Arctic lineage-canine distemper virus as a cause of death in Apennine wolves (Canis lupus) in Italy

Canine distemper virus (CDV) infection is a primary threat affecting a wide number of carnivore species, including wild animals. In January 2013, two carcasses of Apennine wolves (Canis lupus) were collected in Ortona dei Marsi (L'Aquila province, Italy) by the local Veterinary Services. CDV was immediately identified either by RT-PCR or immunohistochemistry in lung and central nervous tissue samples. At the same time, severe clinical signs consistent with CDV infection were identified and taped (Videos S1-S3) from three wolves rescued in the areas surrounding the National Parks of the Abruzzi region by the Veterinary Services. The samples collected from these symptomatic animals also turned out CDV positive by RT-PCR. So far, 30 carcasses of wolves were screened and CDV was detected in 20 of them. The sequencing of the haemagglutinin gene and subsequent phylogenetic analysis demonstrated that the identified virus belonged to the CDV Arctic lineage. Strains belonging to this lineage are known to circulate in Italy and in Eastern Europe amongst domestic dogs. To the best of our knowledge this is the first report of CDV Arctic lineage epidemics in the wild population in Europe.

Development and validation of a real-time PCR assay for specific and sensitive detection of canid herpesvirus 1

A TaqMan-based real-time PCR assay targeting the glycoprotein B-encoding gene was developed for diagnosis of canid herpesvirus 1 (CHV-1) infection. The established assay was highly specific, since no cross-reactions were observed with other canine DNA viruses, including canine parvovirus type 2, canine minute virus, or canine adenovirus types 1 and 2. The detection limit was 10¹ and 1.20 × 10¹ DNA copies per 10 μl⁻¹ of template for standard DNA and a CHV-1-positive kidney sample, respectively: about 1-log higher than a gel-based PCR assay targeting the thymidine kinase gene. The assay was also reproducible, as shown by satisfactory low intra-assay and inter-assay coefficients of variation. CHV-1 isolates of different geographical origins were recognised by the TaqMan assay. Tissues and clinical samples collected from three pups which died of CHV-1 neonatal infection were also tested, displaying a wide distribution of CHV-l DNA in their organs. Unlike other CHV-1-specific diagnostic methods, this quantitative assay permits simultaneous detection and quantitation of CHV-1 DNA in a wide range of canine tissues and body fluids, thus providing a useful tool for confirmation of a clinical diagnosis, for the study of viral pathogenesis and for evaluation of the efficacy of vaccines and antiviral drugs.

Prolonged depletion of circulating CD4+ T lymphocytes and acute monocytosis after pantropic canine coronavirus infection in dogs

A hypervirulent strain (CB/05) of canine coronavirus was employed to infect oronasally 11-week-old pups. Peripheral blood monocytes (CD14⁺), T lymphocytes (CD4⁺ and CD8⁺) and B lymphocytes (CD21⁺) were studied by flow cytometry within 5 days post-infection (p.i.) and at later time points. Infection with CB/05 resulted in a profound depletion of T cells and a slight loss of B cells in the first week p.i. In particular, while the CD8⁺ and the B lymphocytes returned to baseline levels by day 7 p.i., the CD4⁺ T cells remained significantly low until day 30 p.i. and recovered completely only at day 60 p.i. Monocytosis was also observed after CB/05 infection with a peak at day 5 p.i. The prolonged depletion of peripheral CD4⁺ T cells did not alter the levels of serum IgG or IgM. The impact of CB/05 infection on the immune performance of infected pups is discussed.

Glycoprotein C Gene of Caprine Herpesvirus Type 1 Contains Short Sequence Repeats (SSR)

Caprine herpesvirus 1 (CpHV-1) is responsible for vaginal and respiratory disease in goats. Infection by vaginal route is usually restricted to the genital tract whereas by nasal route the virus can spread throughout the body. In order to evaluate genomic diversity, nucleotide sequences of glycoprotein C (gC) of 13 (n.8 vaginal, n.5 nasal) CpHV-1 strains were analyzed. Amino acid (aa) sequences showed a variable number of short sequence repeats (SSR). Nucleotide and amino acid sequences of amplified products showed to contain a variable number of short sequence repeats among the examined strains. These results indicated that CpHV-1 isolates had genetic diversity in the gC gene regarding the number of SSR: 4 SSR of 60 bp in one strain, 2 SSR of 30 bp in seven strains and 1 SSR of 15 bp in three strains. Two strains had no SSR.

