Fighting vector borne diseases in refugee camps, Greece: mosquito and sand fly population structure, pathogen circulation and insecticide resistance

Authors: FOTAKIS, EMMANOULI - AGRICULTURAL UNIVERSITY OF ATHENS; GIANTSIS, IOANNIS - EUROPEAN BIOLOGICAL CONTROL LABORATORY (EBCL); CASTELLS SIERRA, JAVIER - EUROPEAN BIOLOGICAL CONTROL LABORATORY (EBCL); TANTI, FILIANNA - AGRICULTURAL UNIVERSITY OF ATHENS; BALASKA, SOFIA - INSTITUTE OF MOLECULARBIOLOGY AND BIOTECHNOLOGY OF THE FOUNDATION FOR RESEARCH AND TECHNOLOGY - HELLAS; MAVRIDIS, KONSTANTINOS - INSTITUTE OF MOLECULARBIOLOGY AND BIOTECHNOLOGY OF THE FOUNDATION FOR RESEARCH AND TECHNOLOGY - HELLAS; KOURTIDIS, SOFOKLIS - GENERAL DIRECTORATE OF PUBLIC HEALTH, REGION OF EASTERN MACEDONIA AND THRACE; VONTAS, JOHN - AGRICULTURAL UNIVERSITY OF ATHENS; CHASKOPOULOU, ALEXANDRA - EUROPEAN BIOLOGICAL CONTROL LABORATORY (EBCL)

Submitted to: Journal of Infectious Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/3/2020
Publication Date: 3/18/2020
Citation: Fotakis, E., Giantsis, I., Castells Sierra, J., Tanti, F., Balaska, S., Mavridis, K., Kourtidis, S., Vontas, J., Chaskopoulou, A. 2020. Fighting vector borne diseases in refugee camps, Greece: mosquito and sand fly population structure, pathogen circulation and insecticide resistance. Journal of Infectious Diseases. 9:30. https://doi.org/10.1186/s40249-020-0635-4.
DOI: https://doi.org/10.1186/s40249-020-0635-4

Interpretive Summary: Over the last 5 years, hundreds of thousands of refugees have sought refuge/asylum in Greece and other European countries. Often living under poor conditions with limited access to healthcare, these displaced populations have been vulnerable to vector-born disease (VBD), especially when travelling or hosted in VBD-endemic regions. Currently over 135,000 refugees/asylum seekers are hosted in Greece, the majority in temporary accommodation sites/refugee camps with varied levels of infrastructures, housing conditions, and amenities. Refugee settlements, whether temporary or permanent, represent unique ecological settings which inevitably affect and are affected by the surrounding ecosystem. Within these unique, vulnerable communities, the status of arthropod vectors has been unknown. This is the first study reporting entomological information on vector species composition and seasonal abundance, vector insecticide resistance status, and the presence and circulation of arthropod-borne pathogens associated with refugee camps. This information is essential in order to evaluate the risk for VBD transmission within these communities and to design effective and efficient context-specific vector and disease control programs (evidence based controls).

Technical Abstract: Since 2015 a major refugee crisis has been developing on Europe’s doorstep. In Greece, thousands of refugees/asylum seekers are hosted in temporary refugee camps. Displaced populations, travelling and living under poor conditions with limited access to healthcare are at a high risk of exposure to vector borne disease (VBD) infections. This study sought to evaluate the risk for VBD transmission within refugee camps in Greece by analyzing the mosquito and sand fly populations present, in light of designing effective and efficient context specific vector and disease control programs. A vector/pathogen surveillance network targeting mosquitoes and sand flies was deployed in four temporary refugee camps in Greece. Sample collections were conducted bi-weekly over a three month period with use of CDC light traps baited with dry ice and oviposition traps. Using conventional and molecular diagnostic tools we investigated the mosquito/sand fly species composition, population dynamics, pathogen circulation, and insecticide resistance status in the major vector species. Important disease vectors including An. sacharovi (malaria vector) Cx. pipiens (West Nile Virus vector), Ae. albopictus (Chikungunya and Dengue vector) and the Leishmania vectors P. neglectus, P. perfiliewi and P. tobbi were recorded in the study refugee camps. No mosquito pathogens (Plasmodium parasites, Flaviviruses) were detected, yet high sand fly Leishmania infection rates were reported. Cx. pipiens mosquitoes displayed relatively high knock-down resistance (KDR) mutation allelic frequencies in all camps while KDR mutations were also detected in Ae. albopictus populations, but not in Anopheles and sand fly specimens. No Diflubenzuron (DFB) mutations were detected in any of the mosquito species analysed. Presence of pyrethroid resistance mutations in Cx. pipiens and Ae. albopictus may threaten the effectiveness of pyrethroid based vector control efforts. On the contrary absence of pyrethroid and DFB resistant mutations in Anopheles mosquitoes, sand flies and Cx. pipiens, Ae. albopictus respectively suggests suitability of the insecticides for their control. The high Leishmania infection rates indicate high risk for Leishmania infection for the people accommodated in these settings. Vector proof housing facilities, unimpeded refugee access to healthcare facilities and the establishment of systematic integrated surveillance programs are essential steps for the protection of refugee camp populations against VBDs.