Background: As of 2015 thousands of refugees are being hosted in temporary refugee camps in Greece. 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). 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. Methods: 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 during June-September 2017 with the use of Centers for Disease Control (CDC) light traps and oviposition traps. Using conventional and molecular diagnostic tools we investigated the mosquito/sand fly species composition, population dynamics, pathogen infection rates, and insecticide resistance status in the major vector species. Results: Important disease vectors including Anopheles sacharovi, Culex pipiens, Aedes albopictus and the Leishmania vectors Phlebotomus neglectus, P. perfiliewi and P. tobbi were recorded in the study refugee camps. No mosquito pathogens (Plasmodium parasites, flaviviruses) were detected in the analysed samples yet high sand fly Leishmania infection rates are reported. Culex pipiens mosquitoes displayed relatively high knock down resistance (kdr) mutation allelic frequencies (ranging from 41.0 to 63.3%) 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. Conclusions: Important disease vectors and pathogens in vectors (Leishmania spp.) were recorded in the refugee camps indicating a situational risk factor for disease transmission. The Cx. pipiens and Ae. albopictus kdr mutation frequencies recorded pose a potential threat against the effectiveness of pyrethroid insecticides in these settings. In contrast, pyrethroids appear suitable for the control of Anopheles mosquitoes and sand flies and DFB for Cx. pipiens and Ae. albopictus larvicide applications. Targeted actions ensuring adequate living conditions and the establishment of integrated vector-borne disease surveillance programs in refugee settlements are essential for protecting refugee populations against VBDs.
BACKGROUND The control of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) in Spanish field populations mainly relies on the insecticides lambda‐cyhalothrin and spinosad as bait sprays. However, their sustainable used is compromised by the development of lambda‐cyhalothrin resistance and the detection of spinosad resistant alleles. In addition, the use of lure‐and‐kill traps covered with deltamethrin has increased in the last years. It is thus urgent to predict the impact that the combination of both pyrethroids will have in the evolution of lambda‐cyhalothrin resistance and how they could be combined with spinosad so as to establish proper resistance management programs. RESULTS Toxicity bioassays were performed to analyze the current levels of lambda‐cyhalothrin resistance in field populations, proving that it has remained stable in the last decade. An evolutionary model was established to explore the weight of selected parameters in the evolution of lambda‐cyhalothrin resistance in C. capitata and to forecast resistance development under different resistance management scenarios. Our results highlight the importance of fitness cost and inheritance to fit the experimental results. The analyses predicted that the rotation of lambda‐cyhalothrin and spinosad, when deltamethrin traps are also deployed in the field, will slow down the evolution of resistance, especially when cross‐resistance between both pyrethroids is considered. CONCLUSION Lambda‐cyhalothrin resistance has not increased in the last decade, probably due to the alternation of this insecticide with spinosad. Our modelling results indicate that the best option to avoid an increase in lambda‐cyhalothrin resistant alleles, considering that deltamethrin use is growing, would be to continue combining their use with spinosad. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
This is the first report of the invasive rice pest, rice water weevil (Lissorhoptrus oryzophilus Kuschel) in the Balkans. Adult specimens were collected in the rice field region of Central Macedonia, Greece during July-August, 2016. Morphological identification was verified by DNA barcoding, and the first COI sequence of L. oryzophilus from Greece was deposited in the GenBank database. This semi-aquatic insect is considered one of the most important rice pests globally, and its presence in the region may result in important yield and economic losses in rice production. Considering the highly invasive nature of this species, it is possible that it has spread to neighboring rice wetlands of the Southern Balkans, and additional field investigations are essential to accurately determine its geographic distribution and to help contain its spread.Keywords Lissorhoptrus oryzophilus . Rice pest . Invasion . Greece . First record Rice is the second largest cereal crop in the world after wheat, constituting the primary food source for over 3 billion people (Ferrero and Tinarelli 2007). The
The control of the Mediterranean fruit fly (Medfly), Ceratitis capitata, in citrus orchards in Spain is mainly based in three insecticides (spinosad, lambda-cyhalothrin and deltamethrin) and the liberation of sterile males. However, Medfly control is compromised by the development of lambda-cyhalothrin resistance and the detection of spinosad-resistant alleles in field populations. We report here, for the first time, resistance to deltamethrin in populations collected in fields under different management strategies, including MagnetMed™ traps coated with this insecticide and/or spinosad and lambda-cyhalothrin used as bait sprays, and even in populations obtained from non-treated fields. Two deltamethrin-resistant strains (BP-delta and Rfg-delta) were generated from the descendants of some of the field populations that showed lower susceptibility to deltamethrin. Both strains showed low susceptibility to MagnetMed™ traps, moderate susceptibility to Ceratipack traps, and lacked cross-resistance to spinosad and lambda cyhalothrin. Our data suggest that deltamethrin resistance was mediated by P450 enzymes, since bioassays with synergists showed that PBO reverted resistance in a field population and the laboratory strains, whereas the effect of DEF and DEM was minor and no mutations were found in the VGSC gene. The inheritance of resistance for both strains was completely recessive, autosomic and did not fit the mortality expected for a recessive character under a monogenic or digenic model. We also found that deltamethrin resistance presented a fitness cost in terms of males’ weight, males’ and females’ longevity and lifetime fecundity, with a more pronounced effect in the BP-strain than in the Rfg-delta strain. Our results highlight the need to implement insecticide resistance management strategies to prevent control failures.
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