Grassi made his first contribution on malaria in 1890, when he ( with Raimondo Feletti ) discovered " Haemamoeba vivax ", later renamed " Plasmodium vivax ".
His description of the specific characteristics responsible for benign tertian ( " Haemamoeba vivax " ), malignant tertian ( " Laverania malariae ", renamed " P . malariae " ) malaria resolved the confusion of the time.
The 5th and 6th Congresses of Malaria held at Istanbul ( 1953 ) and Lisbon ( 1958 ) respectively recommended the creation and use of subgenera in this genus . " Laverinia " was applied to the species infecting humans and " Haemamoeba " to those infecting lizards and birds.
In 1890, Grassi and Feletti reviewed the available information and named both " P . malariae " and " P . vivax " ( although within the genus " Haemamoeba " . ) By 1890, Laveran's germ was generally accepted, but most of his initial ideas had been discarded in favor of the taxonomic work and clinical pathology of the Italian school.