A new era in the history of fighting the fever began in 1903 when the kala-azar parasite was correctly identified. Thenceforth, further study on it made India one of the world's leading countries that produced enormous medical knowledge about this disease, thereby enriching the knowledge base of black fever. Despite the overwhelming wealth of information on this ailment, the colonial state in India and its subjects had to wage war against kala-azar till the end of colonial rule. Eastern India experienced serious medical intervention by the colonial administration to combat kala-azar, but the progress of the disease could not be checked successfully even in the late colonial period despite pursuing treatment campaigns and health propaganda. The administration failed to prevent its occurrence, though successful treatment from the 1920s saved innumerable people. The disease was rather widely prevalent despite the availability of all possible means to eliminate it. This raised doubt over the efficiency of the anti-kala-azar measures implemented by the health administration.

Despite the fact that the health policy of the British Indian government had certain limitations, the contribution and efficacy of Western medicine cannot be questioned. It had a liberating, though limited, role in the control of communicable diseases. It introduced modern scientific and medical knowledge and evoked interest among the local populace. The notion of public health was certainly attractive to the Indian elite and intelligentsia, who accepted some of its doctrines and wanted to see the principles of public health working in India. The developing concept of public health and hygiene, medical institutions and hospitals, IMS and subordinate medical services, and so on, provided an organized medical system and an iron framework of public health administration in independent India. It gave certain benefits to the Indian people. The Indian medical system was not as methodical, pervasive, and penetrative as Western medicine. Colonial medical research based on the method of experiment and observation carried out by experts on different diseases provided new knowledge about preventive and curative aspects of medicine and also about the containment of dreadful diseases.

Unquestionably, the government was sorely tempted to retaliate against the inroads of kala-azar and set forth plans and strategies for that purpose. Treatment was used as an effective tool to arrest the disease. The sustained and extensive treatment for kala-azar had a great effect on saving lives in the areas under study.