Davide Lelli

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PCV2 shedding after challenge by infected semen in PCV2 vaccinated and non-vaccinated conventional gilts

43rd Annual Meeting AASV, 2012

The Interaction of Hypericin with SARS-CoV-2 Reveals a Multimodal Antiviral Activity

ACS Applied Materials & Interfaces

Hypericin is a photosensitizing drug that is active against membrane-enveloped viruses and theref... more Hypericin is a photosensitizing drug that is active against membrane-enveloped viruses and therefore constitutes a promising candidate for the treatment of SARS-CoV-2 infections. The antiviral efficacy of hypericin is largely determined by its affinity toward viral components and by the number of active molecules loaded on single viruses. Here we use an experimental approach to follow the interaction of hypericin with SARS-CoV-2, and we evaluate its antiviral efficacy, both in the dark and upon photoactivation. Binding to viral particles is directly visualized with fluorescence microscopy, and a strong affinity for the viral particles, most likely for the viral envelope, is measured spectroscopically. The loading of a maximum of approximately 30 molecules per viral particle is estimated, despite with marked heterogeneity among particles. Because of this interaction, nanomolar concentrations of photoactivated hypericin substantially reduce virus infectivity on Vero E6 cells, but a partial effect is also observed in dark conditions, suggesting multiple mechanisms of action for this drug.

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Understanding West Nile virus spread: Mathematical modelling to determine the mechanisms with the most influence on infection dynamics

West Nile disease is a vector-borne disease caused by West Nile virus (WNV), involving mosquitoes... more West Nile disease is a vector-borne disease caused by West Nile virus (WNV), involving mosquitoes as vectors and birds as maintenance hosts. Humans and other mammals can be infected via mosquito bites, developing symptoms ranging from mild fever to severe neurological infection. Due to the worldwide spread of WNV, human infection risk is high in several countries. Nevertheless, there are still several knowledge gaps regarding WNV dynamics. Several aspects of transmission taking place between birds and mosquitoes, such as the length of the infectious period in birds or mosquito biting rates, are still not fully understood, and precise quantitative estimates are still lacking for the European species involved. This lack of knowledge affects the precision of parameter values when modelling the infection, consequently resulting in a potential impairment of the reliability of model simulations and predictions. Further investigations are thus needed to better understand these aspects, but...

Serosrveillance for Schmallenberg Virus (SBV) in Wild Boar (Sus Scorfa) in Northern Italy

Additional file 3: Figure S3. of Isolation of three novel reassortant phleboviruses, Ponticelli I, II, III, and of Toscana virus from field-collected sandÂ flies in Italy

Similarity plots of the concatenated sequences of the genes of the Ponticelli I, II, and III viru... more

Fast and real-time electrical transistor assay for quantifying SARS-CoV-2 neutralizing antibodies

Communications Materials

Due to the SARS-CoV-2 pandemic renewed attention has been directed towards viral neutralization a... more Due to the SARS-CoV-2 pandemic renewed attention has been directed towards viral neutralization assays and neutralizing antibodies quantification, for vaccine pre-clinical trials and determining vaccine efficacy over time. The gold standard to assess antibody titer is the plaque reduction neutralization test, an end-point assay which evaluates the highest serum antibody dilution that neutralizes viral replication, by inspecting the cytopathic effect induced on cell cultures. Here, we use planar, PEDOT:PSS-based organic electrochemical transistors for real-time, remote-controlled, reliable and fast electrical monitoring of the cytopathic effect induced by SARS29 CoV-2 on Vero E6 cell lines, allowing the quantification of serum neutralizing titer. Our low-cost and scalable device has the potential to speed-up large-scale viral neutralization screening without the need for cancerous staining or highly specialized operators. Finally, the technology could be easily transferred to assess ...

