Patrick Manson - Researching Filaria

Researching Filaria

He spent his early years researching filaria (a small worm that causes elephantiasis). Manson focused his time on searching for filaria in blood taken from his patients. From this he began to work out the life cycle of filaria and through painstaking observation discovered that the worms were only present in the blood during the night and were absent during the day.

He conducted experiments on his gardener, Hin Lo, who was infected with filaria. He would get mosquitoes to feed on his blood while he slept and then dissect the mosquitoes filled with Hin Lo's blood. "I shall not easily forget the first mosquito I dissected. I tore off its abdomen and succeeded in expressing the blood the stomach contained. Placing this under the microscope, I was gratified to find that, so far from killing the Filaria, the digestive juices of the mosquito seemed to have stimulated it to fresh activity."

Manson observed that filaria only developed as far as an embryo within the human blood and that the mosquito must have a role in the life cycle. Through these early experiments he started to hypothesise about the role of mosquitoes and the spread of disease. Out of this arose the mosquito-malaria theory, which suggested that the agent that causes malaria was also spread by a mosquito. This discovery was one of the most important medical breakthroughs of the time. Under the constant supervision of Manson, Sir Ronald Ross described the full life cycle of the plasmodium inside the female mosquito. Manson's theory was finally proved by Ross in 1898, who won the Nobel Prize in 1902 for this discovery. Manson also demonstrated a new species of Schistosoma (Bilharzia) known as Schistosoma mansoni.