First report outside Eastern Europe of West Nile virus lineage 2 related to the Volgograd 2007 strain, northeastern Italy, 2014

open11noWest Nile virus (WNV) is a Flavivirus transmitted to vertebrate hosts by mosquitoes, maintained in nature through an enzootic bird-mosquito cycle. In Europe the virus became of major public health and veterinary concern in the 1990s. In Italy, WNV re-emerged in 2008, ten years after the previous outbreak and is currently endemic in many areas of the country. In particular, the northeastern part of Italy experience continuous viral circulation, with human outbreaks caused by different genovariants of WNV lineage 1, Western-European and Mediterranean subcluster, and WNV lineage 2, Hungarian clade. Alongside the WNV National Surveillance Program that has been in place since 2002, regional surveillance plans were implemented after 2008 targeting mosquitoes, animals and humans.openRavagnan, Silvia; Montarsi, Fabrizio; Cazzin, Stefania; Porcellato, Elena; Russo, Francesca; Palei, Manlio; Monne, Isabella; Savini, Giovanni; Marangon, Stefano; Barzon, Luisa; Capelli, GioiaRavagnan, Silvia; Montarsi, Fabrizio; Cazzin, Stefania; Porcellato, Elena; Russo, Francesca; Palei, Manlio; Monne, Isabella; Savini, Giovanni; Marangon, Stefano; Barzon, Luisa; Capelli, Gioi

Mapping of Aedes albopictus abundance at a local scale in Italy

Given the growing risk of arbovirus outbreaks in Europe, there is a clear need to better describe the distribution of invasive mosquito species such as Aedes albopictus. Current challenges consist in simulating Ae. albopictus abundance, rather than its presence, and mapping its simulated abundance at a local scale to better assess the transmission risk of mosquito-borne pathogens and optimize mosquito control strategy. During 2014–2015, we sampled adult mosquitoes using 72 BG-Sentinel traps per year in the provinces of Belluno and Trento, Italy. We found that the sum of Ae. albopictus females collected during eight trap nights from June to September was positively related to the mean temperature of the warmest quarter and the percentage of artificial areas in a 250 m buffer around the sampling locations. Maps of Ae. albopictus abundance simulated from the most parsimonious model in the study area showed the largest populations in highly artificial areas with the highest summer temperatures, but with a high uncertainty due to the variability of the trapping collections. Vector abundance maps at a local scale should be promoted to support stakeholders and policy-makers in optimizing vector surveillance and control

Occurrence of Rickettsia felis in dog and cat fleas (Ctenocephalides felis) from Italy

Rickettsia felis is an obligate intracellular bacterium belonging to the spotted fever group, suspected to cause a murine typhus-like illness in humans, with a cosmopolitan distribution. This study was designed to estimate presence and occurrence of this pathogen in fleas collected from dogs and cats in different areas of Italy. Two species of fleas were identified, Ctenocephalides felis (80.3%) and Ctenocephalides canis (19.7%)

First report of the blood-feeding pattern in Aedes koreicus, a new invasive species in Europe

Aedes koreicus is an invasive mosquito species which has been introduced into several European countries. Compared to other invasive Aedes mosquitoes, little is known of its biology and ecology. To determine Ae. koreicus’ vectorial capacity, it is essential to establish its feeding patterns and level of anthropophagy. We report on the blood‑feeding patterns of Ae. koreicus, examining the blood meal origin of engorged females and evaluating the influence of different biotic and abiotic factors on feeding behavior. Mosquitoes were collected in 23 sites in northern Italy by manual aspiration and BG‑sentinel traps; host availability was estimated by survey. The source of blood meals was identified using a nested PCR and by targeting and sequencing the cytochrome c oxidase subunit I gene. In total, 352 Ae. koreicus engorged females were collected between 2013 and 2020 and host blood meals were determined from 299 blood‑fed mosquitoes (84.9%). Eleven host species were identified, with the highest prevalences being observed among roe deer (Capreolus capreolus) (N = 189, 63.2%) and humans (N = 46, 15.4%). Blood meals were mostly taken from roe deer in forested sites and from humans in urban areas, suggesting that this species can feed on different hosts according to local abundance. Two blood meals were identified from avian hosts and one from lizard. Ae. koreicus’ mammalophilic feeding pattern suggests that it may be a potential vector of pathogens establishing transmission cycles among mammals, whereas its role as a bridge vector between mammals and birds could be negligibl

First detection of Borrelia miyamotoi in Ixodes ricinus ticks from northern Italy.

