20 Years of HIV‐2 Infection in Portugal: Trends and Changes in Epidemiology

To the Editor—The occurrence of HIV-2 infection is geographically restricted, affecting West African countries, such as Guinea-Bissau and Cape Verde [1]. The prevalence of HIV-2 infection is also high in European countries that have socioeconomic relations with this region, such as Portugal and France [1–6]. All evidence points to Guinea-Bissau as the epicenter of HIV-2 infection [7, 8]—in particular to a small area around the Canchungo Medical Centre [7]. Spread of HIV-2 seems to have occurred after 1960–1970, but recent reports show that the interspecies transmission of HIV-2 may have happened as early as 1924 or as late as 1956 [7, 8]. Very likely, the colonial war (1961–1974) contributed to the spread of HIV-2 in Guinea-Bissau, through sexual contacts and blood transfusions as a result of war injuries [1, 6–8]. At the end of the war, in 1974, Portuguese soldiers and Guinean refugees arrived in Portugal, where HIV-2 infection spread by sexual contact and blood products, prior to the universal HIV screening. In fact, HIV-2 was isolated from patients who originated from Guinea-Bissau and Cape Verde [9–11]. Portugal is the European country with the highest prevalence of HIV-2 infection [1–6]. Twenty years after the first cases, very little is known about how much transmission within Europe has contributed to the spread of the infection. At the Department of Infectious Diseases (Santa Maria Hospital, Lisbon), ∼3000 HIV-infected patients are actively followed up. From 1987 through 2006, 142 adult patients received a diagnosis of HIV-2 infection, which represented 5.4% of all 2653 patients on follow-up for HIV infection at that time. Clinical records were reviewed during 2007. The country of birth was known for 123 (86.6%) of the 142 HIV-2–infected individuals: 83 (67.5%) were born in West Africa (14 [11.4%] in Cape Verde and 69 [56.1%] in Guinea-Bissau), 4 (3.3%) in other African countries, and 36 (29.3%) in Portugal. Most patients (95 [66.9%]) were female. The median age at diagnosis was 38 years for women and 46 years for men. Most likely, 101 (71.1%) of the 142 patients were infected in West Africa. The transmission route was known in 89 patients; most (75 [84.3%]) were infected through sexual contact. For 23 (24.2%) of the 95 women, the diagnosis was made during pregnancy. Over time, there has been a clear growth in the number of HIV-2–infected individuals, with a steeper increase since 1996 (figure 1). However, since 2000, there has been an increase in the proportion of patients diagnosed with HIV-2 infection who are from Guinea-Bissau. The number of cases of HIV-2 infection in Portugal, by patients' country of origin The high prevalence of HIV-2 infection found could be explained by the large West African community that lives in Portugal. More than one-half of all HIV-2–infected patients were born in Guinea-Bissau, which might reflect migration to Portugal following the civil war in Guinea-Bissau, in 1998–1999 [12]. Indeed, the peak in the number of patients, during 2000–2006, coincided with periods of political instability in Bissau. In our cohort, of 54 patients who received diagnoses in 2000 or later, almost one-half ( n=26 ) arrived in Portugal after the year 2000 ( n=19 ) or during 1998–1999 ( n=7 ). This study indicates that the number of patients diagnosed with HIV-2 infection in Portugal is likely to increase over the next years. Only one-third of all HIV-2–infected individuals were born in Portugal, without known contact to West Africa, and all but one seem to have acquired the infection through heterosexual contact. African communities residing in Portugal often live rather isolated within the Portuguese society, and, consequently, contacts that may cause HIV infection seem quite limited. This also may explain why the number of Portuguese persons newly diagnosed with HIV-2 infection is rather small, contrary to what is seen for HIV-1. This leaves the impression that HIV-2 infection in Portugal is geographically restricted to those communities, somewhat similar to what is seen in Africa. Potential conflicts of interest. All authors: no conflicts.