Insecticide–impregnated dog collars reduce infantile clinical visceral leishmaniasis under operational conditions in NW Iran: A community–wide cluster randomised trial

Courtenay, Orin; Bazmani, Ahad; Parvizi, Parviz; Ready, P. D.; Cameron, M. M.

doi:10.1371/journal.pntd.0007193

Cited by 24 publications

(23 citation statements)

References 51 publications

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“…For instance, the effectiveness of the community-wide application of collars impregnated with pyrethroids on dogs in reducing the risk of infection in these animals has been demonstrated in several laboratory and field studies [40–42]. In fact, even if there may be obvious operational difficulties in the relation to the large-scale use of dog collars (e.g., collar losses), this strategy is acknowledged to be most effective in reducing the infection risk in dogs and may eventually reduce the risk of infection in humans and human VL incidence [43,44]. Other strategies such as vaccination, preventive use of immune modulator drugs (e.g., domperidone), and treatment of sick dogs with leishmanicidal and leishmaniostatic drugs are nowadays available, but should be recommended by veterinarians on a case-by-case basis [45].…”

Section: Discussionmentioning

confidence: 99%

Failure of the dog culling strategy in controlling human visceral leishmaniasis in Brazil: A screening coverage issue?

et al. 2019

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In the present study, we assessed the annual screening coverage (i.e., the percentage of dogs that are screened for anti- Leishmania antibodies annually) in the municipality of Sobral, Ceará state, Brazil. Data on the number of dogs screened during 2008−2017 (except 2010) were obtained from the Centre for Zoonoses Control of Sobral. The annual screening coverage during 2012−2017 was calculated. Data on human visceral leishmaniasis (VL) cases during 2008−2017 were compiled from the National Disease Notification System. Correlation analyses were performed to assess the correlation between canine and human data. During 2008−2017, 73,964 dogs (range, 0 to 13,980 dogs/year) were serologically screened and 2,833 (3.8%) were positive. The annual screening coverage during 2012−2017 ranged from 11.1% to 45.7%. There were no significant correlations between the number of dogs culled and the number of human VL cases, canine positivity and human VL incidence, number of dogs culled and human VL incidence, or between canine positivity and number of human VL cases. An inconsistent and relatively low annual screening coverage was found in the study area, with no dog being screened in 2010 due to the lack of serological tests. Our results highlight that many dogs potentially infected with Leishmania infantum have been virtually overlooked by public health workers in the study area, perhaps with a negative, yet underestimated, impact on the control of canine and human VL. Hence, the failure of the dog culling strategy in controlling human VL in Brazil may be due to the low screening coverage and low percentage of culled dogs, rather than the absence of associations between canine and human infections.

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Section: Discussionmentioning

confidence: 99%

Failure of the dog culling strategy in controlling human visceral leishmaniasis in Brazil: A screening coverage issue?

et al. 2019

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“…In contrast, successful deployment of bed nets reduced anthroponotic CL incidence in a variety of Old World foci [110]. Against zoonotic VL, an alternative insecticide application is deltamethrin-impregnated dog collars, which provide high levels of individual protection against canine infection [168]. Community-level dog collar implementation in Iran reduced human infection incidence by 43% [169] and infantile clinical VL by 50% [168].…”

Section: Ntds-lagging Behind In Vector Controlmentioning

confidence: 99%

The importance of vector control for the control and elimination of vector-borne diseases

et al. 2020

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Vector-borne diseases (VBDs) such as malaria, dengue, and leishmaniasis exert a huge burden of morbidity and mortality worldwide, particularly affecting the poorest of the poor. The principal method by which these diseases are controlled is through vector control, which has a long and distinguished history. Vector control, to a greater extent than drugs or vaccines, has been responsible for shrinking the map of many VBDs. Here, we describe the history of vector control programmes worldwide from the late 1800s to date. Pre 1940, vector control relied on a thorough understanding of vector ecology and epidemiology, and implementation of environmental management tailored to the ecology and behaviour of local vector species. This complex understanding was replaced by a simplified dependency on a handful of insecticide-based tools, particularly for malaria control, without an adequate understanding of entomology and epidemiology and without proper monitoring and evaluation. With the rising threat from insecticide-resistant vectors, global environmental change, and the need to incorporate more vector control interventions to eliminate these diseases, we advocate for continued investment in evidence-based vector control. There is a need to return to vector control approaches based on a thorough knowledge of the determinants of pathogen transmission, which utilise a range of insecticide and non-insecticide-based approaches in a locally tailored manner for more effective and sustainable vector control. Author summaryVector-borne diseases (VBDs) such as dengue, Chagas disease, human African trypanosomiasis (HAT), leishmaniasis, and malaria exert a huge burden of morbidity and mortality worldwide. The principal method by which these diseases are controlled is through vector control. The authors chart the history of vector control through time from elucidation of the transmission route of VBDs to the present day. Pre-1940 vector control relied heavily PLOS Neglected Tropical Diseases | https://doi.

