In between, he took a hiatus from work and obtained Diploma in Tuberculosis Diseases (TDD) from Cardiff University School of Medicine, Wales, UK, in 1938.
[7] After the war, he retired from the Army and joined the Union Government and worked in various capacities such as an adviser on Tuberculosis (1946–48) and as the Deputy Director General of Health Services (1948–57).
Dr. Viswanathan has two children from his first marriage to Parvathi; his son, Prof. V. Raman, who was an Environmental Engineering scientist and the daughter, V. Kamla, a homemaker.
[4] He was also involved with the activities of the Tuberculosis Association of India as a member of its various committees,[4] and was the leader of the USAID Exchange Program of 1953 as well as the Indian Regent of American College of Chest Physicians during 1957–58 when he was entrusted with the investigation of infectious hepatitis in Delhi.
[5] His studies of autopsy reports of the patients died of tropical eosinophilia helped to define the pathology of the disease for the first time and established positive leucocyte adhesion phenomenon with M. bancrofit.
[7] His researches also covered several other diseases such as cerebral malaria, basal tuberculosis, lung atelectasis, bronchiectasis, emphysema, bagassosis, byssinosis, and high altitude pulmonary oedema, among others.
[7] The National Academy of Sciences, Italy awarded him the Eugeno Morelli Prize in 1969 and the Italian Tuberculosis Association followed suit with its Forlanini Medal.
[7] Three years later, the Government of India included him the 1974 Republic Day Honours list for the third highest civilian award of the Padma Bhushan.