After four deadlines, India is now on the verge of eliminating black fever as a public health problem. Provisional government data show that within a decade, India has drastically reduced the disease’s prevalence, with the number of cases nationwide dropping to fewer than 500 in 2023, down from 9,200 in 2014.

Former Director General of the Indian Council of Medical Research (ICMR), Dr. Nirmal Kumar Ganguly, has hailed this achievement as a significant gain for the country. Dr. Kavita Singh, Director for South Asia at the Drugs for Neglected Diseases initiative (DNDi), expects this success to enhance focus on effective public health initiatives. She believes it would “potentially attract more support and resources for similar endeavors toward other vector-borne diseases.”

Historical Context and Persistent Efforts

Black fever or visceral leishmaniasis, locally known as Kala Azar, is a lethal vector-borne disease transmitted by infected female sandflies. It is the second deadliest parasitic disease after malaria, affecting 200 million people annually in 76 countries. This infection impacts the spleen, liver and bone marrow. Without treatment, 95% of cases can be fatal, leading to weight loss, fever and anemia.

The earliest recorded instances of black fever in India date back to 1824, when an outbreak in Jessore, now part of Bangladesh, resulted in approximately 750,000 deaths over three years. Since then, India has experienced periodic outbreaks of Kala Azar every 10 to 15 years, primarily in the states of Assam, Bihar, Jharkhand and West Bengal. These outbreaks typically lasted about 10 years.

Innovative Approaches

The introduction of the indoor residual spray (IRS) of dichlorodiphenyltrichloroethane (DDT) under the national malaria eradication program in 1950 dramatically curbed the spread of Kala Azar in India. The country launched its campaign against black fever in 1992. While pushing four consecutive deadlines in 2010, 2015, 2017 and 2020, India realigned its strategies with the World Health Organisation’s (WHO) guidelines. It adopted an evidence-based practice that showed promising results in eliminating black fever.

The evolution of single-dose infusion and uninterrupted availability of drugs at the ground level has radicalized India’s battle against black fever. In 2012, 90% of the diagnosed people completed their treatments compared to 55% between 2008 and 2009. Governments at the state and national levels have announced remunerations for the patients to compensate for wage loss.

National Strategies and Surveillance Enhancements

The National Center for Vector Borne Diseases Control (NCVBDC) intensified residual spraying in villages that reported cases in the past three years. Since sandflies typically breed in the crevices of mud walls, targeting these hotspots with indoor residual spray (IRS) has curbed the spread of the disease, protecting more than 35 million people at risk. Additionally, Indian authorities have promoted concrete residential structures through the subsidized housing program, Pradhan Mantri Awas Yojana (Rural), reducing mud walls and eliminating potential breeding grounds.

In 2014, NCVBDC introduced a national database on drugs, diagnostics and vector surveillance for black fever. The database portal’s mobile application helped Accredited Social Health Activists (ASHA) detect cases and administer prescribed dosages. Since the black fever eradication program started in 1992, the number of cases has dropped by 97%, from 77,102 to 2,048 in 2020.

Looking Forward

India needs to maintain its efforts for the next three years to receive official validation from the WHO. Additionally, it is essential to eradicate post-kala azar dermal leishmaniasis (PKDL), the skin condition that occurs after black fever infection and serves as a reservoir for the parasite, to prevent the disease’s recurrence. Moreover, as of October 2023, India has reported 286 cases of PKDL.

– Soham Mitra

Soham is based in London, UK and focuses on Global Health for The Borgen Project.

Photo: Flickr