Successful elimination of PRRS virus from an infected farrow-to-finish herd by vaccination

Toman, M.; Celer, V.; Smoła, J.

doi:10.17221/68/2017-vetmed

Cited by 10 publications

(15 citation statements)

References 14 publications

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“…Despite the fact that many studies focused on PRRS immunoprophylaxis have already been published and many procedures are implemented in the agricultural industry, a universal model does not yet exist (46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60). The use of live attenuated vaccines is generally preferred as was also confirmed in our field study (61). In this study, we controlled the infection by a repeated blanket immunization with MLV vaccine (Porcilis), followed by targeted immunization of gilts, and sows.…”

Section: Discussionsupporting

confidence: 68%

Dynamics and Differences in Systemic and Local Immune Responses After Vaccination With Inactivated and Live Commercial Vaccines and Subsequent Subclinical Infection With PRRS Virus

et al. 2019

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The goals of our study were to compare the immune response to different killed and modified live vaccines against PRRS virus and to monitor the antibody production and the cell mediated immunity both at the systemic and local level. In the experiment, we immunized four groups of piglets with two commercial inactivated (A1—Progressis, A2—Suivac) and two modified live vaccines (B3—Amervac, B4—Porcilis). Twenty-one days after the final vaccination, all piglets, including the control non-immunized group (C5), were i.n., infected with the Lelystad strain of PRRS virus. The serum antibody response (IgM and IgG) was the strongest in group A1 followed by two MLV (B3 and B4) groups. Locally, we demonstrated the highest level of IgG antibodies in bronchoalveolar lavages (BALF), and saliva in group A1, whereas low IgA antibody responses in BALF and feces were detected in all groups. We have found virus neutralization antibody at DPV 21 (days post vaccination) and higher levels in all groups including the control at DPI 21 (days post infection). Positive antigen specific cell-mediated response in lymphocyte transformation test (LTT) was observed in groups B3 and B4 at DPV 7 and in group B4 at DPV 21 and in all intervals after infection. The IFN-γ producing lymphocytes after antigen stimulation were found in CD4 − CD8 + and CD4 + CD8 + subsets of all immunized groups 7 days after infection. After infection, there were obvious differences in virus excretion. The virus was detected in all groups of piglets in serum, saliva, and occasionally in feces at DPI 3. Significantly lower virus load was found in groups A1 and B3 at DPI 21. Negative samples appeared at DPI 21 in B3 group in saliva. It can be concluded that antibodies after immunization and infection, and the virus after infection can be detected in all the compartments monitored. Immunization with inactivated vaccine A1—Progressis induces high levels of antibodies produced both systemically and locally. Immunization with MLV-vaccines (Amervac and Porcilis) produces sufficient antibody levels and also cell-mediated immunity. After infection virus secretion gradually decreases in group B3, indicating tendency to induce sterile immunity.

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Section: Discussionsupporting

confidence: 68%

Dynamics and Differences in Systemic and Local Immune Responses After Vaccination With Inactivated and Live Commercial Vaccines and Subsequent Subclinical Infection With PRRS Virus

et al. 2019

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“…In these stable herds, PRRSV can still be detected but at a low level and with low frequency. By utilising the above principles and practical experience, several countries performed successful local and regional eradication with the use of MLV vaccines and biosecurity measures [19,23]. PRRS eradication of the Hungarian herd was carried out in a complex way, applying strict biosecurity measures and vaccination with Progressis®.…”

Section: Discussionmentioning

confidence: 99%

“…Signi cant percentages (80-85%) of large-scale breeding herds in Hungary are farrow-to-nish farms [18]. According to scienti c literature, infected breeding herds can be stabilised by the use of vaccination and offspring can be kept free of PRRSV until weaning or even to the end of the nursery period [5,19]. However, if not fully implemented age-segregated production and highest levels of internal biosecurity is implemented, the freedom of PRRSV cannot be maintained in the nishing phase in farrow-to-nish farms [16].…”

Section: Introductionmentioning

confidence: 99%

Elimination of PRRS Using An Inactivated Vaccine in Combination With A Roll-Over Method in A Hungarian Large-Scale Pig Herd

