of infection has been most frequent in homosexual men, the majority of cases in the developing world have occurred through heterosexual transmission. Prevalence rates of HIV-1 are particularly high in some areas of Africa, ranging from 17% to 32%. Global AIDS statistics show that the reported case rates vary from 18 to 43 per 100 000 population in Africa to 61 to 70 per 100 000 in parts of the Caribbean. Commercial sex workers are at very high risk for infection. Prevalence rates in this population are remarkably high in major centres around the world: Nairobi, 81%; Kinshasa, 35%; Bangkok, 44%; and Port au Prince, 69%. The prevalence of HIV infection appears to be increasing dramatically in Southeast Asia (especially Thailand) and India. HIV seropositivity has been documented recently in expatriates from the Netherlands (0.4%), Belgium (1.1%) and Denmark (8.6%). A longitudinal study of Peace Corps volunteers showed that since 1987 at least seven volunteers, four of whom were women, became infected as a result of having unprotected sex with host-country nationals.

Another retrovirus, HTLV-1, which is responsible for tropical spastic paraparesis and human T-cell leukemia, is transmitted sexually as well as by other routes. Prevalence rates range from 5% in the Caribbean to 2.2% to 31.5% in Japan.

Drug resistance in STDs

In addition to the higher risk of acquiring STDs in the developing world, travellers will also be faced with the problem of antibiotic-resistant infections. Beta lactamase-producing strains of Neisseria gonorrhoeae or those with chromosomally mediated N. gonorrhoeae penicillin resistance are prevalent in Africa and Asia. Several studies from Africa and Southeast Asia show that penicillin-resistant N. gonorrhoeae occurs in about 50% or more of isolates. This compares with 6% in Japan and Denmark. For Canada the rate was 8.7% in 1992. In addition, low- level chromosomally mediated tetracycline resistance is common in Africa, Asia and Spain. Spectinomycin resistance has also begun to appear.

Resistance of Haemophilus ducreyi, the causative agent of chancroid, to antimicrobial agents has also spread globally. Trimethoprim and sulfonamide resistance are very common, especially in Thailand.

Treatment of STDs

Therapy for STDs in travellers returning from the developing world must be modified to fit the pattern of drug resistance in the area where the infection was acquired. In some cases, such as in the management of syphilis and chlamydia, guidelines published in the Canada Communicable Disease Report [1992; 18S1] will still be applicable. However, therapy for any STD should be based on the susceptibility of individual isolates. Uncomplicated gonococcal infection acquired in a potentially resistant area may be treated empirically with ceftriaxone (250 mg i.m. in one dose), cefixime (400 mg once orally) or spectinomycin (1 g in one dose). The quinolones have also proven to be useful in a single oral dose: norfloxacin (800 mg), ciprofloxacin (500 mg) and ofloxacin (400 mg). Except for spectinomycin, all of these agents are effective in eradicating concomitant gonococcal pharyngeal infection. Presumptive treatment for chancroid may include ceftriaxone, the quinolones or amoxicillin with clavulanic acid.

Prevention of STDs

Sexual activity within a stable monogamous relationship and avoidance of high-risk encounters are clearly the best measures to prevent STDs during travel. Barrier contraceptive devices, specifically condoms, provide the best alternative to abstinence by preventing direct contact with infective genital lesions or secretions. Barrier techniques are more effective when used with spermicides. Condoms made from synthetic materials such as latex provide a more effective barrier than "natural" condoms made from animal membranes. In experimental models, the latter have not been found to be impervious to hepatitis B virus.

Consistent and proper use of latex condoms during sexual activity has a protective efficacy of 40% to 70% against sexually acquired infections. Spermicides such as nonoxynol-9 interfere with sperm viability and have shown in-vitro inhibitory activity against N. gonorrhoeae, herpes simplex virus and HIV. Although the use of spermicidal jelly in conjunction with the proper and consistent use of a diaphragm or condom has been shown to reduce the risk of gonorrhea, its benefit in preventing HIV transmission during intercourse has not yet been established.

Hepatitis B vaccine has been shown to successfully prevent infection from a variety of sources. Vaccination is recommended for travellers who may engage in sexual activity in countries with high seroprevalence rates.

