 Lee ihe ndị ị kwesịrị ịma maka ya bụ ọrịa Nihi etu o si gbuo ọtụtụ mmadụ site nafọ 1346 ruo 1353, a kpọrọ ya Black death Black Death gburu mmadụ nde iri ise 50 million nAfrịka, Asia nakwa Yurop Nafọ 1665 ọrịa a bara obodo Lọndọn ma gbuo ọkankụ mmadụ Ọ banyekwere mpaghara Chaịna na India ka afọ nari atọ na ụma gachara were gbuo mmadụ ihe karịrị mmadụ nde iri na abụọ 12 million. 