Pathogenicity of a skin isolate of porcine parvovirus in swine fetuses

The pathogenic properties of a skin isolate of porcine parvovirus (PPV), designated Kresse isolate, were compared with NADL-8 isolate, a prototype isolate of PPV, by in utero inoculation of mid-term and late-term gestation swine fetuses. Fetuses from pregnant sows of mid-gestation were inoculated with either NADL-8 or Kresse virus. Both isolates were highly pathogenic to mid-gestation fetuses. In contrast, dramatic differences in pathogenicity between these 2 isolates were observed in fetuses inoculated late in gestation. Such fetuses from each of 4 sows were inoculated with NADL-8 or Kresse virus isolate and sacrificed at 10, 18, 21, or 23 days postinoculation (PI). NADL-8-inoculated fetuses were grossly normal. The pathogenic effects of Kresse isolate were evident by gross pathology in fetuses collected at 18, 21, and 23 days PI, but not at 10 days PI. Hemagglutination (HA) and fluorescent antibody (FA) methods were used to identify virus in various tissues of late-gestation fetuses collected at 10 and 21 days PI. At 10 days PI, HA antigens were detected only in livers of NADL-8-inoculated fetuses, but in all tissues examined of Kresse-inoculated fetuses, including the brain. PPV specific fluorescence was demonstrated in tissues of fetuses inoculated with NADL-8 and Kresse virus. The major difference was that virus antigen was found in the brains of fetuses inoculated with Kresse virus, but not in NADL-8 infected fetuses. At 21 days PI, HA antigen was not detected in any of the tissues of fetuses inoculated with NADL-8 virus, with PPV specific fluorescence by FA being found only in the kidney. However, fetuses inoculated with Kresse virus displayed HA antigen in liver and PPV-specific fluorescence in all tissues tested including the brain. Both isolates induced similar antibody responses, 1:128 to 1:256 at 10 days and 1:512 to 1:1024 at 21 days PI. In addition, immunoglobulin G (IgG) deposits were demonstrated in kidneys and skin of fetuses inoculated with Kresse virus and IgM in brain, but not in tissues from fetuses inoculated with NADL-8 virus.     

Oronasal and intramuscular vaccination of swine with a modified live porcine parvovirus vaccine: multiplication and transmission of the vaccine virus

An attenuated strain NADL-2 of porcine parvovirus (PPV) has been used at the 54th cell culture passage as a modified live-virus (MLV) vaccine. The present study was conducted to determine the minimum immunizing dose of MLV, the extent of MLV multiplication in swine tissues, and its transmission from swine administered MLV oronasally or intramuscularly. Immune response to MLV was dose dependent and swine responded to as little as 10(2) median cell-culture infective doses (CCID50). A 10(5) CCID50 of MLV, the largest dose given, induced the best immune response and was used in subsequent experiments. Route of MLV administration also was found to be important. The MLV replicated in tissues of swine after IM inoculation; however, viral antigen in tissues was less, as measured by immunofluorescence, and serum hemagglutination-inhibition titers for PPV were lower in MLV-inoculated swine than we have previously observed in virulent PPV-inoculated swine. In contrast, oronasal inoculation with MLV did not consistently result in infection of pigs; only 5 of 23 swine had virologic and/or serologic evidence of infection. Virus transmission studies indicated that MLV is shed in feces, but shedding occurs later than that in virulent-PPV-inoculated swine and is inconsistent. Delayed transmission of MLV was observed in contact pigs, which were seronegative at 2 weeks, but became seropositive at 4 weeks--indicating that perhaps a virus population capable of infecting pigs by oronasal route was selected by passage through the pig.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison of the virulence of two isolates of porcine parvovirus in 72-day-old porcine fetuses.

Two strains of porcine parvovirus (PPV), designated Kresse and NADL-8, were compared for relative virulence in porcine fetuses. Strain Kresse was injected into the amniotic fluid of all fetuses of 1 uterine horn of each of 2 pregnant gilts at 72 days of gestation. Strain NADL-8 was administered similarly to fetuses of 4 other gilts at the same stage of gestation. All gilts were killed and necropsied 35 days later. Selected tissues of all fetuses were tested for infectious virus and viral antigen. Sera from live fetuses were tested for antibody to PPV. These tests confirmed that most fetuses exposed to PPV by intra-amniotic injection became infected. All of 11 fetuses exposed to strain Kresse by intra-amniotic injection were alive at the time of necropsy, and all appeared clinically normal. In contrast, 8 of 24 fetuses exposed similarly to strain NADL-8 were dead. Many of the fetuses from the uterine horns contralateral to the uterine horns inoculated with virus were infected after 72 days of gestational age by intrauterine spread of the virus. Four such fetuses, 3 infected with the NADL-8 strain and 1 infected with the Kresse strain, were dead at the time of necropsy. These findings were inconsistent with those of a previous report, which indicated that the Kresse strain of PPV was markedly more virulent than the NADL-8 strain of PPV for porcine fetuses. A possible reason for this apparent discrepancy is discussed.     

