Kala-azar, also known as Visceral Leishmaniasis or Black Fever, is a deadly parasitic disease caused by the protozoa parasite Leishmania. This disease primarily affects people in Africa, Asia, and Latin America and if left untreated can result in death. Remarkably, between 2007 and 2022, India saw a substantial decrease of 98.7% in Kala-azar cases, dropping from 44,533 to just 834.
About the Disease
Kala-azar manifests in three forms: Visceral Leishmaniasis, which impacts multiple organs and is the most severe form of the disease; Cutaneous Leishmaniasis that results in skin sores; and, Mucocutaneous Leishmaniasis, which causes skin and mucosal lesions. The disease is principally transmitted to humans via the bite of an infected female phlebotomine sandfly.
Symptoms and Prevention
The most common symptoms are fever, weight loss, anemia, and enlargement of the liver and spleen. Preventative measures include reducing breeding sites for sandflies, protecting people from their bites using insecticides, bed nets, and repellents, and improving housing conditions and access to clean water and sanitation. The World Health Organization (WHO) also recommends Mass Drug Administration in areas where the disease is prevalent.
Treatment Methodology
The treatment strategy for Kala-azar involves the use of drugs such as sodium stibogluconate and meglumine antimoniate. The WHO advocates the usage of a combination of two or more drugs since monotherapy comes with a higher risk of treatment failure and drug resistance.
Global Perspective
According to WHO, Kala-azar is the second-deadliest parasitic disease globally, with 89% of cases reported from eight countries including India. India contributes about 11.5% of all global Kala-azar cases, with over 90% of these being from Bihar and Jharkhand. However, Uttar Pradesh and West Bengal have achieved their elimination targets at the block level.
Initiatives to Control Kala-azar
The WHO has outlined a new roadmap for 2021–2030 aimed at preventing, controlling, eliminating and eradicating 20 diseases termed neglected tropical diseases. The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was formed with a goal to eliminate lymphatic filariasis, onchocerciasis, and Kala-azar by Mass Drug Administration.
Elimination Efforts in India
The Indian government is actively working towards the goal of eliminating Kala-azar from India by 2023. This involves building concrete houses through the PM-AWAS yojana, rural electrification, testing, treatment, periodic high-level review, and award distribution. The government is also aiding states in active case detection, surveillance, treatment, and providing diagnostic kits, medicines, and sprays.
National Policy and Collaboration
As per the National Health Policy-2002, the aim was set to eliminate Kala-azar in India by 2010 which was later revised to 2015. To help realize this objective, a Tripartite Memorandum of Understanding was signed with Bangladesh and Nepal. Currently, all programmatic activities are being implemented through the National Vector Borne Disease Control Programme (NVBDCP), an umbrella programme operating under the National Health Mission.
Zika Virus and its Transmission
Like Kala-azar, other tropical diseases such as the Zika virus are also a major concern. The Zika virus is similar to dengue, in terms of symptoms and transmission as both are spread by Aedes aegypti and Aedes albopictus species of mosquitoes. In addition to mosquito bites, Zika can also be transmitted from mother to child during pregnancy, causing severe fetal brain defects, and through sexual contact with an infected partner, blood transfusion, and possibly through breast milk.