Molecular detection of kobuviruses in European roe deer (Capreolus capreolus) in Italy.

Kobuvirus RNA was found in 6.6 % (13/198) of stool specimens from roe deer (Capreolus capreolus) captured during the regular hunting season. Upon sequence analysis of a fragment of the 3D gene, nine strains displayed the highest nucleotide sequence identity (91.2-97.4 %) to bovine kobuviruses previously detected in either diarrhoeic or asymptomatic calves. Interestingly, four strains were genetically related to the newly discovered caprine kobuviruses (84.2-87.6 % nucleotide identity) identified in black goats in Korea.

Seroprevalence of norovirus genogroup IV antibodies among humans, Italy, 2010-2011.

Noroviruses (NoVs) of genogroup IV (GIV) (Alphatron-like) cause infections in humans and in carnivorous animals such as dogs and cats. We screened an age-stratified collection of serum samples from 535 humans in Italy, using virus-like particles of genotypes GIV.1, circulating in humans, and GIV.2, identified in animals, in ELISA, in order to investigate the prevalence of GIV NoV-specific IgG antibodies. Antibodies specific for both genotypes were detected, ranging from a prevalence of 6.6% to 44.8% for GIV.1 and from 6.8% to 15.1% for GIV.2 among different age groups. These data are consistent with a higher prevalence of GIV.1 strains in the human population. Analysis of antibodies against GIV.2 suggests zoonotic transmission of animal NoVs, likely attributable to interaction between humans and domestic pets. This finding, and recent documentation of human transmission of NoVs to dogs, indicate the possibility of an evolutionary relationship between human and animal NoVs.

Molecular evidence of kobuviruses in free-ranging red foxes (Vulpes vulpes).

Red foxes (Vulpes vulpes) are susceptible to viral diseases of domestic carnivores. In this study, by screening rectal swabs collected from 34 red foxes in Italy, we identified kobuvirus RNA in five samples. Based on analysis of partial RdRp and full-length VP1 genes, all of the strains shared the highest identity with canine kobuviruses (CaKVs) recently detected in the US, the UK and Italy. These findings provide the first evidence of the circulation of these novel viruses in foxes.

Genetic heterogeneity of bovine noroviruses in Italy.

By screening 104 faecal samples from asymptomatic calves in Italy, bovine norovirus RNA was detected with a prevalence rate of 10.5 % (11/104). A continuous sequence spanning the RdRp region and the 5' end of the capsid gene was generated for 7 of the 11 strains. Upon phylogenetic analysis, five strains were grouped with GIII.2 Newbury2-like viruses, and one strain was grouped with GIII.1 Jena-like noroviruses. Interestingly, one strain (80TE/IT) was genetically related to the GIII.1/Jena/80/De in the RdRp but resembled the GIII.2/Newbury2/76/UK in the capsid gene, suggesting a recombination event occurring in the ORF1/ORF2 junction region.

Susceptibility of Mediterranean Buffalo (Bubalus bubalis) following Experimental Infection with Lumpy Skin Disease Virus.

Lumpy skin disease (LSD) is a viral disease of cattle and water buffalo characterized by cutaneous nodules, biphasic fever, and lymphadenitis. LSD is endemic in Africa and the Middle East but has spread to different Asian countries in recent years. The disease is well characterized in cattle while little is known about the disease in buffaloes in which no experimental studies have been conducted. Six buffaloes and two cattle were inoculated with an Albanian LSD virus (LSDV) field strain and clinically monitored for 42 days. Only two buffaloes showed fever, skin nodules, and lymphadenitis. All samples collected (blood, swabs, biopsies, and organs) were tested in real-time PCR and were negative. Between day 39 and day 42 after inoculation, anti-LSDV antibodies were detected in three buffaloes by ELISA, but all sera were negative by virus neutralization test (VNT). Cattle showed severe clinical signs, viremia, virus shedding proven by positive real-time PCR results, and seroconversion confirmed by both ELISA and VNT. Clinical findings suggest that susceptibility in buffaloes is limited compared to in cattle once experimentally infected with LSDV. Virological results support the hypothesis of buffalo resistance to LSD and its role as an accidental non-adapted host. This study highlights that the sensitivity of ELISA and VNT may differ between animal species and further studies are needed to investigate the epidemiological role of water buffalo.

Molecular detection of Aichi virus in raw sewage in Italy.

Aichi virus (AiV) is suspected to play a role in viral gastroenteritis in humans. In this study, we assessed the presence of AiV in untreated influent sewage samples collected at four wastewater treatment plants in central Italy. AiV was detected in 6 (12.5 %) of the 48 specimens and in all plants. All of the Italian strains showed the highest nucleotide and amino acid sequence identity to genotype B AiV detected recently in Asia, especially in China.

