Visceral leishmaniasis (Kala-azar)- Causes, Lab diagnosis, Treatments


Visceral leishmaniasis (VL), also known as kala-azar, is a serious and potentially fatal disease caused by a group of protozoan parasites belonging to the genus Leishmania. These parasites are transmitted to humans by the bite of infected female phlebotomine sandflies, which are small blood-sucking insects that are active at night. VL is the most severe form of leishmaniasis, affecting the internal organs such as the spleen, liver, and bone marrow. It is characterized by irregular bouts of fever, weight loss, enlargement of the spleen and liver, and anemia. If left untreated, VL can be fatal in over 95% of cases.

VL is a neglected tropical disease that affects some of the poorest and most vulnerable populations in the world. It is associated with malnutrition, population displacement, poor housing, a weak immune system, and a lack of financial resources. An estimated 700 000 to 1 million new cases occur annually worldwide, with only a small fraction reported to the World Health Organization (WHO). Most cases occur in Brazil, east Africa, and India, where VL is endemic. VL can also occur in other regions, such as the Mediterranean basin, the Middle East, and Central Asia. VL has outbreak and mortality potential, especially in areas where HIV co-infection is prevalent.

VL can be diagnosed by various methods, such as microscopy, culture, animal inoculation, antigen detection, antibody detection, and molecular techniques. The diagnosis depends on the availability of laboratory facilities, the sensitivity and specificity of the tests, and the clinical presentation of the patient. The treatment of VL depends on the infecting Leishmania species, the geographical location, the drug availability and cost, and the patient`s condition. The standard treatment consists of pentavalent antimonial compounds, which are effective in most regions except in Bihar (India), where resistance has emerged. Other drugs include amphotericin B, liposomal amphotericin B, paromomycin, and miltefosine.

The prevention and control of VL require a combination of strategies, such as vector control, case detection and treatment, surveillance and monitoring, health education, and research. The WHO has set a target to eliminate VL as a public health problem in selected countries by 2020. This means reducing the annual incidence to less than 1 case per 10 000 people at the district level. To achieve this goal, WHO supports national programs and partners to implement effective interventions and strengthen health systems.

VL is a serious but preventable and treatable disease that affects millions of people worldwide. It is important to raise awareness about its causes, symptoms, diagnosis, and treatment among health workers and the general public. It is also essential to improve access to quality health care and diagnostic services for those who need them. Together, we can fight against this neglected tropical disease and save lives.