Response of mink, skunk, red fox and raccoon to inoculation with mink virus enteritis, feline panleukopenia and canine parvovirus and prevalence of antibody to parvovirus in wild carnivores in Ontario.

Mink virus enteritis, feline panleukopenia and canine parvovirus-2 were inoculated separately into groups of raccoon, mink, red fox and striped skunk. Raccoons were highly susceptible to mink virus enteritis and feline panleukopenia, with animals developing clinical illness, and several dying within six to ten days of inoculation with lesions typical of parvovirus infection. Both viruses were shed in high titre in the feces of infected raccoons, and high antibody titres were stimulated. Raccoons inoculated with canine parvovirus-2 showed no signs; shedding of virus was sporadic though moderate titres of antibody developed. Mink inoculated with mink virus enteritis and feline panleukopenia developed signs and lesions of early parvovirus infection. No signs or significant lesions followed canine parvovirus-2 inoculation. Shedding of virus was heavy (mink virus enteritis) or sporadic (feline panleukopenia and canine parvovirus-2), though good serological responses were elicited to all three viruses. Red fox showed no signs of infection, shed all three viruses only sporadically, and the serological response was strong only to feline panleukopenia. Skunks developed low antibody titres, but no signs, and did not shed virus. Antibody to parvovirus was found in 79.2% of 144 wild red foxes; 22.3% of 112 wild raccoons; 1.3% of 157 wild skunks and 6/7 coyotes in southern Ontario. The likely significance of these viruses to wild and captive individuals and populations of these carnivores is discussed.     

Comparisons of feline panleukopenia virus, canine parvovirus, raccoon parvovirus, and mink enteritis virus and their pathogenicity for mink and ferrets

Parvoviruses from mink (mink enteritis virus [MEV]), cats (feline panleukopenia virus [FPV]), raccoons (raccoon parvovirus [RPV]), and dogs (canine parvovirus [CPV]) were compared. Restriction enzyme analysis of the viral replicative-form DNA revealed no consistent differences between FPV and RPV isolates, but CPV and MEV isolates could be distinguished readily from other virus types. Feline panleukopenia virus, RPV, and MEV, but not CPV, replicated to high titers in mink. However, on the first passage, disease and microscopic lesions were observed only in mink inoculated with MEV. Feline panleukopenia virus and RPV isolates replicated in ferrets, but disease or microscopic lesions were not observed. Feline panleukopenia virus and RPV isolates could be passaged repeatedly in mink and ferrets. Virulence of FPV and RPV isolates was low compared with that of MEV, and only a single mink inoculated with FPV or with RPV developed clinical disease on the sixth passage of virus.     

Isolation and immunisation studies of a canine parco-like virus from dogs with haemorrhagic enteritis

A newly recognised canine parvo like virus was isolated from faeces of dogs with haemorrhagic enteritis. Cell cultures from several species were susceptible to it. Virus infected cells could be demonstrated by staining with fluorescent antibody reagents (prepared against canine virus or feline panleucopenia virus) or by haemagglutination with pig or rhesus monkey red blood cells. Inhibition of haemagglutination by specific antiserum prepared in specific-pathogen-free beagles provided a convenient method for viral identification. Experimental inoculation of specific-pathogen-free beagles resulted in elevated body temperatures and caused lymphopenia lasting one to three days. Feline panleucopenia virus vaccines protected dogs against challenge with virulent canine parvo-like virus.     

A comparative study of a new rapid and one-step test for the detection of parvovirus in faeces from dogs, cats and mink

A one-step immunochromatographic test, based on the use of monoclonal antibodies, was developed for the detection of canine parvovirus (CPV) in dog faeces. In addition to canine parvovirus the test can also be used for the diagnosis of infections with viruses causing parvovirus enteritis in cats (feline panleukopenia virus) and mink (mink enteritis virus). Four hundred and forty-three faecal samples were evaluated by comparative testing between this one-step test and three different enzyme-linked immunosorbent assays (ELISA) in Sweden, Denmark and The Netherlands. The result of the evaluation showed an overall relative sensitivity and specificity of 95.8 and 99.7%, respectively. Furthermore, the comparative testing of 83 dog samples in Germany between the one-step test and an immune electron microscopy (IEM) agreed to 85.5%. The sensitivity and specificity were 83.9 and 88.9%, respectively. These results show that the one-step test is a rapid, simple, reproducible and sensitive diagnostic test for the detection of parvovirus in faecal samples of dogs, cats and mink.     