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Detailed epitope mapping of SARS-CoV-2 nucleoprotein reveals specific immunoresponse in cats and dogs housed with COVID-19 patients

Research in Veterinary Science

Co-Circulation of Phleboviruses and Leishmania Parasites in Sand Flies from a Single Site in Italy Monitored between 2017 and 2020

Viruses, 2021

Sand flies transmit Leishmania infantum, which is responsible for causing leishmaniasis, as well ... more Sand flies transmit Leishmania infantum, which is responsible for causing leishmaniasis, as well as many phleboviruses, including the human pathogenic Toscana virus. We screened sand flies collected from a single site between 2017 and 2020 for the presence of both phleboviruses and Leishmania. The sand flies were sampled with attractive carbon dioxide traps and CDC light traps between May and October. We collected more than 50,000 sand flies; 2826 were identified at the species level as Phlebotomus perfiliewi (98%) or Phlebotomus perniciosus (2%). A total of 16,789 sand flies were tested in 355 pools, and phleboviruses were found in 61 pools (6 Toscana virus positive pools, 2 Corfou virus positive pools, 42 Fermo virus positive pools, and 7 Ponticelli virus positive pools, and 4 unidentified phlebovirus positive pools). Leishmania was found in 75 pools and both microorganisms were detected in 16 pools. We isolated nine phleboviruses from another 2960 sand flies (five Ponticelli viru...

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Mammalian Orthoreovirus: Caratterizzazione genomica di isolati da cane, gatto e pipistrello

Ricostruzione filogenetica dell’origine e dispersione geografica di WNV2 in Italia

Best Molecular Tools to Investigate Coronavirus Diversity in Mammals: A Comparison

Viruses

Coronaviruses (CoVs) are widespread and highly diversified in wildlife and domestic mammals and c... more Coronaviruses (CoVs) are widespread and highly diversified in wildlife and domestic mammals and can emerge as zoonotic or epizootic pathogens and consequently host shift from these reservoirs, highlighting the importance of veterinary surveillance. All genera can be found in mammals, with α and β showing the highest frequency and diversification. The aims of this study were to review the literature for features of CoV surveillance in animals, to test widely used molecular protocols, and to identify the most effective one in terms of spectrum and sensitivity. We combined a literature review with analyses in silico and in vitro using viral strains and archive field samples. We found that most protocols defined as pan-coronavirus are strongly biased towards α- and β-CoVs and show medium-low sensitivity. The best results were observed using our new protocol, showing LoD 100 PFU/mL for SARS-CoV-2, 50 TCID50/mL for CaCoV, 0.39 TCID50/mL for BoCoV, and 9 ± 1 log2 ×10−5 HA for IBV. The prot...

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Survey on the Presence of Viruses of Economic and Zoonotic Importance in Avifauna in Northern Italy

Microorganisms

Wild birds play an important role in the circulation and spread of pathogens that are potentially... more Wild birds play an important role in the circulation and spread of pathogens that are potentially zoonotic or of high economic impact on zootechnical production. They include, for example, West Nile virus (WNV), Usutu virus (USUV), avian influenza virus (AIV), and Newcastle disease virus (NDV), which, despite having mostly an asymptomatic course in wild birds, have a strong impact on public health and zootechnical production. This study investigated the presence of these viruses in several wild bird species from North Italy during the biennium 2019–2020. Wild birds derived from 76 different species belonging to 20 orders. Out of 679 birds, 27 were positive for WNV (lineage 2) with a prevalence of 4%; all birds were negative for USUV; one gull was positive for H13N6 influenza virus, and 12 samples were positive for NDV with a prevalence of 2%. Despite the low prevalence observed, the analyses performed on these species provide further data, allowing a better understanding of the diff...

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Dataset of immune responses induced in swine by an inactivated Porcine Circovirus 2b vaccine

Data in Brief

A whole virus, inactivated, Porcine Circovirus 2b (PCV2b) vaccine was submitted to a quantal assa... more A whole virus, inactivated, Porcine Circovirus 2b (PCV2b) vaccine was submitted to a quantal assay of potency, as explained in detail in our companion paper [1]. To this purpose, twenty, 45-day old piglets, checked for maternallyderived antibody (MDA), were allocated to four groups of 5 animals each; these were vaccinated with 800/266/88/0 nanograms, respectively, of an inactivated PCV2b strain, consisting of two distinct virion populations. Twenty-six days later, all the pigs were challenged intranasally with the homologous PCV2b strain. In the presence of a clear dosedependent protection in terms of viremia, no such effect was observed in terms of weight gain after challenge. The 800 and 266-ng payloads were associated with neutralizing antibody titers above the MDA levels in oral fluids. Higher levels of viremia in control and 88-ng groups [1] coincided with a higher Natural Killer activity of tracheobronchial lymph

