How fast could HIV change gene frequencies in the human population?
Infectious diseases have the potential to act as strong forces for genetic selection on the populations they affect. Human immunodeficiency virus (HIV) is a prime candidate to impose such genetic selection owing to the vast number of people it infects and the varying susceptibility of different human leucocyte antigen (HLA) types to HIV disease progression. We have constructed a model of HIV infection that differentiates between these HLA types, and have used reported estimates of the number of people infected with HIV and the different rates of progression to acquired immunodeficiency syndrome (AIDS) to provide a lower bound estimate on the length of time it would take for HIV to impose major genetic change in humans. We find that an HIV infection similar to that currently affecting sub-Saharan Africa could not yet have caused more than a 3 per cent decrease in the proportion of individuals who progress quickly to disease. Such an infection is unlikely to cause major genetic change (defined as a decrease in the proportion of quickly progressing individuals to under 50 per cent of their starting proportion) until 400 years have passed since HIV emergence. However, in very severely affected populations, there is a chance of observing such major genetic changes after another 50 years.
Cromer
Deborah
D
Zoology Department, Institute for Emerging Infections, James Martin 21st Century School, University of Oxford, Oxford, UK. deborahcromer@yahoo.com
Wolinsky
Steven M
SM
McLean
Angela R
AR
D018450:Disease Progression; D005787:Gene Frequency; D005828:Genetics, Population; D006678:HIV / Q000472:pathogenicity*; D015658:HIV Infections / Q000453:epidemiology / Q000235:genetics / Q000503:physiopathology / Q000821:virology; D006801:Humans; D008954:Models, Biological; D015995:Prevalence; D012641:Selection, Genetic; D013997:Time Factors