PRRS eradication from swine farms in five regions of Hungary

Szabó, István; Bognár, L.; Molnár, Tamás; Nemes, Imre; Bálint, Ádám

doi:10.1556/004.2020.00043

Cited by 14 publications

(22 citation statements)

References 12 publications

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“…From 2005 to 2020, serum and organ samples were collected for routine PRRSV monitoring, or from herds suspected to sustain PRRS disease, as described in detail previously ( 18 , 24 , 25 ). Samples were tested within 48 h of arrival to laboratory by PRRSV-specific PCR or ELISA methods.…”

Section: Methodsmentioning

confidence: 99%

Genetic diversity of imported PRRSV-2 strains, 2005–2020, Hungary

et al. 2022

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Porcine reproductive and respiratory syndrome virus 2 (PRRSV-2) remains sporadic in Europe. In this study, we investigated the molecular epidemiology of PRRSV-2 infections encompassing 15 years in Hungary. Partial (423 bp long) ORF5 sequences (n = 44) from 20 Hungarian pig herds were analyzed. The study strains fell into two genetic lineages, L1 and L5, being L5 strains more prevalent (88.6 vs. 11.4%). Pairwise sequence identities within Hungarian representative PRRSV-2 strains ranged between 84.7 to 100% (nucleotide, nt) and 85 to 100% (amino acid, aa). When compared with reference strains, identity values fell between 87 and 100% (L1, nt 87–91%, aa 87–93%, reference strain IAF-exp91; L5, nt 87–100%, aa 88–100%, reference strain Ingelvac MLV). Epidemiologic examination implied that the majority of L5 strains were imported repeatedly from other European countries where Ingelvac MLV was approved for routine use. The emergence of L1 strains was thought to be associated with a single introduction and subsequent dissemination between pig farms of a large integrator. Results presented here contribute to a better understanding of the epizootiology of PRRSV-2 infections and shed light on the genetic diversity of viral strains in non-endemic countries.

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Section: Methodsmentioning

confidence: 99%

Genetic diversity of imported PRRSV-2 strains, 2005–2020, Hungary

et al. 2022

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“…The principle for the eradication of infected swine herds is the strict keeping of the external and internal disease control standards of the farms, laboratory monitoring of different age groups of the herds and immunisation against PRRS (including pregnant and non-pregnant breeding sows, replacing gilts, breeding boars, piglets during lactation, pre-fatteners, and fatteners). The main purposes of immunisation are as follows: (a) Development of homogeneous immune status of infected breeding stock and prevention of intrauterine and neonatal infections; (b) promoting the virus-free raising of progeny of breeding sows; (c) production of PRRS virus-free gilts from their own breeding stock, or from outer source, thereby replacing the infected breeding stock with virus-free sows [ 26 ].…”

Section: Discussionmentioning

confidence: 99%

Genetic Variability of PRRSV Vaccine Strains Used in the National Eradication Programme, Hungary

et al. 2021

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Porcine reproductive and respiratory syndrome (PRRS) is a globally spread, highly infectious viral disease. Live, attenuated vaccines against PRRS virus (PRRSV) decrease virus excretion and evoke protective immunity reducing the economic damage caused by the disease. In a longitudinal molecular epidemiological study accompanying ongoing national eradication programme we evaluated the suitability of PRRSV ORF5 and ORF7 sequences to identify possible field strains of vaccine-origin. In total, 2342 ORF5 sequences and 478 ORF7 sequences were analysed. Vaccine strains were identified by sequence identity values and phylogenetic network analysis. Strains that shared greater than 98% nucleotide identity within ORF5 and/or ORF7 were considered to have originated from vaccine. A total of 882 (37.6%) ORF5 and 88 (18.4%) ORF7 sequences met these criteria. In detail, 618, 179 and 35 ORF5 and 51, 29 and 8 ORF7 sequences were related to Porcilis PRRS vaccine, Unistrain PRRS vaccine, and ReproCyc PRRS EU vaccine, respectively. Data showed that the Porcilis vaccine was genetically more stable. Whereas, the variability of the Unistrain and the ReproCyc strains was significantly higher. Given that ORF7 shares, in some instances, complete identity between a particular vaccine strain and some historic variants of field PRRSV strains, care must be taken when evaluating vaccine relatedness of a field isolate based on the ORF7. On the contrary, ORF5 sequences were more suitable to predict the vaccine origin making a distinction more robustly between field and vaccine strains. We conclude that ORF5 based molecular epidemiological studies support more efficiently the ongoing PRRS eradication programmes. The conclusions presented in this large-scale PRRS molecular epidemiological study provides a framework for future eradication programmes planned in other countries.

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“…Pig breeding in Hungary has been characterised by the parallel presence of two different forms of farming for many decades. Large-scale pig farms produce pigs for the market, while individual farmers (backyard farms) keep one or two sows and a limited number of pigs for fattening (1)(2)(3)(4)(5)(6)(7)(8)(9)(10) intended for on-the-spot processing and consumption. Even before the accession of Hungary to the European Union, the role of backyard farms on the market had signi cantly decreased.…”

Section: Introductionmentioning

confidence: 99%

Eradication of PRRS from Hungarian pig herds 2014–2022

Szabó¹,

Nemes²,

Bognár

et al. 2023

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Background: Porcine reproductive and respiratory syndrome (PRRS) is an infectious disease with widespread distribution and is currently a major cause of economic loss in pig production. In Hungary, a National PRRS Eradication Program was introduced in order to reach a more efficient, economic and competitive international market position. The EU also approved the program, but the resultant legal obligations placed a burden on Hungarian producers in order to comply with EU competition rules. The veterinary authorities carried out the implementation of the program with the consent, continuous support and monitoring by the organizations of the pig industry as well as a scientific committee. The PRRS eradication program in Hungary was based on a regional territorial principle and was obligatory for every swine farm within those regions. In Hungary large fattening farms operate as all-in/all-out or continuous flow system. The large-scale breeding herds are predominantly farrow-to-finish types. Although its significance has decreased in recent decades, 20% of the Hungarian pig population is still kept in small-scale (backyard) farms (< 100 animals). Each PRRS-infected large-scale farm had to develop a unit-adapted eradication plan, including external and internal biosecurity measures, vaccinations, etc. It was crucial to render each fattening unit free of the disease since fattening units play a significant role in spreading the virus across the country. Eradication efforts mainly implemented depopulation-repopulation methods, with some farms using the test and removal method instead. Results: As the eradication progressed over the years, the introduction of infected fattening pigs was restricted. Because of these measures, by the end of 2018, Hungarian large-scale fattening farms became free of PRRS. The PRRS-free status of the small-scale herds was achieved by the end of 2015, and this status was maintained from 2016–2021. By the 31st of December in 2021, all breeding pigs at large scale-farms in Hungary had become free of wild type PRRS virus. By the 31st of March in 2022, the total pig population of the country, including all backyard farms and fattening units, had achieved PRRS-free status. Conclusions: The future goal is to secure and maintain the PRRS free status of Hungary by strict import regulations of live animals combined with continuous and thorough screening of incoming and resident herds for the presence of the virus.

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PRRS eradication from swine farms in five regions of Hungary

Cited by 14 publications

References 12 publications

Genetic diversity of imported PRRSV-2 strains, 2005–2020, Hungary

Genetic diversity of imported PRRSV-2 strains, 2005–2020, Hungary

Genetic Variability of PRRSV Vaccine Strains Used in the National Eradication Programme, Hungary

Eradication of PRRS from Hungarian pig herds 2014–2022

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