Borrelia miyamotoi is a spirochete transmitted by several ixodid tick species. It causes a relapsing fever in humans and is currently considered as an emerging pathogen. In Europe, B. miyamotoi seems to occur at low prevalence in Ixodes ricinus ticks but has a wide distribution. Here we report the first detection of B. miyamotoi in Ixodes ricinus ticks collected in two independent studies conducted in 2016 in the north-eastern and north-western Alps, Italy

Towards improved, cost-effective surveillance of Ixodes ricinus ticks and associated pathogens using species distribution modelling

Various ticks exist in the temperate hilly and pre-alpine areas of Northern Italy, where Ixodes ricinus is the more important. In this area different tick-borne pathogen monitoring projects have recently been implemented; we present here the results of a twoyear field survey of ticks and associated pathogens, conducted 2009-2010 in North-eastern Italy. The cost-effectiveness of different sampling strategies, hypothesized a posteriori based on two sub-sets of data, were compared and analysed. The same two subsets were also used to develop models of habitat suitability, using a maximum entropy algorithm based on remotely sensed data. Comparison of the two strategies (in terms of number of ticks collected, rates of pathogen detection and model accuracy) indicated that monitoring at many temporary sites was more cost-effective than monthly samplings at a few permanent sites. The two model predictions were similar and provided a greater understanding of ecological requirements of I. ricinus in the study area. Dense vegetation cover, as measured by the normalized difference vegetation index, was identified as a good predictor of tick presence, whereas high summer temperatures appeared to be a limiting factor. The study suggests that it is possible to obtain realistic results (in terms of pathogens detection and development of habitat suitability maps) with a relatively limited sampling effort and a wellplanned monitoring strategy

First evidence of resistance to pyrethroid insecticides in Italian Aedes albopictus populations after 26 years since invasion

Aedes albopictus has spread during the last decades all over the world. This has increased significantly the risk of exotic arbovirus transmission (e.g. Chikungunya, Dengue, and Zika) also in temperate areas, as testified by the Chikungunya 2007- and 2017-outbreaks in north-east and central Italy. Insecticides represent a main tool for limiting the circulation of these mosquito-borne viruses. The aim of the present study is to start filling the current gap of knowledge on pyrethroid insecticide resistance of European Ae. albopictus populations focusing on populations from Italy, Albania and Greece

Clinical and virological findings in patients with Usutu virus infection, northern Italy, 2018

Background Usutu virus (USUV) is a mosquito-borne flavivirus, which shares its transmission cycle with the phylogenetically related West Nile virus (WNV). USUV circulates in several European countries and its activity has increased over the last 5 years. Aim To describe human cases of USUV infection identified by surveillance for WNV and USUV infection in the Veneto Region of northern Italy in 2018. Methods From 1 June to 30 November 2018, all cases of suspected autochthonous arbovirus infection and blood donors who had a reactive WNV nucleic acid test were investigated for both WNV and USUV infection by in-house molecular methods. Anti-WNV and anti-USUV IgM and IgG antibodies were detected by ELISA and in-house immunofluorescence assay, respectively; positive serum samples were further tested by WNV and USUV neutralisation assays run in parallel. Results Eight cases of USUV infection (one with neuroinvasive disease, six with fever and one viraemic blood donor who developed arthralgia and myalgia) and 427 cases of WNV infection were identified. A remarkable finding of this study was the persistence of USUV RNA in the blood and urine of three patients during follow-up. USUV genome sequences from two patients shared over 99% nt identity with USUV sequences detected in mosquito pools from the same area and clustered within lineage Europe 2. Conclusions Clinical presentation and laboratory findings in patients with USUV infection were similar to those found in patients with WNV infection. Cross-reactivity of serology and molecular tests challenged the differential diagnosis

