Stop bringing realistic things into manga. If they don't say something in it, it doesn't exist in their world, at least how I see it. Most of the time those fevers are just from being outside and wet. I think a lot of the times it was fall or spring, not summer, but come on, they are coughing after 5 minutes and if they don't dry off or have someone tell them to dry off they have a life threatening fever after only a short time being wet. I was outside in below freezing weather for about an hour the other night and all I got was a sore throat at best. I was wearing a coat, a hoodie, a pair of jeans, and shoes with no socks, and these people in manga get sick after five minutes of being wet. It just frustrates me.
btw, how about avian influenza? it is still a life threatening fever. and maybe in Japan it was cold when they got wet ( like near winter ). if u get ur self soaked wet like that u can get a pneunomia.
Well, girls. if i didn't wrong there are heavier skirt and lighter skirt don't it that depends on the fabric. do not know, never wear one before :P