肉食兽细小病毒通用PCR诊断技术的建立

根据肉食兽细小病毒核苷酸序列高度同源的特点，设计合成了1对引物，以犬细小病毒、貂肠炎病毒和猫泛和白细胞减少症病细胞培养物为DNA模板，进行PCR特异性片段扩增，扩增片段大小为0．6kb。结果表明，扩增产物与设计的2个引物之间的序列大小一致。通过通用性、特异性与敏感性试验及对临床检样品检测，证明本法对肉食兽细小病毒通用。且具有快速、特异和高度敏感的特点。     

A Comparative Study of a New Rapid and One‐Step Test for the Detection of Parvovirus in Faeces from Dogs,Cats and Mink

A one‐step immunochromatographic test, based on the use of monoclonal antibodies, was developed for the detection of canine parvovirus (CPV) in dog faeces. In addition to canine parvovirus the test can also be used for the diagnosis of infections with viruses causing parvovirus enteritis in cats (feline panleukopenia virus) and mink (mink enteritis virus). Four hundred and forty‐three faecal samples were evaluated by comparative testing between this one‐step test and three different enzyme‐linked immunosorbent assays (ELISA) in Sweden, Denmark and The Netherlands. The result of the evaluation showed an overall relative sensitivity and specificity of 95.8 and 99.7 %, respectively. Furthermore, the comparative testing of 83 dog samples in Germany between the one‐step test and an immune electron microscopy (IEM) agreed to 85.5 %. The sensitivity and specificity were 83.9 and 88.9 %, respectively. These results show that the one‐step test is a rapid, simple, reproducible and sensitive diagnostic test for the detection of parvovirus in faecal samples of dogs, cats and mink.     

Preliminary development of a live attenuated canine parvovirus vaccine from an isolate of British origin

Canine parvovirus isolated from a case of haemorrhagic enteritis in a breeding kennel in England was passaged and cloned in cultured feline and canine cells. No significant evidence of pathogenicity was found during six serial passages of the modified virus back through young dogs. The attenuated virus was excreted by inoculated animals and spread rapidly to uninoculated animals held in contact. When high titre attenuated virus was given to the six-week-old offspring of a seropositive dam a prompt seroconversion was observed. When the attenuated virus was used as an experimental vaccine in 108 pups in an infected breeding colony a highly significant improvement was obtained in the accumulated morbidity and mortality compared with a parallel group vaccinated with modified live feline panleucopenia virus.     

A Serological Survey of Enteric Parvovirus Infections in Finnish Fur-Bearing Animals

Parvovirus infections in Finnish fur animals, i.e. ferrets, raccoon dogs, blue foxes and mink, were studied. The ferret was found to be the only insusceptible animal. Parvo enteritis of raccoon dogs, reported since 1980, has spread from East Finland to other parts of the country. A new candidate for the Parvovirus family was found to infect blue foxes. According to serologic investigations, the virus resembled feline panleukopenia virus more than canine parvovirus. Clinical signs during the infection have been mild. Annual vaccination has not eradicated mink enteritis virus on farms, but the disease has taken a subclinical form.     

Feline panleukopaenia virus and mink enteritis virus. A serological study.

The serological relationship of Danish feline panleukopaenia virus and mink enteritis virus and strains from Great Britain, USA, Germany and Canada was examined in neutralization tests using a direct immunofluorescence technique. Vaccine strains of the virus were used representing virus strains from the different countries. It was found that all Danish feline panleukopaenia virus strains and the mink enteritis strain belong to the same serotype and further that they are of similar antigenicity as feline panleukopaenia virus strains and mink enteritis strains isolated in other countries.     

