Costantina Desario

Detection and molecular characterization of a canine norovirus.

We identified a novel calicivirus in a pup with enteritis. The isolate was related genetically (90.1% aa identity in the capsid protein) to a lion norovirus strain.

Occurrence of canine parvovirus type 2c in the United States.

Canine parvovirus (CPV) type 2 (CPV-2) emerged around 1978 as a major pathogen of dogs worldwide. In the mid-1980s, the original CPV-2 had evolved and was completely replaced by 2 variants, CPV-2a and CPV-2b. In 2000, a new variant of CPV (named CPV-2c) was detected in Italy and now cocirculates with types 2a and 2b in that country. The CPV-2c has also been reported from single outbreaks in Vietnam and Spain. This study was conducted to determine if CPV-2c occurs in the United States. Thirty-three fecal samples were collected from dogs in 16 states between April 2006 and April 2007 and were tested for CPV using real-time polymerase chain reaction (PCR). Positive samples were further tested using conventional PCR and minor-groove binding TaqMan PCR assays to determine the viral type and to differentiate vaccine strains from field strains. Twenty-seven samples were positive for CPV, 7 of which were CPV-2c from 5 states: Arizona, California, Georgia, Oklahoma, and Texas. Of the 7 isolates, 4 differed from European CPV-2c isolates by 2 additional single-nucleotide mutations at positions 4076 and 4104, the latter of which produces a ThrAla change at residue 440 located near a major antigenic site. The coast-to-coast geographic distribution of the states in which CPV-2c was detected strongly suggests that this new CPV variant is probably widespread in the United States. The continuous evolution of CPV requires that monoclonal antibody-based and nucleic acid-based diagnostic assays should be periodically checked for sensitivity on prevalent CPV strains.

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

Summary 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.

Molecular Epidemiology of Canine Parvovirus, Europe

Canine parvovirus (CPV), which causes hemorrhagic enteritis in dogs, has 3 antigenic variants: types 2a, 2b, and 2c. Molecular method assessment of the distribution of the CPV variants in Europe showed that the new variant CPV-2c is widespread in Europe and that the viruses are distributed in different countries.

Norovirus in Captive Lion Cub (Panthera leo)

African lions (Panthera leo) are susceptible to viral diseases of domestic carnivores, including feline calicivirus infection. We report the identification of a novel enteric calicivirus, genetically related to human noroviruses of genogroup IV, in a lion cub that died of severe hemorrhagic enteritis.

Clinical and Virological Findings in Pups Naturally Infected by Canine Parvovirus Type 2 Glu-426 Mutant

An outbreak of canine parvovirus type 2 infection caused by the Glu-426 mutant in 2 litters of pups is reported. The infected pups (n = 6) were monitored daily for evidence of clinical signs and hematological changes and for the evaluation of viral shedding in the feces. The disease induced by the Glu-426 mutant was mild in all the infected pups. Vomiting and hemorrhagic diarrhea were not observed; however, the pups developed mucoid diarrhea (3.5 median days), depression (1.5 median days), and relative leukopenia and lymphopenia (2.5 median days). Fever and loss of appetite were observed only in 2 pups. Virus was detected in the feces for 4.5, 6.5, and 46 median days by hemagglutination, virus isolation on cell cultures, and real-time polymerase chain reaction (PCR), respectively. By real-time PCR, the highest viral DNA titers were detected in the feces of both litters at day 10, reaching median values of more than 1010 DNA copies/mg of feces.

Canine coronavirus highly pathogenic for dogs.

Canine coronavirus (CCoV) is usually responsible for mild, self-limiting infections restricted to the enteric tract. We report an outbreak of fatal disease in puppies caused by a pathogenic variant of CCoV that was isolated from organs with severe lesions.

A minor groove binder probe real-time PCR assay for discrimination between type 2-based vaccines and field strains of canine parvovirus

Abstract A minor groove binder (MGB) probe assay was developed to discriminate between type 2-based vaccines and field strains of canine parvovirus (CPV). Considering that most of the CPV vaccines contain the old type 2, no longer circulating in canine population, two MGB probes specific for CPV-2 and the antigenic variants (types 2a, 2b and 2c), respectively, were labeled with different fluorophores. The MGB probe assay was able to discriminate correctly between the old type and the variants, with a detection limit of 101 DNA copies and a good reproducibility. Quantitation of the viral DNA loads was accurate, as demonstrated by comparing the CPV DNA titres to those calculated by means of the TaqMan assay recognising all CPV types. This assay will ensure resolution of most diagnostic problems in dogs showing CPV disease shortly after CPV vaccination, although it does not discriminate between field strains and type 2b-based vaccines, recently licensed to market in some countries.

Occurrence of severe gastroenteritis in pups after canine parvovirus vaccine administration: a clinical and laboratory diagnostic dilemma.

Abstract A total of 29 faecal samples collected from dogs with diarrhoea following canine parvovirus (CPV) vaccination were tested by minor groove binder (MGB) probe assays for discrimination between CPV vaccine and field strains and by diagnostic tests for detection of other canine pathogens. Fifteen samples tested positive only for CPV field strains; however, both vaccine and field strains were detected in three samples. Eleven samples were found to contain only the vaccine strain, although eight of them tested positive for other pathogens of dogs. Only three samples were found to contain the vaccine strain without evidence of canine pathogens. The present study confirms that most cases of parvovirus-like disease occurring shortly after vaccination are related to infection with field strains of canine parvovirus type 2 (CPV-2) rather than to reversion to virulence of the modified live virus contained in the vaccine.

Genotype-specific fluorogenic RT-PCR assays for the detection and quantitation of canine coronavirus type I and type II RNA in faecal samples of dogs.

Abstract Two genotype-specific fluorogenic RT-PCR assays were developed for the detection and quantitation of canine coronavirus (CCoV) type I and type II RNA in the faeces of dogs with diarrhoea. Both the fluorogenic assays showed high specificity, sensitivity and reproducibility, allowing a precise quantitation of CCoV type I and type II RNA over a linear range of about eight orders of magnitude (from 101 to 108 copies of standard RNA). Comparison with genotype-specific gel-based RT-PCR assays revealed that the fluorogenic assays were more sensitive and more rapid than conventional amplifications, with a large increase in throughput. The genotype-specific fluorogenic assays were then used to detect and measure viral loads in the faecal samples collected from dogs naturally or experimentally infected with type I, type II, or both genotypes. Of 174 samples collected from naturally infected dogs, 77 were positive for CCoV type I and 46 for CCoV type II. Thirty-eight dogs were found to be infected naturally by both genotypes, with viral RNA titres generally higher for type I in comparison to type II. At the same time, dogs infected experimentally shed type I RNA with higher titres with respect to type II.