1. History of Parasitology & Tropical
Medicine
Helminthes:
• Known in ancient Greece, Rome, China & the Arab world
• Spontaneous generation
Malaria:
• Recognized for over 4000 years
• Reference can be found in a Chinese document from 1700
B.C.
• Hippocrates worked on it but his teachings were lost until
mid 17th century & then another Physician rediscovered it
& found the cure
Chagas disease:
• Trypanosoma cruzi
• He first described it in 1909, ignored in 1920s and not considered as a major problem till 1960

2. Work of Robert Hooke:
• Invention of microscope in 1665
Work of Leeuwenhoek:
• In later part of 17th century, He made the first descriptions of protozoa, bacteria &
spermatozoa, (animalcules)
• Giardia
Advances in microscope technology:
• In 1823, achromatic lens was developed that led to the discovery of cell nucleus
by R. Brown in 1833, the nucleolus in plant cells by Schleiden, cells in animals by
Schwann, mitochondria in 1858 by Kolliker & finally The Cell Theory by Schleiden
& Schwann in 1839
• In 1858, Virchow stated that cells come from cells & each cell is an organism
• In 1878, oil immersion lens led to the discovery of chromosomes by Flemming in
1879
• In 1886, apochromatic lens
• Pasteur proved that spontaneous generation did not occur
• Koch discovered that microorganisms caused diseases

3. • Concept of vector-borne parasitic diseases & foundation of Tropical Medicine (Patrick Manson)
from which modern parasitology was derived. In 1877, He learned of the discoveries of
Bancroft (Filarial worm in blood & tissues of a patient with elephantiasis disease)
• In 1898, Manson was convinced by Ronal Ross that mosquitoes could possibly transmit
malaria. He tested his theory by using Anopheles mosquitoes
Kala Azar or Black Fever:
• Probably existed for centuries in Bengal & China but first recognized outbreaks was in 1824
in Jessore, India (Deaths of 750,000 people in 3 years)
• Thought to be type of malaria with relapses, emaciation & enlargement of liver & spleen
Leishmann-Donovan Work:
• Leishmann in 1901 studied & then published in 1903 the amastigote forms of Leishmania
donovani
• At the same time Donovan discovered same parasites
• Ross realized that they were same parasites & created the genus Leishmania in their
honour
• Sometime called Leishmann-Donovan bodies & now amastigotes

4. Bruce’s Work:
• Discovered a new trypanosome, T. brucei (In South Africa the cause of a disease of domestic
animals called Nagana)
• Transmitted from antelopes to cattle by tsetse fly, Glossina morsitans
• First to prove that an insect carries a protozoan causing a disease
Sleeping Sickness:
• In 1903, Bruce went to Uganda to investigate human Sleeping Sickness
• Prolonged debilitating fever, after few months become confused & stuporous & often may
develop enlarged lymph nodes & spleen & ultimately they relapse into coma & die
• Dr. Aldo Castellani found trypanosomes in the CSF in all patients.
• Tsetse fly carries trypanosomes
• Glossina palpalis transmit T. gambiense
Plasmodium:
• Charles Laveran in 1880 in Algeria described that malaria is caused by parasite
• In 1882, Laveran visited Rome & showed his parasite to 2 scientists, Marchiafava & Celli
• In 1884, they saw an active amoeboid movement (trophozoite) in red blood cells of malarial patients
& named it Plasmodium malariae & did not refer to Laveran
• Camillo Golgi in Pavia was also studying malaria & recognized several other species

5. • Italians discovered P. falciparum
• Ross in 1895 showed exflagellation of Plasmodium in Anopheles mosquitoes
• Grassi discovered the life cycle of Plasmodium
Chagas’ Work:
• Schizotryanum cruzi today called Trypanosoma cruzi
• Armadillos (natural reservoirs)
Trager’s Work:
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Worked on Plasmodium & attempted to culture P. lophorae
He & Jensen discovered a simple method to grow the pathogenic human malaria, P. falciparum(1926)
Modern Parasitology:
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In recent years the study of parasites has had a resurgence of interest due to development of genetics & cell
& molecular biology
Close attachment of parasitology with Tropical Medicine
WHO has recently stated six major human tropical diseases, schistosomiasis, malaria, filariasis, African
trypanosomiasis, leishmaniasis & leprosy. First 5 are caused by parasites
Also occur in temperate industrial countries
Revolution in terms of diagnosis, vaccine development & rational chemotherapy

6. Six Major Human Tropical Diseases
• African trypanosomiasis
• Leishmaniasis
• Schistosomiasis
• Filarosomia
• Malaria
• Leprosy