Pertich¹,

Barna²,

Makai³

et al. 2021

Preprint

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Background:Four countries are free from the porcine reproductive and respiratory syndrome virus (PRRSV) in Europe, a virus that causes severe economic losses worldwide. A number of countries have initiated eradication programmes against the disease. Among the applied methods, complete depopulation-repopulation is the safest and fastest but at the same time the most expensive process. Another possible way of heard eradication is to replace the infected breading stock by gilts reared PRRSV free on the infected farm. This way maintaining continued farm production. In this paper, the authors present a successful complex method of eradication (including the application of an inactivated vaccine and segregated rearing of offspring) in a Hungarian large scale pig farm. Case presentation:A farm of 1475 sows (Farm A) was infected with PRRSV and the clinical signs of reproductive failure were eliminated by using an inactivated vaccine (Progressis®, Ceva). At the beginning of eradication, gilts selected for breeding were vaccinated at 60 and 90–100 days of age, respectively. The subsequent vaccinations of breeding animals were applied at 6 months of age, on the 60–70th day of pregnancy and at weaning. The 7weeks-old piglets of the vaccinated sows, approximately 1200 piglets were transported in groups of 300 animals to a closed, empty farm (Farm B) after a testing negative with PCR, and they were reared here until 14 weeks of age. These seronegative gilts were subsequently transported to a third, closed, empty farm (Farm C), and (having reached the breeding age) they were inseminated here after a negative serological test (ELISA). At the same time, Farm A was depopulated, cleaned and disinfected. All pregnant gilts were transported from Farm C to Farm A after being tested negative with ELISA, where follow-up was performed after farrowing by two serological tests with an interval of six months. Based on the subsequent negative test results, the competent authority declared the herd PRRSV free. Conclusions:The farm presented in this study was the first in the course of the National PRRS Eradication Programme to eradicate PRRSV successfully by vaccinating the sows with an inactivated vaccine and performing segregated rearing of the offspring. Production was almost continuous during the whole process of the population replacement. Testing for monitoring purposes was also cheaper and simpler because of the use of an inactivated vaccine.

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“…The management of large breeding swine herds had complete freedom to decide whether eradication of the PRRS virus was to be carried out by complete depopulationrepopulation (Rathkjen and Dall, 2018), herd closure (Torremorell and Christianson, 2002), test and removal (Dee, 2004), applying more stringent site management methods, rationalisation of infection chain interruption (Dee et al, 1993;Dee and Joo, 1994;Baker, 2010;Berton et al, 2017;Rathkjen and Dall, 2018) or supportive vaccination for all or specified ages (Philips and Dee, 2003;Toman et al, 2017), and by the introduction of systematic laboratory testing processes. The criterion was to find an optimal method suited to the particular technological processes of the swine herd that according to the current state of science was likely to lead to a PRRSV-free status with high probability.…”

Section: Methodsmentioning

confidence: 99%

PRRS eradication from swine farms in five regions of Hungary

Szabó

Bognár

Molnár

et al. 2020

AVet

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Porcine reproductive and respiratory syndrome (PRRS) causes significant losses to the swine industry worldwide, which leads to launching eradication programmes. The PRRS eradication programme in Hungary is based on the territorial principle, and it is obligatory for each swine farm irrespective of the number of animals kept there. Hungary has an exceptionally large herd size in large-scale pig farms. Large fattening farms operate as all-in/all-out or continuous flow systems. The large-scale breeding herds are predominantly farrow-to-finish types. In large-scale breeding farms, PRRS eradication was carried out by the depopulation-repopulation method in 33 farms, of which 23 received state compensation, 18 farm units either finished production or changed to producing fatteners only. Two farms used the test and removal method for eradication. One farm was classified as ‘vaccinated free’. At this farm the breeding animals are vaccinated continuously but there is no vaccination of the progeny at any age, and the PRRS-free status of the farm is strictly controlled and monitored. By 31 December 2019, all pigs in five euroregions of Hungary had become free from PRRS virus, while the PRRS eradication process is still ongoing in the remaining two regions.

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Successful elimination of PRRS virus from an infected farrow-to-finish herd by vaccination

Cited by 10 publications

References 14 publications

Dynamics and Differences in Systemic and Local Immune Responses After Vaccination With Inactivated and Live Commercial Vaccines and Subsequent Subclinical Infection With PRRS Virus

Dynamics and Differences in Systemic and Local Immune Responses After Vaccination With Inactivated and Live Commercial Vaccines and Subsequent Subclinical Infection With PRRS Virus

Elimination of PRRS Using An Inactivated Vaccine in Combination With A Roll-Over Method in A Hungarian Large-Scale Pig Herd

PRRS eradication from swine farms in five regions of Hungary

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