HoBi-Like Pestivirus and Its Impact on Cattle Productivity.

The clinical features and economic impact of the infection caused by an emerging group of pestiviruses, namely HoBi-like pestivirus, in a cattle herd of southern Italy are reported. In 2011, the virus was first associated with respiratory disease, causing an abortion storm after 1 year and apparently disappearing for the following 3 years after persistently infected calves were slaughtered. However, in 2014, reproductive failures and acute gastroenteritis were observed in the same herd, leading to a marked decrease of productivity. A HoBi-like strain closely related to that responsible for previous outbreaks was detected in several animals. Application of an intensive eradication programme, based on the detection and slaughtering of HoBi-like pestivirus persistently infected animals, resulted in a marked improvement of the productive performances.

Lights and shades on an historical vaccine canine distemper virus, the Rockborn strain.

Both egg- and cell-adapted canine distemper virus (CDV) vaccines are suspected to retain residual virulence, especially if administered to immuno-suppressed animals, very young pups or to highly susceptible animal species. In the early 1980s, post-vaccine encephalitis was reported in dogs from various parts of Britain after administration of a particular batch of combined CDV Rockborn strain/canine adenovirus type-1 vaccine, although incrimination of the Rockborn strain was subsequently retracted. Notwithstanding, this, and other reports, led to the view that the Rockborn strain is less attenuated and less safe than other CDV vaccines, and the Rockborn strain was officially withdrawn from the markets in the mid 1990s. By sequencing the H gene of the strain Rockborn from the 46th laboratory passage, and a commercial vaccine (Candur(®) SH+P, Hoechst Rousell Vet GmbH), the virus was found to differ from the commonly used vaccine strain, Onderstepoort (93.0% nt and 91.7% aa), and to resemble more closely (99.6% nt and 99.3% aa) a CDV strain detected in China from a Lesser Panda (Ailurus fulgens). An additional four CDV strains matching (>99% nt identity) the Rockborn virus were identified in the sequence databases. Also, Rockborn-like strains were identified in two vaccines currently in the market. These findings indicate that Rockborn-like viruses may be recovered from dogs or other carnivores with distemper, suggesting cases of residual virulence of vaccines, or circulation of vaccine-derived Rockborn-like viruses in the field.

Heterogeneity within the hemagglutinin genes of canine distemper virus (CDV) strains detected in Italy.

Canine distemper virus (CDV) is a highly contagious viral pathogen causing lethal disease in dogs and other mammalians. A high degree of genetic variation is found between recent CDV strains and the old CDV isolates used in the vaccines and such genetic variation is regarded as a possible cause of the increasing number of CDV-related diseases in dogs. The H gene shows the greatest extent of genetic variation that allows for distinction of various lineages, according to a geographical pattern of distribution and irrespective of the species of identification. In the present study, hemagglutinin (H) genes obtained from field strains detected from clinical specimens of Italian dogs were analyzed genetically. Phylogenetic analysis revealed that a homogeneous group of CDV strains is widespread in Italian dogs, all which are included into the European lineage. Unexpectedly, strains 179/04 and 48/05 clustered along with CDVs of the Arctic lineage, the highest identity being to strain GR88 (98.0 and 98.4%aa, respectively). The full-length sequence of a red fox CDV strain, 207/00 was also determined and analyzed. The H protein of the fox CDV strain was unrelated to strains within the major European lineage. These results suggest that at least three different CDV lineages are present in Italy.

Antibody levels and protection to canine parvovirus type 2.

The relationship between maternally derived antibody (MDA) levels and protection to canine parvovirus (CPV) infection in pups is reported. Twelve pups with a wide range of haemagglutination inhibiting (HI) titres of MDA to CPV were divided into four groups, with each group balanced for antibody titres. The dogs were inoculated with a field CPV-2b strain and clinical signs, virus shedding and antibody response were assessed. The CPV was not detected in the faeces of dogs with HI titres of 320 at any time. In dogs with HI titres up to 160, active CPV replication after challenge was demonstrated by real-time polymerase chain reaction. The successful infection of dogs with HI titres of 80 and 160 was confirmed by seroconversion, evaluated at day 14 post-infection. These findings demonstrated that CPV infection could also occur in the presence of MDA HI titres (> or =80) usually considered fully protective.

