Disease overview

Parasitic

Kala-azar

黑热病

Evidence-backed informationEN 6/7 applicable sections · ZH 6/7 applicable sectionsUpdated Sep 3, 2026

Kala-azar, or visceral leishmaniasis, is the most severe form of leishmaniasis and is caused by protozoan parasites of the genus Leishmania ^[1]^[2]. Transmission occurs through the bite of infected sand flies, and the parasites can involve internal organs such as the liver, spleen, and bone marrow ^[1]^[2]. The disease causes substantial worldwide mortality and is described as the second-largest parasitic killer after malaria ^[1]. There are no available vaccines or preventive drugs, and prevention centers on protecting people from sand fly bites ^[1].

Read the full clinical and epidemiological profile7

Definition

Visceral leishmaniasis (VL), also known as kala-azar or black fever, is the most severe form of leishmaniasis, a protozoan disease caused by parasites of the genus Leishmania ^[1]^[2]. It is transmitted by infected sand flies and is characterized by spread through the reticuloendothelial system and internal organs, including the liver, spleen, and bone marrow ^[1]^[2]. VL is described as a worldwide zoonotic infection, with dogs identified as main hosts in some epidemiologic contexts ^[3].

Clinical features

Typical manifestations include fever, fatigue, weight loss, anemia, and enlargement of the spleen and liver ^[1]. Hepatosplenomegaly and pancytopenia are also described among the main clinical features ^[3]. Clinical severity and presentation can vary with the infecting Leishmania species and host immune response, and immunosuppressed patients may have atypical or severe courses ^[2]^[3]. Without proper diagnosis and treatment, visceral leishmaniasis is associated with very high fatality, and symptoms can be mistaken for malaria ^[1].

Epidemiology

Visceral leishmaniasis is distributed worldwide and is described as a zoonotic infection transmitted by sandflies, with dogs as main hosts in the cited epidemiologic context ^[3]. It has been characterized as the second-largest parasitic killer after malaria, with an estimated 20,000 to 30,000 deaths annually worldwide ^[1]. In low-prevalence countries such as Germany, prevalence is low and affected persons are predominantly migrants and travelers returning from Mediterranean countries ^[3].

Transmission

Transmission occurs through the bite of a sand fly infected with Leishmania parasites ^[2]. In visceral leishmaniasis, infection can spread throughout the reticuloendothelial system ^[2].

Risk groups

Risk is related to exposure to sand fly bites, particularly outdoor activity from dusk to dawn, being in unprotected quarters, and having uncovered skin ^[1]. Persons in areas where leishmaniasis is endemic are relevant for serologic testing ^[1].

Prevention

As of 2018, there are no available vaccines or preventive drugs for visceral leishmaniasis, although vaccines are in development ^[1]^[4]. The most effective method to prevent infection is to protect from sand fly bites ^[1]. Suggested measures include avoiding outdoor activities from dusk to dawn when sand flies are generally most active, minimizing exposed skin by wearing long-sleeved shirts, long pants, and socks, and applying insect repellent to exposed skin ^[1]. Protective immunity can develop after successful treatment or asymptomatic infection that resolves without disease, involving cell-mediated immune responses ^[1].

References

1Wikipedia contributors. Visceral leishmaniasis - Wikipedia [Internet]. Wikipedia. cited 2 Sept 2026.Available from: https://en.wikipedia.org/wiki/Visceral_leishmaniasis
2Grevelink SA et al. Leishmaniasis. J Am Acad Dermatol. 1996 Feb. PMID: 8642091. doi: 10.1016/s0190-9622(96)80121-6.PubMed: https://pubmed.ncbi.nlm.nih.gov/8642091/
3Wilhelm TJ et al. [Visceral leishmaniasis]. Chirurg. 2019 Oct. PMID: 31297548. doi: 10.1007/s00104-019-0994-1.PubMed: https://pubmed.ncbi.nlm.nih.gov/31297548/
4Mann S et al. A Review of Leishmaniasis: Current Knowledge and Future Directions. Curr Trop Med Rep. 2021. PMID: 33747716. doi: 10.1007/s40475-021-00232-7.PubMed: https://pubmed.ncbi.nlm.nih.gov/33747716/

Coding Register

ICD-10: B55
ICD-11: 1F51

Key Statistics

Total cases: 159K
Total deaths: 12
Peak month: 2014-01
Coverage: 2 reporting countries · 2000-01-01 → 2026-07-01

Coverage

Reporting countries and regions

2 locations

Trends by reporting country

Monthly patterns over time

Research Radar

Recent related research

View all research →

Peer reviewedOpen accessKala-azarTreatment

DOI 10.1371/journal.pntd.0014666 ↗

From visceral to visible: A systematic review and meta-analysis of post-kala-azar dermal leishmaniasis incidence, risk factors, and treatment outcomes in Eastern Africa

Eyob Girma Abera, Surafel Worku Megersa, Kedir Negesso Tukeni +1 more

PLOS Neglected Tropical DiseasesAug 18, 2026

Open article ↗Kala-azar surveillance →

Peer reviewedOpen accessLeishmaniasisTreatment

DOI 10.1371/journal.pntd.0013952 ↗

Risk factors for post-kala-azar dermal leishmaniasis (PKDL): Challenges in understanding pathophysiology

Eduard E. Zijlstra

PLOS Neglected Tropical DiseasesFeb 23, 2026

Open article ↗Leishmaniasis surveillance →

Peer reviewedOpen accessLeishmaniasisOutbreak investigation

DOI 10.1186/s12879-019-4719-3 ↗

Intensely clustered outbreak of visceral leishmaniasis (kala-azar) in a setting of seasonal migration in a village of Bihar, India

Arvind Kumar, Suman Saurabh, Sarosh Jamil +1 more

BMC Infectious DiseasesJan 6, 2020

Open article ↗Leishmaniasis surveillance →

Literature links are provided for discovery and do not alter or validate the surveillance series above.

Rows1,062

Updated2026-09-01

Coverage—

Partitions6

Source2 series · 317 observations

Official sourcesAuthority, cadence, notes42

monthlyftp_dbc

Brazil Ministry of Health DATASUS/SINAN public DBC microdata aggregated to national monthly notification counts.

MONTHLYweb

Monthly notifiable infectious disease reports published by China CDC.

MONTHLYweb

Official China public health bulletin and query portal.

MONTHLYweb

Biomedical literature discovery feed used as supplementary context.