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Several attempts have been made to control malaria since its discovery by Ronald Ross in 1897 in Secunderabad, India. Yet, as per the Global Malaria Report 2022 [1], an estimated 247 million malaria cases and 619,000 deaths in 84 malaria-endemic countries were recorded in 2021. Among these, about 95% of global malaria burden was reported in Africa [1].
WHO’s Global Technical Strategy has targeted malaria elimination by 2030, conforming with the sustainable development goals (SDGs). And since 1900, 129 countries have successfully eliminated malaria using existing intervention tools and strategies including Azerbaijan and Tajikistan, that were recently declared malaria free on 29th March 2023 [2].
In 2021, India accounted for 79% of malaria cases and 83% of all malaria deaths in the WHO South-East Asia Region and is the only country outside Africa among the world’s 11 “high burden to high impact” (HBHI) countries. Over 90% of India’s malaria cases were concentrated in 24 districts in 8 states that have significant tribal population. While these tribal districts contribute only 8.6% of India’s population, they account for 50% of India’s malaria cases and 30% of all malaria-related deaths. States of Madhya Pradesh, Chhattisgarh, Jharkhand and West Bengal are under HBHI. Besides these, states of Odisha, Uttar Pradesh and some North-Eastern states need special attention [3].
In terms of the malarial parasite variants in India, the situation is very complex with 10 vector mosquito species in different geo-ecological settings, and two predominant human malaria parasites Plasmodium vivax and P. falciparum with much localized other parasites P. malariae and two genetically divergent sub-species P. ovale curtisi and P. ovale wallikeri of P. ovale cases in tribal areas. In rural settings, two-third of the cases are transmitted by Anopheles culicifacies; while An. stephensi is present in all urban areas.
India has a great history of malaria control efforts. The highest incidence of malaria was recorded in the 1950s, with an estimated 75 million cases with 0.8 million deaths per year. Till 1950, malaria control primarily relied on vector sanitation under larval source management (LSM). With the unprecedented historical success of dichlorodiphenyltrichloroethane (DDT) trials, National Malaria Control Programme was launched in 1953 followed by the National Malaria Eradication Programme in 1958, which together made it possible to bring down malaria cases to 100,000 with no reported deaths by 1965-66, when the population was 360 million. Unfortunately, from nearing a stage of elimination, malaria resurged to approximately 6.4 million cases in 1976. This was mainly due to cessation of surveillance and discontinuation of all malaria-related activities. It was this critical turn that necessitated the establishment of NIMR, the National Institute of Malaria Research (formerly Malaria Research Centre) under the Indian Council of Medical Research in July 1977 to address the research support for national malaria control programme. Several research initiatives were initiated. Bioenvironmental control of malaria was one such long-term project that contributed significantly to malaria elimination in India. Introduction of insecticide treated nets and reintroduction of LSM aiming long-term, sustainable vector control involving community paid huge dividends.
Today, malaria continues to take a huge toll on India. Towards malaria elimination, India has launched the National Framework for Malaria Elimination (NFME) 2016-2030 aiming for elimination by 2030. However, as we march towards this goal, there are several grey areas that need to be looked at and addressed.
Entomologists/Medical Entomologists/Public Health Entomologists play important roles in managing vector control operations. Unfortunately, this area has remained grey for over three decades. In fact, in the post-malaria eradication period most Entomologists were also eliminated resulting in a serious resurgence and re-emergence of many vector-borne diseases in India. Even today many posts are still vacant or being recruited on contractual basis, and even these employees are on payrolls without any career promotion avenues. Recently, ICMR has initiated efforts to look into this and this need will have to be overcome if India is to contain vector-borne diseases like malaria.
The current approach of mass blood screening with Rapid Diagnostic Tests (RDTs) fails to detect sub-microscopic/asymptomatic malaria cases (<100 parasites/µL blood), as well as lack the ability to diagnose genes like HRP2/3 often associated with Plasmodium falciparum dominated areas. To overcome this, a micro PCR-based point-of-care device that detects <5 parasites/µL blood should be used [4] [5]. The same technology is being used for Tuberculosis and COVID-19 diagnosis. Development of sensitive and non-invasive diagnostics is the need of the hour in malaria.
