S.K. Kritas, G. Filioussis, K. Papageorgiou Department of Microbiology & Infectious Diseases, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece Classification of farrow-to-finish swine herds regarding to their PRRS status. A study in Greece. EuroPRRS.net COST FA902 Thessaloniki, Greece. Aug 23-25, 2012

Introduction PRRS is the most important and costly infectious disease of pig industry worldwide nowadays. EuroPRRS.net COST FA902 Thessaloniki, Greece. Aug 23-25, 2012

Cause: Arterivirus (F:Arteriviridae, O: Nidovirales - RNA) There are 2 major antigenically distinct genotypes. Only 66% homology –European type (type Ι or EU-type, Lelystad virus) –North American type (type IΙ, NA-type) –Strains of each genotype show antigenic differentiation at a lower level. Within both genotypes  Strains with different virulence  Efficacy problems with vaccinations

What was the appearance of PRRS in Greece? Reproductive disorders (early farrowings, returns to estrus, abortions, births of stillborn/ mummies/ weak piglets Increased pre- and postweaning mortality Increased incidence of respiratory infections (primary or secondary) Fatteners delay to reach slaughter weight Economic impact of PRRSV has not been estimated, but this is very high

What policy applies for PRRS identification? No compulsory national policy for examining the herds e.g. only farmers who wish to examine their herd send few samples to laboratories. This presentation is aiming to record and characterize the PRRS status in farms throughout the majority of Greek territory ELISA developed by T. Stadejek and PCR as described in the COST workshops

Materials and Methods

Fig 1. Number of farms / Pig density (pigs/km 2 ) Albania FYROM Bulgaria Turkey Greece 18/6 70/2 126/9 14/1 114/20 192/13 140/22 62/8 81/6 61/8

Fig 1. Pig density (Blinking ☺ > 20 pigs/ km 2 ) Albania FYROM Bulgaria Greece Turkey PRRS first diagnosed in Greece in 1993 (mainly importing breeders at that time)

Fig 1. Number of farms sampled ( ✩ = 1 farm sampled ) Albania FYROM Bulgaria Greece Turkey Size of farms (# sows) No of farms (estimate) Sample size (# farms) 100 to to >850206

Fig 1. Number of farms sampled ( ✩ = 1 farm sampled ) Albania FYROM Bulgaria Greece Turkey

Fig 1. Number of farms sampled ( ✩ = 1 farm sampled ) Albania FYROM Bulgaria Greece Turkey Size of farms (# sows) No of farms (estimate) Sample size (# farms) # PRRS- posve farms % of farms 100 to % 301 to % > %

Classification of farrow-to-finish swine herds based on their PRRS status (Holtkamp DJ, et al 2011) CasePRRS ELISA (exposure) PRRS PCR (shedding) Interpretation 0neg Farm is negative 1pos Farm is positive (virus is still circulating within the herd-Herds going through a clinical PRRS outbreak and those with chronically recurring shedding of virus) 2posnegFarm is stable positive (virus undergoes elimination) or provisional negative 3negposFarm is very recently (acutely) infected ? (it became recently infected) Derald J. Holtkamp, DVM, MS; Dale D. Polson, DVM, PhD; Montserrat Torremorell, DVM, PhD; and committee members Bob Morrison, DVM, PhD, MBA (chair); Dyneah M. Classen, DVM; Lisa Becton, DVM; Steve Henry, DVM; Max T. Rodibaugh, DVM; Raymond R. Rowland, PhD; Harry Snelson, DVM; Barb Straw, DVM, PhD; Paul Yeske, DVM, MS; Jeff Zimmerman, DVM, PhD

Herd size, e.g. the number of sows. Pig herd density in the municipality (herds per 1,000 sq km), The direct (straight) distance from the closest pig farm (km) as checked in google maps, the purchase of breeding animals from sources outside the farm. Gilts self produced (0), or purchased from other herds (1). Non practicing (0) or practicing (1) of at least one month quarantine in distant building for the newly purchased breeding animals. Non practicing (0) or practicing (1) of hygienic/ biosecurity measures within the farm. Non practicing (0) or practicing (1) of all-in, all-out (AIAO) flow in all production stages.. Non practicing (0) or practicing of vaccination of sows for PRRS. Absence (0) or presence (1) of other health problems in the farm. Parameters recorded

Serological and PCR testing 8 blood samples from 22-week old pigs were collected. These samples were tested by: ELISA for the presence of antibodies against PRRS virus PCR for the presence of the PRRS virus in pools of 4 samples. Since maternal antibodies for PRRS virus rarely remain after 4-6 weeks of age, antibodies detected at the end of the fattening period were considered to indicate the presence of an infection by a wild-type virus in the farm. The detection of virus by PCR during the end of the fattening period also was considered as indicative of recent infection in the farm.

Results

PRRS status x Farm size (not significant) CaseFarm designation (ELISA exp/PCR shed) SMLTotal 0NEGATIVE (neg/neg) POSITIVE (pos/pos) POSITIVE STABLE (pos/neg)4419 PRRS status x Farm distance (significant) CaseFarm designation (ELISA exp/PCR shed) ≤3km>3km 0NEGATIVE (neg/neg)311 1POSITIVE (pos/pos)127 2POSITIVE STABLE (pos/neg)54

PRRS status x Quarantine (NS) PRRS status x Gilt purchase (Significant) CaseFarm designation (ELISA exp/PCR shed) Purch NoPurch Yes 0NEGATIVE (neg/neg)77 1POSITIVE (pos/pos)316 2POSITIVE STABLE (pos/neg)36 CaseFarm designation (ELISA exp/PCR shed) Quarant NoQuarant Yes 0NEGATIVE (neg/neg)104 1POSITIVE (pos/pos)172 2POSITIVE STABLE (pos/neg)53

PRRS status x AIAO (NS) PRRS status x Farm Hygiene (Significant) CaseFarm designation (ELISA exp/PCR shed) Hygiene NoHygiene Yes 0NEGATIVE (neg/neg)68 1POSITIVE (pos/pos)127 2POSITIVE STABLE (pos/neg)18 CaseFarm designation (ELISA exp/PCR shed) AIAO NoAIAO Yes 0NEGATIVE (neg/neg)59 1POSITIVE (pos/pos)109 2POSITIVE STABLE (pos/neg)35

PRRS status x Other health problems (Significant) PRRS status x PRRS sow vaccination (NS) CaseFarm designation (ELISA exp/PCR shed) Vacc NoVacc Yes 0NEGATIVE (neg/neg)86 1POSITIVE (pos/pos)712 2POSITIVE STABLE (pos/neg)27 CaseFarm designation (ELISA exp/PCR shed) Problems NoProblems Yes 0NEGATIVE (neg/neg)77 1POSITIVE (pos/pos)019 2POSITIVE STABLE (pos/neg)36

In the PRRS positive farms, respiratory and reproductive problems were by far the most prominent (versus death, nervous and gastrointestinal problems) In the PRRS positive farms, growers and finishers were mostly affected (versus neonatal and nursery)

Our team Petridou E 1, Filioussis G 1,2, Papageorgiou Κ 1,2, Burriel ΑR 3, Christodoulopoulos G 4, Stadejek T 5, Morrison RB 5