Clinical, virologic, and histopathologic observations of induced porcine parvovirus infection in boars

Twelve 8- to 12-month-old crossbred boars were inoculated with a virulent strain (NADL-8) of porcine parvovirus (PPV). Hemicastrations were performed on 6 boars 3, 7, 10, 14, 21, and 28 days after an IM injection of 10(8) median cell culture infectious dose (CCID50) of PPV (n = 3) or injection of 10(7.4) CCID50 given intratesticularly (IT, n = 3). Noninfected cell culture medium (0.25 ml) was injected into each testicle of a 7th boar (IT inoculated control). Virus or viral antigen was detected in testicular and epididymal tissues up to 14 days after inoculation. Direct immunofluorescence indicated that viral antigen was mainly associated with the vasculature of the interstitium. Microscopic lesions were not evident in the testicles and epididymides of IM inoculated boars. Acute-to-chronic testicular degeneration was evident in the IT inoculated boars, as well as in the IT inoculated control boar. Six boars were inoculated IM or orally/nasally with 10(7.9) CCID50 of PPV. Semen was collected twice weekly for 8 weeks after inoculation. Virus was not detected in any ejaculates. Semen also was collected from 4 boars for 5 weeks before inoculation, and preinoculation and post-inoculation semen quality was compared. Pronounced changes in sperm output, ejaculate volume, motility, or morphologic defects were not observed. The reproductive consequences of experimental PPV infection in boars were minimal because reproductive function was unaffected and venereal transmission of PPV was not detected.     

猪细小病毒L株VP2基因片段的克隆及序列分析

对自行分离的PPVL株VP2基因片段进行克隆和测序。序列分析表明:L株VP2基因片段与其他PPV毒株的VP2基因片段的核苷酸同源性均在99.19%以上,氨基酸同源性在98.87%以上。表明L株与国内流行毒株之间同源性极为接近,其中与NADL-2(4973)株的亲缘关系最近(核苷酸同源性为99.81%,氨基酸同源性为99.62%)。在决定毒株组织嗜性的关键氨基酸位点上(378,383及436),L株与NADL-2株相同,据此推测L株的毒性与组织嗜性可能与NADL-2相似。     

猪瘟病毒猪细小病毒猪繁殖与呼吸综合征病毒猪伪狂犬病病毒多重PCR方法的建立以及初步应用

猪瘟病毒、猪细小病毒、猪繁殖与呼吸综合征病毒及猪伪狂犬病病毒均能导致猪繁殖障碍,对养猪生产影响很大。本研究通过设计4对针对这4种病毒的特异引物建立了多重PCR方法,分别对其最佳反应条件、特异性及敏感性进行了测定,结果表明:其敏感性可达到CSFV 10 TCID50,PPV 10TCID50,PRRSV 1 TCID50,PRV 100 TCID50 CSFV 10TCID50,PPV 10TCID50,PRRSV 1 TCID50,PRV 100 TCID50。同时具有较好的特异性,对猪瘟病毒石门株、猪瘟病毒兔化弱毒株、PRV闽南A株、PPV弱毒疫苗株、PRRSV KY 35株及PRRSV B13株6个毒株均能扩增出相应的片段,而BVDV、BDV均未扩增出相应的片段。本方法的建立对于这4种病毒病的早期快速检测具有十分重要的意义。     

Detection of challenge virus in fetal tissues by nested PCR as a test of the potency of a porcine parvovirus vaccine

