An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Parra M, Hui G, Johnson AH, Berzofsky JA, Roberts T, Quakyi IA, Taylor DW.Parra M, et al. Among authors: hui g.Infect Immun. 2000 May;68(5):2685-91. doi: 10.1128/IAI.68.5.2685-2691.2000.Infect Immun. 2000.PMID: 10768960Free PMC article.