Further Evidence of Humans as Source of Leishmania viannia for Sandflies

Montoya-Lerma, James; Palácios, Ricardo; Osório, Lyda; Jaramillo, Consuelo; Cadena, Horacio

doi:10.1590/s0074-02761998000600006

Cited by 7 publications

(5 citation statements)

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“…11 Clinical response is considered to be the main indicator of the therapeutic response in New World cutaneous leishmaniasis because of the lack of concordance between the parasitological and clinical response to treatment in this trial and other studies in which viable parasites have been isolated from healed lesions. 14,15,18 The role of these parasites in the reactivation of lesions or metastasis 17 and as a source of infection in a putative anthroponotic cycle of the Leishmania Viannia 19 are issues that need to be elucidated through experiments to demonstrate the availability of the parasite in infected humans.…”

Section: Discussionmentioning

confidence: 99%

Treatment failure in children in a randomized clinical trial with 10 and 20 days of meglumine antimonate for cutaneous leishmaniasis due to Leishmania viannia species.

Palácios¹,

Osório²,

Grajalew³

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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113

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Abstract. Clinical response to supervised treatment of Colombian patients with cutaneous leishmaniasis was evaluated in a randomized controlled trial comparing 10 days versus 20 days of treatment with meglumine antimonate (20 mg Sb/kg/day). Masked examiners evaluated clinical response defined as 100% re-epithelialization of all lesions at 13 weeks and no relapses during 52 weeks of follow-up. The efficacy of meglumine antimonate for 10 days' treatment was 61% (28 of 46) compared to 67% (24 of 36) for 20 days. There was a significantly lower clinical response for children Ͻ 5 years in both 10-day (11%) and 20-day (25%) groups compared to patients aged 5-14 years (67% and 75%, respectively) and 15 years or more (81% and 83%, respectively). Overall efficacy of treatment schedules was comparable, but lower than expected, mainly because of low efficacy in children. Pathogenicity of infection and pharmacokinetics may affect the treatment response in children. New therapeutic alternatives should be evaluated in trials that include children and women.

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Section: Discussionmentioning

confidence: 99%

Treatment failure in children in a randomized clinical trial with 10 and 20 days of meglumine antimonate for cutaneous leishmaniasis due to Leishmania viannia species.

Palácios¹,

Osório²,

Grajalew³

et al. 2001

The American Journal of Tropical Medicine and Hygiene

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113

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“…Occasionally, there is evidence of L. (V.) braziliensis or L. (L.) amazonensis DNA in Lutzomyia longipalpis caught in the wild [ 50 , 51 , 52 , 53 ]—although these reports are not sufficient to incriminate this phlebotomine as a vector of leishmanine parasites. It is extremely relevant that the laboratory-bred sandfly vector can become experimentally infected after feeding on blood from the skin lesion edges of a patient with ACL caused by L. (V.) braziliensis [ 54 ]—reinforcing its potential as a vector for transmitting a Leishmania species other than L. (L.) infantum chagasi —which has never been definitively demonstrated under natural conditions. It, therefore, appears easier to accept that Lutzomyia longipalpis has developed a species-specific interaction with native L. (L.) infantum chagasi and its main wild reservoir (the crab-eating fox, Cerdocyon thous ) over thousands of years and represents an ecologically balanced enzootic cycle that is widely distributed in Latin America [ 3 , 4 , 37 , 55 , 56 , 57 ].…”

Section: Discussionmentioning

confidence: 99%

Comparative Genomic Analyses of New and Old World Viscerotropic Leishmanine Parasites: Further Insights into the Origins of Visceral Leishmaniasis Agents