Conclusion

Travellers who have sex outside of stable monogamous relationships, especially those who are sexually active with overseas nationals, are at risk for a variety of STDs, some of which are more likely to be resistant to standard North American antibiotic regimens. Hepatitis B, hepatitis C, HIV and other sexually acquired infections are a significant risk for individuals who engage in unprotected sex, especially with overseas commercial sex workers. Although barrier contraceptives provide considerable protection against STDs, they are not 100% protective. Celibacy and sexual monogamy with a "known" partner carry a much lower risk than the safest of "safer sex" practices. However, where sexual activity with a new partner may occur, hepatitis B immunization and the consistent and proper use of a latex condom are strongly recommended.
Source: Committee to Advise on Tropical Medicine and Travel: Members: Dr. S. Dumas, Dr. G. Horsman (Advisory Committee on Epidemiology), Dr. J.S. Keystone, Dr. D. Lawee, Dr. J.D. MacLean, Dr. D.W. MacPherson (chairman), Dr. J. Robert, Dr. R. Saginur, Dr. D. Scheifele (National Advisory Committee on Immunization) and Mrs. R. Wilson (CUSO). Ex-officio members: Dr. P. Percheson (Health Protection Branch [HPB], Health Canada), Dr. E. Gadd (HPB, Health Canada), Dr. S. Mohanna (Medical Services Branch, Health Canada), Dr. R. Nowak (Department of National Defence), Dr. M. Tipple (US Centers for Disease Control and Prevention), Dr. C.W.L. Jeanes (secretary), Dr. J.S. Spika (Laboratory Centre for Disease Control [LCDC], Health Canada), Ms. S. Ladouceur (Advisory Committee Secretariat Officer), Dr. J. Losos (LCDC, Health Canada) and Mrs. S. Herman (secretary).

Selected bibliography

  1. Canadian guidelines for the prevention, diagnosis, management and treatment of sexually transmitted diseases in neonates, children, adolescents and adults. Can Commun Dis Rep 1992; 18S1
  2. Cates W, Stone KM: Family planning, sexually transmitted diseases and contraceptive choice: a literature update. Fam Plann Perspect 1992; 24: 75-84
  3. CUSO Health Support Service: AIDS and HIV infection: information for Canadians working overseas. Healthy Exchange 1993; 3 (1 [special issue]): 1-54
  4. De Schryver A, Meheus A: Epidemiology of sexually transmitted diseases: the global picture. Bull World Health Organ 1990; 68: 639-654
  5. De Schryver A, Meheus A: Sexually transmitted diseases and migration. Int Migr 1990; 29: 13-22
  6. Hättich A, Milano D, Steffen R: Casual sex abroad: a methodological pilot study. [abstract 301] In Program of the Third Conference on International Travel Medicine, Paris, France, Apr 25-29, 1993
  7. Mann JM: AIDS -- the second decade: a global perspective.
    J Infect Dis 1992; 165: 245-250
  8. Mulhall BP: Sexually transmissible diseases and travel. Br Med Bull 1993; 49: 394-411
  9. Parenti DM: Sexually transmitted diseases and travelers. Med Clin North Am 1992; 76: 1449-1461
  10. Piot P, Tezzo R: The epidemiology of HIV and other sexually transmitted infections in the developing world. Scand J Infect Dis 1990; 69 (suppl): 89-97
  11. Romanowski B: "Imported" sexually transmitted diseases. Can Fam Phys 1990; 36: 1311-1314
  12. Update: Barrier protection against HIV infection and other sexually transmitted diseases. MMWR 1993; 42: 589-591, 597
  13. Von Reyn CF, Mann JM, Chin J: International travel and HIV infection. Bull World Health Organ 1990; 68: 251-259
  14. WHO global statistics. AIDS 1992; 6: 243-247

Disclaimer

This guideline is for reference and education only and is not intended to be a substitute for the advice of an appropriate health care professional or for independent research and judgement. The CMA relies on the source of the CPG to provide updates and to notify us if the guideline becomes outdated. The CMA assumes no responsibility or liability arising from any outdated information or from any error in or omission from the guideline or from the use of any information contained in it.
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