Leishmaniasis

            Leishmaniasis is a disease caused by parasitic protozoa in the genus Leishmania. There are three main forms of the disease: cutaneous, mucocutaneous, and visceral.  In the Amazon region, the most common species is Leishmania braziliensis (Bezmer et al., 2023). The disease is transmitted by sandflies of the genus Lutzomyia (Valdivia et al., 2021), with Lutzomyia wellcomei being one of the primary vectors of L. braziliensis in forested environments (Gramiccia & Gradoni, 2005).

Leishmania braziliensis causes cutaneous leishmaniasis, which is the most common form of the disease worldwide (Magill et al., 2012; WHO, 2023). This form produces skin ulcers or lesions, especially on exposed areas, which can lead to significant scarring (CDC, 2025).

In some cases, species within the Leishmania (Viannia) subgenus—including L. braziliensis—can cause mucocutaneous leishmaniasis. This more severe form results in lesions of the nose, mouth, and throat, which can be deeply disfiguring if left untreated (CDC, 2025).

Leishmania infantum is responsible for visceral leishmaniasis, the most severe form of the disease (Soares et al., 2024). This form attacks the liver, spleen, and bone marrow, leading to symptoms like fever, anemia, and weight loss. Without treatment, visceral leishmaniasis is 95% fatal (WHO, 2023).

Deforestation in the Amazon has been linked to increased incidence of leishmaniasis, particularly the urbanization-driven spread of visceral leishmaniasis (Dos Santos et al., 2021). As human activity disrupts forest ecosystems, it brings people into closer contact with infected sandflies and animal reservoirs.  Several treatments are available, with one of the most widely used being miltefosine, an oral medication effective against multiple forms of leishmaniasis (CDC, 2024).

References:

Bezmer, Jacob M. Freire-Paspuel Byron P. Schallig, Henk D F H. De Vries, Henry J C. Calvopina, Manuel. (June 12, 2023) Leishmania species and clinical characteristics of Pacific and Amazon cutaneous leishmaniasis in Ecuador and determinants of health-seeking delay: a cross-sectional study PubMed

https://pubmed.ncbi.nlm.nih.gov/37308815/#:~:text=braziliensis%20are%20the%20most%20common,eight%20CL-causing%20Leishmania%20species.

Valdivia, Hugo O. Zorrilla, Victor O. Espada, Liz J. Perez, Jocelyn G. Razuri, Hugo R. Vera, Hugo. Fernandez, Roberto, Tong, Carlos. Ghersi, Bruno M. Vasquez, Gissella M. Burrus, Roxanne G. Lescano, Andres G. Montgomery, Joel M. (February 10, 2021) Diversity, distribution and natural Leishmania infection of sand flies from communities along the Interoceanic Highway in the Southeastern Peruvian Amazon PLOS Neglected Tropical Diseases

https://pmc.ncbi.nlm.nih.gov/articles/PMC7875382/

Gramiccia, Marina. Gradoni, Luigi. (October 2005) The current status of zoonotic leishmaniases and approaches to disease control International Journal for Parasitology Volume 35 Issues 11-12 Pages 1169-1180

https://www.sciencedirect.com/science/article/abs/pii/S0020751905002420

Magill, Alan J. Hill, David R. Ryan, Edward T. (2012) Hunter’s Tropical Medicine and Emerging Infectious Disease Ninth Edition Elsevier

(January 12, 2023) Leishmaniasis World Health Organization

https://www.who.int/news-room/fact-sheets/detail/leishmaniasis#:~:text=Cutaneous%20leishmaniasis%20(CL)%20is%20the,Middle%20East%20and%20central%20Asia.

(April 23, 2025) Leishmaniasis Center for Disease Control and Prevention

https://www.cdc.gov/yellow-book/hcp/travel-associated-infections-diseases/leishmaniasis.html

Soares, Rodrigo Pedro. Fontes, Igor Campos. Dutra-Rego, Felipe. Rugani, Jeronimo Nunes. Moreira, Paulo Otavio L. Da Matta, Vania Lucia Ribeiro. Flores, Gabriela Venicia Araujo. Pacheco, Maria Sandoval. De Andrade, Andrey Jose. Da Costa-Ribeiro, Magda Clara Vieira. Shaw, Jeffrey Jon. Laurenti, Marcia Dalastra (August 9, 2024) Unveiling the Enigmatic nature of six neglected Amazonian Leishmania (Viannia) species using the hamster model: Virulence, Histopathology and prospection of LRV1 PLOS Neglected Tropical Diseases

https://pmc.ncbi.nlm.nih.gov/articles/PMC11315283/

Dos Santos, Cleber Vinicius Brito. Seva, Anaia de Paixao. Werneck, Guilherme Loureiro. Struchiner, Claudio Jose (August 25, 2021) Does deforestation drive visceral leishmaniasis transmission? A causal analysis Proceedings of the Royal Society Biological Sciences

https://royalsocietypublishing.org/doi/full/10.1098/rspb.2021.1537  

(March 13, 2024) Clinical Care of Leishmaniasis Center for Disease Control and Prevention

https://www.cdc.gov/leishmaniasis/hcp/clinical-care/index.html