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“…Canine vaccination, topical insecticides and therapeutic treatments are also promoted, but variably adopted or effective in reducing transmission (MOH 2014; Dantas-Torres 2020; Miro 2017; Nogueira 2019). That transmission persists (Shimozako 2017;PAHO 2019;da Rocha et al, 2018), and its range is expanding from rural into urban settings, and across national and international borders (PAHO 2019; Harhay 2011A; Seva 2017), is a strong motivation to develop sustainable preventative vector control methods.…”

Section: Discussionmentioning

confidence: 99%

“…Leishmania (Kinetoplastida: Trypanosomatidae) are intracellular protozoan parasites that primarily infect macrophages in the mammalian host causing human visceral leishmaniasis (VL), characterized by prolonged fever, wasting, splenomegaly, and hepatomegaly, with 90% case fatality in the absence of treatment (Martins-Melo 2014). Between 50,000 to 90,000 new human VL cases are reported per year (Alvar 2012; WHO 2017) (Mazloumi et al, 2002) and clinical VL incidence when implemented under MoH operational conditions (Courtenay 2019b).…”

Section: Introductionmentioning

confidence: 99%

Spatial modelling of sand fly vector’s response to a synthetic sex-aggregation pheromone: impact on the incidence of visceral leishmaniasis in rural and urban settings

Retkute

Dilger

Hamilton

et al. 2020

Preprint

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Background. Visceral leishmaniasis (VL) is a potentially fatal protozoan parasitic disease of humans and dogs. In the Americas, dogs are the reservoir and Lutzomyia longipalpis is the sand fly vector. A synthetic version of the vector's sex-aggregation pheromone attracts conspecifics to co-located lethal insecticide, reducing reservoir infection and vector abundance. Mathematical models of spatially deployed interventions are lacking, thus best practise using this novel lure-and-kill vector control approach to reduce infection incidence has not been fully explored. Methods. We developed a predictive mathematical model of vector host-seeking behaviour combined with spatially explicit transmission models to evaluate changes in human and canine spatial infection incidence under variable pheromone implementation scenarios and demographic conditions. Results. The risk of human infection increased exponentially with canine incidence, but at different rates between rural and urban settings with spatial clustering of high forces of human infection related to their proximity to canine infected households. A predicted 70% household coverage using a cost-effective amount (50mg) of pheromone, plus insecticide, reduced rural and urban setting infection incidence by approximately 44% and 50% in dogs, and by 64% and 68% in humans, within 1-2 years. Near or complete transmission elimination in dogs and humans was achieved after 10 years intervention using 50mg of pheromone under 70% household coverage in urban settings when newly acquired (immigrant) dogs had no pre-existing infections, but in rural settings required 90% coverage using 500mg. The willingness to pay (WTP) price per 10mg unit of pheromone is likely to be <$3 USD, making it a cost-beneficial intervention compared to current alternative strategies. Conclusions. Integrated stochastic and spatial models capturing vector host-seeking behaviour, is a useful mathematical framework to evaluate spatially dependent intervention methods, fine-scale transmission dynamics, and to identify best practise.

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Insecticide–impregnated dog collars reduce infantile clinical visceral leishmaniasis under operational conditions in NW Iran: A community–wide cluster randomised trial

Cited by 24 publications

References 51 publications

Failure of the dog culling strategy in controlling human visceral leishmaniasis in Brazil: A screening coverage issue?

Failure of the dog culling strategy in controlling human visceral leishmaniasis in Brazil: A screening coverage issue?

The importance of vector control for the control and elimination of vector-borne diseases

Spatial modelling of sand fly vector’s response to a synthetic sex-aggregation pheromone: impact on the incidence of visceral leishmaniasis in rural and urban settings

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