GEOGRAPHICAL CLUSTERING OF HUMAN T-CELL LYMPHOTROPIC VIRUS TYPE-1 INFECTION IN HONDURAS

Geographical clustering of human T-cell lymphotropic virus type 1 (HTL V-1) infection has been identified in the nonmestizo communities in se veral cities along the Atlantic coast of Honduras. Of the 2,651 serum samples tested, 122 samples were repeatedly reactive for HTLV-1 antibo dies in two different enzyme immunoassays and 3 were indeterminate. Th ese sera did not react in the HTLV-2-specific antibody tests. The pres ence pf HTLV-1 antibodies was confirmed by HTLV-1 immunoblots or Weste rn blots (immunoblots), and the infection was verified by the detectio n df HTLV-1-specific genetic sequences in the cellular DNA by PCR; Gen omic DNA from the peripheral blood mononuclear cells was first tested with generic primers and probes that identified both HTLV-1 and HTLV-2 . Next, all DNA samples that showed HTLV reactivity were tested by PCR with specific primers and probes that distinguished HTLV-1 sequences from those of HTLV-2 Our results indicate that only HTLV-1 infection w as present in the blood of both mestizo and nonmestizo residents of 15 cities in the Republic of Honduras. The overall prevalence of HTLV-1 infection in the nonmestizo population was 8.1% (95% confidence limit, 6.6 to 9.7%). The mestizo population residing in the same geographica l vicinities showed HTLV-1 antibodies in 0.5% of serum samples tested (95% confidence limit, 0.6 to 1.7%), indicating a significantly greate r prevalence of HTLV-1 infection in the nonmestizo population than in the mestizo ethnic groups living in Honduras (P = <0.0001). Since no H TLV-2 antibody reactivity or HTLV-2-specific genetic sequences were de tected by PCR with different primers and probes, it was concluded that HTLV-2 infection was not present in the Honduran population groups we tested. Our study also suggested an endemic nature for this virus bec ause there was no difference in the prevalence rate of HTLV-1 antibodi es in the nonmestizo community living in the coastal towns of Honduras between 1989 and 1993. This is the first report of HTLV-1 cluster ide ntification in Honduras, Central America.