The Carter Center, a leader in the global elimination and eradication of diseases, recently reported that guinea worm disease was close to eradication. From 3.5 million cases a year in 21 countries in 1986, the number had come down to 13 in five countries in 2023, a reduction of 99.99%. This would be the second disease after smallpox to be eradicated and the first one with no known medicines or vaccines. This has created increased attention to disease elimination, the first step in eradication. Ending the epidemics of malaria, tuberculosis and Neglected Tropical Diseases by 2030 is one of the Sustainable Development Goals set by the United Nations.
On disease elimination, its focus
Elimination of transmission, which targets achieving zero transmission in a defined region, is different from eradication, which is the permanent cessation of infection by a pathogen with no risk of reintroduction. It is a highly desirable objective to enhance the health of the people, especially the poor who are most vulnerable to infectious diseases. There are many reasons to recommend disease elimination as a public health strategy. As a national goal it energises the public health system.
The requirements for certification by international agencies are rigorous and preparing for it improves primary health care, diagnostics and surveillance. It will lead to increased involvement of field staff and community health workers, enthused by the clearly defined goal, and attract international support. Above all, it generates high political and bureaucratic commitment, and public support. These efforts positively impact the health system.
But, elimination of transmission is challenging and resource intensive. It imposes an onerous load on the system and could lead to the neglect of other important health functions, especially for weak health systems. Therefore, disease elimination should be planned only after careful analysis of the costs and benefits and with informed political support to generate the best outcomes with the least adverse impact.
While elimination is scientifically feasible for all the diseases targeted by India, it will be strategic to focus on those pathogens whose impact on the population is high and whose numbers are low enough to make elimination feasible. If the prevalence of a disease in a population is high, at the first stage, the aim should be to reduce their numbers to the level where elimination is practical, through disease control. This will enable an understanding of the processes and cost of elimination and provide an opportunity to strengthen the existing health systems to handle the rigour of implementing elimination.
Need for surveillance systems
The government must be prepared to invest in developing surveillance systems capable of capturing every incidence of the disease, strengthening laboratories for screening and confirmation, ensuring that medicines and consumables are available, and training the workforce on the rigorous requirements of an elimination strategy. Even after elimination is achieved, surveillance has to be continued to detect reintroduction as the pathogen would not have been eradicated.
From this point of view, elimination of many of the diseases targeted by the country may be difficult to achieve for the entire nation within the declared time frame. But they are achievable for some diseases in some parts of the country. For instance, kala azar is now limited to five States in India, primarily prevalent in a few blocks in two States.
India accounts for 40% of the global case load of lymphatic filariasis, which was targeted for elimination by the World Health Assembly in a resolution in 1997. It is prevalent only in a few States and can be eliminated by a combination of surveillance, vector control, drug administration and morbidity management.
On the other hand, pathogens of some targeted diseases have long incubation periods. They are prevalent in high numbers in many parts of the country, and have developed drug resistance. For them, the strategy of elimination needs to be reworked into a localised and phased one. The diseases that can be eliminated easily in defined geographical regions — States, districts, blocks — can be targeted for elimination within those regions.
After regional certification, such areas can be ring-fenced with better control in the adjoining areas which can then move to elimination, when they are assessed to be ready.
From the regional level
Multisectoral collaboration, encouraging innovation and adopting locally effective solutions which facilitate disease elimination, is done more effectively at the regional level. Smaller units can also redeploy resources to better manage the additional load without affecting other essential tasks. While elimination can proceed region wise, national and State governments should own the process. The phasing of regional elimination to culminate at the national level has to be planned from the perspective of the entire country. Regional implementation needs technical and material support and the progress of regional elimination has to be monitored. Similarly, only the Union government can deal with the spread of diseases across States and at the ports of entry, to control reintroduction. In India, national elimination can be achieved most effectively, by starting with elimination and scaling it up, region by region, across the country.
Rajeev Sadanandan is CEO, Health Systems Transformation Platform and a former Health Secretary, Kerala