Molecular detection of bovine kobuviruses in Italy.

Faecal samples obtained from either asymptomatic or diarrhoeic calves in Italy were screened for bovine kobuviruses (BKVs) using specific primers. BKV RNA was detected in 4.9 % of the samples, with higher positivity rates in diarrhoeic calves (5.3 %) than in asymptomatic animals (4.8 %), although the difference was not statistically significant. Upon sequence analysis, all of the Italian viruses formed a tight group along with BKV-like sequences previously detected in Thailand and Japan.

A Deletion Encompassing the Furin Cleavage Site in the Spike Encoding Gene Does Not Alter SARS-CoV-2 Replication in Lung Tissues of Mink and Neutralization by Convalescent Human Serum Samples.

SARS-CoV-2 has been shown to lose the furin polybasic cleavage site (FCS) following adaptation on cell culture. Deletion occurring in this region, which may include also the FCS flanking regions, seem not to affect virus replication in vitro; however, a chimeric SARS-CoV-2 virus without the sole FCS motif has been associated with lower virulence in mice and lower neutralization values. Moreover, SARS-CoV-2 virus lacking the FCS was shed to lower titers from experimentally infected ferrets and was not transmitted to cohoused sentinel animals, unlike wild-type virus. In this study, we investigated the replication kinetics and cellular tropism of a SARS-CoV-2 isolate carrying a 10-amino acid deletion in the spike protein spanning the FCS in lung ex vivo organ cultures of mink. Furthermore, we tested the neutralization capabilities of human convalescent SARS-CoV-2 positive serum samples against this virus. We showed that this deletion did not significantly hamper neither ex vivo replication nor neutralization activity by convalescent serum samples. This study highlights the importance of the preliminary phenotypic characterization of emerging viruses in ex vivo models and demonstrates that mink lung tissues are permissive to the replication of a mutant form of SARS-CoV-2 showing a deletion spanning the FCS. Notably, we also highlight the need for sequencing viral stocks before any infection study as large deletions may occur leading to the misinterpretation of results.

Analysis of Synchronous and Asynchronous In Vitro Infections with Homologous Murine Norovirus Strains Reveals Time-Dependent Viral Interference Effects.

Viral recombination is a key mechanism in the evolution and diversity of noroviruses. In vivo, synchronous single-cell coinfection by multiple viruses, the ultimate prerequisite to viral recombination, is likely to be a rare event and delayed secondary infections are a more probable occurrence. Here, we determine the effect of a temporal separation of in vitro infections with the two homologous murine norovirus strains MNV-1 WU20 and CW1 on the composition of nascent viral populations. WU20 and CW1 were either synchronously inoculated onto murine macrophage cell monolayers (coinfection) or asynchronously applied (superinfection with varying titres of CW1 at half-hour to 24-h delays). Then, 24 h after initial co-or superinfection, quantification of genomic copy numbers and discriminative screening of plaque picked infectious progeny viruses demonstrated a time-dependent predominance of primary infecting WU20 in the majority of viral progenies. Our results indicate that a time interval from one to two hours onwards between two consecutive norovirus infections allows for the establishment of a barrier that reduces or prevents superinfection.

West Nile Virus Lineage 1 in Italy: Newly Introduced or a Re-Occurrence of a Previously Circulating Strain?

In Italy, West Nile virus (WNV) appeared for the first time in the Tuscany region in 1998. After 10 years of absence, it re-appeared in the areas surrounding the Po River delta, affecting eight provinces in three regions. Thereafter, WNV epidemics caused by genetically divergent isolates have been documented every year in the country. Since 2018, only WNV Lineage 2 has been reported in the Italian territory. In October 2020, WNV Lineage 1 (WNV-L1) re-emerged in Italy, in the Campania region. This is the first occurrence of WNV-L1 detection in the Italian territory since 2017. WNV was detected in the internal organs of a goshawk (Accipiter gentilis) and a kestrel (Falco tinnunculus). The RNA extracted in the goshawk tissue samples was sequenced, and a Bayesian phylogenetic analysis was performed by a maximum-likelihood tree. Genome analysis, conducted on the goshawk WNV complete genome sequence, indicates that the strain belongs to the WNV-L1 Western-Mediterranean (WMed) cluster. Moreover, a close phylogenetic similarity is observed between the goshawk strain, the 2008-2011 group of Italian sequences, and European strains belonging to the Wmed cluster. Our results evidence the possibility of both a new re-introduction or unnoticed silent circulation in Italy, and the strong importance of keeping the WNV surveillance system in the Italian territory active.

