Men often seem to be hit harder by illnesses – and that could be because certain viruses may have evolved to be more virulent in men than in women. Viruses are “programmed” to want to
spread, and to do this, they must multiply in the host’s body. This is what makes people ill, but causing illness is not the virus’s intention: indeed, to incapacitate or kill their host may be counterproductive – especially in the case of women, as they can easily pass viruses on to their children during pregnancy, birth and breastfeeding. Professor Vincent Jansen and Dr Francisco
Úbeda, of Royal Holloway, University of London, thus suggest that certain viruses have evolved to go easier on women. Many viruses cause more severe illness in men: for instance, men with tuberculosis are 1.5 times more likely to die than women; and men infected with human papillomavirus are five times more likely to develop cancer than women. These discrepancies are usually put down to differences in men and women’s immune systems. But Jansen and Úbeda propose that it could also be because some viruses can detect their host’s gender, and alter their virulence accordingly. Alas, the scientists don’t think their theory can explain the severity of “man flu”, however, as mother-child transmission isn’t important for cold viruses. “To me, man
flu sounds like an excuse for men not to go to work,” Jansen told New Scientist.
