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

Prevalence and genetic variability of Anaplasma phagocytophilum in wild rodents from the Italian alps

Background: Human granulocytic anaplasmosis is a zoonotic bacterial disease with increasing relevance for public health in Europe. The understanding of its sylvatic cycle and Identification of competent reservoir hosts are essential for improving disease risk models and planning preventative measures. Results: In 2012 we collected single ear biopsy punches from 964 live-trapped rodents in the Province of Trento, Italy. Genetic screening for Anaplasma phagocytophilum (AP) was carried out by PCR amplification of a fragment of the 16S rRNA gene. Fifty-two (5.4%) samples tested positive: 49/245 (20%) from the bank vole (Myodes glareolus) and 3/685 (0.4%) samples collected from the yellow-necked mouse (Apodemus flavicollis). From these 52 positive samples, we generated 38 groEL and 39 msp4 sequences. Phylogenetic analysis confirmed the existence of a distinct rodent strain of AP. Conclusions: Our results confirm the circulation of a specific strain of AP in rodents in our study area; moreover, they provide further evidence of the marginal role of A. flavicollis compared to M. glareolus as a reservoir host for this pathogen

West Nile Virus circulation detected in Northern Italy in sentinel chickens

Ninety percent (56/62) of sentinel chickens introduced to two regions within the Italian Alps seroconverted to West Nile virus (WNV) during the summer of 2005, showing a range of antibody titres from 1/20 to 1/320 in a virus neutralization test. Neutralization specificity for WNV antibodies was confirmed on an additional 34 sera that were tested in parallel against WNV (16/34 seropositivity), Usutu virus (3/34 seropositivity) and Koutango virus. The geometric mean neutralizing titre (GMT) calculated for WN-specific antibodies was 33.68 and did not differ significantly amongst sample sites, although the overall results indicate more active circulation of WNV at the higher elevations. Such high levels of seroconversion raise the possibility that many chickens may have been exposed to virus via routes other than mosquito transmission. No chickens or any other local animals were associated with illness due to WNV implying that WNV, and to a much lower extent Usutu virus, circulate harmlessly amongst wildlife species in northern Italy from late May onwards until early autumn

Blood meal analysis, flavivirus screening, and influence of meteorological variables on the dynamics of potential mosquito vectors of West Nile virus in northern Italy

An extended area of northern Italy has experienced several West Nile virus (WNV) outbreaks and the emergence of Usutu virus (USUV) during previous years. Our aim was to study some of the factors that could explain disease patterns in the Trentino region, where circulation was detected in human sera and sentinel chickens, but no human or equine cases were reported. We collected Culex species (Diptera: Culicidae) in peridomestic environments. The collected specimens were analyzed for feeding behavior, the influence of temperature and rainfall on the abundance of mosquitoes, and the occurrence of flaviruses. Analysis of blood meals showed that Culex pipiens fed mainly on blackbirds (Turdus merula) and house sparrows (Passer domesticus), while Culex hortensis fed strictly on lizards. The abundance of Cx. pipiens females correlated positively with mean temperature and negatively with rainfall (one to four weeks before capture). This negative relationship could be due to the direct effect of the flushing of habitats together with an indirect effect of oviposition repellency. The mean weekly temperature influenced the abundance of Cx. hortensis. No flaviviruses were detected in the analyzed Culex mosquitoes. These data suggest a silent cycle at low enzootic transmission levels in the area. Furthermore, we present the first contribution to understanding the transmission role of Cx. pipiens mosquitoes in Italy by identifying vertebrate hosts to species level.Peer Reviewe

Detection of a new insect flavivirus and isolation of Aedes flavivirus in Northern Italy

