BACTERIOLOGY
Mycoplasma hyopneumoniae
• Field study on the efficacy of two different vaccination schedules with HYORESP® in a Mycoplasma hyopneumoniae-infected commercial pig unit.
Escherichia coli
• Prevalence of serogroups and virulence genes in Escherichia coli associated with post-weaning diarrhoea and oedema disease in pigs and a comparison of diagnostic approaches.
• Genotypic prevalence of the fimbrial adhesins (F4, F5, F6, F41 and F18) and toxins (LT, STa, STb and Stx2e) in Escherichia coli isolated from post-weaning pigs with diarrhoea or oedema disease in Korea.

VIROLOGY
Swine Influenza
• Genetic characterization of H1N2 Influenza A viruses isolated from pigs throughout the United States
PRRS
• Transmission of porcine reproductive and respiratory syndrome virus by needles.
• Establishment of a PRRS virus ELISA-negative boar population using previously exposed boars.
• Experimental inoculation of conventional pigs with porcine reproductive and respiratory syndrome virus and porcine circovirus 2.
PMWS-PCV2 (Circovirus)
• Experiences in the management of porcine multisystemic wasting syndrome (PMWS) on a farm in East Anglia.
• The evolution of porcine dermatitis and nephropathy syndrome (PDNS) and post-weaning multisystemic wasting syndrome (PMWS) on one unit.
• Post-weaning multisystemic wasting syndrome (PMWS) : the current European situation.
• The effect of different lysine levels in the food on post-weaning piglet performance.
• Porcine multisystemic wasting syndrome
• Dynamics of porcine circovirus type 2 infection in a herd of pigs with post-weaning multisystemic wasting syndrome.

RIPP (Rencontre Internationale de Production Porcine)
• Physiological mechanisms involved in Escherichia coli diarrhoea and related risk factors. Digestive system and immunity in piglet.
• Acclimatization of gilts

Field study on the efficacy of two different vaccination schedules with HYORESP® in a Mycoplasma hyopneumoniae-infected commercial pig unit.
KYRIAKIS SC, ALEXOPOULOS C, VLEMMAS J, SARRIS K, LEKKAS M, KOUTSOVITI-PAPADOPOULOU M, SAOULIDIS K
J Vet Med B 2001, 48:675-684
Two vaccination regimens with HYORESP® were tested in piglets from a farm with a previous history of enzootic pneumonia. An early vaccination (at 3 and 25 days of age + placebo at 70) was carried out together with a late vaccination (placebo at 3 and 25 days and vaccination at 70) and both were compared with a non–vaccinated group (sham inoculated). Improvement in growth performance and reduction in lung lesion scores were recorded for the two vaccinated groups. Furthermore, double vaccination in early life proved to be more effective. However the choice of the best vaccination regimen should be made according to the type of herds and time of natural infection within a herd.

Prevalence of serogroups and virulence genes in Escherichia coli associated with post-weaning diarrhoea and oedema disease in pigs and a comparison of diagnostic approaches.
FRYDENDAHL, K
Vet Microbiol 2002, 85: 169-182
E. coli was isolated from intestinal contents of Danish dead pigs with post-weaning diarrhoea (PWD) and oedema disease (ED) in order to determine the serogroup distribution, the hemolytic activity and virulence factor gene profiles of the pathogenic E. coli isolates and assess these characteristics as diagnostic approaches. It was found that the most common serogroup was O149 among the 563 isolates tested with monovalent o-antisera. This serogroup together with four others (O138, O139, O141 and O8) accounted for 79.5% of all isolates. Hemolytic activity was detected in almost all isolates. The following virulence factor genes were detected in 219 isolates: the adhesion factors F4 (44.7%) and F18 (39.3%) with the classical enterotoxin genes STb, Sta, LT as well as EAST1. Six pathotypes based on the relationship between serotyping and virulence factor genes represented 65.7% of the 219 isolates. Although serotyping and hemolytic activity are commonly used as markers of pathogenicity, a number of false results were found in this study and the detection of adhesion factor genes was proposed as a more accurate alternative.

