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Superinfection Leads to Recombination and Boosts Viral Load
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2nd International Workshop on HIV Transmission
August 26-28, 2007
Washington, DC
Mark Mascolini
HIV superinfection--picking up a second HIV infection on top of another--occurred in 3 members of 13 Zambian couples [1]. In each case superinfection resulted in recombination of the two infecting viruses and a jump in HIV load. The findings have implications not only for HIV disease progression in superinfected people but also possibly for vaccine development, since recombination results in more diverse viral populations.
US and European researchers have reported HIV superinfection regularly over the past few years [2-5]. But the frequency of superinfection with HIV remains uncertain--and controversial.
The Zambian study involved 13 cohabitating couples in the ZEHRP Lusaka Discordant Couple Cohort. About 15% of cohort members get infected by someone other than their partner. Researchers tracked genetic changes in viral samples collected every 3 months for at least 24 months.
Of these 26 people, 3 individuals in two couples became superinfected. A chronically infected man in one couple got superinfected during the acute phase of his main partner's infection, which was caused by a third person. The superinfected man's viral load rose 10-fold and he died. Later, his female partner became superinfected herself, and her viral load surged.
Phylogenetic analyses of viral samples after superinfection indicated recombination between the original and superinfecting viruses in all 3 people. Recombination resulted in rapid diversification of each person's viral population.
The researchers postulate that superinfection may be frequent in people who do not know their HIV status (a common occurrence in the US and Europe as well as Africa) and so do not take steps to protect their partners from their virus or to protect themselves from superinfection.
References
1. Kraft C, Hawkins P, Manigart O, et al. Superinfection in couples by
genotypically different viruses. 2nd International Workshop on HIV Transmission. August 26-28, 2007. Washington, DC. Abstract 50.
2. Gottlieb GS, Nickle DC, Jensen MA, et al. HIV type 1 superinfection with a dual-tropic virus and rapid progression to AIDS: a case report. Clin Infect Dis. 2007;45:501-509.
3. Pernas M, Casado C, Fuentes R, et al. A dual superinfection and recombination within HIV-1 subtype B 12 years after primoinfection. J Acquir Immune Defic Syndr. 2006;42:12-18.
4. Steain MC, Wang B, Dwyer DE, Saksena NK. HIV-1 co-infection, superinfection and recombination. Sex Health. 2004;1:239-250.
5. Smith DM, Richman DD, Little SJ. HIV superinfection. J Infect Dis. 2005;192:438-444.
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