Illustration of Leishmania parasite transmission by sandfly

Visceral Leishmaniasis: Understanding, Treating, and Preventing This Tropical Disease

Avery Sinclair in Health & Wellness August 2025 • 3 min read.

"Learn about visceral leishmaniasis (VL), a severe parasitic disease, including its causes, symptoms, treatments, and prevention strategies, and recent developments in research."

Visceral leishmaniasis (VL), also known as Kala-azar, is the most severe form of leishmaniasis, a parasitic disease transmitted through the bite of infected female sandflies. The disease primarily affects the internal organs, such as the spleen, liver, and bone marrow. If left untreated, VL is almost always fatal.

Visceral leishmaniasis is prevalent in certain tropical and subtropical regions, particularly in parts of Africa, Asia, and South America. According to the World Health Organization (WHO), an estimated 50,000 to 90,000 new cases occur globally each year. The disease disproportionately affects populations living in poverty, with limited access to healthcare and sanitation.

This article aims to provide a comprehensive overview of visceral leishmaniasis, covering its causes, symptoms, diagnosis, treatment, and prevention strategies. Understanding the complexities of VL is crucial for healthcare professionals, researchers, and individuals living in or traveling to affected regions.

Causes and Transmission

Illustration of Leishmania parasite transmission by sandfly

Visceral leishmaniasis is caused by protozoan parasites belonging to the Leishmania genus. The parasites are transmitted to humans through the bite of infected female phlebotomine sandflies. These tiny insects are typically most active during dusk and dawn. Several species of Leishmania parasites can cause VL, with Leishmania donovani and Leishmania infantum being the most common.

The transmission cycle involves the sandfly biting an infected animal reservoir, such as rodents, dogs, or other mammals, and ingesting the Leishmania parasites. The parasites then develop within the sandfly's gut before being transmitted to a human during a subsequent bite.

Common risk factors:

Living in or traveling to endemic regions.
Poverty and poor living conditions.
Malnutrition and weakened immune systems.
Co-infection with HIV.

Individuals with weakened immune systems, such as those with HIV or malnutrition, are at a higher risk of developing VL. Children are also particularly vulnerable. Understanding the transmission cycle and risk factors is essential for implementing effective prevention and control measures.

The Future of VL Research

Despite the challenges posed by visceral leishmaniasis, ongoing research efforts offer hope for improved diagnostics, treatments, and prevention strategies. Scientists are exploring novel drug targets, developing more effective vaccines, and implementing innovative vector control methods. With continued investment and collaboration, the global community can make significant progress in reducing the burden of this neglected tropical disease and improving the lives of millions.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

Everything You Need To Know

What is visceral leishmaniasis, and what makes it such a dangerous disease?

Visceral leishmaniasis, also known as Kala-azar, is the most severe form of leishmaniasis. It is caused by protozoan parasites belonging to the *Leishmania* genus and is transmitted through the bite of infected female phlebotomine sandflies. The parasites primarily affect internal organs such as the spleen, liver, and bone marrow. Without treatment, visceral leishmaniasis is almost always fatal. The disease's impact is particularly pronounced in poverty-stricken areas with limited access to healthcare and sanitation.

How exactly are the Leishmania parasites transmitted to humans, and what role do animals play in this process?

The *Leishmania* parasites, responsible for visceral leishmaniasis, are transmitted to humans through the bite of infected female phlebotomine sandflies. These sandflies acquire the parasite by biting infected animal reservoirs, such as rodents, dogs, or other mammals. The parasites then develop within the sandfly before being transmitted to a human during a subsequent bite. This cycle highlights the importance of vector control and understanding the role of animal reservoirs in managing the disease.

What are the main risk factors that make someone more susceptible to contracting visceral leishmaniasis?

Several factors increase the risk of contracting visceral leishmaniasis. These include living in or traveling to endemic regions, poverty and poor living conditions, malnutrition, weakened immune systems, and co-infection with HIV. Children are also particularly vulnerable. Individuals with weakened immune systems are at a higher risk of developing visceral leishmaniasis. Recognizing these risk factors is crucial for implementing effective prevention and control measures.

What kind of research is currently underway to combat visceral leishmaniasis, and what are the potential future advancements?

Current research efforts are focused on improving diagnostics, treatments, and prevention strategies for visceral leishmaniasis. Scientists are exploring novel drug targets, developing more effective vaccines, and implementing innovative vector control methods. This includes investigating the genetic makeup of *Leishmania donovani* and *Leishmania infantum* to identify vulnerabilities, as well as developing vaccines that target different stages of the parasite's life cycle. Furthermore, research is being conducted on improving early detection methods and point-of-care diagnostics suitable for resource-limited settings.

What are the current strategies for treatment and prevention of visceral leishmaniasis?

While specific treatment details aren't outlined, ongoing research offers hope for improved therapies and prevention of visceral leishmaniasis. The development of more effective vaccines is a significant area of focus, aiming to provide long-term protection. Innovative vector control methods are also crucial, targeting the sandflies that transmit the *Leishmania* parasites. Ideally, new treatments will also address issues of drug resistance and reduce treatment duration.