Genotypic prevalence of the fimbrial adhesins (F4, F5, F6, F41 and F18) and toxins (LT, STa, STb and Stx2e) in Escherichia coli isolated from post-weaning pigs with diarrhoea or oedema disease in Korea.
KWON D, CHOI C, JUNG T, KIM JP, BAE SS, CHO WS, KIM J, CHAE C
Vet Rec 2002, 150:35-37
230 E coli isolates from post-weaning pigs with diarrhoea or oedema disease were examined by PCR to determine the genotypic prevalence of the fimbrial adhesins (F4, F5, F6, F41 and F18) and the toxins (LT, STa, STb and Stx2e) produced by ETEC (Enterotoxigenic Escherichia coli) isolates and STEC (shiga toxin producing E coli) isolates. The results of this Korean study demonstrated a high prevalence of F18 fimbrial adhesins (42 isolates carried the gene for F18 ) associated with a high prevalence of shiga toxin 2e (36 isolates carried the gene for Stx2e, 28 of which also contained the gene for F18).

Genetic characterization of H1N2 Influenza A viruses isolated from pigs throughout the United States.
KARASIN AI, LANDGRAF J, SWENSON S, ERICKSON G, GOYAL S, WOODRUFF M, SCHERBA G, ANDERSON G, OLSEN CW
J Clin Microbiol 2002, 40: 1073-1079
The present study provides genetic and phylogenetic evidence of the identical overall genotype between the H1N2 influenza A viruses isolated in different American farms (2000 and 2001) and the original Sw/IN/99 H1N2 virus isolated from a pig in Indiana. These H1N2 viruses are now widely co-circulating with other types of viruses (H1N1 and H3N2) and further epidemiological investigation is required to clearly distinguish them according to NA and HA subtypes.

Transmission of porcine reproductive and respiratory syndrome virus by needles.
OTAKE S, DEE SA, ROSSOW KD, JOO HS, DEEN J, MOLITOR TW, PIJOAN C
Vet Rec 2002, 150:114-115
An experimental study was conducted to provide evidence of a possible transmission of PRRSV from infected to PRRSV free pigs by a contaminated needle. The study involved four replicates of 15 pigs with each replicate comprising an infected group (G1,10 pigs), a sentinel group (G2, 3 pigs) and a negative control group (G3, 2 pigs). Seven pigs from Group 1 were intranasally inoculated with a PRRSV isolate and were administered 2ml of vaccine with the same needle and syringe on various days after inoculation. A similar injection was performed in group 2 with the same instruments. Sera from the three groups were collected and analysed for virus isolation, PRRSV antibodies by ELISA and viral nucleic acid by PCR. Transmission of PRRSV to all pigs in group 1 was effective and two out of 4 replicates for group 2 were PRRSV infected. Control pigs in the third group of each replicate remained PRRSV negative. Consequently, a contaminated needle may be a vector for the transmission of the virus. However these findings need to be reassessed under field conditions.

Establishment of a PRRS virus ELISA-negative boar population using previously exposed boars.
DEE S, DEEN J
Vet Rec 2001, 149:678-680
In an attempt to find control strategies for the elimination of PRRSV in swine herds, a protocol was designed for the inclusion of PRRSV negative boars in an artificial insemination (AI) centre following a four month isolation of boars originating from a PRRSV infected farm. This study was based on previous data assuming that over time and with isolation the virus is cleared from the body, antibodies decay and a seronegative status is recovered. All 10 week-old boars were ELISA positive on entry and after the testing period, 85 of them were ELISA negative and were introduced in the AI centre. Several tests were conducted over 12 months after population of the AI centre and showed that 12 boars turned out to be ELISA positive and were thus removed from the centre. Complementary tests indicated that out of 73 boars, 2 animals were tested positive by ELISA (and not by PCR) and removed. Doses of semen from the remaining 71 boars were sold to 10 farms of which 4 were PRRSV negative. Introduction of a new PRRSV in these farms was not demonstrated. This protocol must be extended to other farms and further tested to be regarded as a reliable means of establishing PRRSV negative breeding stock from originally PRRSV infected source.