Detection of Caprine herpesvirus 1-specific antibodies in goat sera using an enzyme-linked immunosorbent assay and serum neutralization test

An enzyme-linked immunosorbent assay (ELISA) was developed to detect immunoglobulin G (IgG) antibodies directed to whole Caprine herpesvirus 1 (CpHV-1). Sera from 248 goats were obtained from CpHV-1-free and CpHV-1-infected flocks and were subjected to both IgG ELISA and serum neutralization (SN) assays, with the latter considered the gold standard for the diagnosis of CpHV-1 infection. In flocks where CpHV-1 infection was detected, 57 sera were negative by the SN and the ELISA tests and 97 sera were positive with both tests. Thus, although based on biologically different principles, the ELISA was as sensitive as the SN assay in detecting seropositive animals and could be efficiently used as a faster and less expensive alternative to the SN test for the screening of many samples.

Methicillin-resistant coagulase negative staphylococci isolated from horses

A methicillin-resistant (MR) Staphylococcus epidermidis strain was isolated from a saddle horse affected by osteolysis. MR coagulase-negative staphylococci (MRCNS) were isolated from 11 of 14 (78.8%) horses housed in the same riding club. By typing of the SCCmec region, almost the strains displayed a non typeable (NT) pattern and possessed the ccr type 2. Altogether, the high prevalence of MRCNS and the detection of NT SCCmec types support the hypothesis that horses may represent a reservoir of MRCNS for humans and that equine MRCNS may act as potential source of resistance genes for other staphylococci.

Comparison of methods for the detection of methicillin resistance in Staphylococcus aureus isolates from food products

AIMS

To compare several methods for detection of methicillin resistance in Staphylococcus aureus isolates from food.

METHODS AND RESULTS

Two hundred S. aureus isolates from food of animal origin were screened for methicillin resistance by a PCR assay specific for the mecA gene, an oxacillin agar screen test and a cefoxitin disk diffusion test. Six out of 200 strains (3%) were found to be methicillin-resistant Staphylococcus aureus (MRSA) by PCR. The oxacillin agar screen test detected only one of the MRSA isolates (sensitivity of 16.7%) and mischaracterized three additional strains as MRSA (specificity of 98.45%). None of the MRSA strains was detected by the cefoxitin test (sensitivity of 0%), while 15 methicillin-susceptible S. aureus (MSSA) strains were misclassified as resistant (specificity of 92.3%). Fifteen MSSA strains displayed a beta-lactamase hyperproducer-like phenotype. The six MRSA (mecA-positive) strains resembled the characteristics of heteroresistant strains.

CONCLUSIONS

As MRSA of animal origin may display atypical phenotypes, PCR appears to be more reliable for detection of methicillin resistance in animal strains.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study stresses the need for implementing the methods of screening S. aureus from food of animal origin for methicillin resistance.

Potent Inhibition of Genital Herpesvirus Infection in Goats by Cidofovir

Background

Like human herpesvirus 2 (HHV-2) in humans, infection by caprine herpesvirus 1 in goats is associated with genital lesions, and this provides a unique model to study the efficacy and effects of anti-herpetic drugs.

Methods

The antiviral activity of cidofovir was assessed in goats infected experimentally, using various therapeutic protocols.

Results

Topic administration of cidofovir 1% cream prevented the onset of virus-induced genital lesions and drastically reduced virus shedding.

Conclusion

Cidofovir appears to be a very efficient drug for the prevention of genital lesions caused by an alphaherpesvirus.

