Giovanni Battista Grassi (27 March 1854 – 4 May 1925) was an Italian physician and zoologist, best known for his pioneering works on parasitology, especially on malariology. He was Professor of Comparative Zoology at the University of Catania from 1883, and Professor of Comparative Anatomy at Sapienza University of Rome from 1895 until his death. His first major research on the taxonomy and biology of termites earned him the Royal Society's Darwin Medal in 1896.
Grassi's scientific contributions covered embryological development of honey bees, on helminth parasites, the vine parasite phylloxera, on migrations and metamorphosis in eels, on arrow worms and termites. He was the first to demonstrate the life cycle of human dwarf tapeworm Taenia nana, and that this tapeworm does not require an intermediate host, contrary to popular belief. He was the first to demonstrate the direct life cycle of the roundworm Ascaris lumbricoides by self-experimentation. He described canine filarial worm Dipetalonema reconditum, and demonstrated the parasite life cycle in fleas, Pulex irritans. He invented the genus of threadworms Strongyloides. He named the spider Koenenia mirabilis in 1885 after his wife, Maria Koenen. He pioneered the foundation of pest control for phylloxera of grapes.
The most important contributions of Grassi are on malariology, discovering different species of malarial parasites in birds and humans, and their transmission. With Raimondo Feletti, he discovered Haemamoeba praecox and H. relictum (now under the genus Plasmodium) in birds. They correctly described Haemamoeba malariae and H. vivax (both now under Plasmodium), which became fundamental to clinical distinction of different human malaria: benign tertian caused by P. vivax, malignant tertian by P. falciparum and benign quartan by P. malariae). He was the first to describe and establish the life cycle of the human malarial parasite, Plasmodium falciparum, the most prevalent and deadliest species. He discovered that only female anopheline mosquitoes are capable of transmitting the disease.
Grassi's works in malaria remain a lasting controversy in the history of Nobel Prizes. Since the inception of Nobel Prizes in 1901 until his death, he was nominated 21 times. For the 1902 Nobel Prize in Physiology or Medicine, he was nominated alongside French physician Charles Louis Alphonse Laveran, who discovered P. falciparum, and British army surgeon Ronald Ross. He and Ross were shortlisted for the final award, but Ross who appeared to have make the least important discovery, the transmission of malarial parasite in birds, was the sole winner. Grassi, who demonstrated the complete route of transmission of human Plasmodium, and correctly identified the types of malarial parasite as well as the mosquito vector, Anopheles claviger, was denied.
Grassi was born in Rovellasca, Italy, in what is now the Province of Como. His father Luigi Grassi was a municipal official, and mother Costanza Mazzuchelli was a noted peasant of unusual intelligence. He completed elementary education at Bolchi-Stucchi private school in Saronno, and secondary education at Volta high school in Como.
From 1872 he studied medicine at the University of Pavia under professors Camillo Golgi and Giulio Bizzozero and graduated in 1878. After graduation he worked first at Messina in the Naples Zoological Station and the Oceanographic Station founded by Nicolaus Kleinenberg and Anton Dohrn where he studied Chaetognatha, then completed his training at the University of Heidelberg in Germany under the guidance of Carl Gegenbaur and Otto Bütschli. While in Heidelberg, he met a fellow student Maria Koenen whom she married in 1879.
In 1883, he became Professor of Comparative Zoology at the University of Catania, studying cestodes, the life cycle of the European eel (Catania) and the Moray eel (Rome). Also in Catania he began to study entomology and wrote a student text "The Origin and Descent of Myriapods and Insects" in addition to scientific papers. He also began to study malaria working with Raimondo Feletti on malaria, discovering the parasite species of human and bird malaria.
