Detection of West Nile Virus – Lineage 2 in Culex pipiens mosquitoes, associated with disease outbreak in Greece, 2017

Mavridis, Konstantinos; Fotakis, Emmanouil Alexandros; Kioulos, Ilias; Mpellou, Spiridoula; Konstantas, Spiros; Varela, Evangelia; Gewehr, Sandra; Diamantopoulos, Vasilis; Vontas, John

doi:10.1016/j.actatropica.2018.02.024

Cited by 31 publications

(23 citation statements)

References 27 publications

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“…caspius shown previously to be present in Greece [47,48]. The presence of the pipiens type, molestus type and hybrids in both the Attica and Peloponnese regions is consistent with previous studies in Greece [22,49,50]. We found variation in the prevalence of the different types with the pipiens type comprising 54.5% (n=79) in the RU of Palaio Faliro, 20.0% (n=20) molestus type and 25.5% (n=37) of hybrids.…”

Section: Discussionsupporting

confidence: 91%

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The abundance and diversity of West Nile virus mosquito vectors in two Regional Units of Greece during the onset of the 2018 transmission season

Bisia

Jeffries

Lytra

et al. 2019

Preprint

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17Background: West Nile virus (WNV) is a zoonotic arbovirus of great medical and veterinary 18 importance, threatening the health of humans and equines worldwide. Mosquitoes belonging 19 to the Culex (Cx.) pipiens complex are major vectors but numerous other mosquito species 20 have also been implicated as vectors of WNV. Due to variations in blood-feeding behaviour, 21 the different biotypes and hybrids of Cx. pipiens influence the transmission of WNV, from 22 enzootic cycles (between mosquitoes and birds), to spill-over transmission to humans and 23 equines. 24Methods: In this study, mosquitoes were collected and analysed from two regional units 25 (RUs) of Greece with reported cases of WNV within the past 4 years; Palaio Flairo and 26 Argolida (in Attica and Peloponnese regions, respectively). Collections using different types 27 2 of mosquito surveillance traps were undertaken in May-June 2018 during the early period of 28 the WNV transmission season.29 Results: A total of 1062 mosquitoes were collected, with Biogents Sentinel traps (BG traps) 30 collecting both a greater number of mosquitoes across all species and Cx. pipiens complex 31 individuals than Centres for Disease Control miniature light traps (CDC traps) or Heavy Duty 32 Encephalitis Vector Survey traps (EVS traps). Identification of collected mosquitoes (using 33 both morphological keys and molecular barcoding) confirmed the presence of additional 34 species including Aedes (Ae.) albopictus, Ae. caspius and Culiseta (Cs.) longiareolata. The 35 prevalence of Cx. pipiens biotypes in the RU of Palaio Faliro was 54.5% pipiens type, 20.0% 36 molestus type and 25.5% hybrids. In the RU of Argolida, the collection comprised 68.1% 37 pipiens type, 8.3% molestus type and 23.6% hybrids. Screening individual unfed female38 mosquitoes for WNV (molecular xenomonitoring) resulted in detection in three females of the 39 pipiens type and in one hybrid; all collected from the RU of Argolida.40 Conclusions: As hybrids play an important role in spill-over transmission of WNV to 41 humans and equines, these findings highlight the importance of undertaking entomological 42 surveillance programs incorporating molecular xenomonitoring at the onset of the 43 transmission season to provide an early warning system for health authorities aiming to 44 prevent WNV outbreaks in Greece. 45 46 Keywords 47 52 genus [1-4]. Natural transmission of WNV mainly occurs in enzootic cycles between birds 53 and competent ornithophilic mosquito vectors, with avian species being the principal 54 3 maintenance and amplifying hosts of WNV as many species develop sufficient viremia for 55 onward transmission. This allows transmission to continue where competent mosquitoes are 56 present in a specific area under suitable environmental conditions [5]. Additionally, spill-over 57 transmission can occur when competent vectors feed on humans or horses. During natural 58 transmission these mammalian species are considered dead-end hosts since they cannot 59 sustain sufficient viraemia for further vec...

