Enhancing protection against vector-borne diseases in forcibly displaced communities: evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in North-East Syria
Abstract Background In Syria, during the 14 years after the outbreak of civil war, 16.7 million people have been forced to flee their homes, of which 7.2 million remain internally displaced in 2025. Breakdown in waste management caused by aerial bombardment has created ideal conditions for cutaneous...
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BMC
2025-07-01
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| Online Access: | https://doi.org/10.1186/s12916-025-04244-2 |
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| author | Richard Allan Ramona Scherrer Ozge Erisoz Kasap Laura Paris Thomas Scott Hendrik Sauskojus Olivia Wetherill Sara Estecha-Querol Zaid Alkhalaf Mehmet Karakus Ayda Yilmaz Bülent Alten Louisa A. Messenger |
| author_facet | Richard Allan Ramona Scherrer Ozge Erisoz Kasap Laura Paris Thomas Scott Hendrik Sauskojus Olivia Wetherill Sara Estecha-Querol Zaid Alkhalaf Mehmet Karakus Ayda Yilmaz Bülent Alten Louisa A. Messenger |
| author_sort | Richard Allan |
| collection | DOAJ |
| description | Abstract Background In Syria, during the 14 years after the outbreak of civil war, 16.7 million people have been forced to flee their homes, of which 7.2 million remain internally displaced in 2025. Breakdown in waste management caused by aerial bombardment has created ideal conditions for cutaneous leishmaniasis (CL) transmission, vectored by phlebotomine sandflies. Displaced populations reside in flimsy shelters where conventional vector control tools are operationally unfeasible. A small, lightweight, portable transfluthrin-based spatial repellent (Mosquito Shield™) has been developed which may circumvent some of these logistical issues and provide improved protection from vector-borne diseases in harsh environments. Methods A two-arm, non-randomised cluster trial was undertaken in Ar-Raqqa governorate, North-East Syria, to evaluate the efficacy of Mosquito Shield™ in reducing CL case incidence and sandfly densities in shelters. Weekly epidemiological monitoring was performed by MENTOR Initiative mobile clinics and supported health facilities. Entomological monitoring was performed fortnightly using indoor US Centers for Disease Control and Prevention light traps in 40 randomly selected households per study arm. Phlebotomine sandflies were morphologically identified; a subset were analysed for molecular species confirmation, blood-meal preferences and pyrethroid resistance. Household surveys and focus group discussions were used to assess intervention feasibility, acceptability and uptake. Results Assuming a 2-month diagnosis cut-off, the CL incidence rate was 9.9 and 5.2 per 1000 in the control and intervention arms, respectively; Mosquito Shield™ demonstrated a significant impact on rate of CL infection in all ages (incidence rate ratio; IRR: 0.52 [95% CI: 0.37–0.74]; p < 0.0001). Mosquito Shield™ demonstrated a significant impact on all female sandfly density (IRR: 0.22 [95% CI: 0.14–0.33]; p < 0.0001) and blood-fed female sandfly density (IRR: 0.21 [95% CI: 0.11–0.40]; p < 0.0001). Mosquito Shield™ was received positively and perceived to be easy to use, to protect from CL, sandflies and other insect bites and required minimal behaviour change. Conclusions Trial findings provide the first demonstrable impact of spatial repellents on CL transmission, strengthening the growing evidence basis for the effectiveness of this intervention against multiple vector species and their associated pathogens. Study results strongly support the deployment of spatial repellents to control CL in humanitarian crises. Trial registration ClinicalTrials.gov, NCT06917040. |
| format | Article |
| id | doaj-art-e2ff2a675cda4737933794f25ad9e3f9 |
| institution | DOAJ |
| issn | 1741-7015 |
| language | English |
| publishDate | 2025-07-01 |
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| spelling | doaj-art-e2ff2a675cda4737933794f25ad9e3f92025-08-20T03:03:28ZengBMCBMC Medicine1741-70152025-07-0123111510.1186/s12916-025-04244-2Enhancing protection against vector-borne diseases in forcibly displaced communities: evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in North-East SyriaRichard Allan0Ramona Scherrer1Ozge Erisoz Kasap2Laura Paris3Thomas Scott4Hendrik Sauskojus5Olivia Wetherill6Sara Estecha-Querol7Zaid Alkhalaf8Mehmet Karakus9Ayda Yilmaz10Bülent Alten11Louisa A. Messenger12The MENTOR InitiativeThe MENTOR InitiativeDepartment of Biology, Faculty of Science, VERG Laboratories, Hacettepe UniversityThe MENTOR InitiativeThe MENTOR InitiativeThe MENTOR InitiativeThe MENTOR InitiativeThe MENTOR InitiativeThe MENTOR InitiativeDepartment of Medical Microbiology, Hamidiye, Faculty of