Kala-azar (leishmaniases)

•    Leishmaniases come in three primary types: cutaneous, visceral, and mucocutaneous. Visceral leishmaniasis is the most dangerous type because it almost results in death without treatment (affecting mouth, nose and throat).

 

•    The protozoan parasites that cause leishmaniasis are spread by the bite of infected female phlebotomine sandflies.

 

•    The illness is linked to starvation, population displacement, substandard housing, a weakened immune system, and a lack of financial means, it affects some of the poorest people in the world.

 

•    Each year, between 700 000 and 1 million new instances are thought to arise.

 

•    Only a small percentage of those infected with the parasites that cause leishmaniasis may eventually get unwell.

 

A protozoa infection from more than 20 different Leishmania species causes leishmaniasis. There are over 90 sand-fly species that can spread the parasite Leishmania. The disease comes in three primary forms:

 

Over 95% of cases of visceral leishmaniasis (VL), often known as kala-azar, are fatal if untreated. It is distinguished by irregular fever attacks, weight loss, spleen and liver enlargement, and anemia. Brazil, east Africa, and India account for the majority of instances. Only 25–45% of the estimated 50,000 to 90,000 new cases of VL that are reported to WHO each year are actually seen worldwide. There is a chance of outbreak and fatality.

 

The most prevalent type of leishmaniasis, known as cutaneous leishmaniasis (CL), results in skin lesions, primarily ulcers, on exposed body parts. These may cause severe impairment or stigma and leave lifelong scars. The Americas, the Mediterranean basin, the Middle East, and central Asia account for about 95% of all CL cases. A total of 600 000 to 1 million new cases are thought to arise annually over the world, although only about 200 000 are reported to WHO.

 

The mucous membranes of the nose, mouth, and throat can be completely or partially destroyed as a result of mucocutaneous leishmaniasis. Brazil, Ethiopia, Peru, Bolivia, and Brazil account for more than 90% of cases of mucocutaneous leishmaniasis.

 

Phlebotomine sandflies, which feed on blood to create eggs, bites of infected females carry the leishmania parasite. Humans are one of the approximately 70 animal species that can produce leishmania parasites.

 

•    Algeria has a high prevalence of cutaneous leishmaniasis, although there is little epidemiological data on the disease in West Africa. Visceral leishmaniasis epidemics are common in east Africa, where all kinds are endemic.

 

•    The most common form of leishmaniasis is cutaneous, and it has a complicated epidemiology due to the fact that multiple animals are the parasite's primary hosts as well as numerous sand-fly species and Leishmania species are in the same region. The main VL-endemic nation in the area is Brazil.

 

•    80% of the cutaneous leishmaniasis cases reported globally originate from this area. Iraq, Somalia, Sudan, and Yemen all have significant levels of visceral leishmaniasis endemicity.

 

•    Both visceral and cutaneous leishmaniasis are common. The majority of imported cases originate from Africa and the Americas.

 

•    The primary type of the illness, which is also endemic for cutaneous leishmaniasis, is visceral leishmaniasis.

 

Following visceral leishmaniasis, post-kala-azar dermal leishmaniasis (PKDL) typically manifests as a macular, papular, or nodular rash on the face, upper arms, and trunk. It occurs in east Africa, primarily in Sudan, and in the Indian subcontinent, where it is documented in 5–10% of kala-azar patients. Although rare, it has also been documented from Brazil and in L. infantum-caused VL patients with HIV coinfection. Though it can happen earlier, it typically manifests 6 months to 1 or more years after kala-azar has supposedly been treated. A potential source of Leishmania infection is someone who has PKDL.

 

Leishmaniasis infection and HIV co-infection increase the risk of developing the full-blown disease, as well as the likelihood of relapse and fatality. Treatment with antiretrovirals shortens the duration of the disease, prevents relapses, and improves survival. Leishmania-HIV coinfection has been documented from 45 different countries as of 2021. There have been reports of high coinfection rates in Brazil, Ethiopia, and the state of Bihar (India). WHO updated their treatment guidelines for people with Leishmania-HIV coinfection in east Africa and South-East Asia in 2022.

 

•    The risk of leishmaniasis rises with economic hardship. Lack of waste management or open sewers can increase sandfly breeding and resting sites, as well as their access to humans, in unsanitary dwellings and domestic settings. Because it is simpler to bite humans and consume their blood when living in crowded dwellings, sandflies are drawn to it. Risk may increase as a result of human behavior, such as sleeping outside or on the ground.

 

•    Malnutrition Diets deficient in protein, energy, iron, vitamin A, and zinc raise the possibility that an infection may develop into a serious illness.

 

•    Leishmaniasis epidemics frequently arise when a large population of infected individuals relocates to a region with a high rate of transmission.

 

•    Changes in urbanization, deforestation, or human incursion into forested areas may have an impact on leishmaniasis occurrence.

 

•    Changes in temperature and rainfall, which have an impact on the size and geographic dispersion of sandfly populations, are contributing to the spread of leishmaniasis. People move into locations where the parasite transmission is strong as a result of drought, starvation, and flooding, among other natural disasters.

 

•    People who think they may have visceral leishmaniasis should get immediate medical treatment. When diagnosing visceral leishmaniasis, parasitological or serological testing are combined with clinical symptoms (such as rapid diagnostic tests). Serological tests aren't very useful for diagnosing cutaneous and mucocutaneous leishmaniasis, clinical manifestation and parasitological testing are required.

 

•    Leishmaniasis treatment is influenced by a number of variables, such as the disease kind, coexisting diseases, parasite species, and geographic location. Leishmaniasis is a treatable and curable condition that needs an immune system that is functioning normally because medications will not completely eradicate the parasite from the body, increasing the chance of relapse if immunosuppression takes place. 

 

•    All patients with a diagnosis of visceral leishmaniasis need quick and thorough care. The WHO Technical Report Series 949, Control of Leishmaniasis, as well as the most recent treatment guidelines for leishmaniasis in the Americas and HIV-VL in east Africa and South-East Asia, contain comprehensive information on the procedure.

 

Leishmaniasis control and prevention is a difficult task requiring a variety of instruments. Important tactics include:

•    Early detection and fast, efficient treatment lower the disease's prevalence and prevent disability and death. As well as monitoring the prevalence and burden of disease, it aids in reducing transmission. Even though they can be challenging to use, there are anti-leishmanial medications that are both extremely effective and safe, especially for visceral leishmaniasis. Thanks to a WHO-negotiated price plan and a drug donation programme, access to medications has considerably improved.

 

•    By reducing the quantity of sandflies, vector management aids in slowing down or stopping the spread of disease. Spraying insecticide, using nets treated with insecticide, managing the environment, and using personal protection are all examples of control strategies.

 

•    To quickly monitor and take action during epidemics and circumstances with high case fatality rates while being treated, effective disease surveillance is essential.

 

•    Animal reservoir hosts are difficult to control and need to be handled locally.

 

•    Social mobilization and partnership building, community education and mobilization with successful behavioral change interventions must always be locally tailored. 

 

•    Collaboration and partnership with other vector-borne illness management programs and other stakeholders are essential.

 

Supporting national leishmaniasis control programs financially and technically to update recommendations, guarantee access to quality-assured medications, create disease control plans, surveillance systems, and epidemic preparedness and response systems, monitoring disease trends and evaluating the impact of control efforts through the web-based global surveillance system that will allow for advocating for the reduction of the global burden of leishmaniasis and promoting ethical behavior, and By the end of 2023, countries hope to receive WHO certification of elimination. The area unveiled a regional strategic framework for the South-East Asia region's 2022–2026 for accelerated and sustained elimination of kala-azar.