Worldwide, some 500,000,000 humans suffer from this scourge. Cockroaches, which thrive in filth, are also suspected of mechanically transmitting disease.
माना जाता है कि गंदगी में पलनेवाला तिलचट्टा भी यांत्रिक प्रसार से बीमारी फैलाता है ।