The importance of understanding enzootic cycles in the epidemiology of zoonotic diseases with special reference to the American leishmaniases

Shaw, Jeffrey Jon

doi:10.1093/trstmh/try090

Cited by 8 publications

(7 citation statements)

References 11 publications

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“…27,28 The single case report of CL could be explained by the zoonotic nature of the disease, where transmission to a human depends on his or her contact with the vector in biomes where the enzootic cycle exists. 29 In the study area, it is likely that the transmission cycle of L. braziliensis or L. panamensis 30 has been maintained, over time, at an enzootic level involving wild mammals and sand flies, both with a low level of interaction with humans. However, in recent decades, as has happened in other areas, the loss of mammalian biodiversity as a result of deforestation and agricultural practices may have forced vectors to feed on humans and on a smaller number of synanthropic reservoirs.…”

Section: Discussionmentioning

confidence: 98%

Behavioral Aspects of Phlebotomine Sand Flies Associated with a Case of Cutaneous Leishmaniasis in Atlántico, Northern Colombia

Santamaría

Cabrera

Marceló-Díaz

et al. 2020

The American Journal of Tropical Medicine and Hygiene

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After the first autochthonous case of cutaneous leishmaniasis was reported in the Atlántico department in the Caribbean region of Colombia, entomological sampling was conducted in the specific areas where the infection might have occurred. CDC traps were installed inside and outside dwellings in the peri-urban and rural areas of a settlement in the municipality of Luruaco. Sampling was performed during the night with protected human bait, and phlebotomine sand flies were actively sampled from potential diurnal resting sites within dwellings. Ten species of the genus Lutzomyia were identified; Lutzomyia evansi was the dominant species (78%) in the rural and peri-urban areas as well as in the different sampled habitats, followed by Lutzomyia panamensis and Lutzomyia gomezi. There was a 100% household infestation by Lu. evansi, and its indoor mean abundance was 13.3 sand flies/CDC trap/night. The indoor mean abundance of Lu. panamensis and Lu. gomezi was only 0.9 and 0.8 sand flies/CDC trap/night, respectively. Female Lu. evansi were collected with protected human bait, mostly in the peridomestic area, with sustained activity during the night and a slight increase in the activity from 19:00 to 23:00 hours. Of the total sand flies captured in the diurnal resting sites, 73.1% were collected from the walls of bedrooms and corresponded to Lu. evansi, Lutzomyia cayennensis cayennensis, and Lutzomyia trinidadensis. Owing to their vectorial importance, the species on which entomological surveillance should be focused are Lu. evansi, Lu. panamensis, and Lu. gomezi. The biting and resting behavior reported in this study will help guide vector prevention and the control of leishmaniasis within the study area.

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Section: Discussionmentioning

confidence: 98%

Behavioral Aspects of Phlebotomine Sand Flies Associated with a Case of Cutaneous Leishmaniasis in Atlántico, Northern Colombia

Santamaría

Cabrera

Marceló-Díaz

et al. 2020

The American Journal of Tropical Medicine and Hygiene

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Section: Discussionmentioning

confidence: 99%

“…In addition, another factor to be discussed is the high dispersion capacity and longevity of bats, which if infected, can have an important impact on the spread of Leishmania parasites. 54 Regarding vectors, Ramos et al 39 states that some species of phlebotomines tend to synanthropize, due an increase in food availability and places for rest and oviposition. In settled regions, the presence of domestic and savage animals provides a food source for vectors, thus favoring their adaptation to new environments.…”

Section: Discussionmentioning

confidence: 99%

Factors associated with the expansion of leishmaniasis in urban areas: a systematic and bibliometric review (1959–2021)

