Modified haemagglutination inhibition assay for the detection of canine parvovirus type 2 antibodies in dog sera.

Canine parvovirus type 2 (CPV-2) infection is associated with severe gastroenteritis in puppies. Quantification of CPV-2 specific antibodies before vaccination can reveal the presence of interfering maternal-derived immunity and facilitate timing of effective immunisation. Inhibition of haemagglutination (HI) is commonly used to measure CPV-2-specific antibody levels in serum. However, the presence of nonspecific agglutinins in canine serum and artefactual precipitation of red blood cells (RBC) are both limitations of the assay. In this study, we compared the standard HI protocol with a refined HI protocol, in which canine serum was pre-incubated with porcine RBC for 12 h to remove nonspecific agglutinins and a lower concentration (0.1% vs. 0.8%) of porcine RBC suspensions was used to limit artefactual precipitation of RBC. A panel of canine sera, collected from 80 dogs of different ages and with different neutralising antibody titres, was analysed. Nonspecific agglutinins were identified in most (97%) serum samples from puppies <4 months of age and in only 7% dogs 6 months old. Pre-treatment of serum samples was effective in removing nonspecific agglutinins from all samples and artefactual precipitation of RBCs was not noted when 0.1% RBC suspensions were used. Refinement of the HI protocol has increased the accuracy of interpretation and reduced the interference of nonspecific agglutinins, primarily seen in puppies. This reduces the likelihood of incorrect assessment of passive or active immunity in puppies when deciding whether to administer or defer vaccination, which could potentially leave them susceptible to CPV-2 infection.

Mutation analysis of the spike protein in Italian feline infectious peritonitis virus and feline enteric coronavirus sequences.

Feline coronavirus (FCoV) exists as two different genotypes, FCoV type I and II, each including two biotypes, feline enteric coronavirus (FECV) and feline infectious peritonitis virus (FIPV), the latter being a virulent variant originating from the former virus. Recently, two amino acid substitutions, M1058L and S1060A, within the spike protein have been associated to the FECV/FIPV virulence change. In this study, we have analysed the frequency of detection of such mutations in FIPV and FECV strains circulating in Italian cats and obtained information about their evolutionary relationships with reference isolates. A total of 40 FCoV strains, including 19 strains from effusions or tissue samples of FIP cats and 21 strains from faecal samples of non-FIP cats, were analysed. Mutation M1058L was detected in 16/18 FCoV-I and 1/1 FCoV-II strains associated with FIP, while change S1060A was presented by two FIPV strains. By phylogenetic analysis, FCoV sequences clustered according to the genotype but not according to the biotype, with FECV/FIPV strains recovered from the same animal being closely related. Further studies are needed to better define the genetic signatures associated with the FECV/FIPV virulence shift.

Evidence of exposure to SARS-CoV-2 in cats and dogs from households in Italy.

SARS-CoV-2 emerged from animals and is now easily transmitted between people. Sporadic detection of natural cases in animals alongside successful experimental infections of pets, such as cats, ferrets and dogs, raises questions about the susceptibility of animals under natural conditions of pet ownership. Here, we report a large-scale study to assess SARS-CoV-2 infection in 919 companion animals living in northern Italy, sampled at a time of frequent human infection. No animals tested PCR positive. However, 3.3% of dogs and 5.8% of cats had measurable SARS-CoV-2 neutralizing antibody titers, with dogs from COVID-19 positive households being significantly more likely to test positive than those from COVID-19 negative households. Understanding risk factors associated with this and their potential to infect other species requires urgent investigation.

Evidence of exposure to SARS-CoV-2 in cats and dogs from households in Italy.

SARS-CoV-2 originated in animals and is now easily transmitted between people. Sporadic detection of natural cases in animals alongside successful experimental infections of pets, such as cats, ferrets and dogs, raises questions about the susceptibility of animals under natural conditions of pet ownership. Here we report a large-scale study to assess SARS-CoV-2 infection in 817 companion animals living in northern Italy, sampled at a time of frequent human infection. No animals tested PCR positive. However, 3.4% of dogs and 3.9% of cats had measurable SARS-CoV-2 neutralizing antibody titers, with dogs from COVID-19 positive households being significantly more likely to test positive than those from COVID-19 negative households. Understanding risk factors associated with this and their potential to infect other species requires urgent investigation. ONE SENTENCE SUMMARY: SARS-CoV-2 antibodies in pets from Italy.

Oral administration of modified live canine parvovirus type 2b induces systemic immune response.

Different strategies have been proposed to overcome maternally derived antibody (MDA) interference with canine parvovirus type 2 (CPV-2) immunisation, including intranasal vaccination, which presents some practical limitations. In the present study, the results of the oral administration of a commercial CPV-2b modified live virus (MLV) vaccine in pups with MDA are reported. The CPV-2b vaccine was orally administered to 14 6-week-old pups with a bait. Blood samples and rectal swabs were collected at different days post-vaccination (dpv) to determine CPV-2 antibody titres and DNA loads. Thirteen pups were positive to serological and virological tests after the first vaccination and one pup became positive after the second vaccine administration. The findings of this study suggest that systemic immunity against CPV-2 may be achieved by the use of an MLV CPV-2b vaccine administered orally even in the presence of MDA titres that usually interfere with vaccination.

Bubaline alphaherpesvirus 1 induces a latent/reactivable infection in goats.

