just a matter of time and history will repeat itself.
Whatever the new plague mutates into, it can only sustain itself and spread if there are enough host victims to carry and spread the germs. That means, for the Muslims to be felled by it, the germs would have to be able to infect non-Muslims as well, just so that enough carriers exist to get the germs to the Muslims. Besides, there is no guarantee any new plague will be unable to overcome past defenses (least of all, defenses evolved over 600+ years ago, whose selection and sustenance has been silenced due to the end of the previous plague. That means Europeans will fall en-masse as well. Then again, a large proportion of Muslims are Europeans too, converts and Eastern European migrants. Add to that the propensity for white women to marry and mate with Muslims there (and here as well) while the males jump from affair to affair, unwilling to be monogamous.