Molecular Malaria Surveillance (MMS) methods hold the potential to quickly find out the prevalence of drug-resistant parasites and insecticide-resistant vector mosquitoes in specific areas. For example, malaria outbreak in Laos in 2020-2021 was driven by a selective sweep by P. falciparum kelch13 (k13) R539T mutant for resistance in artemisinin drug [6]. MMS can help in situations like these. MMS can also help in genetic-relatedness studies to find out the imported or indigenous malaria cases, which is an important requirement to guide malaria elimination efforts. Moreover, MMS will help in testing gametocyte carriage rate and finding cases of low level of P. falciparum gametocytes, which are responsible for residual transmission in endemic settings.
Strong surveillance is a key pillar for malaria elimination. In India, we have indigenously developed GIS-tagged smart digital surveillance that is currently being used successfully in Mangalore for over six years, and has resulted in a drastic reduction of malaria cases [7]. Such methods must be deployed in other areas that are struggling for malaria surveillance. NCVBDC has also launched web-based Malaria Monitoring Information System (MMIS) in 2018. Two states — Himachal Pradesh and Odisha — have been selected for piloting this scheme. In fact, through this the results of each malaria case reported can be registered in a central dashboard at the NCVBDC, as it was done for COVID-19 cases by the Indian Council of Medical Research.
Innovations that could cut down malaria transmission such as Attractive Toxic Sugar Baits (ATSB), use of ivermectin, new biotraps [8] can prevent of many diseases like malaria, dengue, chikungunya and zika. Recent most powerful tool of gene editing in vector management may find a way to effectively control malaria. This method has been useful especially for invasive species such as Anopheles stephensi in Africa [9].
Currently drone-based vector surveillance and intervention is underway. Recent reports from Rwanda have found drones to be very effective in malaria control [10]. Similar methods of vector control could find their way in India especially in remote areas where manual operation is not possible.
Today, India stands on a very critical stage on the doorstep of malaria elimination. It is good that till now the parasites and vectors are amenable to drugs and insecticides, respectively. But certain decisions have to be taken to tackle P. vivax malaria. Compared to P. falciparum, it is a complex human malaria parasite due to its relapse-causing hypnozoites in the liver. Primaquine is used for P. vivax to kill the hypnozoites. However, this drug is not recommended for infants and pregnant women as well as G6PD-deficient cases. Several policy questions remain on the usage and dosage of Primaquine as well as the use of another anti-relapse drug Tefenoquine.
Another grey area that remains is the use and replacement of old long-lasting insecticidal nets. It is suggested that this exercise may be executed engaging the community and the old nets be recycled to avoid serious environmental pollution.
About the Author:
Susanta Kumar Ghosh: Formerly, ICMR-National Institute of Malaria Research, Bangalore; Adjunct Faculty, Manipal Academy of Higher Education, Manipal, Karnataka; Member, Scientific Programme Committee, American Society of Tropical Medicine and Hygiene, USA; Member, RBM Vector Control Working Group (VCWG) Task Team on Anopheles stephensi in Africa; Member, RBM VCWG on Human Behavior/Human-Centered Design Taskforce; Member, Executive Council, Society for Community Health Awareness, Research and Action (SOCHARA), Bangalore; Advisor, Absolute Human Care Foundation, New Delhi
The author has published three related articles 1. Malaria elimination in India – the way forward [11], 2. New ways to tackle malaria [12] and 3. New Challenges in Malaria Elimination [13].
Disclaimer: The opinion expressed in this article by the author is of his own.
Acknowledgement: The author would like to thank all malaria warriors, the Director General(s), Indian Council of Medical Research, New Delhi, The Director(s), ICMR-National Institute of Malaria Research, the staff and the malaria community.
Publication Date: 4th May 2023
India Health Fund is registered as Confluence for Health Action and Transformation Foundation (CHATF), a Section 8
charitable company incorporated in India, supported by the Tata Trusts.