Detection of hepatitis E virus in slaughtered pigs in Italy.

The stools of slaughtered pigs were screened for hepatitis E virus (HEV). HEV RNA was detected in 7.3% of the samples. HEV strains were characterized as genotype 3 subtype c, a cluster previously not described in Italy. These findings provide evidence that slaughterhouse workers may be exposed to HEV infection.

Complete Coding Sequences of Lumpy Skin Disease Virus Strains Isolated from Cutaneous Lesions in Namibian Cattle during 2016 Outbreaks.

Between September and October 2016, an outbreak of lumpy skin disease (LSD) was monitored in the Okakarara veterinary district of Namibia. The complete coding sequences were obtained for LSD virus isolates from skin nodules from two symptomatic animals.

Circovirus in domestic and wild carnivores: An important opportunistic agent?

Circoviruses are relatively novel pathogens with increased importance in canids. In this study, we first screened the presence of dog circovirus (DogCV) by molecular methods from a total number of 389 internal organ samples originating from 277 individuals of domestic dogs and wild animals including wolves, foxes and badgers. All the animals originated from Central-Southern Italy, specifically from Abruzzi and Molise regions, areas hosting several natural parks. DogCV was detected in 9/34 wolves (P=26.4%; IC 95%: 14.6-43.1%), 8/209 dogs (P=3.8%; IC 95%: 1.9-7.3%), 0/24 foxes (P=0%; IC 95%: 0-13.8%), 1/10 badgers (P=10%; IC 95%: 1.79-40.4%). However, all DogCV positive animals were shown to be infected at least by an additional key pathogen, including canine distemper virus (CDV) and canine parvovirus type 2. All wolves, but one, presenting DogCV in the internal tissues suffered from CDV infection. The DNA purified from 17 DogCV infected organs was used for whole genome sequencing and phylogenetic analysis.

Bovine noroviruses: A missing component of calf diarrhoea diagnosis.

Noroviruses are RNA viruses that belong to the Genus Norovirus, Family Caliciviridae, and infect human beings and several animal species, including cattle. Bovine norovirus infections have been detected in cattle of a range of different ages throughout the world. Currently there is no suitable cell culture system for these viruses and information on their pathogenesis is limited. Molecular and serological tests have been developed, but are complicated by the high genetic and antigenic diversity of bovine noroviruses. Bovine noroviruses can be detected frequently in faecal samples of diarrhoeic calves, either alone or in association with other common enteric pathogens, suggesting a role for these viruses in the aetiology of calf enteritis.

First report of feline morbillivirus in Europe.

Feline morbillivirus was detected in urine samples of a 15 year old cat suffering from severe nephropathy. Viral RNA was not detected in blood and faecal samples and also the most common pathogens associated to cat kidney failure were not found. This report describes the first evidence of feline morbillivirus in Europe.

Canine kobuviruses in diarrhoeic dogs in Italy.

Canine kobuviruses (CaKVs) are newly recognized picornaviruses recently detected in dogs in the US. By molecular analysis of the whole genome, CaKV that appeared genetically closest to the murine kobuvirus (MuKV) and to the human Aichi virus (AiV), may be classified in the Kobuvirus genus as new genotype (CaKV type 1) within the species Aichivirus A. To date, there are no information on the epidemiology of these novel viruses in other continents. In this study, by screening a collection of 256 dog fecal samples either from diarrhoeic or asymptomatic animals, CaKV was identified in six specimens with an overall prevalence of 2.34% (6/256). All the positive dogs presented diarrhea and were found to be infected by CaKV alone or in mixed infections with canine coronavirus (CCoV) and/or canine parvovirus type 2 (CPV-2). By molecular analysis of the partial 3D gene, all the strains detected displayed a close relatedness with the CaKVs recently identified in the US. This study provides evidence that CaKVs circulate in diarrhoeic dogs in Italy and are not geographically restricted to the North American continent, where they were first signaled.

Molecular detection of porcine kobuviruses in Italian swine.

In this study, fecal specimens (n=260) collected from Italian healthy pigs aged between 6 and 10 months were screened by RT-PCR using generic kobuvirus primers. Porcine kobuviruses (PKVs) were detected in 3.85% of the samples tested. Based on the analysis of the partial 3D gene, the Italian sequences identified here were more closely related to PKVs previously identified in Japan, Thailand, Korea, China and Brazil than to the European PKVs recently detected in Hungary and in the Netherlands.