Instructions on how to make an Outbreak of American Cutaneous Leishmaniasis

Abstract

Outbreaks of American Cutaneous Leishmaniasis (ACL) are triggered by the confluence of multidimensional biological, climate, and social factors: the eco-epidemiological momentum. Despite the diversity of epidemiological scenarios, there are common "Ingredients for the recipe" to make an ACL outbreak. To describe the "Where", "When", and "Why" of this momentum could contribute to the understanding of the causes of epidemics, preventing their occurrence, and to define better strategies to control them. Typically, due to sylvatic-rural transmission, most urban ACL are still related in time and space to peripheral city deforestations, riparian forest, and green patches within the cities. Therefore, the "Where" of the ACL outbreaks could be characterized in the space as an edge effect, and afterwards the "When" of this edge could be categorized as an ephemeral, transient or permanent. The "Why" question is far more complex, as it includes the exposure of humans to vector due to anthropic activities in each edge scenario. The evidence for ACL outbreak control strategies: barricading the edge by chemical and physical barriers, environmental management, and individual prevention, were reviewed. Answers to questions regarding these "Where", "When", "Why", and "How to control" guided the content of the questions to be asked in the new focus of ACL transmission, not only to mitigate current transmission and prevent future outbreaks, but also to highlight the biological factors that might contribute to the possibility of an epidemic, and those conditions that modulate its actual probability, the climate and the social determination of risk. "Urban" ACLUrban transmission of ACL has been proposed during the Citation: Salomon OD (2019) Instructions on how to make an Outbreak of American Cutaneous Leishmaniasis.

Distribution of Phlebotominae (Diptera: Psychodidade) species and human cases of leishmaniasis in the Province of Corrientes, Argentina

“…However, although the sites where the vector and cases were recorded coincide, it is not possible to state that the site of the reporting is the same as the transmission site, as only the residence or place of diagnosis is the usually recorded data. Meanwhile, the place of transmission may be even in localities far away of the residence related to recreational or work activities within areas of wild vegetation (e.g., fishing, hunting, or forest clearing work), where the vectors involved in transmission are generally found (Salomón, 2019). In order to evaluate the possible sites of transmission and predict the appearance of new cases, it is important to record and detect new vector-competent species in time, for which vector surveillance and knowledge of the species present are essential.…”

The perfect storm: Cutaneous leishmaniasis in troops deployed in the Atlantic forest of Argentina

“…In Argentina, Misiones province is endemic for this disease, with more than 2900 confirmed cases since 2006 (National Health Ministry, 2020). Outbreak studies demonstrated patterns of infection cycles in peri‐urban areas close to primary or residual forest, in rural areas or urban–rural interfaces (Andreo et al., 2022; Salomon, 2019; Salomón et al., 2001, 2006). Nevertheless, there exists an epidemiological pattern of transmission associated with more intensive exposure to vector contact in sylvatic areas.…”

“…It is caused by trypanosomatid parasites of the genus Leishmania, which are transmitted by dipterans of the Phlebotominae subfamily (Killick-Kendrick, 1990).In South America, one of the various agents of ACL, Leishmania (Viannia) braziliensis, is associated with an ulcerative and stigmatizing mucocutaneous pathology (PAHO, 2019). In Argentina, Misiones province is endemic for this disease, with more than 2900 confirmed cases since 2006 (National Health Ministry, 2020).Outbreak studies demonstrated patterns of infection cycles in peri-urban areas close to primary or residual forest, in rural areas or urban-rural interfaces (Andreo et al, 2022;Salomon, 2019;Salomón et al, 2001Salomón et al, , 2006. Nevertheless, there exists an epidemiological pattern of transmission associated with more intensive exposure to vector contact in sylvatic areas.…”