To estimate the potency of a porcine parvovirus (PPV) vaccine, three vaccinated and three non-vaccinated pregnant gilts were infected with PPV and the distribution of the virus was studied in the tissues of their 51 fetuses. Virus detection was attempted using haemagglutination (HA) and immunofluorescence (IF) assays, as well as by standard (single) and nested polymerase chain reactions (PCR). None of the detection methods yielded positive results when used to test for the presence of virus in suspensions of organs from the fetuses from the vaccinated gilts. However, the virus was detected in the fetuses from non-vaccinated gilts as follows: HA was positive in 14 cases out of 23 (60.8%), IF in 16/23 (69.5%), standard PCR in 12/20 (60%), and the nested PCR in 19/23 (82.6%). Although the correlation among the results of various methods of virus detection was rather close (r<0.83), the sensitivity of the nested PCR was the highest, both when testing dilutions of PPV and when analysing the fetal organs. The nested PCR therefore provides a reliable approach for studies of virus distribution in fetal organs, with special reference to potency tests on vaccines.     

Antibody response of calves after intranasal inoculation with parainfluenza-3 virus and resistance of inoculated calves to experimental homologous viral infection

The immunologic response of colostrum-deprived calves to parainfluenza-3 (PI-3) virus given by intranasal inoculation was studied. Inoculation of calves with 3.2 x 10(6) median cell culture infective doses (CCID50) of either virulent (SF-4) virus or a modified strain of PI-3 virus, or with 2.0 x 10(8) CCID50 of SF-4 virus, stimulated development of both serum antibody and nasal secretion (NS) antibody. However, NA antibody decreased in all calves between the 16th and 42nd postinoculation days and was present only at low or moderately low concentrations on the 126th day, when the immunity of the calves was challenged. Generally, calves that were inoculated with 3.2 x 10(6) CCID50 of SF-4 virus developed slightly higher concentrations of serum and NS antibodies than did calves inoculated with modified virus. Calves that were inoculated with 2.0 x 10(8) or 3.2 x 10(6) CCID 50 of SF-4 virus developed comparable concentrations of serum antibody, but large doses of SF-4 virus were less effective than smaller doses of the same virus in stimulating the development of NS antibody. Reinoculation of 3 calves with modified PI-3 virus resulted in a demonstrable increase in serum antibody in 2 calves and an increase and subsequent decrease in NS antibody in all calves. Challenge exposure of inoculated calves to aerosols of SF-4 virus failed to cause clinical signs of disease, and the challenge virus was not isolated from the nasal passages.     

Diagnosis of canine parvovirus by rapid immunomigration on a membrane

Rapid immunomigration on a membrane was applied to the diagnosis of canine parvovirus (CPV) in 128 samples of faeces containing four strains of parvovirus (two CPV-2a strains, including one vaccine strain, and two CPV-2b strains). The results were compared with the results of haemagglutination and ELISA sandwich techniques. The new test was quick and easy to use, and made it possible to identify both the CPV-2a and CPV-2b strains. Its detection thresholds per gram of faeces corresponded to specific haemagglutination titres of between 320 and 640 and a virus titre of between 10(4) and 10(5) CCID50 (dose required to infect 50 per cent of cell cultures).     

Persistence of porcine parvovirus in swine infected in utero and followed through maturity

The potential of porcine parvovirus (PPV) to persistently infect swine exposed in utero was studied. Forty eight 80- to 95-day-old fetuses from 5 PPV seropositive sows were inoculated intramusculary with a virulent strain of PPV or with cell culture medium (controls). Blood samples were collected at birth prior to nursing and at monthly intervals thereafter and tested for antibodies to PPV. Virus-inoculated and control pigs were euthanized at either 1 week before birth (-1), at birth (0) and at weeks 2, 4, 6, 8, 10, 22, and 28 after birth. Presence of viral DNA and antigen was evaluated using slot blot DNA hybridization and indirect FA techniques, respectively. All inoculated fetuses (n = 26) and 7 control fetuses (n = 22) seroconverted in utero, and these pigs maintained antibody titers greater than log10 2 for the period of testing (0-38 weeks after birth). After passive antibody titers had reached subdetectable levels in control animals, animals remained seronegative through an additional 14 weeks of testing in spite of close contact with infected pigs. Virus antigen was not detected in any tissues examined from pigs euthanized at term. In contrast, PPV DNA was detected consistently from pigs at birth from various tissues, and from the lung of one pig at 6 weeks of age and from the lymph nodes of one pig euthanized at 28 weeks of age. The results indicate that pigs infected with PPV in utero may be persistently infected, however the likelihood of shedding to contact animals is minimal.     

Characterization of encephalomyocarditis virus isolated from aborted swine fetuses.