Prevalence of group C rotaviruses in weaning and post-weaning pigs with enteritis

Diarrheic fecal specimens collected from porcine herds were screened for the presence of group C rotaviruses using a reverse transcription-polymerase chain reaction (RT-PCR) assay. A total of 188 samples were tested and 54 were positive. When compiled these data with diagnostic results on group A rotaviruses and enteric caliciviruses we found that all but 5 group C rotavirus positive samples contained at least one additional virus. A subset of samples were subjected to nucleotide sequencing. The selected strains showed an unexpectedly wide range of nucleotide sequence heterogeneity (88.6-100%) to each other and to the reference porcine group C rotavirus strain, Cowden. The nucleotide sequence identity to the genuine bovine and human strains were, respectively, 86.8 and 87.2% or less. In conclusion, our study demonstrates that infection with group C rotavirus is frequent in Italian piggeries. The considerable rate of multiple infections requires further studies to investigate the pathogenic potential of group C rotaviruses in pigs, alone or in mixed infection, and raises challenges in the laboratory diagnosis of porcine enteric infections.

Methicillin-resistant Staphylococcus aureus (MRSA) in foods of animal origin product in Italy

Methicillin-resistant Staphylococcus aureus (MRSA) strains are a global health concern. The present study regarded 160 S. aureus strains that had been isolated from 1634 foodstuff samples of animal origin in a previous survey conducted in Italy during 2003-2005. The strains were characterized by detecting the mecA gene, the production of type A to D staphylococcal enterotoxins (SEs), and studying their resistance properties against several antibiotics; their ecological origin was determined by biotyping. Of the 160 analyzed S. aureus strains six (3.75%) were mecA positive and derived from six different samples; four isolates were from bovine milk and two from dairy products (pecorino cheese and mozzarella cheese). Two strains isolated from milk belonged to the non-host-specific biovar while the others to the ovine biovar. The strain isolated from mozzarella cheese belonged to the non-host-specific biovar and the strain isolated from pecorino cheese to the ovine biovar. All the MRSA strains isolated were enterotoxigenic; two strains synthesized SEA/SED two SED and one SEC. All the strains showed resistance to at least one of the antibiotics tested but none was resistant to glycopeptides.

Intravaginal administration of an inactivated vaccine prevents lesions induced by caprine herpesvirus-1 in goats

To evaluate the efficacy of mucosal vaccination with a beta-propiolactone inactivated caprine herpesvirus-1 (CpHV-1) vaccine, goats received vaginal administrations of two 7-day cycles at 2 weeks intervals. Seven days after the end of the second cycle, goats were challenged intravaginally with 4 ml of virulent BA.1 strain of CpHV-1. Vaccinated goats shed challenge virus for 8 days but, in comparison with control unvaccinated-challenged goats, were significantly protected from the classical clinical signs of genital lesions. Even without adjuvants, prolonged mucosal vaccination induced production of secretory IgA and provided significant clinical protection.

Potent inhibition of genital herpesvirus infection in goats by cidofovir

BACKGROUND

Like human herpesvirus 2 (HHV-2) in humans, infection by caprine herpesvirus 1 in goats is associated with genital lesions, and this provides a unique model to study the efficacy and effects of anti-herpetic drugs.

METHODS

The antiviral activity of cidofovir was assessed in goats infected experimentally, using various therapeutic protocols.

RESULTS

Topic administration of cidofovir 1% cream prevented the onset of virus-induced genital lesions and drastically reduced virus shedding.

CONCLUSION

Cidofovir appears to be a very efficient drug for the prevention of genital lesions caused by an alphaherpesvirus.

Cidofovir is effective against caprine herpesvirus 1 infection in goats

Caprine herpesvirus 1 (CpHV-1) is a virus able to cause genital infection leading to vulvovaginitis or balanoposthitis in adult goats. CpHV-1 shares several biological similarities with herpes simplex type 2 (HSV-2) infection in man, such as genital tropism, type and site of typical lesions and it might provide an animal model for studies on antiviral drugs for HSV-2 infection in man. In this view the efficacy of cidofovir (CDV) drug was tested in six goats intravaginally infected with BA.1 strain of CpHV-1. Three goats received an intravaginal application of 3 ml of a 1% CDV preparation at 4h post infection and then every 12 h for five consecutive days. Three goats were kept as untreated controls. The goats were daily examined for clinical evidence of the infection and viral shedding. CDV was able to protect against disease progression and inhibited the onset of the local lesions due to the CpHV-1 replication. Treated animals shed virus for a shorter period (3 days less) and at lower titres than the control animals. CpHV-1 infection in goats may represent an excellent animal model for the study of novel strategies for the treatment of primary genital HSV-2 infection in man.