Efficacy of an inactivated canine coronavirus vaccine in pups.

The efficacy of an inactivated CCoV vaccine (Duramune PC) was evaluated in four pups. Two dogs were maintained non-vaccinated. Ten days after the booster shot all the pups were challenged with a field CCoV strain administered by oro-nasal route. The vaccinated pups did not display clinical signs and shed the challenge-virus for 11.25 days, evaluated by virus isolation, and 13.5 days, evaluated by PCR assay. The two non vaccinated pups displayed mild diarrhoea at day post-challenge 4 and shed the challenge-virus for 14 and 15 days respectively, by virus isolation, and for 22 and 24 days respectively, by PCR assay.

Serological analysis and identification of feline calicivirus strains isolated in Sicily.

The isolation and characterization of calicivirus strains from symptomatic cats are reported. The correlations between the feline calicivirus strains isolated and the vaccinal strain FCV F9 were investigated by a virus-neutralization test, suggesting a strong antigenic variability.

Detection and genetic characterization of canine distemper virus (CDV) from free-ranging red foxes in Italy.

Fragments of the genes encoding the haemoagglutinin (H) and the nucleocapsid protein (N) of a canine distemper (CDV)-like virus affecting a red fox (Vulpes vulpes) were sequenced and analysed. The CDV-like virus detected in the fox was found to be not dissimilar, in both the H and N gene, from other CDVs spreading in Italy, as well as all over the world, and phylogenetic analysis on the H protein-encoding gene allowed to include all the Italian CDVs in the H European genotype.

Genomic characterization of pestiviruses isolated from lambs and kids in southern Italy.

A nested polymerase chain reaction was used to identify 13 pestivirus strains isolated from small ruminants in several mixed (sheep and goats) flocks of Southern Italy, and for classification as bovine viral diarrhoea virus (BVDV) type 1, BVDV type 2, and Border disease virus (BDV) genotypes. Of the nine ovine isolates, two were characterized as BVDV type 1, and seven as BVDV type 2. The four pestiviruses isolated from kids belong to BVDV type 1. None of the pestivirus strains tested could be classified as 'true' BDV (genotype 3). Although BVDV type 2 has been described in Europe rarely, the characterization of BD/90-1M strain as BVDV type 2, isolated in Italy in 1990, demonstrates that this genotype has been circulating in Italy since the 1990s.

Evaluation of the natural immunity in pups inoculated with a modified-live canine parvovirus type 2b (CPV-2b) strain.

Three pups 2-4 months old were vaccinated subcutaneously with the modified live canine parvovirus, CPV-2b/29-97 strain. During an observation period of two weeks pups remained clinically health, exhibiting a vigorous post-vaccinal active serological response (haemoagglutinating inhibiting antibody titers for CPV-2 ranging from 1:2560 to 1:5120 at 21 days post inoculation). Phagocytosis and killing of Candida albicans exerted by polymorphonuclear cells and monocytes did not undergo significant modifications 3-6 days post vaccination up to 30 days. Antibacterial activity mediated by peripheral blood lymphocytes (Salmonella typhi was used as a target) was slightly, but not significantly decreased 3 days post vaccination. Conclusively, in pups the CPV type 2b vaccine seems to be safe as far as natural immune responses are concerned, while its immunogenicity is preserved.

Antigenic characterization of canine parvovirus strains isolated in Italy.

28 isolates of canine parvovirus type-2 (CPV-2) were obtained from dogs with hemorrhagic gastroenteritis in Italy. The antigenic structure of CPV-2 isolates was characterized, using four discriminating monoclonal antibodies. In addition, four vaccinal strains were examined. Similar to reports from Australia and the United Kingdom, a much higher prevalence of CPV-2a (25/28 isolates) was observed than the other variant type, CPV-2b (3/28 isolates). DNA fragments (2.2 kbp) of representative strains of CPV-2, CPV-2a and CPV-2b were amplified by the polymerase chain reaction (PCR) and the products were digested by the restriction enzymes (RE) RsaI, HpaII, HindIII and PvuII. The RvaI enzyme allows the differentiation of CPV-2 from CPV-2a and CPV-2b.