Experimental inoculation of conventional pigs with porcine reproductive and respiratory syndrome virus and porcine circovirus 2.
ROVIRA A, BALASH M, SEGALES J, GARCIA L, PLANA-DURAN J, ROSELL C, ELLERBROK H, MANKERTZ A, DOMINGO M
J Virol 2002, 76:3232-3239
Experimental intranasal inoculation of three groups of 5-week-old pigs with either PRRSV, PCV2 or both virus (compared to one control group) was performed in order to determine whether PMWS can be reproduced in these pigs. Several laboratory techniques (serological analysis, PCR, in situ hybridization, Taq Man PCR) were used to detect antibodies to both viruses, PCV2 or PRRSV nucleic acid and PCV2 load. Macroscopic and microscopic lesions in pigs were also described. It was found that a majority of co-infected pigs (6/7) developed mild to moderate signs of PMWS (growth retardation, lymphoid lesion, interstitial pneumonia) while pigs inoculated with PCV2 only did not. All dually inoculated pigs were infected with the two viruses, they had higher rectal temperature, lower weight gain as well as a higher PCV2 load in serum. Similarly, more severe microscopic lesions were observed in dually infected pigs compared to PCV2 infected pigs. These findings thus confirm that it is possible to clinically reproduce PMWS in PRRSV and PCV2 inoculated pigs, and that PRRSV can serve as a predisposing factor to the development of PMWS.

Experiences in the management of porcine multisystemic wasting syndrome (PMWS) on a farm in East Anglia.
DENNIS, I
Pig Journal 2002, 49: 103-109.
In an attempt to control PMWS which had become widespread in East Anglia by the summer of 2000, different management practices were adopted on affected farms. Previous attempts at reducing mortality and morbidity with medication had proved unsatisfactory. A change from a continuous flow system to batch management was applied to an East Anglian farrow-to-finish farm with strict enforcement of new management rules (strict sanitation, reduced batch mixing, weaner accommodation extended, longer rest period between batches ..). After four months, the overall health status of pigs was markedly improved with reduced mortality rates, fewer clinical cases of PMWS, and improved growth rates. It was thus decided to introduce this new system to other farm units.

The evolution of porcine dermatitis and nephropathy syndrome (PDNS) and post-weaning multisystemic wasting syndrome (PMWS) on one unit.
DONE SH, HICKS D, TERRY L, GRESHAM ACJ, WILLIAMSON S, CHENNELS D, TAYLOR L, ARMSTRONG D, DEMMERS T, WHITE R, WATHES C
Pig Journal 2002, 49:184-201
This longitudinal study on the evolution of PMWS and PDNS reports the various clinical and pathological findings observed in eights batches of pigs over a three year experiment (1999-2001) which forms part of a larger study (4 years) assessing the effects of ammonia and dust on the health status of pigs. Many pathogens were already present in the herd: PRRSV, Swine influenza, APP, PCV1 and PCV2, PRCV, PCMV. Post mortem examinations were performed at different time intervals (5, 10, 12 weeks and slaughter time) for lung and snout scores, together with histopathological and microbial examinations. The first five batches (1999-2001) showed little evidence of PMWS and PDNS but had hyperplasic tracheobronchial nodes and rubbery lungs. Batch 6 could not be examined. Batch 7 (Sept. 2001) had similar clinical signs in addition to 2 cases of PDNS and PMWS (pigs with lymphocyte depletion). Batch 8 (Nov. 2001) included a high number of poorly doing pigs (hairy, pale, wasted, etc.) and full blown PMWS in three pigs. It may be concluded that the early occurrences of hyperplasic lymph nodes may represent a first step towards a change in lymph node observed in porcine circoviral disease and followed by classical lymphocyte depletion.

Post-weaning multisystemic wasting syndrome (PMWS) : the current European situation.
DONE SH, BAILEY M, GRESHAM ACJ, WHITE R, POTTER RA, CHENNELS D, THOMSON J
Pig Journal 2002, 49:215-232
The clinical, pathological and histological features of PMWS and PDNS are reviewed in this study which compares the UK situation with other European countries and the USA. A clear distinction is being made between sporadic PDNS in and epizootic PDNS, which appeared to be a British occurrence. Also there are marked differences between Europe and the USA concerning PMWS. In Europe, PMWS is often associated with PDNS while in the USA, PDNS is not seen with PMWS infected herds. Similarly the most common clinical signs of the disease in the USA are respiratory signs and wasting, which make it undistinguishable from PRDC. In Europe, wasting, weight loss, inappetence and depression are the major characteristic signs. The authors also provide some epidemiological data and advice on management strategies which may be useful in reducing PMWS occurrence.

