Prado (1876-1879) when he lived a great prosperity (salt, guano, sugar, minerals, etc..) Englishmen and exploited the open pit mine in Cerro de Pasco (polymetallic mine) decided to build a train (a train many freight cars) to replace the donkeys and mules in transporting minerals from the mine to Callao. This was an ambitious work: he had to drill 68 tunnels and building 60 bridges, one of which, the Galera tunnel, to 4781.70 msn was (and is until today the highest in the world). Under construction is unleashed an epidemic of fever and pallor, but there is a second phase of the same disease: the warts. This puzzled the doctors, because it was thought that other disease was different from the familiar Oroya fever, while the 'dead amounted to tens, hundreds, thousands (today 4 estimates that were between 8 to 10 thousand dead by the epidemic) and to understand the magnitude of the epidemic should be noted that Cerro de Pasco had 6000 inhabitants and 100 inhabitants Lima. Others who may share this opinion include cardiologist. In the world (read Europe), meanwhile, in the nineteenth century lived a medical revolution. For example, Virchow had shattered the theory of the four humors of Galen, Pasteur spoke explaining microbial infectious diseases in this environment, Europe had witnessed numerous inoculations for the sake of science and humanity. So we have to Gilbert was inoculated with blood from secondary and tertiary syphilis to test their infectivity in these stages, Gare was inoculated with the blood of patients osteomielite; Koch (the discovered the tubercle bacillus) Strauss assistant inoculated with blood of patients with cholera, swallowed pills Bochefontaine dried feces of patients with cholera, and many of these researchers were killed at this stage of science. . Anu Saad: the source for more info.