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Section: Discussionsupporting

confidence: 91%

“…pipiens complex were 68.1% (n=98) of pipiens type, 8.3% (n=12) of molestus type and 23.6% (n=34) of molestus and pipiens hybrids. The high percentage of hybrids in the RU is similar to a previous study conducted in the area after the 2017 outbreak that reported 37% hybrids, 41% pipiens and 22% molestus types [50].…”

Section: Discussionsupporting

confidence: 86%

The abundance and diversity of West Nile virus mosquito vectors in two Regional Units of Greece during the onset of the 2018 transmission season

Bisia

Jeffries

Lytra

et al. 2019

Preprint

View full text Add to dashboard Cite

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“…The majority of samples with amplified esterases harboured between 2-10 gene copies. Individuals with more than 10 (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and more than 20 gene copies (in the case of one individual from Rethymno) were also recorded. Attica was the region with the highest percentage of individuals carrying ≥2 copies of either CCEae3a or CCEae6a gene (84% and 80%, respectively) and Chios of individuals with >10 copies (25% and 33.3%, respectively) ( Figure 2).…”

Section: Esterase Gene Amplificationmentioning

confidence: 99%

Phenotypic and molecular analysis of insecticide resistance in Aedes albopictus populations from Greece

Balaska¹,

Fotakis²,

Kioulos³

et al. 2020

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Abstract Background: Aedes albopictus has a well-established presence in southern European countries, associated with recent disease outbreaks (e.g. Chikungunya). Development of insecticide resistance in the vector is a major concern as it’s control mainly relies on the use of biocides. Data on the specie’s resistance status is essential for efficient and sustainable control. Methods: We investigated the insecticide resistance status of several Ae. albopictus populations from Greece. Bioassays were performed against diflubenzuron (DFB), B. thuringiensis var. israelensis (Bti), deltamethrin and malathion. Molecular analysis of known insecticide resistance loci was performed, i.e. voltage-gated sodium channel (VGSC) mutations associated with pyrethroid resistance; presence and frequency of carboxylesterases 3 (CCEae3a) and 6 (CCEae6a) gene amplification associated with organophosphate (OP) resistance and; chitin synthase-1 (CHS-1) for the possible presence of DFB resistance mutations. Results: Bioassays showed full susceptibility to DFB, Bti and deltamethrin, but resistance against the OP malathion. VGSC analysis revealed a widespread distribution of mutations F1534C (in all populations, with allelic frequencies between 6.6% - 68.3%), and I1532T (in 6 populations), but absence of V1016G. CCE gene amplifications were recorded in 8 out of 11 populations. Co-presence of mutation F1534C and CCEae3a amplification was reported in a subgroup of samples. No mutations at the CHS locus I1043 were detected. Conclusions: The results indicate: (i) the suitability of larvicides DFB and Bti for Ae. albopictus control in Greece, (ii) a possible incipient pyrethroid resistance due to the presence of kdr mutations and (iii) a possible reduced efficacy of OPs, in a scenario of re-introducing them for vector control. The study highlights the need for systematic resistance monitoring for developing and implementing appropriate evidence-based control programs. Key words: diagnostic, arbovirus, mosquito tiger, insecticide resistance, vector control, Europe

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“…Greece displays an intense history of VBDs, posing a situational risk factor for disease transmission among vulnerable refugee populations. West Nile virus (WNV) lineage two outbreaks, attributed to Culex pipiens mosquitoes [6,7] have taken place from 2010 onwards with the largest occurring in 2018, resulting in 311 cases and 47 deaths [8]. Autochthonous malaria transmission, though eradicated in the 1970s re-appeared in 2009 reaching a peak of 42 locally acquired cases in 2011 [9].…”

Section: Introductionmentioning

confidence: 99%

Population dynamics, pathogen detection and insecticide resistance of mosquito and sand fly in refugee camps, Greece

et al. 2020

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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.

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Detection of West Nile Virus – Lineage 2 in Culex pipiens mosquitoes, associated with disease outbreak in Greece, 2017

Cited by 31 publications

References 27 publications

The abundance and diversity of West Nile virus mosquito vectors in two Regional Units of Greece during the onset of the 2018 transmission season

The abundance and diversity of West Nile virus mosquito vectors in two Regional Units of Greece during the onset of the 2018 transmission season

Phenotypic and molecular analysis of insecticide resistance in Aedes albopictus populations from Greece

Population dynamics, pathogen detection and insecticide resistance of mosquito and sand fly in refugee camps, Greece

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