Dr Pfau first visited Pakistan in 1960 and was so touched by the plight of leprosy victims that she made a decision to stay forever in the country to treat them.
A symbol of selflessness and dedication to leprosy patients, Dr Ruth Pfau, aged 87, passed away in Karachi on Wednesday night.
"It was due to her endless struggle that Pakistan defeated leprosy", German Consulate Karachi posted on Facebook. "Pakistani nation salutes Dr Pfau and her great tradition to serve humanity will be continued", President Mamnoon Hussain said in another statement. On her way she stopped in Karachi on March 8, 1960, because of some visa problems.
From the early 1960s on, Pfau helped lead the Marie Adelaide Leprosy Centre, transforming what was once a tiny makeshift dispensary into the hub for a system of 157 medical centers across the country, often in remote regions.
From then onwards she dedicated herself to the fight against the disease, and by 1996 it was declared to have been brought under control. She became known as the Mother Theresa of Pakistan, a reference to Mother Theresa of India, the nun and missionary who became a saint in the Roman Catholic Church.
The Pakistan government recognized her selfless service by awarding her the country's second-highest civilian award "Hilal-i-Imtiaz" in 1979, and later "Hilal-e-Pakistan" in 1989.
"She came to Pakistan 56 years ago and spent her life looking after the diseased and dispossessed", Sen.
Saddened to learn of Dr Ruth Pfau's passing. She has treated over 50,000 patients. "That is the worst", she told German newspaper Der Spiegel in 2015.
He said we will remember her for her courage, loyalty, service to the eradication of leprosy, and most of all, patriotism.