The pandemic of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) has raised a variety of issues related to international travel. Individual travellers ask about the risk of acquiring HIV infection during travel; national governments consider whether entering travellers should be screened for HIV infection; and tourist organizations and international transport companies attempt to prevent fear of AIDS from disrupting the travel industry.
This article summarizes the current global epidemiology of AIDS and HIV infection, considers the risk of acquiring HIV infection during international travel, addresses the issue of HIV screening of international travellers, and offers advice for preventing HIV infection during international travel. Finally, recommendations are provided for medical counselling of the prospective traveller who is HIV-infected.
Global epidemiology of AIDS and
A total of 222 740 cases of AIDS had been reported to WHO from 153 countries by 1 March 1990 (Table 1). Cases have been reported from every continent. These data should not be interpreted to indicate that countries that have reported no AIDS cases, or those that have reported few cases, are either free of or have
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a low prevalence of HIV infection. Few seroprevalence studies have been carried out, and there is also significant underrecognition, underdiagnosis, and underreporting of AIDS in many areas of the world, especially in developing countries with limited laboratory and clinical facilities.
Available data on reported AIDS cases and HIV seroprevalence information permit a reasonable description of the current global patterns of AIDS and HIV infection (Fig. 1). Distinct patterns have been observed, and are presumably related to the different time of introduction or extensive spread of HIV and to different social and behavioural characteristics (1, 2).
In Pattern I countries, where HIV appears to have spread extensively in the late 1970s or early 1980s, most AIDS cases are due to sexual transmission among homosexual and bisexual men with only a small percentage of cases being due to heterosexual contact. Parenteral transmission is due principally to intravenous drug use. Data from volunteer blood donors indicate that the overall population seroprevalence in such countries is less than 1%, although in some groups with high-risk behaviour (homosexual or bisexual men with multiple sexual partners, and intraveous drug users), seroprevalence may be 50% or higher. This pattern is observed in North America, western Europe, Australia, New Zealand, South Africa and many urban areas of Latin America.
The epidemiological pattern in many Pattern I countries is still evolving. For example, in many Latin American countries HIV transmission among heterosexuals who have had multiple sexual partners has increased since the mid-1980s, to the extent that this mode of transmission has become the predominant one. As a result of this shift, Latin America has been reclassified as Pattern I/II (2).
In Pattern II countries, where extensive spread of HIV probably began in the 1970s, most sexual transmission occurs among heterosexuals and the male-to-female ratio is approximately 1:1. Parenteral transmission occurs in areas where blood may not be routinely screened for antibodies to HIV and from use of unsterile needles, syringes, and other skinpiercing instruments. The overall population seroprevalence among adults, especially in urban areas, is usually over 1% and may range as high as 5-25%. Pattern II has been observed in central, eastern, western, and southern Africa and in some areas of the Caribbean.
In Pattern III countries, where HIV appears to have been introduced in the early to mid-1980s, information about AIDS cases is either incomplete or the number of reported cases is insufficient to identify the predominant modes of transmission. …