Zebu were imported to Africa over many hundreds of years, and interbred with taurine cattle there. Genetic analysis of African cattle has found higher concentrations of zebu genes all along the east coast of Africa, with especially pure cattle on the island of Madagascar, either implying that the method of dispersal was cattle transported by ship or alternatively, the zebu may have reached East Africa via the coastal route (Pakistan, Iran, Southern Arabian coast) much earlier and crossed over to Madagascar. Partial resistance to rinderpest led to another increase in the frequency of zebu in Africa.