The effect of different lysine levels in the food on post-weaning piglet performance.
BAUMAN BG, BILKEI G
Pig Journal 2002, 49:92-102
This paper reports the results of an experiment conducted in a large pig production unit with a history of PWW (Post Weaning Wasting). The objective of this study was to provide evidence of the benefits of a relatively high lysine diet on growth performance in piglets suffering from growth retardation due to E. Coli infection. Four groups of piglets were fed with different amounts of lysine (1%, 1.3%, 1.6% and 1.9%) content in their food over a period of 4 weeks. Average daily weight gain (ADG), average food intake (AFI) and average food conversion (FC) were recorded. The best weaning formula turned out to be the 1.6% lysine containing diet which was associated with higher AFI, ADG and lower FC. In conclusion, pigs suffering from PWW need higher protein levels than healthy animals.

Porcine multisystemic wasting syndrome
NASH WA
Pig Journal 2002, 49:110-112
The study of PMWS cases in Britain revealed that fluid accumulation in lungs created favourable conditions for secondary infection and that enlarge lymph nodes preceded other lesions in PMWS infected pigs.

Dynamics of porcine circovirus type 2 infection in a herd of pigs with post-weaning multisystemic wasting syndrome.
RODRIGUEZ-ARRIOJA GM, SEGALES J, CALSAMIGLIA M, RESENDES AR, BALASCH M, PLANA-DURAN J, CASAL J, DOMINGO M
AJVR 2002, 63 (3): 354-357
This study focused on the pattern of infection for PCV2 in a population of 250 pigs, offspring of 29 sows from a herd experiencing a severe outbreak of PMWS. A second objective was to assess the role of PPV in the course of the disease. Blood samples were obtained from both sows and pigs and were tested for PCV2 by PCR, in situ hybridization and for PCV2/PPV antibodies by ELISA. Postmortem examination was carried out on pigs that died during the study (83). Seroconversion to PCV2 was evident in all pigs during the grower phase (increase in serologic titers from 7 to 12 weeks and stabilization until 28 weeks). PCV2 DNA was detected in serum samples at various times for some pigs. Viremia was first detected by PCR at 7 weeks of age and increased until 12 weeks of age. This increase coincided with the outbreak of PMWS starting from 8 weeks until 12. It was also noted that some clinically healthy pigs remained viremic until 28 weeks of age. Only one sow was tested positive for PCV2. PPV serological analysis revealed that the virus did not have any effects on the outcome of the disease. The development of a persistent viremia in some pigs needs to be further investigated.

Physiological mechanisms involved in Escherichia coli diarrhoea and related risk factors.
Digestive system and immunity in piglet.
FAIRBROTHER JM
Rencontre Internationale de Production Porcine (RIPP), Loudéac, France, June 2002 :1-13
Escherichia coli diarrhoea is a significant disease of swine affecting neonatal, weaning and post-weaning pigs. Enterotoxigenic E. coli are the major class of pathogens causing diarrhoea and dehydration by secreting electrolytes and fluids. Non-infectious factors increase the occurrence of the disease such as poor sanitation, poor environmental conditions, other infectious agents, nutrition, age of piglets at weaning. Piglets acquire immunity against ETEC with maternal antibodies from colostrum and milk. Active immunity is not effective before 4 to 7 weeks of age. To prevent neonatal diarrhoea, vaccination of late gestating sows results in increased antibody levels in colostrum and milk, thereby providing protection. However this type of vaccination does not prevent diarrhoea in post-weaning pigs. Other prevention strategies are being investigated such as the introduction of eggs vaccinated with F4 and F18 adhesins into the food of piglets.

Acclimatization of gilts
BARCELÒ BONADA J
Rencontre Internationale de Production Porcine (RIPP), Loudéac, France, June 2002 :60-73
The acclimatization process of replacement gilts is of the utmost importance to achieve optimal productivity and genetic potential of gilts and avoid a new round of virus circulation in the receiving herd. Quarantine and acclimatization units are the keys to a successful acclimatization. Identification of the health status of the source herd as well as the receiving herd are prerequisites for an acclimatization programme to help gilts acquire specific immunity.