In 1895, he was appointed Chair of Comparative Anatomy at Sapienza University of Rome, where he would spend the rest of his life. He joined Angelo Celli, Amico Bignami, Giuseppe Bastianelli and Ettore Marchiafava, who were working on malaria in districts around Rome. Grassi was the group's entomologist. The group announced at the session of the Accademia dei Lincei on 4 December 1889 that a healthy man in a non-malarial zone had contracted tertian malaria after being bitten by an experimentally infected Anopheles claviger.
In 1902, Grassi abandoned his study of malaria and began work on the sandfly responsible for Leishmaniasis (Phlebotomus papatasii) and on a serious insect pest of the grape vine (Phylloxera vastatrix). In 1903, Rome university created a department of agricultural entomology in which Grassi became the first teacher. Endemic malaria returned to Italy during and after the First World War and Grassi resumed his mosquito studies.
Grassi spent much of his later years in Fiumicino, a commune in the province of Rome, where his family had settled. There, he built a private clinic for children with malaria, and which he bestowed to her daughter Isabella for continued service after his death. He died in Rome in 1925 while reading the proof of his last paper, Lezione sulla malaria.
Following his will, he was interred at a village cemetery in Fiumicino, as he achieved his most important medical services there. His wife Maria (1860–1942) and daughter were also interred at the same tomb.
General zoology and entomology
Grassi's earlier works were on anatomy and then entomology. He studied the development of the vertebral column in bony fishes and also endemic goiter. His studies on bees, myriapods and termites were monumental. His reports on termites and their biology earned him an international recognition as a zoologist. He described 21 species of termites and documented the first observations of the protozoan parasites inside them. He also studied the arrow worms and the reproduction of eels. He published his first report on the arrow worms in 1881 and a monograph in 1883 by which he described 14 new species and established that the animals are not related to molluscs and coelenterates, as then believed to be. Earlier 1881, he had discovered that arrow worms harbour amoeboid parasites, and described one new species, Janickina pigmentifera. The arrow worms were later classified as a separate phylum Chaetognatha, and are recognised as "enigmatic" animals. His associate Salvatore Calandruccio collected an unusual spider from Mount Etna in Sicily. Grassi identified it as not only new species but as belonging to a new family, and gave the name, Koenenia mirabilis in 1885, dedicated to his wife.
He also made significant contribution to the study of the phylloxera of grapes, which he pursued for several years. The notes of his observations La questione fillosserica in Italia (1904) influenced the Italian Ministry of Agriculture, which eventually requested him to do an exhaustive study of this subject. In 1912 he produced a monumental investigation of the morphology and biology of the Italian and other European genera of phylloxera. It was a foundation for systematic control of agricultural pests.
In 1876, Grassi investigated his native hometown Rovellasca for the high mortality of cats and discovered that they were heavily infected with the nematode (roundworm) Dochmius balsami. In 1878, while still a student at the University of Pavia, he made the first description of Ancylostoma caninum, a roundworm that causes ancylostomiasis in cats, after identifying the eggs from the faeces of infected individuals. His method of egg identification was immediately useful for the detection of A. duodenale infection in humans. He continued to make great impacts on the study of Anguillula intestinalis, filarial worms, Trichocephalus dispar, and Bilharzia. He was the first to show that the human dwarf tapeworm Taenia nana (Hymenolepis nana) is able to go through its entire life cycle in one animal, without the need of an intermediate host, a notion that had long been rejected. At the time, it was known that a closely related species H. dimunita required rats as definitive hosts and arthropods as intermediate hosts, which was the basis of presumption that all dwarf tapeworms must use two different hosts. He was also the first to show that the flea Pulex serraticeps is the intermediate host of feline tapeworm Taenia elliptica. Thus he proposed that swallowing of infected fleas (for example, with milk) might be the reason for taeniasis in children. In 1879 he published a work on the life cycle of Strongyloides stercoralis, and erected the genus Strongyloides. In 1890 he, with Salvatore Calandruccio, described Dipetalonema reconditum, a non-pathogenic filarial worm of dogs, and showed that the parasite completed its development in human fleas, Pulex irritans.