Appearance of acute PRRS‐like symptoms in sow herds after vaccination with a modified live PRRS vaccine

Bøtner, Anette; Strandbygaard, Bertel; Sørensen, K. J.; Have, P.; Madsen, K.G.; Madsen, E. S.; Alexandersen, Søren

doi:10.1136/vr.141.19.497

Cited by 203 publications

(139 citation statements)

References 7 publications

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“…It is possible to distinguish between herds infected with respectively the American and the European type of PRRSV by means of serological analysis of blood samples using blocking ELISAs or immunoperoxidase monolayer assays (IPMAs) [8,13,14]. Both types of PRRSV are prevalent in the Danish swine population [3]. The presence of the American strain is due to the use of a modified live vaccine based on the American isolate VR2332.…”

Section: Serological Assaysmentioning

confidence: 99%

Monitoring porcine reproductive and respiratory syndrome virus infection status in swine herds based on analysis of antibodies in meat juice samples

Mortensen

Strandbygaard²,

Bøtner³

et al. 2001

Vet. Res.

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-An indirect ELISA test was developed as a novel tool aimed at monitoring the herd infection status of swine herds. Meat juice samples from pig carcasses were analysed for the presence of antibodies against porcine reproductive and respiratory syndrome virus (PRRSV). A study of samples from herds with known PRRS status was undertaken. The PRRS status of the herds was evaluated based on the analysis of blood samples by another serological test (blocking ELISA) capable of differentiating between infection with PRRSV of the American type and European type. The specificity of the indirect ELISA test on meat juice samples was 0.98. The sensitivity of the test depended on the type of the PRRSV strain involved. The apparent prevalence in herds infected with the American type of PRRSV was 0.44. The apparent prevalence in herds infected with the European type of PRRSV was 0.64. Herd level sampling and herd level criteria for assessing the PRRS status of herds by the new test were developed. Herds were classified as PRRS negative or PRRS seropositive based on 10 meat juice samples collected randomly at slaughter throughout a 3-month-period. Herd PRRS status classification by the indirect ELISA was validated in 47 herds by collection of blood samples from the herds. Eighteen herds were classified as PRRS negative by both test systems. Twenty-nine herds were classified as PRRS seropositive by both test systems. Acceptable herd classification was achieved using this test.ELISA / PRRSV / sensitivity /specificity / herd-level / meat juice Vet. Res. 32 (2001) [441][442][443][444][445][446][447][448][449][450][451][452][453] 441

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Section: Serological Assaysmentioning

confidence: 99%

Monitoring porcine reproductive and respiratory syndrome virus infection status in swine herds based on analysis of antibodies in meat juice samples

Mortensen

Strandbygaard²,

Bøtner³

et al. 2001

Vet. Res.

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“…However, the protective immune response induced by attenuated PRRSV vaccines is influenced by genetic diversity, as these vaccines do not always sufficiently protect against virus strains that are genetically different from the vaccine virus strain [11,15]. Besides, there are major concerns about the safety of attenuated PRRSV vaccines, as the vaccine virus on itself can cause viremia and can spread transplacentally and horizontally with the risk of reverting to virulence [2,18,22]. Inactivated vaccines on the other hand are safe and it has been shown by Misinzo et al that it is possible to stimulate the VN antibody response in naïve piglets by immunization with inactivated PRRSV [16].…”

Section: Introductionmentioning

confidence: 99%

Development of an experimental inactivated PRRSV vaccine that induces virus-neutralizing antibodies

et al. 2009

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-Porcine reproductive and respiratory syndrome virus (PRRSV) can induce reproductive disorders and is involved in the porcine respiratory disease complex, causing tremendous economic losses to the swine industry. Inactivated PRRSV vaccines are preferred over attenuated vaccines because of their safety and flexibility towards emerging virus strains, but the efficacy of current inactivated PRRSV vaccines is questionable. In this study, experimental inactivated PRRSV vaccines were developed, based on two formerly optimized inactivation procedures: UV irradiation and treatment with binary ethylenimine (BEI). In a first experiment, it was shown that vaccination with UV-or BEI-inactivated virus in combination with Incomplete Freund's Adjuvant induced virus-specific antibodies and strongly primed the virus-neutralizing (VN) antibody response. Subsequently, the influence of adjuvants on the immunogenicity of neutralizing epitopes on the inactivated virus was investigated. It was shown that vaccination with BEI-inactivated virus in combination with a commercial oil-in-water adjuvant induced high titers (3.4 log 2 ) of VN antibodies in 6/6 pigs, instead of only priming the neutralizing antibody response. After challenge, neutralizing antibody titers in these vaccinated animals rose to a mean value of 5.5 log 2 , and the duration of the viremia was reduced to an average of 1 week. This study shows that, by the use of an optimized inactivation procedure and a suitable adjuvant, inactivated PRRSV vaccines can be developed that induce VN antibodies and offer partial protection upon challenge.

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“…Antigenic variations among PRRSV isolates are well documented (26,32,75; reviewed in reference 34). Since the emergence of PRRSV, intermingling of the two genotypes has occurred in Europe as a result of the use of a live, United States-derived (type 2) PRRSV vaccine (5,31). There have been several recent reports of European-like PRRSV strains appearing in North America.…”

mentioning

confidence: 99%

Characterization of Emerging European-Like Porcine Reproductive and Respiratory Syndrome Virus Isolates in the United States

Ropp

Wees

Fāng

et al. 2004

J Virol

165

124

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European-like field isolates of porcine reproductive and respiratory syndrome virus (PRRSV) have recently emerged in North America. The full-length genomic sequence of an index isolate characterized in 1999, strain EuroPRRSV, served as the reference strain for further studies of the evolution and epidemiology of Europeanlike isolates (type 1) in the United States. Strain EuroPRRSV shared 90.1 to 100% amino acid identity with the prototype European strain, Lelystad, within the structural and nonstructural open reading frames (ORFs) and 95.3% overall nucleotide identity. The 5 untranslated region and two nonstructural regions within ORF 1 were closely examined due to significant divergence from strain Lelystad. A 51-bp deletion in a region within ORF 1a, coding for nonstructural protein 2 (NSP2), was observed. Sequence analysis of the structural ORFs 2 to 7 of additional European-like isolates indicated that these isolates share 93% nucleotide identity with one another and 95 to 96% identity with the Lelystad strain but only 70% identity with the North American reference strain VR-2332. Phylogenetic analysis with published PRRSV ORF 3, 5, and 7 nucleotide sequences indicated that these newly emerging isolates form a clade with the Lelystad and United Kingdom PRRSV isolates. Detailed analysis of four of these isolates with a panel of 60 monoclonal antibodies directed against the structural proteins confirmed a recognition pattern that was more consistent with strain Lelystad than with other North American isolates.

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Appearance of acute PRRS‐like symptoms in sow herds after vaccination with a modified live PRRS vaccine

Cited by 203 publications

References 7 publications

Monitoring porcine reproductive and respiratory syndrome virus infection status in swine herds based on analysis of antibodies in meat juice samples

Monitoring porcine reproductive and respiratory syndrome virus infection status in swine herds based on analysis of antibodies in meat juice samples

Development of an experimental inactivated PRRSV vaccine that induces virus-neutralizing antibodies

Characterization of Emerging European-Like Porcine Reproductive and Respiratory Syndrome Virus Isolates in the United States

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