犬瘟热,猫细小病毒,犬腺病毒弱毒株的理化特性及生物学试验

以鸡胚成纤维细胞（ＣＥＦ）、猫肾传代细胞（ＣＲＦＫ）、狗肾传代细胞（ＭＤＣＫ）从引进的疫苗中分别分离到犬瘟热ＣＤＶ－Ａ株、猫细小病毒ＦＰＶ株、犬腺病毒ＣＡＶ１株。对三个弱毒株的细胞病变规律,形态特征,病毒滴度,理化特性,核酸型,血清学交叉反应,本动物的安全性及免疫原性等内容进行了试验。鉴定结果表明,３个弱毒株均可作为制苗用毒种     

Molecular and structural basis of the evolution of parvovirus tropism.

Parvoviruses have small genomes and, consequently, are highly dependent on their host for various functions in their reproduction. Since these viruses generally use ubiquitous receptors, restrictions are usually intracellularly regulated. A lack of mitosis, and hence absence of enzymes required for DNA replication, is a powerful block of virus infection. Allotropic determinants have been identified for several parvoviruses: porcine parvovirus, canine parvovirus (CPV), feline parvovirus (feline panleukopenia virus), minute virus of mice, Aleutian disease virus, and GmDNV (an insect parvovirus). Invariably, these identifications involved the use of infectious clones of these viruses and the exchange of restriction fragments to create chimeric viruses, of which the resulting phenotype was then established by transfection in appropriate cell lines. The tropism of these viruses was found to be governed by minimal changes in the sequence of the capsid proteins and, often, only 2 or 3 critical amino acids are responsible for a given tropism. These amino acids are usually located on the outside of the capsid near or on the spike of the threefold axis for the vertebrate parvoviruses and on loops 2 or 3 for the insect parvoviruses. This tropism is not mediated via specific cellular receptors but by interactions with intracellular factors. The nature of these factors is unknown but most data point to a stage beyond the conversion of the single-stranded DNA genome by host cell DNA polymerase into monomeric duplex intermediates of the replicative form. The sudden and devastating emergence of mink enteritis virus (MEV) and CPV in the last 50 years, and the possibility of more future outbreaks, demonstrates the importance of understanding parvovirus tropism.     

Hemagglutination by canine parvovirus: serologic studies and diagnostic applications

Conditions for canine parvoviral hemagglutination (HA) and hemagglutination-inhibition (HI) reactions were defined. The HA phenomena were used to differentiate canine parvovirus (CPV) from feline panleukopenia virus (FPV), mink enteritis virus (MEV), and minute virus of canines. Serologic comparisons of the CPV, FPV, and MEV by HA-HI and serum-neutralization tests indicated that CPV, FPV, and MEV were antigenically similar but were different from minute virus of canines. Diagnostic application of HA tests to fecal samples from acute cases of enteritis was discussed. Combinating HA tests with HI tests on fecal samples provided a rapid and specific diagnostic method for CPV infection. Secular seroprevalence studies indicated the emergence of CPV infeciton in the United States dog population-at-large in 1978.     

Antigenic and genomic comparisons of some feline parvovirus subspecies strains.

Fourteen feline parvovirus (FPV) strains isolated from cats, mink and dogs were comparatively examined on their antigenic and genetic diversities by using monoclonal antibodies against feline panleukopenia virus (FPLV) and restriction enzyme analysis of viral DNA. Mink enteritis virus (MEV) strains recently isolated in the northeastern area of the People's Republic of China were found to possess more similar antigenic and genetic properties to the antigenic variant virus of canine parvovirus (CPV) ("new" antigenic type CPV), than to FPLV strains and MEV Abashiri strain of Japan. A feline isolate detected in normal cat feces was considered to be rather CPV because of its antigenic and genetic characteristics. An early isolate of "new" antigenic type CPV strains showed a similar cleavage pattern to those of "old" antigenic type CPV strains when digested with HinfI. The results including some features above-mentioned suggest the presence of antigenic heterogeneities and genomic polymorphisms among FPV subspecies viruses.     

