Not everyone is susceptible to the attack. I believe some can even be carriers and not feel anything. It is apparently something to do with hormones that make one susceptible to the disease and attractive to this bug.

So far, in the 2 years of reading the results of surveys victims have answered, no young men have reported getting this. Every other gender and age has contacted me. There does not appear to be any other patterns in the victims. Many are strong and healthy with no weakness in their immune system as a contributing factor.