et al. 2022

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Visceral leishmaniasis (VL), also known as kala-azar, is an anthropozoonotic disease affecting human populations on five continents. Aetiologic agents belong to the Leishmania (L.) donovani complex. Until the 1990s, three leishmanine parasites comprised this complex: L. (L.) donovani Laveran & Mesnil 1903, L. (L.) infantum Nicolle 1908, and L. (L.) chagasi Lainson & Shaw 1987 (=L. chagasi Cunha & Chagas 1937). The VL causal agent in the New World (NW) was previously identified as L. (L.) chagasi. After the development of molecular characterization, however, comparisons between L. (L.) chagasi and L. (L.) infantum showed high similarity, and L. (L.) chagasi was then regarded as synonymous with L. (L.) infantum. It was, therefore, suggested that L. (L.) chagasi was not native to the NW but had been introduced from the Old World by Iberian colonizers. However, in light of ecological evidence from the NW parasite’s enzootic cycle involving a wild phlebotomine vector (Lutzomyia longipalpis) and a wild mammal reservoir (the fox, Cerdocyon thous), we have recently analyzed by molecular clock comparisons of the DNA polymerase alpha subunit gene the whole-genome sequence of L. (L.) infantum chagasi of the most prevalent clinical form, atypical dermal leishmaniasis (ADL), from Honduras (Central America) with that of the same parasite from Brazil (South America), as well as those of L. (L.) donovani (India) and L. (L.) infantum (Europe), which revealed that the Honduran parasite is older ancestry (382,800 ya) than the parasite from Brazil (143,300 ya), L. (L.) donovani (33,776 ya), or L. (L.) infantum (13,000 ya). In the present work, we have now amplified the genomic comparisons among these leishmanine parasites, exploring mainly the variations in the genome for each chromosome, and the number of genomic SNPs for each chromosome. Although the results of this new analysis have confirmed a high genomic similarity (~99%) among these parasites [except L. (L.) donovani], the Honduran parasite revealed a single structural variation on chromosome 17, and the highest frequency of genomic SNPs (more than twice the number seen in the Brazilian one), which together to its extraordinary ancestry (382,800 ya) represent strong evidence that L. (L.) chagasi/L. (L.) infantum chagasi is, in fact, native to the NW, and therefore with valid taxonomic status. Furthermore, the Honduran parasite, the most ancestral viscerotropic leishmanine parasite, showed genomic and clinical taxonomic characteristics compatible with a new Leishmania species causing ADL in Central America.

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“…In addition to demonstrating the permanence of Leishmania in the blood and tissues of healthy individuals, there is empirical evidence that humans can act as a reservoir due to the positivity to xenodiagnosis with sandflies on the lesion's edges (36,49,50). Epidemiological evidence suggests that a high proportion of infected individuals play an important role in L. (Viannia) species transmission, when associated with high population density and the anthropophilia of sandflies adapted to areas altered by human action in Brazil, Bolivia, and Peru (36,51).…”

Section: Humans and Domestic Animals As Possible Sources Of Infectionmentioning

confidence: 99%

Anthropogenic Dispersal of Leishmania (Viannia) braziliensis in the Americas: A Plausible Hypothesis

Marzochi

Fagundes

et al. 2021

Front. Trop. Dis

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There are several gaps in our knowledge on the origin and spread of Leishmania (Viannia) braziliensis, an etiological agent of cutaneous and mucocutaneous or American tegumentary leishmaniasis, to different biomes, hosts, and vectors, with important epidemiological implications, including the possible existence of an anthroponotic component. Historical, biological, and epidemiological evidence suggests that Leishmania (V.) braziliensis and its variants were preexistent in Amazonia with great genetic variability, where they dispersed with less variability to other regions (clonal expansion). During pre-Columbian times the parasite may have been transported by migrating humans and probably also their dogs, from western Amazonia to the high inter-Andean valleys and from there to other regions of South America. The same thing could have happened later, in the same way, when it spread to non-Amazonian regions of Brazil and other countries of South and Central America, between the late 19th and early 20th centuries, during the so-called Rubber Boom and construction of the Madeira-Mamoré Railway in the Brazilian Amazon, by migrant workers who later returned to their places of origin, transporting the agent. The parasite’s dispersal in genetic correlated clusters, involving unexpectedly distinct ecosystems in Brazil (Amazonian, Cerrado, Caatinga and Atlantic Forest biomes), has continued until the present through human displacement. The infection of certain species of domestic, synanthropic and even wild animals, could be secondary to anthropogenic introduction of L. (V.) braziliensis in new environments. We admit the same phenomena happening in the probable transference of Leishmania infantum (visceral leishmaniasis), and of Yersinia pestis (plague) from the Old world to the New world, generating domestic and wild enzotic cycles from these agents. These assumptions associated with human infections, chronicity and parasite persistence with possibility of recovery of Leishmania in peripheral blood, skin and scars of cured or asymptomatic patients, (that may provide an alternative blood meal), along with the sand flies’ adaptation to the peri-domicile and the high susceptibility of domestic dogs, horses, mules and cats to the parasite, can reinforce the evidence of anthropogenic spread of L. (V.) braziliensis.

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Further Evidence of Humans as Source of Leishmania viannia for Sandflies

Cited by 7 publications

References 0 publications

Treatment failure in children in a randomized clinical trial with 10 and 20 days of meglumine antimonate for cutaneous leishmaniasis due to Leishmania viannia species.

Treatment failure in children in a randomized clinical trial with 10 and 20 days of meglumine antimonate for cutaneous leishmaniasis due to Leishmania viannia species.

Comparative Genomic Analyses of New and Old World Viscerotropic Leishmanine Parasites: Further Insights into the Origins of Visceral Leishmaniasis Agents

Anthropogenic Dispersal of Leishmania (Viannia) braziliensis in the Americas: A Plausible Hypothesis

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