The bioinformatics Basic Local Alignment Search Tools (BLASTN and TBLASTN) were used to search public databases for nucleic acid (NA) and amino acid (AA) sequences identical or similar to HIV-1 DNA and proteins. Several significant alignments were detected in a variety of non-HIV-1 taxa and other sources deposited in public genomic and protein repositories. Homologies between a number of HIV-1 proteins and those of Candida, Cryptococcus and Schistosoma mansoni are of uncertain significance and suggest the need for further analyses. The overwhelmingly likely cause for these data is contamination.