Ronald Ross Indian physician and parasitologist of Scottish origin, winner of the Nobel Prize in Physiology or Medicine in 1902. Date of Birth: 13.05.1857 Country: Great Britain

1. Biography of Ronald Ross
2. Early Career
3. Discovery of the Malarial Parasite in Mosquitoes
4. Epidemiology and Prevention of Malaria

Biography of Ronald Ross

Ronald Ross was an Indian doctor and parasitologist of Scottish descent, who was awarded the Nobel Prize in Physiology or Medicine in 1902. He was born into a British Army officer's family and was the eldest of ten children. At the age of eight, Ronald was sent to England for schooling. Although he always dreamed of being a writer, artist, or musician (he published numerous poems, plays, and novels), at his father's insistence, he enrolled in the medical college at St. Bartholomew's Hospital in 1874. After five years, he graduated and began working as a physician in the British organization "Indian Medical Service" in 1881.

Early Career

During the early years of his work in India, Ronald Ross focused more on literary pursuits and the study of mathematics than medicine. He later admitted, "I neglected my medical duties. I was always busy with literary work and did nothing to help people find the causes of diseases that may be the scourge of humanity." The most common disease in India at the time was malaria, so Ross decided to study its causes. In 1888, during his first leave to England, he obtained a diploma in public health and attended a course in bacteriology. In 1889, he returned to India and began studying the blood of malaria patients using a microscope. In the 1880s, Charles Louis Alphonse Laveran discovered that malaria is caused by a single-celled parasite called a plasmodium. Today, it is known that plasmodia infiltrate red blood cells, undergo asexual reproduction inside them, then rupture the red blood cells to form spores and start a new cycle of asexual reproduction. Eventually, the plasmodia transform into adult crescent-shaped forms and are transmitted from humans to mosquitoes through mosquito bites. Since the sexual reproduction of plasmodia occurs in the mosquito's body, humans are considered intermediate hosts for these parasites.

Discovery of the Malarial Parasite in Mosquitoes

During his second leave to England in 1894, Ross met Patrick Manson, who showed him the plasmodia discovered by Laveran in the blood of malaria patients. Manson, a physician and parasitologist, suggested to Ross that malaria could also be transmitted through mosquito bites, but he could not prove it. Ross was immediately intrigued by this hypothesis and decided to thoroughly investigate it upon his return to India. Manson supported his intentions and used his influence to persuade the government to send Ross back to India the following year. In Secunderabad, Ross began histological studies of mosquitoes to find plasmodia in them. However, his work was hindered by the lack of support from his superiors, his limited knowledge of entomology, and his persistence in writing novels and poetry. Additionally, there was very little scientific literature available in India, and Ross lacked materials for the scientific classification of mosquitoes, so he had to create his own classification.

For two years, Ross studied common mosquitoes and finally discovered pigmented cysts in the stomach wall of Anopheles mosquitoes, similar to the plasmodia found by Laveran in the blood of malaria patients. His assumption that these cysts were one of the forms of plasmodia was confirmed through careful experiments. Ross not only caught mosquitoes but also bred them to ensure that they did not initially carry the parasite. He then fed them the blood of malaria patients at different stages of the disease and examined the mosquitoes' stomachs. As he later wrote, his conclusion that plasmodia mature in the bodies of specific species of mosquitoes "solved the problem of malaria. The further direction of work became clear, and it was obvious that science and humanity had achieved another victory." Shortly after completing these experiments, Ross was transferred to Rajputana. Since malaria did not occur in humans there, Ross began studying avian malaria, which is similar to human malaria. After six months, Manson once again used his influence and ensured Ross was transferred to Calcutta, where human malaria was prevalent. Here, Ross unsuccessfully attempted to discover the malaria parasite in various mosquitoes that had bitten infected individuals. He then turned his attention back to avian malaria and, in 1898, elucidated the life cycle of the parasite, including a crucial stage that occurs in the mosquito's salivary glands.

Epidemiology and Prevention of Malaria

In 1899, Ross resigned from the "Indian Medical Service" and returned to England. His career in experimental medicine ended there, but his work on avian malaria was used in the study of human malaria by a group of Italian researchers, including Battista Grassi and Amico Bignami. Grassi and his colleagues demonstrated that both avian and human malaria are transmitted by mosquitoes of the Anopheles genus. They described the life cycle of the plasmodia in the human body, established the infection of previously unexposed individuals through the bite of Anopheles mosquitoes, and proved that people living in marshy areas could protect themselves from malaria using ordinary mosquito nets. Ross, however, claimed that "the work of Bignami and Grassi was clearly hasty and unreliable" and referred to their discovery that human malaria could be transmitted by mosquitoes as "an obvious fallacy, the scientific destiny of which can be confidently predicted even now." Nevertheless, Ross's work on avian malaria was unquestionably completed earlier than Grassi's research on human malaria, and in 1902, Ross was awarded the Nobel Prize in Physiology or Medicine "for his work on malaria, in which he showed how the parasite enters the body and thus laid the foundation for further successful research in this field and the development of methods to combat malaria." In his speech, Carl Mörner from the Karolinska Institute acknowledged the "great importance of his work as a basis for recent successful research in the field of malaria and its rich content from the perspective of medical practice and particularly hygiene."

For the last 20 years of his professional career, Ross dedicated himself to the epidemiology and prevention of malaria. Working at the Liverpool School of Tropical Medicine, the British Ministry of Defence, and the London School of Tropical Medicine, which was established in 1926 and named after Ross, he advocated for the eradication of mosquitoes as the key to combating malaria. His methods proved effective in fighting the disease in Cuba and other countries. Several decades later, when Paul Müller invented DDT, these methods became even more effective. In 1889, Ross married Rosa Bessie Bloxam, and they had two sons and two daughters. After a prolonged illness, Ronald Ross passed away on September 16, 1932, at the London institute that bore his name.

Ross served as the president of the Society of Tropical Medicine. In 1911, he was awarded a knighthood. He received an honorary medical degree from the Karolinska Institute and was an honorary member of numerous European scientific societies. For his consultation work with the British Ministry of Defence during World War I, he was awarded the Orders of St. Michael and St. George in 1918.