 In the same year Friedrich Loeffler (1852–1915) and Paul Frosch (1860–1928) passed the first animal virus through a similar filter and discovered the cause of foot-and-mouth disease.The first human virus to be identified was the yellow fever virus.In 1881, Carlos Finlay (1833–1915), a Cuban physician, first conducted and published research that indicated that mosquitoes were carrying the cause of yellow fever, a theory proved in 1900 by commission headed by Walter Reed (1851–1902).