Characteristics of 2 encephalomyocarditis virus (EMCV) isolates (MN-25 and MN-30) recovered from aborted swine fetuses were examined along with 2 other swine isolates (NVSL-MDV and NVSL-PR) and a reference ATCC strain (VR-129). All 5 EMCV isolates were found to be serologically related by cross testing, using serum neutralization and fluorescent antibody assays. Hemagglutination (HA) properties of the 5 isolates were compared, using 5 diluents. The MN-25 and NVSL-MDV strains had HA activity with guinea pig RBC in all 5 diluents, whereas MN-30, NVSL-PR, and VR-129 had HA activity only in KCl-borate buffer. The HA ability with RBC of various animal species was examined, using KCl-borate diluent. All virus isolates had high HA titer (1:512 to 1:2,048) with guinea pig, rat, and horse RBC and lower HA titer (1:16 to 1:64) with sheep RBC. The MN-25 and NVSL-MDV isolates agglutinated dogs RBC, whereas MN-30, NVSL-PR, and VR-129 strains did not. Viral replication was evident in 8 of 10 cell lines tested, although infectivity titers of each virus varied by cell line used. Plaque-forming ability was similar for all 5 isolates, but plaque size was different by virus and cell culture used. Virus isolates were found to be stable after being heated at 56 C and subjected to a wide range of pH. A viral polypeptide pattern difference for all 5 isolates was not found by use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Efficacy of viral components of a nonabortigenic combination vaccine for prevention of respiratory and reproductive system diseases in cattle

Efficacy and safety of components of an IM-administered vaccine for prevention of infectious bovine rhinotracheitis virus (IBRV), parainfluenza type-3 (PI-3) virus, bovine viral diarrhea virus (BVDV), and respiratory syncytial virus (RSV) infections and campylobacteriosis and leptospirosis were evaluated in cattle, including calves and pregnant cows. Challenge of immunity tests were conducted in calves for IBRV, PI-3 virus, or BVDV vaccinal components. All inoculated calves developed serum-neutralizing antibodies and had substantially greater protection (as measured by clinical rating systems) than did controls after challenge exposure to virulent strains of IBRV, PI-3 virus, BVDV, or RSV. In in utero tests, IBRV or bovine RSV vaccinal strains were inoculated into fetuses of pregnant cows. Histologic changes or abortions did not occur after fetal inoculation of the RSV vaccinal strain, and 10 of 14 fetuses responded serologically. Of 9 fetuses, one responded serologically to the IBRV vaccinal strain after in utero inoculation and was aborted 3 weeks later. In an immunologic interference test, 10 calves vaccinated with 2 doses of the multivalent vaccine, containing the 4 viral components and a Campylobacter-Leptospira bacterin, developed serum-neutralizing antibodies to IBRV, PI-3 virus, BVDV, and RSV without evidence of serologic interference. Under field conditions, 10,771 cattle, including 4,543 pregnant cows, were vaccinated. Vaccine-related abortions did not occur.     

猪细小病毒疫苗株NS1基因克隆及生物信息学分析

为进一步开展猪细小病毒（porcine parvovirus,PPV）NS1蛋白功能研究,根据GenBank登录的PPV参考株NADL-2（登录号：NC001718）的NS1基因序列设计1对特异性引物,采用PCR技术扩增PPV疫苗株NS1基因,将PCR扩增产物克隆入pTA2载体构建重组质粒pTA2-NS1,并进行测序鉴定。测序结果显示,构建的pTA2-NS1质粒含有一个开放阅读框（ORF）,全长1989 bp,共编码662个氨基酸,与GenBank登录的PPV参考株NADL-2、Kresse株的NS1基因的核苷酸同源性分别为99.85%和99.65%,氨基酸同源性分别为99.70%和99.70%。上述结果表明试验成功构建了含有PPV NS1基因的重组质粒pTA2-NS1。应用DNAStar软件及在线ProtScale、SignalP 4.1、TMHMM、Scansite、PSORTⅡ等生物信息学软件对NS1基因及其编码蛋白进行生物信息学分析,结果显示NS1蛋白分子质量为75.7 ku,等电点PI为6.82,是弱酸性蛋白;NS1蛋白不含信号肽序列,无跨膜区,为可溶性蛋白,主要定位于细胞核内,T199、Y309、T338、T512、S631、T635为其潜在磷酸化位点。以上研究为进行PPV NS1蛋白表达,进一步开展NS1蛋白功能研究奠定了基础。     