Latent infection is a common mechanism used by several alphaherpesviruses to persist in their host but it is not clear whether this mechanism is also triggered in heterologous infections. Cross-species infections have been documented repeatedly for alphaherpesviruses of ruminants, a group of closely related viruses. Herewith we report latent infection with bubaline alphaherpesvirus 1 (BuHV-1) in experimentally infected goats and subsequent virus reactivation after treatment with dexamethasone (DMS) at 10 months after infection. After DMS treatment, the virus was isolated in one such animal in the nasal swabs from day 3 to 9 post treatment and in the ocular swabs at day 6. The goat was euthanized 48 days after DMS treatment and viral DNA was detected by PCR in the trigeminal ganglia and in two cervical ganglia. Additionally, BuHV-1 DNA was detected by PCR in the trigeminal ganglia of the other 3 goats.

Equine hepacivirus persistent infection in a horse with chronic wasting.

Equine hepacivirus is the closest homologue of hepatitis C virus. Limited data on the clinical features of this infection are available. We report the identification of a horse with high-titre viremia by equine hepacivirus. Over a 15-month follow-up, the clinical signs and the viremic status persisted, suggesting a chronic evolution.

Circulation of multiple subtypes of bovine viral diarrhoea virus type 1 with no evidence for HoBi-like pestivirus in cattle herds of southern Italy.

Pestiviruses of cattle include bovine viral diarrhoea 1 (BVDV-1) and 2 (BVDV-2) plus an emerging group, named HoBi-like pestivirus. In the present paper, the results of an epidemiological survey for pestiviruses circulating in cattle in southern Italy are presented. Molecular assays carried out on a total of 924 bovine samples detected 74 BVDV strains, including 73 BVDV-1 and 1 BVDV-2 viruses. Phylogenetic analysis carried out on partial 5'UTR and Npro sequences revealed the presence of 6 different subtypes of BVDV-1 and a single BVDV-2c strain. BVDV-1 displayed a high level of genetic heterogeneity, which can have both prophylactic and diagnostic implications. In addition, the detection of BVDV-2c highlights the need for a continuous surveillance for the emergence of new pestivirus strains in cattle farms in southern Italy.

Evidence for Circulation of Bovine Viral Diarrhoea Virus Type 2c in Ruminants in Southern Italy.

Recently, bovine viral diarrhoea virus type 2c (BVDV-2c) was responsible for a severe outbreak in cattle in northern Europe. Here, we present the results of an epidemiological survey for pestiviruses in ruminants in southern Italy. Pooled serum samples were obtained from 997 bovine, 800 ovine, 431 caprine and eight bubaline farms, and pestiviral RNA was detected by molecular methods in 44 farms consisting of 16 cattle and one buffalo herds and of 21 sheep and six goat flocks. Twenty-nine and 15 farms were infected by BVDV-1 and BVDV-2 strains, respectively. BVDV-1 strains were recovered mainly from cattle and were heterogeneous, belonging to the subtypes 1b, 1u, 1e, 1g and 1h. In contrast, all BVDV-2 viruses but two were detected in sheep or goats and were characterized as BVDV-2c by sequence analysis of 5'UTR. These strains displayed high genetic identity to BVDV-2c circulating in cattle in northern Europe and were more distantly related to a BVDV-2c isolate recovered from a cattle herd in southern Italy more than 10 years before. The circulation of a BVDV-2c in small ruminants suggests the need for a continuous surveillance for the emergence of pestivirus-induced clinical signs in southern Italian farms.

Novel bocaparvoviruses in rabbits.

Bocaparvovirus is a newly established genus within the family Parvoviridae and has been identified as a possible cause of enteric, respiratory, reproductive/neonatal and neurological disease in humans and several animal species. In this study, metagenomic analysis was used to identify and characterise a novel bocaparvovirus in the faeces of rabbits with enteric disease. To assess the prevalence of the novel virus, rectal swabs and faecal samples obtained from rabbits with and without diarrhoea were screened with a specific PCR assay. The complete genome sequence of the novel parvovirus was reconstructed. The virus was distantly related to other bocaparvoviruses; the three ORFs shared 53%, 53% and 50% nucleotide identity, respectively, to homologous genes of porcine bocaparvoviruses. The virus was detected in 8/29 (28%) and 16/95 (17%) samples of rabbits with and without diarrhoea, respectively. Sequencing of the capsid protein fragment targeted by the diagnostic PCR identified two distinct bocaparvovirus populations/sub-types, with 91.7-94.5% nucleotide identity to each other. Including these novel parvoviruses in diagnostic algorithms of rabbit diseases might help inform their potential pathogenic role and impact on rabbit production and the virological profiles of laboratory rabbits.

Analysis of early strains of the norovirus pandemic variant GII.4 Sydney 2012 identifies mutations in adaptive sites of the capsid protein.

Global surveillance for norovirus identified in 2012 the emergence of a novel pandemic GII.4 variant, termed Sydney 2012. In Italy, the novel pandemic variant was identified as early as November 2011 but became predominant only in the winter season 2012-2013. Upon sequencing and comparison with strains of global origin, the early Sydney 2012 strains were found to differ from those spreading in 2012-2013 in the capsid (ORF2) putative epitopes B, C and D, segregating into a distinct phylogenetic clade. At least three residues (333, 340 and 393, in epitopes B, C and D, respectively) of the VP1 varied among Sydney 2012 strains of different clades. These findings suggest that the spread of the pandemic variant in Italy during the winter season 2012-2013 was due to the introduction of strains distinct from those circulating at low frequency in the former winter season and that similar strains were also circulating elsewhere worldwide.

Evidence for recombination between pandemic GII.4 norovirus strains New Orleans 2009 and Sydney 2012.

During 2012, a novel pandemic GII.4 norovirus variant, Sydney 2012, emerged worldwide. A signature of the variant was a GII.Pe ORF1, in association with GII.4 Apeldoorn 2008-like ORF2-ORF3 genes. We report the detection of recombinant GII.4 Sydney 2012 strains, possessing the ORF1 gene of the former pandemic variant New Orleans 2009.