Presence of human T-cell lymphotropic virus types I and II infections in Honduras.

Abstract

To the Editor: The human T-cell lymphotropic virus type I (HTLV-I) is the etiological agent of adult T-cell leukemia/lymphoma (ATL) and tropical spastic paraparesis/HTLV-associated myelopathy. Three routes of transmission of the infection have been identified: mother-to-child transmission, mainly via breast milk; parenteral transmission; and sexual transmission. It is endemic in Japan, some areas of Africa, and the Caribbean basin. It has also been reported in the United States, Mexico, Colombia, Brazil, and Chile (1-5). HTLV-II, closely related to HTLV-I, has not been associated with any disease, but it has occasionally been associated with neurological and lymphoproliferative disorders (6,7). It shares the same HTLV-I transmission routes and has been found in Amerindian tribes and among injecting drug users in the United States and Europe. Native Americans with infection include the Navajo and Pueblo Indians of New Mexico; Seminole Indians of Florida; Guaymi of Panama, Wayu, Guahibo, and Tunebo in Colombia; Toba and Mataco of Argentina; and the Kayapo and Kraho of Brazil. It has also been reported in Mexico and Chile (2,3,5,8-11). We conducted a study of HTLV seroprevalence in Honduras from 114 serum samples obtained from the black population and from a group of prostitutes native to Puerto Cortés (Atlantic coast) and San Pedro Sula, respectively (Table 1). All individuals were selected randomly. Of 62 individuals from the black population (66% female), four had neuropathy or hemiparesis and two were HIV seropositive. Of 52 individuals from the group of prostitutes, two had sexually transmitted diseases (gonorrhea, syphilis), and seven were HIV seropositive. Antibody screening was carried out with an enzyme immunoassay (EIA) that incorporates an HTLV-I-recombinant env protein into an HTLV-I viral lysate (Cambridge Biotech Corporation, Worcester, MA, U.S.A.). Of the 114 samples studied, 33 were repeatedly reactive. These samples were confirmed with other EIAs (Biokit, Spain) that use envelope synthetic peptides of HTLV-I and HTLV-II. This assay confirmed 18 serum samples as repeatedly reactive. These samples were confirmed by using a Western immunoblot (HTLV version 2.3; Diagnostic Biotechnology Ltd., Singapore) that incorporates a recombinant envelope protein (rgp21) common to both HTLV-I and HTLV-II and two gp46 polypeptides specific to either HTLV-I (MTA-1) or HTLV-II (K55). Of 18 synthetic peptide-based EIA-reactive serum samples, 11 fulfilled the criteria for HTLV-I infection and one for HTLV-II infection; six were indeterminate. Some of the indeterminate samples showed seroreactivity against rgp21, and some did not react with p24 or p19 but did react with other HTLV-specific proteins (i.e., p53). All of the HTLV-I-positive cases belonged to the black population. Of the group studied, only two were male (18%), one of whom was 78 years old and had hemiparesis. One of the women was HIV positive and had syphilis. The prevalence of HTLV infection within the black population studied was 17.7%—exclusively HTLV-I. The only case of HTLV-II infection was in a prostitute with no history of injecting drug use and who was HIV-1 negative. Therefore, the prevalence of HTLV-II infection found among this group was 1.9%. To our knowledge, this is the first report of HTLV seroprevalence in Honduras. Although the number of individuals studied has to be increased, the high prevalence (17.7%) of HTLV-I infection found in this small group of blacks with no risk factors leads us to suggest that it may be advisable to routinely screen blood donors in this population for antibodies to HTLV-I/II infection. This prospective study should also be carried out in the general population to clarify its impact on public health. Alejandro Vallejo; *José M. Dubón; Alfredo García-Sáiz Laboratory of Diagnostic and Reference; Instituto de Salud Carlos III; Majadahonda, Spain *Laboratory of Microbiology; Instituto de Seguridad Social; San Pedro Sula, Honduras