猪流感病毒H3N2亚型的分离鉴定与全基因组序列测定

通过鸡胚接种、MDCK细胞培养、血凝及血凝抑制试验、RT-PCR等方法,笔者在四川首次分离并鉴定了1株既能在鸡胚上稳定传代又能在MDCK细胞上稳定产生CPE的H3N2亚型猪流感病毒,命名为A／swine／Sichuan／01／2006（H3N2）;NS基因的测序结果表明：该病毒分离株与A／swine／HongKong／4361／99（H3N2）、A／NewYork／429／2003（H3N2）、A／Queensland／6／2000（H3N2）、A／New South Wales／4／1999（H3N2）等具有代表性的标准毒株的同源性都达到99％;从MDCK细胞中抽提流感病毒基因组进行全基因克隆,构建了11个包含全基因8个基因片段的文库。全基因测序结果表明,A／swine／Siehuan／01／2006（H3N2）共8个节段,全基因序列共计13577bp;基于HA、NA推导蛋白的无根进化树结果显示,四川分离株与人流感标准株A／Queensland／6／2000（H3N2）、A／South Australia／81／2000（H3N2）有较近的亲缘关系,而与猪流感标准株A／swine／Spain／42386／2002（H3N2）的亲缘关系较远。     

Cross protection of mice and swine inoculated with culture filtrate of attenuated Erysipelothrix rhusiopathiae and challenge exposed to strains of various serovars

Mice and swine inoculated subcutaneously with culture filtrate vaccine prepared from acriflavine-fast attenuated Erysipelothrix rhusiopathiae strain Koganei 65-0.15 (serovar 2), were challenge exposed to 20 pathogenic strains of E rhusiopathiae of 18 serovars and type N. Vaccinated mice survived after challenge exposure to serovars 1b, 2, 8 (strain Goda), and type N, but mortality occurred in vaccinated mice challenge exposed to other strains: 20% to 30% mortality in mice challenge exposed to serovars 1a, 11, 12, 15, 16, or 21; 40% to 50% mortality in mice challenge exposed to serovars 4, 5, 6, 7, or 8 (strain 911); and 60% to 80% mortality in mice challenge exposed to serovars 9, 10, 18, or 19. All vaccinated mice died after challenge exposure with strain 2553 (serovar 20). Non-vaccinated control mice died after challenge exposure to all strains. Of 2 vaccinated swine challenge exposed to strain 2553, 1 developed a local urticarial lesion at the site of intradermal exposure. Vaccinated swine challenge exposed to serovars 1a, 1b, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 15, 16, 18, 19, 21, or type N did not have clinical signs of acute erysipelas. Nonvaccinated control swine developed acute generalized erysipelas or localized urticarial lesions at the site of intradermal exposure.     

不同毒株猪细小病毒VP2基因的克隆与序列分析

应用PCR扩增了猪细小病毒NJ-1株、NJ-2株、7909株和Vaccine株的VP2基因,分别克隆于pGEM-TEasy载体中,测定其核苷酸序列,并推导出相应的氨基酸序列,对其核苷酸和氨基酸序列进行分析和同源性比较。所测4个序列中,NJ-1株、NJ-2株和7909株序列均为1437bp,共编码479个氨基酸;而Vaccine序列为657bp,比其他毒株缺失780bp,共编码219个氨基酸。将所得4个序列与GenBank中NADL-2株、Kresse株、China株及VR-1株相应的核苷酸及氨基酸进行同源性比较,发现其核苷酸和氨基酸的同源性分别在97.7%~99.9%和97.2%~99.2%之间,具有高度同源性;通过绘制系统进化树可知,分离自国内的China株、NJ-1株、NJ-2株、7909株及Vaccine株亲缘性最为相近,与其他毒株的亲缘关系较远。     

Cross protection of mice and swine given live-organism vaccine against challenge exposure with strains of Erysipelothrix rhusiopathiae representing ten serovars

