Dr. Pylore Krishnaier Rajagopalan (also known as P.K. Rajagopalan; 27 October 1930 – 29 April 2024) was a pioneering Indian vector-control scientist, biologist and acarologist. He made major contributions to the control of vector-borne diseases in India and served as the founding director of the Vector Control Research Centre (VCRC) in Pondicherry (now Puducherry). The Government of India awarded him the Padma Shri in 1990.

Born in Mukteshwar in the Kumaon region of present-day Uttarakhand, he graduated from Banaras Hindu University in 1949 and obtained a master’s degree in Zoology with a university first rank in 1951. In 1952 he joined the Virus Research Centre in Pune, where he trained under leading vector-control specialists including Dr. T. Ramachandra Rao.

He later received a Rockefeller Foundation fellowship to pursue a Master’s in Public Health at the University of California, Berkeley. On returning to India he played a key role in investigating Kyasanur Forest Disease (KFD), a tick-borne viral haemorrhagic fever first recorded in Karnataka in 1957. His ecological and epidemiological studies on the disease and its tick vectors became foundational work in the field.

In 1975 he established the Vector Control Research Centre (VCRC) under the Indian Council of Medical Research in Pondicherry. He served as its officer-in-charge from 1977 and as director from 1980 until his retirement in 1990. Under his leadership the centre pioneered biological control methods that combined minimal chemical use with environmental management and natural larval predators of mosquitoes. These approaches successfully reduced the incidence of filariasis in areas such as Pondicherry and Shertallai in Kerala, and also contributed to the control of Japanese encephalitis.

Rajagopalan started India’s first M.Sc. programme in medical entomology at the VCRC and guided numerous doctoral students. He published extensively on vector ecology, acarology and disease control, and later served on World Health Organization steering committees on filariasis and the biological control of vectors.

In addition to the Padma Shri (1990), he received the Om Prakash Bhasin Award, the P.N. Raju Oration Award of the ICMR, and other national and international recognitions. He was a Fellow of the Royal Society of Tropical Medicine and Hygiene.

Dr. P.K. Rajagopalan passed away in Chennai on 29 April 2024. He is remembered as a scientist who combined rigorous field research with practical public-health solutions, helping shape India’s capacity to combat mosquito- and tick-borne diseases through environmentally sound and sustainable methods.