A disease which mildly inconveniences men of fighting age for at most a couple weeks makes a poor weapon. They would be full of grief and anger at losing some

A disease which mildly inconveniences men of fighting age for at most a couple weeks makes a poor weapon. They would be full of grief and anger at losing some of their grandparents, but that won't affect their ability to fight and would be likely to motivate them to continue. Smallpox had up to 90% mortality in Native American populations, across all demographics. Fair to say it was a different beast.