Virological Survey in free-ranging wildcats (Felis silvestris) and feral domestic cats in Portugal

To determine the presence of viral pathogens in natural areas a survey was conducted on an opportunistic sample of fifty eight wild (Felis silvestris silvestris) and feral cats (F. s. catus). The biological materials included serum, lung tissue extract and stool. Feline leukemia virus p27 antigen was detected in 13/50 serum/lung tissue extract samples (26%), canine distemper virus antibodies were detected in 2/26 serum/lung tissue extract samples (7.7%), feline coronavirus RNA was present in 6/29 stool samples (20.7%) and feline parvovirus DNA in 2/29 stool samples (6.9%). Canine distemper virus RNA was not detected. Feline immunodeficiency virus and feline coronavirus antibodies were not detected. Evidence of exposure to feline leukemia virus, canine distemper virus, feline coronavirus and feline parvovirus was found in wild and feral cats raising the importance of performing a comprehensive survey to correctly evaluate the potential threat of infectious diseases to endangered species, namely to the wildcat and to the Iberian lynx, which is meant to be reintroduced after 2012 in Portugal.     

水貂病毒性肠炎巢式PCR,PCR-RFLP联合诊断方法的建立

根据水貂肠炎细小病毒的VP2基因序列设计4条特异性引物,建立了检测水貂肠炎细小病毒的巢式PCR方法。采用一次扩增的敏感性来检测5个TCID50/mL的细小病毒MEVB株,二次扩增的敏感性来检测0.05个TCID50/mL的细小病毒MEVB株。同时,利用该方法第一轮PCR产物酶切,能够区分犬细小病毒与水貂肠炎细小病毒,具有重要的实用价值和应用的前景。     

Canine distemper virus associated proliferation of canine footpad keratinocytes in vitro

Infection of canine footpads with canine distemper virus (CDV) can result in so-called hard pad disease characterized by footpad epidermal proliferation and hyperkeratosis. Cultured canine footpad keratinocytes (CFK) were inoculated with a virulent canine distemper virus strain (A75/17-CDV) to study the effects of CDV-infection on keratinocyte proliferation. Infection was analyzed by immunohistochemistry and in situ hybridization for CDV nucleoprotein (N-protein) antigen and mRNA. CDV caused a persistent, non-cytocidal infection with spread from single cells to infection of the confluent cell layer 7 days post infection (p.i.). Absolute cell numbers were significantly higher in infected cultures compared to control cultures from day 4 until day 6 p.i. Infected cultures contained significantly more total DNA on day 5 p.i. compared to controls. Immunohistochemical investigation of proliferation markers Ki67 and BrdU demonstrated a nearly two-fold increase in numbers of positive cells on day 5 p.i. compared to controls. These findings demonstrate that canine distemper virus infection of canine footpad keratinocytes in vitro was associated with proliferation.     

Genetic complexity and multiple infections with more Parvovirus species in naturally infected cats

ABSTRACT: Parvoviruses of carnivores include three closely related autonomous parvoviruses: canine parvovirus (CPV), feline panleukopenia virus (FPV) and mink enteritis virus (MEV). These viruses cause a variety of serious diseases, especially in young patients, since they have a remarkable predilection for replication in rapidly dividing cells. FPV is not the only parvovirus species which infects cats; in addition to MEV, the new variants of canine parvovirus, CPV-2a, 2b and 2c have also penetrated the feline host-range, and they are able to infect and replicate in cats, causing diseases indistinguishable from feline panleukopenia. Furthermore, as cats are susceptible to both CPV-2 and FPV viruses, superinfection and co-infection with multiple parvovirus strains may occur, potentially facilitating recombination and high genetic heterogeneity. In the light of the importance of cats as a potential source of genetic diversity for parvoviruses and, since feline panleukopenia virus has re-emerged as a major cause of mortality in felines, the present study has explored the molecular characteristics of parvovirus strains circulating in cat populations. The most significant findings reported in this study were (a) the detection of mixed infection FPV/CPV with the presence of one parvovirus variant which is a true intermediate between FPV/CPV and (b) the quasispecies cloud size of one CPV sample variant 2c. In conclusion, this study provides new important results about the evolutionary dynamics of CPV infections in cats, showing that CPV has presumably started a new process of readaptation in feline hosts.     