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Absence of SARS‐CoV‐2 RNA and anti‐SARS‐CoV‐2 antibodies in stray cats

Transboundary and Emerging Diseases

Abstract SARS‐CoV‐2 positive or seropositive owned cats have been reported worldwide. The detecti... more Abstract SARS‐CoV‐2 positive or seropositive owned cats have been reported worldwide. The detection of seropositive stray cats in the proximity of farms of infected minks, coupled with the demonstration of cat‐to‐cat transmission in experimental settings, raise the question whether stray cats may have an epidemiological role in the COVID‐19 pandemic and may act as sentinel for the circulation of SARS‐CoV‐2. The aim of this study was to evaluate the presence of SARS‐CoV‐2 RNA and anti‐SARS‐CoV‐2 antibodies in free roaming cats belonging to colonies located in an area highly affected by the COVID‐19 pandemic and to correlate the results with the positivity rate in people sharing the same area. Interdigital, cutaneous, oropharyngeal, nasal and rectal swabs, as well as blood samples, were collected from 99 cats living in colonies and admitted to our hospital for neutering. This caseload corresponds to the 24.2% of the feline population living in the 25 sampled colonies and to the 5.6% of all the free‐roaming registered cats. The presence of SARS‐CoV‐2 RNA in swabs was assessed using real time RT‐PCR. Anti‐SARS‐CoV‐2 serum antibodies were assessed using commercially available ELISA kits and confirmed by serum virus neutralization. In people, the SARS‐CoV‐2 positivity rate ranged from 3.0% to 5.1% (mean rate: 4.1%) and the seropositive rate from 12.1% to 16.3% (mean rate: 14.2%). Most of the colonies were in urban areas and resident cats had frequent contacts with external cats or people. A COVID‐19 positive caretaker was found, whereas all the cats were negative for SARS‐CoV‐2 RNA and seronegative. Although the negative results cannot exclude previous infections followed by decrease of antibodies, this study suggests that colony cats do not have an important epidemiological role in SARS‐CoV‐2 transmission dynamics. Further studies on larger caseloads are warranted, also in the light of the emerging new viral variants, on a One Health perspective.

Non-Assembled ORF2 Capsid Protein of Porcine Circovirus 2b Does Not Confer Protective Immunity

Pathogens

Porcine Circovirus 2 (PCV2) vaccines are based on either inactivated whole virion, or recombinant... more Porcine Circovirus 2 (PCV2) vaccines are based on either inactivated whole virion, or recombinant ORF2 capsid protein assembled into Virus-like Particles (VLPs). No data are available about the immunizing properties of free, non-assembled capsid protein. To investigate this issue, ORF2 of a reference PCV2b strain was expressed in a Baculovirus-based expression system without assembly into VLPs. The free purified protein was formulated into an oil vaccine at three distinct Ag payloads: 10.8/3.6/1.2 micrograms/dose. Each dose was injected intramuscularly into five, 37-day old piglets, carefully matched for maternally-derived antibody. Five control piglets were injected with sterile PBS in oil adjuvant. Twenty-eight days later, all the pigs were challenged intranasally with 105.3 TCID50 of PCV2b strain DV6503. After challenge infection, all the pigs remained in good clinical conditions. The recombinant vaccine did not induce significant antibody and PCV2-specific IFN-γ responses. ELISP...

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West Nile and Usutu Viruses’ Surveillance in Birds of the Province of Ferrara, Italy, from 2015 to 2019

Viruses

West Nile (WNV) and Usutu (USUV) viruses are mosquito-borne flaviviruses. Thanks to their importa... more West Nile (WNV) and Usutu (USUV) viruses are mosquito-borne flaviviruses. Thanks to their importance as zoonotic diseases, a regional plan for surveillance of Arboviruses was implemented in Emilia-Romagna in 2009. The province of Ferrara belongs to the Emilia-Romagna region, and it is an endemic territory for these viruses, with favorable ecological conditions for abundance of mosquitoes and wild birds. From 2015 to 2019, we collected 1842 dead-found birds at a wildlife rehabilitation center, which were analysed by three different PCRs for the detection of WNV and USUV genomes. August was characterized by the highest infection rate for both viruses. Columbiformes scored the highest USUV prevalence (8%), while Galliformes and Strigiformes reported the highest prevalence for WNV (13%). Among Passeriformes (the most populated Order), Turdus merula was the most abundant species and scored the highest prevalence for both viruses. To optimize passive surveillance plans, monitoring should ...