Mice and swine vaccinated (subcutaneous inoculation) with live acriflavine-fast attenuated Erysipelothrix rhusiopathiae, strain Koganei 65-0.15 (serovar 2), were challenge exposed with 10 strains of E rhusiopathiae pathogenic for swine; the latter strains comprised serovars 9 and 10 and other previously undetermined. Vaccinated mice did not die after they were challenge exposed (subcutaneous inoculation) with serovars 4, 6, 7, 8, 9, 10, 15, 16, or N, but vaccinated mice challenge exposed with strain 2553 (serovar 20) had 30% mortality. Nonvaccinated control mice died after they were challenge exposed with all serovars tested. One of 2 vaccinated swine challenge exposed (intradermal inoculation) with each of strains 911 (serovar 8), 2179 (serovar 10), or 2553 developed localized urticarial lesion at the site of intradermal inoculation. Vaccinated swine challenge exposed with serovars 4, 6, 7, 9, 15, 16, or N did not have clinical signs of acute swine erysipelas. Nonvaccinated control swine developed localized lesions at the site of intradermal challenge inoculation.     

A current assessment of the role of porcine parvovirus as a cause of fetal porcine death.

One hundred one litters containing 1 or more dead porcine fetuses were collected at an Iowa abattoir during a 2-month interval and examined for evidence of viral infection. Each of 1,137 fetuses (302 dead, 835 alive) of these litters was tested for porcine parvovirus (PPV) antigens by direct immunofluorescence microscopy (FA) of fetal lung. Antigens of PPV were detected in the lungs of most of the fetuses of 11 of the litters. The 11 FA-positive litters contained 105 dead (100 FA-positive) and 14 live (12 FA-positive) fetuses. Infectious PPV was isolated from 10 of the 11 FA-positive litters and from 3 of the 90 FA-negative litters. No cytopathogenic agents other than PPV were isolated from any of the litters. Eleven of 101 (11%) litters examined and 100 of 302 (33%) dead fetuses examined were FA positive for viral antigen, indicating that PPV remains as a major cause of porcine fetal death.     

Efficacy of acyclovir against herpesvirus infection in Quaker parakeets.

We evaluated the efficacy of acyclovir against experimentally induced herpesvirus infection (Pacheco's parrot disease) in Quaker parakeets. Thirty-two of 40 birds were challenge-exposed with 0.1 ml of a suspension of herpesvirus (10(4) median cell culture infective doses [CCID50]) given IM. Treatment with acyclovir was started 24 hours later and was continued for 7 days. The birds were allotted to 5 groups of 8 birds each. There was a considerable difference in mortality between groups 1-5. Of 8 bird in each group, 6 died in group 1 (control), 1 died in group 2 (gavage), 3 died in group 3 (low dose, IM), 4 died in group 4 (high dose, IM), and none died in group 5 (contact controls). There was a significant (P = 0.023) difference in mortality between groups 1 and 2, thus the oral form of acyclovir administered by gavage was the most efficacious therapeutic regimen. Clinical signs and death occurred after discontinuation of acyclovir in groups 2 and 3, whereas the mean time of death for the control group was 6 days after challenge exposure. Herpesvirus was recovered by inoculation of chick embryo cell culture with pooled tissue suspensions from all birds that died. Histologic evidence of herpesvirus infection was found in most birds that died, with the control group having the most severe lesions. Surviving Quaker parakeets were transferred to cages with seronegative Quaker parakeets with no known exposure to herpesvirus. There have been no deaths attributable to herpesvirus infection in a period exceeding 2 years.     

Identification of viral pathogens in aborted fetuses and stillborn piglets from cases of swine reproductive failure in Spain

The objective of the present study was to determine the presence of recognised abortifacient viruses such as porcine reproductive and respiratory virus (PRRSV), Aujeszky's disease virus (ADV), porcine parvovirus (PPV) and porcine circovirus type 2 (PCV2), in tissues from aborted fetuses and stillborn neonates in cases of late reproductive failure in swine. A total of 293 specimens (fetuses aborted in the last third of gestation and stillborn piglets) from 100 different cases of late-term abortions and premature farrowing from 15 different Spanish provinces were studied. PRRSV was detected in 9/100 cases by RT-PCR. Only 1/100 cases analysed (corresponding to a late-term aborted fetus with a negative PRRSV RT-PCR result) was positive for PCV2 by PCR. Neither ADV (monitored by viral isolation plus antigen detection) nor PPV (monitored by ELISA antigen capture test) infection was identified. The results suggest that PRRSV is one of the most important infectious agents, if not the most relevant one, associated with fetal infection leading to abortion or premature farrowing in Spain. Moreover, other viral pathogens such as ADV, PPV and PCV2 seem to have a minor impact on reproductive disease.