WHAT IS LEISHMANIASIS?

Leishmaniasis is a parasitic disease that is found in parts of the tropics, subtropics, and southern Europe. It is classified as a neglected tropical disease (NTD).

IMPACT

According to drug for neglected disease initiative 50,000-90,000 new cases of visceral leishmaniasis occur annually and 600,000-1,200,000 new cases of cutaneous leishmaniasis also occurs annually respectively, while About 20,000-30,000 deaths due to visceral leishmaniasis occur annually and 1 billion people are at risk of leishmaniasis.

Leishmaniasis affects some of the poorest people on earth, and is associated with malnutrition, populace displacement, poor and bad housing, a vulnerable immune system, lack and shortage of financial resources. Leishmaniasis is linked to environmental adjustment such as deforestation, building of dams, irrigation schemes, and urbanization.

WHAT ARE THE DIFFERENT TYPES OF LEISHMANIASIS?

The disease is caused by different species of Leishmania, and it is manifested by three major clinical forms namely cutaneous, muco-cutaneous and visceral leishmaniasis and the most common forms are cutaneous leishmaniasis, which causes skin sores, and visceral leishmaniasis, which affects several internal organs (usually spleen, liver, and bone marrow).

1. Cutaneous leishmaniasis

This causes ulcers on the skin and is the most common form of leishmaniasis.

2. Mucocutaneous leishmaniasis

Mucocutaneous leishmaniasis is a rare form of the disease and is normally considered a subset of cutaneous leishmaniasis, it is more serious. It does not heal on its own and always requires treatment. With this type of leishmaniasis, the parasites spread to the nose, throat, and mouth and this can lead to partial or complete destruction of the mucous membranes in those areas.

3. Visceral leishmaniasis

Visceral leishmaniasis is sometimes known as kala azar. It typically occurs two to eight months after being bitten by a sand fly. It damages inner or internal organs, including the spleen and liver. It also affects the bone marrow, as well as the immune system through damage to these organs. Visceral leishmaniasis is almost always fatal if it’s not treated.

HOW IS LEISHMANIASIS TRANSMITTED?

Leishmaniasis is caused by the protozoan Leishmania parasites which are transmitted by the bite of infected female phlebotomine sandflies.

WHAT ARE THE SYMPTOMS OF LEISHMANIASIS?

People can carry some species of Leishmania for long duration without becoming sick or ill.  Signs and Symptoms depend on the form of the disease.

1. Cutaneous leishmaniasis

The most important symptom of this condition is painless skin ulcers. This sign and symptoms may seem to appear a few weeks after being bitten by an infected sand fly. However, sometimes symptoms will not appear for months or years.

2. Mucocutaneous leishmaniasis

In humans with the mucocutaneous leishmaniasis form of the disease, signs and symptoms typically appear one to five years after the skin lesions. These are often ulcers on the mouth and nose or on their lips.

Other signs and symptoms may include:

runny  nose

nosebleeds

problem in breathing

3. Visceral leishmaniasis

Symptoms often do not appear for months after the bite with this type of leishmaniasis. Most cases are apparent two to six months after the infection occurred. Common signs and symptoms include:

weight loss

weakness

fever that lasts for weeks or months

enlarged spleen

enlarged liver

decreased manufacturing of blood cells

bleeding

swollen lymph nodes

DIAGNOSIS AND TREATMENT OF LEISHMANIASIS

In visceral leishmaniasis, diagnosis is made by combining clinical symptoms with parasitological, or serological checks which include rapid diagnostic test.

In cutaneous and mucocutaneous leishmaniasis serological assessment has limited value and clinical manifestation with parasitological tests confirms the diagnosis.

The treatment of leishmaniasis depends on several elements including type of disease, concomitant pathologies, parasite species and geographic region. It is a treatable and curable disease, which requires an immuno-competent system because medicines will not get rid of the parasite from the body, thus the risk of relapse if immuno-suppressant occurs. All patients identified and diagnosed as with visceral leishmaniasis require prompt and complete treatment. Detailed records on treatment of the numerous type of the disease by way of  geographic location is available in the World Health Organization (WHO) technical report series 949, “Control of leishmaniasis“.

PREVENTION AND CONTROL

Prevention and control of leishmaniasis calls for a combination of intervention strategies because transmission takes place in a complex or complicated biological system regarding the human or animal reservoir host, parasite and sand fly vector. Key strategies for prevention are indexed below:

1. Early diagnosis and effective prompt treatment

 Reduces the prevalence of the disease and prevents disabilities and death. It enables to lessen transmission and to monitor the spread and burden of disease. Presently there are highly effective and safe anti-leishmania medicines particularly for visceral leishmaniasis, although they can be hard to use. Access to medicines has appreciably improved thanks to a World Health Organization (WHO) negotiated price scheme and a medicine donation program through World Health Organization (WHO).

2. Vector control

 Helps to lessen or interrupt transmission of disease by means of lowering the number of sand flies. Control techniques consists insecticide spray, use of insecticide treated nets, environmental management and personal protection.

3. Effective disease surveillance 

It is important to promptly screen and take action during epidemics and conditions with high case fatality rates under treatment.

4. Control of animal reservoir hosts is complex and should be tailored to the local situation.

5. Social mobilization and strengthening partnerships 

 Mobilization and education of the community with effective behavioural change interventions must always be locally adapted. Partnership and collaboration with various stakeholders and other vector-borne disease control program is critical.

Reviewed on 18/04/2020

REFERENCES
Leishmaniasis: A Review on Parasite, Vector and Reservoir Host Bereket Alemayehu1* and Mihiretu Alemayehu2

Cdc  https://www.cdc.gov/parasites/leishmaniasis/index.html

W.H.O https://www.who.int/news-room/fact-sheets/detail/leishmaniasis

Drug for neglected disease initiative https://www.dndi.org/diseases projects/leishmaniasis/

Hailu T, et al. (2016). Challenges in visceral leishmaniasis control and elimination in the developing countries: A review.nimr.org.in/assets/533193.pdf

Kala azar (leishmaniasis). (2015). doctorswithoutborders.org/our-work/medical issues/kala-azar-leishmaniasis

Leishmaniasis: Access to essential antileishmanial medicines and treatment.(n.d.). who.int/leishmaniasis/research/en/

Leishmaniasis FAQs. (2013) cdc.gov/parasites/leishmaniasis/gen_info/faqs.html

Linsoso JAL, et al. (2016). Leishmaniasis-HIV coinfection: Current challenges.
ncbi.nlm.nih.gov/pmc/articles/PMC5063600/

Parasites – leishmaniasis: Epidemiology and risk factors. (2013).
cdc.gov/parasites/leishmaniasis/epi.html

Parasites – leishmaniasis: Resources for health professionals. (2016).
cdc.gov/parasites/leishmaniasis/health_professionals/

World Health Organization (2017). Leishmaniasis [Fact sheet].
who.int/mediacentre/factsheets/fs375/en/.