Diagnostic tools based on minor groove binder probe technology for rapid identification of vaccinal and field strains of canine parvovirus type 2b

TaqMan-based diagnostic tests have been developed for the identification of canine parvovirus type 2 (CPV-2) strains in the faeces of dogs with diarrhoea, including a minor groove binder (MGB) probe assay for identification of type 2-based vaccines and field strains (types 2a, 2b and 2c). Since type 2b vaccines have been licensed recently in Europe, two novel MGB assays were developed for discrimination between type 2b vaccines and field strains of CPV. Such assays have been found to be highly sensitive, specific and reproducible, allowing for simultaneous detection of type 2b vaccinal and field strains present in the same specimens. These new assays will help resolution of the diagnostic problems related to the detection of a type 2b strain in the faeces of dogs shortly after the administration of a type 2b vaccine.

First detection of canine parvovirus type 2c in pups with haemorrhagic enteritis in Spain

Canine parvovirus type 2 (CPV-2), the aetiological agent of haemorrhagic enteritis in dogs, includes three antigenic variants, types 2a, 2b and 2c. CPV-2c has been detected initially in Italy and subsequently in Vietnam. We report the first identification of this novel antigenic variant in Spain, where it caused an outbreak of fatal enteritis in basset hound pups in association with canine coronavirus type I and type II. We suggest that this new antigenic variant of CPV-2 could spread throughout Europe and that there is a subsequent need to update current CPV vaccines.

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.

New approaches for the molecular characterization of canine parvovirus type 2 strains

Characterization of the canine parvovirus type 2 (CPV-2) is sometimes ambiguous, frequently requiring more than one technique for definitive prediction of the viral type. Taking into account the single-nucleotide polymorphisms encountered in the VP2-protein gene between types 2a and 2b and between type 2b and Glu-426 mutant (type 2c), two different minor groove binder (MGB) probe assays were developed for rapid identification of the CPV-2 variants. A total of 315 samples collected from dogs with diarrhoea were screened for CPV-2 by a real-time polymerase chain reaction (PCR) assay capable of detecting all CPV-2 types. In order to compare the type-specific assays with the traditional techniques [haemagglutination inhibition with monoclonal antibodies, PCR-restriction fragment-length polymorphism (RFLP), sequence analysis] for prediction of CPV-2 antigen specificity, the 203 samples tested CPV-2 positive were analysed using the different methods. The results showed a 100% concordance between the MGB probe assays and the combined conventional methods, with 116 samples characterized as type 2a, 32 as type 2b and 55 as type 2c. Therefore, the MGB probe assays represent a quick, reliable tool for prediction of CPV-2 antigen specificity, with regard to the more time-consuming assays currently used.

A live attenuated glycoprotein E negative bovine herpesvirus 1 vaccine induces a partial cross-protection against caprine herpesvirus 1 infection in goats

Taking into account the close antigenic relationship between bovine herpesvirus 1 (BoHV-1) and caprine herpesvirus 1 (CpHV-1), a live attenuated glycoprotein E (gE) negative BoHV-1 vaccine was assessed in goats with the aim to protect against CpHV-1 infection. Vaccine safety was evaluated by intranasal inoculation of two groups of goats with either a gE-negative BoHV-1 vaccine or a virulent BoHV-1. The length of viral excretion and the peak viral titre were reduced with the gE-negative vaccine. To assess the efficacy, two goats were inoculated intranasally twice 2 weeks apart with a gE-negative BoHV-1 vaccine. Four weeks later, immunised and control goats were challenged with CpHV-1. A 2 log(10) reduction in the peak viral titre was observed and the challenge virus excretion lasted 2 days more in immunised than in control goats. These data indicate the safety and the partial efficacy of a live attenuated gE-negative BoHV-1 vaccine intranasally administrated in goats.