Report Viruses may have evolved to hit men hard but go easy on women

tom_mai78101

The Helper Connoisseur / Ex-MineCraft Host
Staff member
Reaction score
1,633
Is man-flu a quirk of viral evolution? Some viruses might cause weaker symptoms in women than in men because it makes them more likely to spread.

Many infections cause more severe illness in men than women. Men infected with tuberculosis are 1.5 times more likely to die than women; men infected with human papillomavirus are five times more likely to develop cancer than women; and men infected with Epstein-Barr virus are at least twice as likely to develop Hodgkin’s lymphoma as women.

Many think this pattern is because of differences between the sexes’ immune systems. But another explanation is that women are more valuable hosts. Women can pass infections to their children during pregnancy, birth and breastfeeding, so there’s an evolutionary pressure on viruses to be less harmful to them, say Francisco Úbeda and Vincent Jansen at Royal Holloway University of London.

In order for a virus to infect others, it needs to produce more copies of itself in the body. Making their host ill is an unavoidable consequence of this. “That’s not something a pathogen particularly sets out to do because it’s shooting itself in the foot, should it have one,” says Jansen.

The researchers used mathematical modelling to show that, for pathogens that affect both sexes, natural selection in theory should favour those that cause less illness in women – as long as they can be transmitted from mother to child.

This evolutionary pressure, they argue, could explain a longstanding puzzle: why human T-cell lymphotropic virus type 1 (HTLV-1) progresses to leukaemia much more commonly in Japanese men than Japanese women, but affects both sexes equally in the Caribbean. They argue that this discrepancy is because women breastfeed their babies more commonly and for longer in Japan – giving the virus more opportunity to enter another host.

 
Last edited by a moderator:
General chit-chat
Help Users
  • No one is chatting at the moment.

      The Helper Discord

      Staff online

      Members online

      Affiliates

      Hive Workshop NUON Dome World Editor Tutorials

      Network Sponsors

      Apex Steel Pipe - Buys and sells Steel Pipe.
      Top