Medicine , University of Health SciencesDepartment of Biology, Faculty of Science, VERG Laboratories, Hacettepe UniversityDepartment of Biology, Faculty of Science, VERG Laboratories, Hacettepe UniversitySchool of Public Health, University of NevadaAbstract Background In Syria, during the 14 years after the outbreak of civil war, 16.7 million people have been forced to flee their homes, of which 7.2 million remain internally displaced in 2025. Breakdown in waste management caused by aerial bombardment has created ideal conditions for cutaneous leishmaniasis (CL) transmission, vectored by phlebotomine sandflies. Displaced populations reside in flimsy shelters where conventional vector control tools are operationally unfeasible. A small, lightweight, portable transfluthrin-based spatial repellent (Mosquito Shield™) has been developed which may circumvent some of these logistical issues and provide improved protection from vector-borne diseases in harsh environments. Methods A two-arm, non-randomised cluster trial was undertaken in Ar-Raqqa governorate, North-East Syria, to evaluate the efficacy of Mosquito Shield™ in reducing CL case incidence and sandfly densities in shelters. Weekly epidemiological monitoring was performed by MENTOR Initiative mobile clinics and supported health facilities. Entomological monitoring was performed fortnightly using indoor US Centers for Disease Control and Prevention light traps in 40 randomly selected households per study arm. Phlebotomine sandflies were morphologically identified; a subset were analysed for molecular species confirmation, blood-meal preferences and pyrethroid resistance. Household surveys and focus group discussions were used to assess intervention feasibility, acceptability and uptake. Results Assuming a 2-month diagnosis cut-off, the CL incidence rate was 9.9 and 5.2 per 1000 in the control and intervention arms, respectively; Mosquito Shield™ demonstrated a significant impact on rate of CL infection in all ages (incidence rate ratio; IRR: 0.52 [95% CI: 0.37–0.74]; p < 0.0001). Mosquito Shield™ demonstrated a significant impact on all female sandfly density (IRR: 0.22 [95% CI: 0.14–0.33]; p < 0.0001) and blood-fed female sandfly density (IRR: 0.21 [95% CI: 0.11–0.40]; p < 0.0001). Mosquito Shield™ was received positively and perceived to be easy to use, to protect from CL, sandflies and other insect bites and required minimal behaviour change. Conclusions Trial findings provide the first demonstrable impact of spatial repellents on CL transmission, strengthening the growing evidence basis for the effectiveness of this intervention against multiple vector species and their associated pathogens. Study results strongly support the deployment of spatial repellents to control CL in humanitarian crises. Trial registration ClinicalTrials.gov, NCT06917040.https://doi.org/10.1186/s12916-025-04244-2ConflictInternally displaced personsCutaneous leishmaniasisTemporary shelterVector controlSpatial repellents |
| spellingShingle | Richard Allan Ramona Scherrer Ozge Erisoz Kasap Laura Paris Thomas Scott Hendrik Sauskojus Olivia Wetherill Sara Estecha-Querol Zaid Alkhalaf Mehmet Karakus Ayda Yilmaz Bülent Alten Louisa A. Messenger Enhancing protection against vector-borne diseases in forcibly displaced communities: evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in North-East Syria BMC Medicine Conflict Internally displaced persons Cutaneous leishmaniasis Temporary shelter Vector control Spatial repellents |
| title | Enhancing protection against vector-borne diseases in forcibly displaced communities: evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in North-East Syria |
| title_full | Enhancing protection against vector-borne diseases in forcibly displaced communities: evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in North-East Syria |
| title_fullStr | Enhancing protection against vector-borne diseases in forcibly displaced communities: evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in North-East Syria |
| title_full_unstemmed | Enhancing protection against vector-borne diseases in forcibly displaced communities: evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in North-East Syria |
| title_short | Enhancing protection against vector-borne diseases in forcibly displaced communities: evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in North-East Syria |
| title_sort | enhancing protection against vector borne diseases in forcibly displaced communities evaluating the efficacy of spatial repellents for cutaneous leishmaniasis control in north east syria |
| topic | Conflict Internally displaced persons Cutaneous leishmaniasis Temporary shelter Vector control Spatial repellents |
| url | https://doi.org/10.1186/s12916-025-04244-2 |
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