Efficacies of insecticide dog collars against visceral leishmaniasis in low and high-income areas and the effects for non-collared neighbor dogs

Matsumoto, Patrícia Sayuri Silvestre; Taniguchi, Helena Hilomi; Richini-Pereira, Virgínia Bodelão; Hiramoto, Roberto Mitsuyoshi; Rampazzi, Karla Letícia Seviero; Barbosa, José Eduardo de Raeffray; Neto, Roldão Antonio Puci; Camprigher, Valéria Medina; Cortez, Luiz Ricardo Paes de Barros; Rahaman, Khan Rubayet; Novak, Mathew; Tolezano, José Eduardo

doi:10.1016/j.actatropica.2022.106626

Cited by 4 publications

(6 citation statements)

References 27 publications

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“…Finally, spillover effects between units might affect the validity of effectiveness estimates of intervention [ 30 , 31 ]. For instance, the repellent effect of DMCs in an intervention area might increase the sand fly population in a control area [ 32 ].…”

Section: Discussionmentioning

confidence: 99%

Impact of 4% Deltamethrin-Impregnated Dog Collars on the Incidence of Human Visceral Leishmaniasis: A Community Intervention Trial in Brazil

Werneck,

Figueiredo,

Cruz

2024

Pathogens

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Background: In Brazil, human visceral leishmaniasis (HVL) is caused by the protozoan parasite Leishmania infantum, primarily transmitted by the sand fly Lutzomyia longipalpis, with dogs acting as the main urban reservoir. This study aims to evaluate the effectiveness of 4% deltamethrin-impregnated dog collars (DMC) on HVL incidence. Methods: This is a community intervention study carried out from 2012 to 2015 in the municipalities of Araguaína, State of Tocantins, and Montes Claros, State of Minas Gerais, Brazil. Two areas in each were randomly allocated to either (1) culling seropositive dogs + residual insecticide spraying (control area—CA) or (2) culling seropositive dogs + residual insecticide spraying + DMC fitted to dogs every six months for two years (intervention area—IA). Cases of HVL (n = 1202) occurring from 2008 to 2020 were identified from the Brazilian Reportable Diseases Information System and georeferenced to the control and intervention areas. The HVL cases from 2008 to 2012 were considered as occurring in the “pre-intervention” period. Those cases from 2013 to 2016 and from 2017 to 2020 were regarded as occurring in the “intervention” and “post-intervention” periods, respectively. We used a mixed-effects Poisson regression model to estimate the effectiveness of the intervention, comparing the changes from the pre-intervention period to the intervention and post-intervention periods in the control and intervention areas. Results: In Araguaína, there was a statistically significant reduction in the incidence of HVL in both the control and intervention areas, comparing both the intervention and post-intervention periods with the pre-intervention period. The intervention with DMC was significantly associated with a reduction in HVL when comparing the intervention and pre-intervention periods, yielding an effectiveness estimate of the DMC of 27% (IC95% 1–46%, p = 0.045). No differences were observed when comparing the pre- and post-intervention periods (p = 0.827). In Montes Claros, cases reduced in both the control and intervention areas from the pre-intervention period to the intervention period (p = 0.913). In the post-intervention period, the incidence increased in the control area, while cases continued to decrease in the DMC area (p = 0.188). Conclusions: The use of DMC was associated with a reduction of 27% in the incidence of HVL during the period of DMC delivery, indicating that DMC is effective as an additional strategy for controlling visceral leishmaniasis in Brazil. However, no significant reduction associated with DMC was detected after the intervention period, suggesting that a control program based on the large-scale deployment of DMC might have to be maintained for more extended periods without interruption.

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Section: Discussionmentioning

confidence: 99%

Impact of 4% Deltamethrin-Impregnated Dog Collars on the Incidence of Human Visceral Leishmaniasis: A Community Intervention Trial in Brazil

Werneck,

Figueiredo,

Cruz

2024

Pathogens

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“…Severe infection affects humans and domestic dogs in peridomestic and domestic transmission foci, and is included in the neglected diseases. If adequate treatment is not initiated in a timely manner, infected hosts progress to death in 90% of cases [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Currently, human and canine infections are present in wild and rural environments as well as in urban centers. Unfortunately, the control strategies against the disease, vectors, and reservoirs of VL have been ineffective [1][2][3][4] The life cycle of L. (L.) infantum is heteroxenic with two main life forms. Promastigotes, which live in infected female sandflies and are regurgitated during the blood meal, and amastigotes, which live inside the phagocytic cells of the vertebrate host [2,8].…”