Borges

Niero

Rosa

et al. 2022

Journal of Public Health Research

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This work describes a systematic and bibliometric review of the factors that contribute to the expansion of leishmaniasis in urban areas. Three scientific databases were used: Scientific Electronic Library (Sci ELO), Scopus and Web of Science, encompassing all original and review articles between 1959 and 2021. Three descriptors were used: “leishmaniasis” AND “urban” AND “rural.” Planning, execution, summarization, and selection processes were performed using StArt ( State of the Art through Systematic Review) software. We obtained a total of 304 articles, 60 of which concerned canine leishmaniasis. The factors associated with the expansion of leishmaniasis in urban areas are interrelated, including socioenvironmental and economic complexity, the type of leishmaniasis, the reservoirs, vectors, deforestation, disorderly occupation of space, poor sanitary conditions, and human migration trends. A lack of diagnosis and underreporting of cases in some regions may reflect the increase of cases seen in urban areas. A majority ( n = 121) of studies were conducted in Brazil, followed by Iran ( n = 43). In relation to publications; in general, output has increased over the years, particularly in 2021. The majority of published studies were in the area of epidemiology ( n = 158).

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“…Cutaneous leishmaniasis (CL) is the most common clinical form, characterized by one or more skin ulcers well delimited by a raised border at the site of the sand-fly infected bite. The Leishmania species implicated in CL can vary according to geographic region, and eight species have been identified in Brazil ( 2 , 3 ). Although most patients develop cutaneous ulcers, increasing evidence indicates clinical presentation characteristics associated with a particular Leishmania species ( 4 – 7 ).…”

Section: Introductionmentioning

confidence: 99%

A Cytokine Network Balance Influences the Fate of Leishmania (Viannia) braziliensis Infection in a Cutaneous Leishmaniasis Hamster Model

et al. 2021

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The golden hamster is a suitable model for studying cutaneous leishmaniasis (CL) due to Leishmania (Viannia) braziliensis. Immunopathological mechanisms are well established in the L. (L.) major-mouse model, in which IL-4 instructs a Th2 response towards progressive infection. In the present study, we evaluated the natural history of L. braziliensis infection from its first stages up to lesion establishment, with the aim of identifying immunological parameters associated with the disease outcome and parasitism fate. To this end, hamsters infected with 104, 105, or 106 promastigotes were monitored during the first hours (4h, 24h), early (15 days, 30 days) and late (50 days) post-infection (pi) phases. Cytokines, iNOS and arginase gene expression were quantified in the established lesions by reverse transcription-quantitative PCR. Compared to the 105 or 106 groups, 104 animals presented lower lesions sizes, less tissue damage, and lower IgG levels. Basal gene expression in normal skin was high for TGF-β, and intermediary for TNF, IL-6, and IL-4. At 4hpi, no cytokine induction was observed in the 104 group, while an upregulation of IL-6, IL-10, and IL-4 was observed in the 106 group. At 15dpi, lesion appearance was accompanied by an increased expression of all assessed cytokines, markedly in the 105 and 106 groups. Upregulation of all investigated cytokines was observed in the late phase, although less expressive in the 104 group. IFN-γ was the depending variable influencing tissue damage, while IL-6 was associated to parasite load. The network correlating gene expression and clinical and laboratorial parameters indicated inoculum-independent associations at 15 and 30dpi. A strong positive network correlation was observed in the 104 group, but not in the 105 or 106 groups. In conclusion, IL-4, IL-6, IL-10, and TGF-β are linked o L. braziliensis progression. However, a balanced cytokine network is the key for an immune response able to reduce the ongoing infection and reduce pathological damage.

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The importance of understanding enzootic cycles in the epidemiology of zoonotic diseases with special reference to the American leishmaniases

Cited by 8 publications

References 11 publications

Behavioral Aspects of Phlebotomine Sand Flies Associated with a Case of Cutaneous Leishmaniasis in Atlántico, Northern Colombia

Behavioral Aspects of Phlebotomine Sand Flies Associated with a Case of Cutaneous Leishmaniasis in Atlántico, Northern Colombia

Factors associated with the expansion of leishmaniasis in urban areas: a systematic and bibliometric review (1959–2021)

A Cytokine Network Balance Influences the Fate of Leishmania (Viannia) braziliensis Infection in a Cutaneous Leishmaniasis Hamster Model

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