Abstract Background During recent years, numerous novel ‘insect flaviviruses’ have been discovered in natural mosquito populations. In a previous study we described the presence of flavivirus DNA sequences integrated in Aedes albopictus (Asian tiger mosquito) populations from Northern Italy in 2007. Methods During 2008 we collected and tested Aedes females for flavivirus presence and developed phylogenetic analysis, virus isolation, electron microscopy studies and RNAse treatments. Results We detected a high prevalence of flavivirus in Ae. albopictus (77.5%). The phylogenetic analysis identified the insect flavivirus sequences as Aedes flavivirus (AEFV) recently described in Japan, and that may have been introduced in Italy travelling with the tiger mosquito. Some of these pools grew in C6/36 cells, producing cytopathic effects, and the RNase treatment results showed the presence of the detected sequences in RNA forms. Furthermore, we detected a new insect flavivirus in one pool of Aedes cinereus/geminus mosquitoes. Phylogenetic analysis of this virus shows that it forms a distinct cluster within the clade of insect flavivirus. Conclusions This is the first study to report a high prevalence, to describe the seasonal activity and an isolation of the insect flavivirus Aedes flavivirus in Europe. Moreover we describe the detection of a new insect flavivirus detected from Ae. cinereus mosquitoes from Italy. These flavivirus may be common, ubiquitous and diverse in nature and we discuss the implications of the insect flavivirus group in virus evolution and transmission.This work was supported by The Autonomous Province of Trento, postdoctoral project Risktiger, “Risk assessment of new arbovirus diseases transmitted by Aedes albopictus (Diptera: Culicidae) in the Autonomous Province of Trento” and EuroWestNile EU grant HEALTH.2010.2.3.3-3 Project 261391.Peer Reviewe

Why account for biodiversity for mitigating tick-borne disease risk? Insights and perspectives from eastern Italian Alps

The biodiversity crisis is one of the most critical environmental issues of our time. Species losses affect ecosystem functioning by depriving those services - such as carbon sequestration, nutrient cycling and resistance to drought - on which also humans rely. Among these, control of infectious diseases is a highly valuable service provided by biodiversity with implications for human health. Habitat degradation and the resulting biodiversity loss, alter the ratio among generalist species and specialist, thus increasing the risk of zoonotic emergence since many generalist species are competent reservoirs. Currently, scientific studies considered either the role of anthropogenic changes (e.g., climate and land-use) on disease emergence or how biodiversity affects dynamics of endemic diseases. Indeed, a multitude of studies performed in the Eastern Italian Alps (Autonomous Province of Trento, Italy) unveiled what are the environmental and climatic factors driving risk of tick-borne zoonoses emergence. In particular, findings from a systematic review evidenced that temperature-dependent variables were negatively associated to the variation of Tick borne encephalitis (TBE) across Europe. Further, habitat diversity seemed to also dilute TBE virus (TBEv) incidence. Conversely, covariates related to the presence of competent hosts (i.e., rodents) and forest cover had a positive role in TBEv circulation, while incompetent hosts (i.e., deer) showed a hump-shaped effect. These patterns were confirmed also through empirical studies. Specifically, a study found that TBEv detection was related with number of co-feeding ticks carried by rodents, which in turn is negatively correlated with autumnal cooling rate and increased with tick burden on rodents, deer and rodent abundance. Therefore, a specific combination of climatic conditions and certain rodent and deer densities resulted the principal determinants of the TBEv incidence. Similarly, another study highlighted the strong relation between TBEv cases and air pollen abundance, a proxy for seed production. This suggested the major role of rodents as amplifying hosts, being favored by the availability of seeds and thus by pollen quantities. Similar insights were observed in experimental research evaluating the role of artificial ungulate feeding sites in disease spreading. Here, food availability promoted the density of mice, while favoring revisitation patterns of roe deer and interspecific competition among rodents’ species. Co-occurrence of roe deer and mice at these sites affected infectious pathogen transmission, with lower prevalence of tick-borne pathogens (Borrelia burgdorferi s.l., Babesia microti, Anaplasma phagocytophylum and Hepatozoon spp.), while the opposite was found for rodent-borne ones (hantaviruses). Beyond hosts, also land-use plays a crucial role in driving disease circulation. In this sense, a study investigating the effects of land-use type on acarological hazard for Ixodes ricinus and on its infection rate found a positive effect of climate on relative abundance of questing nymphs, while no differences were observed among land-use categories. However, when considering the density of infected nymphs (DIN), the effect of land-use emerged with the natural habitats having the highest DIN values for B. burgdorferi s.l., the urban habitats the highest ones for A. phagocytophilum, while for Rickettsia spp., no differences were observed. Overall, this provides evidence for complex ecological factors to consider for predicting microbial hazard. However, so far, few studies have tried to reconcile the relationship between biodiversity, anthropogenic change, circulation of endemic pathogens and risk of disease emergence. By considering the cascading eco-epidemiological processes occurring in ecosystems with different degrees of naturalness we aim to identify the anthropogenic impacts on biodiversity, and the role of the latter in driving infectious disease circulation and emergence

