Lee ihe ndị ị kwesịrị ịma maka ya bụ ọrịa N'ihi etu o si gbuo ọtụtụ mmadụ site n'afọ 1346 ruo 1353, a kpọrọ ya "Black death" "Black Death gburu mmadụ nde iri ise (50 million) n'Afrịka, Asia nakwa Yurop N'afọ 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).
