India’s fight against malaria is well-known, with the country showing remarkable progress in curbing the disease. From the World Health Organisation to Asia Pacific Leaders Malaria Alliance, the global health monitors have acknowledged that the burden of this killer disease is severe, even as nine more countries have been certified malaria-free since 2012.
Despite a concerted global effort to eliminate malaria, India accounted for a staggering 83% of the estimated 241 million malaria cases and 82% of the 6.27 lakh malaria-related deaths in the Southeast Asia region, as per the World Malaria Report, 2021.
However, India also continued to report a decline in malaria morbidity and mortality, reporting 4.2 million estimated malaria cases and 7,341 estimated malaria deaths even though the rate of reduction decreased compared with that in the pre-pandemic years.
What generates a glimmer of hope is that India is the exception among high burden to high impact (HBHI) countries as it did not report an increase in cases and deaths in spite of the pandemic. Reaching the malaria elimination target for India requires identification and addressing every single case of the disease.
Several gaps exist that lead to discrepancies in reporting, the burden of hidden malaria being of major concern. Malaria manifests itself in several forms and often goes undetected due to misattribution, thereby remaining unreported and maintaining the gap between estimation and true measurement of the disease burden.
Further, in pregnant women, from anaemia to postpartum haemorrhage, cases of deaths are not recorded as malaria deaths due to a lack of systematic investigation establishing their attribution to the disease, which is again due to the absence of the cardinal symptoms of malaria.
Additionally, the lack of attention towards asymptomatic malaria adds to the challenges of addressing the hidden malaria burden. There are several reports identifying the burden of sub-microscopic and asymptomatic malaria in different regions of the country. Previously, it was believed that only areas of high endemicity are at risk of subclinical infection, but more recent studies from other malaria endemic regions (e.g., countries in Africa) have observed that communities living in low-transmission areas are also at the risk of asymptomatic malaria.
This can be further substantiated by another study, where it has been shown that a proportionally high burden of asymptomatic and sub-microscopic infections is prevalent in each of the high, medium, and low transmission settings. This was evident both from the community survey and from the study conducted by investigators at clinics.
There is a need to acknowledge the fact that there are communities where there are generations living with the parasite in their systems that impact their vitals, causing health issues such as stunting and anaemia. Since in these cases malaria is not manifested through fever, people living with asymptomatic malaria do not seek malaria testing, thus leading to the gap in malaria case identification that is crucial to achieving the disease elimination goal of India.
Most high endemic areas witness many cases of asymptomatic malaria that often go unreported in the process of regular surveillance as they do not qualify for a malaria test due to lack of symptoms, as per the guideline. Such areas require mass screening to address elimination. While mass screening is resource-intensive and requires protocols to be followed, it is important to adopt the process to address the problem.
For many communities living on the fringes of society, especially in malaria-endemic areas, mass screening of the disease is not happening at the scale required for India to achieve its 2030 target.
States such as Odisha that have undertaken such screening have seen success in the identification and treatment of such cases. There is a critical need that similar screening programmes be adopted across states to identify pockets of asymptomatic malaria and address the issues of underreporting.
As per a study conducted by the New York University in Sundergarh district of Odisha, a total of 30.6% of the infections (malaria-infected persons) were sub- microscopic and 40.6% were asymptomatic. Numerous studies have tried to characterise asymptomatic infections, unanimously revealing that host immunity is the underlying factor in the maintenance of these infections, which in turn act as precursors to malaria illness.
According to a study conducted by researchers from the National Institute of Malaria Research, Delhi, and Department of Infectious Disease Epidemiology of the London School of Hygiene and Tropical Medicine, a large proportion of asymptomatic cases in the community, including children, can be attributed to their immunity status, as per the study report.
Asymptomatic malaria cases that are not captured under routine fever surveillance can develop later into clinical malaria with severe symptoms.
Despite the small sample size, the study clearly highlights that the underlying challenge facing the national malaria control programme in its efforts towards malaria elimination is the burden of asymptomatic malaria.
As these symptom-less infections do not motivate an active search for treatment, they remain invisible to the system. The concern is that they remain potentially transmissible to mosquitoes and thus maintain the transmission. Therefore, addressing hidden malaria is the key to addressing malaria elimination in the country.
To address the issues arising from the hidden burden of malaria, the government must take active steps. With help from experts, the government can enhance the use of technology and big data in healthcare to explore the best methods to identify and redress the burden of asymptomatic malaria.
The National Strategic Plan for Malaria Elimination (2022-27) must come out with strategies for strengthening the system, reinforcing ASHA interventions in diagnosis and treatment of malaria at community level, provisioning of advanced diagnostic tools & RDTs to identify and address the hidden malaria pockets, improving the technical strength of the district malaria teams and newer interventions.
The government needs to show the same urgency in combating malaria as it displayed against Covid. The time has come for the government to acknowledge the hidden burden of malaria and create a framework that reaches the hinterlands and makes a profound impact at the
grassroots.
(The writer is Dean and Head, Central University of South Bihar)