Wednesday, January 26, 2011

The Black Death and HIV resistance?

An article from China Daily dated from March 2005 claims that the Black Death may have provided ten percent of the European population with immunity to HIV.

There is a mutation in the CCR5 receptor called delta-32, which provides immunity to the HIV disease; scientists think that this mutation arose sometime during the Black Death epidemic when there was favorable selection pressure for it, given that it may have provided carriers with protection from the bubonic plague bacteria or from smallpox. European populations have the highest numbers of people with this favorable mutation.

According to the little picture above, HIV binds to the CCR5 molecule in order to enter the body's cells; however, the delta-32 mutation may prevent CCR5 from showing up on the cells, therefore preventing HIV from entering the body's cells.

1 comment:

John Latto said...

This is interesting research. Something certainly caused the frequency of this allele to increase dramatically. Although one suggestion is that it was the black death another suggestion, by Galvani and Slatkin, is that it was the more prolonged selection pressure caused by smallpox that may have been responsible. With the recent evidence that black death was caused by bubonic plague it looks like Galvani and Slatkin may have been correct:
'No single smallpox pandemic was as devastating as the Black Death, but the cumulative toll of human life caused by smallpox constituted an even stronger selection pressure than the episodic decimation of bubonic plague.'