HIV-2: the Portuguese Connection

SIR—We read with great interest the paper by Mullins et al. [1] about HAART and viral response to human immunodeficiency virus type 2 (HIV-2) infection, which included their compilation of all available data on 10 HIV-2–infected patients. Although we do not wish to minimize the importance of the data presented, we would like to clarify some of the points raised.

The results provided by Mullins et al. [1] are based on data from a very small number of patients, making any meaningful analysis unfeasible and leaving readers with doubts concerning the conclusions. Unfortunately, this impression is reinforced by the incorrect account of the first identification of HIV-2. To our knowledge, HIV-2 was identified for the first time at the Pasteur Institute in Paris and not in Senegal, as stated in the article by Mullins et al. [1]. This new virus was isolated from 2 patients who were in a Lisbon Hospital in Portugal at the time. The patients were originally from Guinea-Bissau and from Cape Vert, 2 former Portuguese colonies located in West Africa that, historically, have had a very close relationship. The identification of the virus was published in 1986 as the result of close collaboration between Portuguese and French researchers [2]. One year later, data on the clinical spectrum of disease collected from 30 Portuguese patients infected with HIV-2 was reported [3], and it showed that this new virus was another cause of AIDS. Perhaps Mullins et al. confused these facts with the almost simultaneous report of the isolation of another purportedly new virus named human T-cell lymphotropic virus type 4 (HTLV-4), which had infected prostitutes in Senegal [4]. However, shortly after this report it was found that HTLV-4 was not a human but a simian virus.

It is well known that the prevalence of HIV-2 infection outside West Africa is very low and that infection rates decrease as one travels from Guinea-Bissau and Cape Vert to surrounding French-speaking African countries [5]. In fact, most patients who acquired the infection in Africa had been in Guinea-Bissau during the 1960s and 1970s, when HIV-2 started to spread [6]. This was also the time of the Portuguese colonial wars, when many thousands of soldiers were sent to the former Portuguese colonies, including Guinea-Bissau. Thus, it is not very surprising that Portugal and France are the countries outside West Africa that have the highest prevalence rates of HIV-2 infection [7]. In Portugal, 389 HIV-2–related AIDS cases had been reported by 2003 [8]. However, it is worth noting that the country of origin of the HIV-2–infected patients in Portugal differs from region to region. In the Lisbon area, more than half of the HIV-2–infected patients (57%) are from Guinea-Bissau or Cape Vert [9], possibly reflecting the influx of already infected immigrants from these countries. Contrary to this, in northern Portugal almost all HIV-2–infected patients (95%) are of Portuguese origin, and 21 (16%) of 132 patients studied had had multiple sexual partners yet no contact with African people [10]. Because of the slow progression of HIV-2 infection, it is possible that the infection is continuing to spread unnoticed, and for this reason alone it is important to continue research in this field, including clinical studies of HIV-2 infection and HAART, as reported by Mullins et al. [1]. However, it is desirable that much more experienced centers—those that have seen and continue to see hundreds of HIV-2–infected patients—contribute to this end.

Acknowledgments

Potential conflicts of interest. E.V. and F.A.: No conflict.