Before that war ended, a terrible flu epidemic struck on a global scale and killed 20 million people ​ — more than twice the number of soldiers that died in the war itself.
तब से, कर्क रोग, और ज़्यादा हाल में, एड्‌स जैसी बीमारियों ने मनुष्यजाति को भयभीत किया है ।