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Mosquitoes of the Maculipennis complex in Northern Italy

Scientific Reports

The correct identification of mosquito vectors is often hampered by the presence of morphological... more The correct identification of mosquito vectors is often hampered by the presence of morphologically indiscernible sibling species. The Maculipennis complex is one of these groups that include both malaria vectors of primary importance and species of low/negligible epidemiological relevance, of which distribution data in Italy are outdated. Our study was aimed at providing an updated distribution of Maculipennis complex in Northern Italy through the sampling and morphological/molecular identification of specimens from five regions. The most abundant species wasAnopheles messeae(2032), followed byAnopheles maculipennis s.s.(418),Anopheles atroparvus(28) andAnopheles melanoon(13). Taking advantage of ITS2 barcoding, we were able to finely characterize tested mosquitoes, classifying all theAnopheles messeaespecimens asAnopheles daciae, a taxon with debated rank to which we referred asspecies inquirenda(sp. inq.). The distribution of species was characterized by Ecological Niche Models (...

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Detection and Molecular Characterization of Two Gammaherpesviruses from Pantesco Breed Donkeys during an Outbreak of Mild Respiratory Disease

Viruses

Equid and asinine gammaherpesviruses (GHVs; genus Percavirus) are members of the Herpesviridae fa... more Equid and asinine gammaherpesviruses (GHVs; genus Percavirus) are members of the Herpesviridae family. Though GHVs have been reported in horse populations, less studies are available on gammaherpesviral infections in donkeys. This study reports the co-infection with two GHVs in Pantesco breed donkeys, an endangered Italian donkey breed. Samples (n = 124) were collected on a breeding farm in Southern Italy from 40 donkeys, some of which were healthy or presented erosive tongue lesions and/or mild respiratory signs. Samples were analysed by using a set of nested PCRs targeting the DNA polymerase, glycoprotein B, and DNA-packaging protein genes, and sequence and phylogenetic analyses were performed. Twenty-nine donkeys (72.5%) tested positive, and the presence of Equid gammaherpesvirus 7 and asinine herpesvirus 5 was evidenced. In 11 animals, we found evidence for co-infection with viruses from the two species. Virions with herpesvirus-like morphology were observed by electron microsco...

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Thirteen Years of Phleboviruses Circulation in Lombardy, a Northern Italy Region

Viruses

Phleboviruses transmitted by phlebotomine sandflies are endemic in the Mediterranean basin. Tosca... more Phleboviruses transmitted by phlebotomine sandflies are endemic in the Mediterranean basin. Toscana phlebovirus (TOSV), Sicilian phlebovirus (SFSV), and Naples phlebovirus (SFNV) are responsible of summer fever, with well-known pathogenic potential for humans ranging from asymptomatic to mild fever, in addition to neuro-invasive infections during summer. Although TOSV, in particular, is a significant and well-known human pathogen, SFVs remain neglected, with many gaps in the relevant knowledge. Sero-epidemiological studies and case reports recently showed a geographical wider distribution than previously considered, although the real incidence of phleboviruses infections in the Mediterranean area is still unknown. Here we retrospectively evaluated the circulation of phleboviruses during summer seasons between 2007 and 2019 in 649 patients showing neurological symptoms using both molecular and serological approaches. We found that 42/649 (6.5%) subjects experienced phlebovirus infect...

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Human-to-Cat SARS-CoV-2 Transmission: Case Report and Full-Genome Sequencing from an Infected Pet and Its Owner in Northern Italy

Pathogens

There have been previous reports of the human-to-cat transmission of SARS-CoV-2, but there are on... more There have been previous reports of the human-to-cat transmission of SARS-CoV-2, but there are only a few molecular studies that have compared the whole genome of the virus in cats and their owners. We here describe a case of domestic SARS-CoV-2 transmission from a healthcare worker to his cat for which nasopharyngeal swabs of both the cat and its owner were used for full-genome analysis. The results indicate that quarantine measures should be extended to pets living in SARS-CoV-2-infected households.

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