Born in London in 1933, Marsden earned his medical degree from University College Hospital.
[1] He completed his thesis on pediatric health in Gambia, focusing on the challenges faced by children in that region.
[2] Beginning his fieldwork in Brazil in 1967, Marsden was later appointed a professor of tropical medicine at the University of Brasília.
[2] Marsden held academic positions at the London School of Hygiene and Tropical Medicine, Cornell Medical Center in Manhattan, and Makerere University in Uganda.
[2][1] Marsden was honored with the Order of the British Empire and received the Chalmers Medal from the Royal Society of Tropical Medicine and Hygiene for his contributions to the field.