Section: Introductionmentioning

confidence: 99%

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Extracellular Vesicles from Leishmania (Leishmania) infantum Contribute in Stimulating Immune Response and Immunosuppression in Hosts with Visceral Leishmaniasis

Carneiro,

da Cruz,

Maia

et al. 2024

Microorganisms

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Visceral leishmaniasis (VL) is a chronic systemic disease. In Brazil this infection is caused by Leishmania (Leishmania) infantum. Extracellular vesicles (EVs) released by Leishmania species have different functions like the modulation of host immune systems and inflammatory responses, among others. This study evaluated the participation of EVs from L. (L.) infantum (Leish-EVs) in recognition of the humoral and cellular immune response of hosts with VL. Promastigotes were cultivated in 199 medium and, in the log phase of growth, they were centrifuged, washed, resus-pended in RPMI medium, and incubated for 2 to 24 h, at 25 °C or 37 °C to release Leish-EVs. This dynamic was evaluated using transmission (TEM) and scanning (SEM) electron microscopies, as well as nanoparticle tracking analysis (NTA). The results suggested that parasite penetration in mammal macrophages requires more Leish-EVs than those living in insect vectors, since promastigotes incubated at 37 °C released more Leish-EVs than those incubated at 25 °C. Infected THP-1 cells produced high EV concentration (THP-1 cells-EVs) when compared with those from the control group. The same results were obtained when THP-1 cells were treated with Leish-EVs or a crude Leishmania antigen. These data indicated that host–EV concentrations could be used to distinguish infected from uninfected hosts. THP-1 cells treated with Leish-EVs expressed more IL-12 than control THP-1 cells, but were unable to express IFN-γ. These same cells highly expressed IL-10, which inhibited TNF-α and IL-6. Equally, THP-1 cells treated with Leish-EVs up-expressed miR-21-5p and miR-146a-5p. In conclusion, THP-1 cells treated with Leish-EVs highly expressed miR-21-5p and miR-146a-5p and caused the dysregulation of IL-10. Indirectly, these results suggest that high expression of these miRNAs species is caused by Leish-EVs. Consequently, this molecular via can contribute to immunosuppression causing enhanced immunopathology in infected hosts.

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“…Using mosquito nets and insecticide spraying can effectively block the bite rate of sandflies. It is helpful for dogs with collars containing insect repellent to reduce the infection rate [13]. However, in remote rural areas where the prevalence of VL is high, the lack of awareness of the disease and inadequate health systems have not led to a fundamental improvement in the prevalence of VL.…”

Section: Introductionmentioning

confidence: 99%

Transmission dynamics of visceral leishmaniasis with PKDL and periodic delays

Wang

Fan

et al. 2023

Math Methods in App Sciences

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We consider the transmission of visceral leishmaniasis in three populations: humans, dogs and sandflies. To investigate the effects of spatial heterogeneity and temporal periodicity on disease transmission, a nonlocal periodic reaction-diffusion equation model is developed. We introduce the basic reproduction number R 0 and establish the global dynamics. Numerical simulations show that (i) R 0 is overestimated in the absence of spatial heterogeneity; (ii) R 0 is underestimated without considering the effect of temporal seasonality; and (iii) shortening periodic delays of visceral leishmaniasis reduces the risk of disease transmission.

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Efficacies of insecticide dog collars against visceral leishmaniasis in low and high-income areas and the effects for non-collared neighbor dogs

Cited by 4 publications

References 27 publications

Impact of 4% Deltamethrin-Impregnated Dog Collars on the Incidence of Human Visceral Leishmaniasis: A Community Intervention Trial in Brazil

Impact of 4% Deltamethrin-Impregnated Dog Collars on the Incidence of Human Visceral Leishmaniasis: A Community Intervention Trial in Brazil

Extracellular Vesicles from Leishmania (Leishmania) infantum Contribute in Stimulating Immune Response and Immunosuppression in Hosts with Visceral Leishmaniasis

Transmission dynamics of visceral leishmaniasis with PKDL and periodic delays

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