dynamAedes: a unified modelling framework for invasive Aedes mosquitoes

Mosquito species belonging to the genus Aedes have attracted the interest of scientists and public health officers because of their capacity to transmit viruses that affect humans. Some of these species were brought outside their native range by means of trade and tourism and then colonised new regions thanks to a unique combination of eco-physiological traits. Considering mosquito physiological and behavioural traits to understand and predict their population dynamics is thus a crucial step in developing strategies to mitigate the local densities of invasive Aedes populations. Here, we synthesised the life cycle of four invasive Aedes species (Ae. aegypti, Ae. albopictus, Ae. japonicus and Ae. koreicus) in a single multi-scale stochastic modelling framework which we coded in the R package dynamAedes. We designed a stage-based and time-discrete stochastic model driven by temperature, photo-period and inter-specific larval competition that can be applied to three different spatial scales: punctual, local and regional. These spatial scales consider different degrees of spatial complexity and data availability by accounting for both active and passive dispersal of mosquito species as well as for the heterogeneity of the input temperature data. Our overarching aim was to provide a flexible, open-source and user-friendly tool rooted in the most updated knowledge on the species’ biology which could be applied to the management of invasive Aedes populations as well as to more theoretical ecological inquirie

Aedes koreicus, a vector on the rise: Pan-European genetic patterns, mitochondrial and draft genome sequencing

25openYesBackground The mosquito Aedes koreicus (Edwards, 1917) is a recent invader on the European continent that was introduced to several new places since its first detection in 2008. Compared to other exotic Aedes mosquitoes with public health significance that invaded Europe during the last decades, this species’ biology, behavior, and dispersal patterns were poorly investigated to date. Methodology/Principal findings To understand the species’ population relationships and dispersal patterns within Europe, a fragment of the cytochrome oxidase I (COI or COX1) gene was sequenced from 130 mosquitoes, collected from five countries where the species has been introduced and/or established. Oxford Nanopore and Illumina sequencing techniques were combined to generate the first complete nuclear and mitochondrial genomic sequences of Ae. koreicus from the European region. The complete genome of Ae. koreicus is 879 Mb. COI haplotype analyses identified five major groups (altogether 31 different haplotypes) and revealed a large-scale dispersal pattern between European Ae. koreicus populations. Continuous admixture of populations from Belgium, Italy, and Hungary was highlighted, additionally, haplotype diversity and clustering indicate a separation of German sequences from other populations, pointing to an independent introduction of Ae. koreicus to Europe. Finally, a genetic expansion signal was identified, suggesting the species might be present in more locations than currently detected. Conclusions/Significance Our results highlight the importance of genetic research of invasive mosquitoes to understand general dispersal patterns, reveal main dispersal routes and form the baseline of future mitigation actions. The first complete genomic sequence also provides a significant leap in the general understanding of this species, opening the possibility for future genome-related studies, such as the detection of ‘Single Nucleotide Polymorphism’ markers. Considering its public health importance, it is crucial to further investigate the species’ population genetic dynamic, including a larger sampling and additional genomic markers.Kurucz, Kornélia; Zeghbib, Safia; Arnoldi, Daniele; Marini, Giovanni; Manica, Mattia; Michelutti, Alice; Montarsi, Fabrizio; Deblauwe, Isra; Van Bortel, Wim; Smitz, Nathalie; Pfitzner, Wolf Peter; Czajka, Christina; Jöst, Artur; Kalan, Katja; Šušnjar, Jana; Ivović, Vladimir; Kuczmog, Anett; Lanszki, Zsófia; Tóth, Gábor Endre; Somogyi, Balázs A; Herczeg, Róbert; Urbán, Péter; Bueno-Marí, Rubén; Soltész, Zoltán; Kemenesi, GáborKurucz, K.; Zeghbib, S.; Arnoldi, D.; Marini, G.; Manica, M.; Michelutti, A.; Montarsi, F.; Deblauwe, I.; Van Bortel, W.; Smitz, N.; Pfitzner, W.P.; Czajka, C.; Jöst, A.; Kalan, K.; Šušnjar, J.; Ivović, V.; Kuczmog, A.; Lanszki, Z.; Tóth, G.E.; Somogyi, B.A.; Herczeg, R.; Urbán, P.; Bueno-Marí, R.; Soltész, Z.; Kemenesi, G