Neutralizing antibodies against feline parvoviruses in nondomestic felids inoculated with commercial inactivated polyvalent vaccines

The virus neutralization (VN) antibody titers of serum samples from 18 individuals representing 8 carnivore species vaccinated with commercial polyvalent vaccines optimized for domestic cats containing inactivated feline panleukopenia virus (FPLV) were evaluated against canine parvovirus type 2 (CPV2). In addition, the titers among 5 individuals from 4 carnivore were evaluated against antigenic variants of feline parvoviruses; FPLV, CPV2, CPV2a, CPV2b, CPV2c, mink enteritis virus type 1 (MEV1) and MEV2. The polyvalent vaccines induced cross-reactive VN titers against antigenic variants of feline parvoviruses in nondomestic felids. However, we observed very low cross-reactive VN antibody in lions and Siberian tigers, therefore we should pay attention to CPV infections in these animals even if they were vaccinated with inactivated FPLV vaccines.     

Serologic evaluation of vaccinated American river otters

The Oklahoma Department of Wildlife Conservation acquired 20 American river otters (Lutra canadensis) between 1984 and 1985 for reintroduction into Oklahoma waterways. In 1985, 10 otters were evaluated for serum antibody titers after vaccination with canine distemper virus, canine adenovirus type 2, canine parvovirus (CPV), feline panleukopenia virus (FPV), feline rhinotracheitis virus (FRV), and feline calicivirus. Prevaccination serum-virus neutralization (SVN) antibody to feline rhinotracheitis virus was found in 2 otters and to feline calicivirus in 1 otter. Using an indirect fluorescent antibody (IFA) assay, prevaccination antibody to CPV and FPV was found in 2 otters. A significant increase in SVN antibody titers was found after vaccination of otters with canine adenovirus type 2 (6 of 8 animals) and feline calicivirus (1 of 8 animals). One of 8 otters developed significant antibody titers to CPV and FPV, as measured by IFA assay. Otters did not develop SVN antibody titers to canine distemper virus after vaccination. Antigens of feline leukemia virus, using ELISA, or antibodies to feline infectious peritonitis, using IFA assay, were not found in the 20 otters.     

Comparison of feline parvovirus subspecific strains using monoclonal antibodies against a feline panleukopenia virus

Four monoclonal antibodies (mAb) against a feline panleukopenia virus (FPLV) TU 1 strain, one of the host range variants of feline parvovirus (FPV), were produced and applied for antigenic analysis of FPLV, canine parvovirus (CPV) and mink enteritis virus (MEV). All mAbs were considered to be directed at epitopes on the virus capsid surface because they neutralized the infectivity and inhibited the hemagglutination (HA) of the homologous virus as well as other FPV strains. They were of the mouse IgG1 type. High antigenic homogeneity among FPLV strains was confirmed by HA-inhibition (HI) test with the mAbs and polyclonal immune sera against FPLV or CPV. But the TU 11 strain of FPLV was antigenically distinguished from the remaining 14 FPLV strains by both the HI test and the micro-neutralization test with one of the mAbs produced. MEV Abashiri strain was found to be antigenically indistinguishable from FPLV. Most of the CPV strains isolated after 1981 were considered to be antigenically different from earlier CPV isolates when some mAbs were applied in the serological tests, confirming the replacement of CPV by an antigenic variant in Japan. However, antigenically different CPVs were detected at the end of 1984 from unrelated epizootics occurred a month apart in the same area.