Changes in host densities and co-feeding pattern efficiently predict tick-borne encephalitis hazard in an endemic focus in northern Italy

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Detection of a new insect flavivirus and isolation of <it>Aedes</it> flavivirus in Northern Italy

Abstract Background During recent years, numerous novel ‘insect flaviviruses’ have been discovered in natural mosquito populations. In a previous study we described the presence of flavivirus DNA sequences integrated in Aedes albopictus (Asian tiger mosquito) populations from Northern Italy in 2007. Methods During 2008 we collected and tested Aedes females for flavivirus presence and developed phylogenetic analysis, virus isolation, electron microscopy studies and RNAse treatments. Results We detected a high prevalence of flavivirus in Ae. albopictus (77.5%). The phylogenetic analysis identified the insect flavivirus sequences as Aedes flavivirus (AEFV) recently described in Japan, and that may have been introduced in Italy travelling with the tiger mosquito. Some of these pools grew in C6/36 cells, producing cytopathic effects, and the RNase treatment results showed the presence of the detected sequences in RNA forms. Furthermore, we detected a new insect flavivirus in one pool of Aedes cinereus/geminus mosquitoes. Phylogenetic analysis of this virus shows that it forms a distinct cluster within the clade of insect flavivirus. Conclusions This is the first study to report a high prevalence, to describe the seasonal activity and an isolation of the insect flavivirus Aedes flavivirus in Europe. Moreover we describe the detection of a new insect flavivirus detected from Ae. cinereus mosquitoes from Italy. These flavivirus may be common, ubiquitous and diverse in nature and we discuss the implications of the insect flavivirus group in virus evolution and transmission.</p

"Delirium Day": A nationwide point prevalence study of delirium in older hospitalized patients using an easy standardized diagnostic tool

Background: To date, delirium prevalence in adult acute hospital populations has been estimated generally from pooled findings of single-center studies and/or among specific patient populations. Furthermore, the number of participants in these studies has not exceeded a few hundred. To overcome these limitations, we have determined, in a multicenter study, the prevalence of delirium over a single day among a large population of patients admitted to acute and rehabilitation hospital wards in Italy. Methods: This is a point prevalence study (called "Delirium Day") including 1867 older patients (aged 65 years or more) across 108 acute and 12 rehabilitation wards in Italian hospitals. Delirium was assessed on the same day in all patients using the 4AT, a validated and briefly administered tool which does not require training. We also collected data regarding motoric subtypes of delirium, functional and nutritional status, dementia, comorbidity, medications, feeding tubes, peripheral venous and urinary catheters, and physical restraints. Results: The mean sample age was 82.0 ± 7.5 years (58 % female). Overall, 429 patients (22.9 %) had delirium. Hypoactive was the commonest subtype (132/344 patients, 38.5 %), followed by mixed, hyperactive, and nonmotoric delirium. The prevalence was highest in Neurology (28.5 %) and Geriatrics (24.7 %), lowest in Rehabilitation (14.0 %), and intermediate in Orthopedic (20.6 %) and Internal Medicine wards (21.4 %). In a multivariable logistic regression, age (odds ratio [OR] 1.03, 95 % confidence interval [CI] 1.01-1.05), Activities of Daily Living dependence (OR 1.19, 95 % CI 1.12-1.27), dementia (OR 3.25, 95 % CI 2.41-4.38), malnutrition (OR 2.01, 95 % CI 1.29-3.14), and use of antipsychotics (OR 2.03, 95 % CI 1.45-2.82), feeding tubes (OR 2.51, 95 % CI 1.11-5.66), peripheral venous catheters (OR 1.41, 95 % CI 1.06-1.87), urinary catheters (OR 1.73, 95 % CI 1.30-2.29), and physical restraints (OR 1.84, 95 % CI 1.40-2.40) were associated with delirium. Admission to Neurology wards was also associated with delirium (OR 2.00, 95 % CI 1.29-3.14), while admission to other settings was not. Conclusions: Delirium occurred in more than one out of five patients in acute and rehabilitation hospital wards. Prevalence was highest in Neurology and lowest in Rehabilitation divisions. The "Delirium Day" project might become a useful method to assess delirium across hospital settings and a benchmarking platform for future surveys