Quarterly Surveillance Report Pigs: Vol.11 No.4 October-November 2007 Published February 2008 Contents HIGHLIGHTS NOTIFIABLE DISEASES ZOONOSES & FOOD SAFETY OVERVIEW OF PIG INDUSTRY HIGHLIGHTS OF ENDEMIC DISEASE SCANNING SURVEILLANCE FOR NEW & EMERGING DISEASES PUBLICATIONS

HIGHLIGHTS

No notifiable diseases of pigs were recorded in the fourth quarter of this year.

One Food Safety Incident concerning pigs was recorded in the fourth quarter this year by VLA Carmarthen and related to DON on barley. This involved pet pigs and was not a major incident.

Salmonellosis remains the most significant potential zoonosis. Salmonella submissions and isolations were much reduced this quarter when compared with the same quarter of 2006. Salmonellae were isolated from 14.7% of the samples this quarter. Salmonella enterica enterica Typhimurium U288 (70%) predominates with DT193 (18.5%) and PT104 7%. Of the other 30% of salmonellae 67% were Salmonella Derby.

The demand for ZAP visits was much reduced in this fourth period. Only 15 new visits were carried out and salmonellae were isolated from 25% of the samples.

Streptococcus suis type 2 still accounts for many of the isolates serotyped this quarter. No zoonotic incidents were recorded.

VTEC O157 was not found in any of the pig submissions of the enhanced E.coli surveillance.

HIGHLIGHTS OF ENDEMIC DISEASE SURVEILLANCE

Analysis of the submissions without a diagnosis did not indicate the emergence of a novel pig disease during the fourth quarter of 2007.

No new and emerging diseases or recrudescence of old disease as a significant endemic disease has occurred in pigs. However, the VLA surveillance centre at Leahurst, Liverpool has identified the atypical fungus Pneumoncystis carinii in the lungs of finishing pigs. This has previously been reported on a big scale in finishing pigs in Denmark. It is suggested that it has been reported in the UK in the past but there are no documented cases until this one. No new strains of avian and/or swine influenza have been seen and in this fourth quarter and few isolations of viruses were made.

PRRS and PMWS/PCV2 continue to be the main causes of pig morbidity and mortality.Reproductive failure and myocarditis are still not a large problem with PCV2.

HIGHLIGHTS FOR THE THIRD QUARTER OF 2007

SALMONELLAS AND SALMONELLOSIS: Salmonellosis continues to be a relatively rare occurrence in pigs. Isolation of salmonellae particularly S. Typhimurium continues to be a common occurrence.

PIG RELATED QUARTERLY SUBMISSIONS, MAIN CLINICAL SIGNS: These were similar to the ones for the last few years being related to wasting, diarrhoea in its various forms and the occurrence of coughing or dyspnoea.

DIAGNOSIS NOT REACHED (DNR): For the four quarters the overall diagnosis not reached was 17.6%.

PMWS: The condition continues to be lesser importance as the clinical effects are reduced with careful attention to the use of alternative boars and crosses particularly involving the Pietrain.

THE IMPROVED POST-WEANING MORTALITY FIGURES ARE A TESTAMENT TO THE PROGRESS THAT HAS BEEN MADE UNDER THE AUSPICES OF B-PEX.

Those producers who have tried the Merial vaccine in sows (now on general release) and the Boehringer vaccine for piglets (under ATC licence) have been impressed with theirperformance in reducing mortality and improving production characteristics.

PRRS: The overall summary is that there is much more diversity now than there was at the start of the outbreak 15 years ago. Many of the new strains are similar to vaccine strains. We do not know the ability of the commercial vaccine strains to protect against the myriad of new strains.

It is still difficult to make a herd diagnosis by isolating a strain from a single pig and multiple samples are necessary.

RESPIRATORY DISEASE: Nothing has changed in the rest of the respiratory disease field (except for PRRS and PCV2) certainly from the gross and microscopic point of view.

In addition Pneumocystis carinii (now classified as an atypical fungus, and formerly thought to be a protozoan), has been described in finishing pigs. The occurrence of this agent is usually taken to indicate an immunosuppressive condition.

Actinobacillus porcitonsillarum has not yet been isolated as yet in the UK. P. urae has not been isolated from any further abortion cases.

SWINE INFLUENZA: There are no new indications of new influenza strains in pigs.

REPRODUCTIVE DISEASE: In this fourth quarter of 2007 few problems were encountered. There was believed to be the usual seasonal increase associated with seasonal infertility.

ALIMENTARY DISEASE: No new patterns of disease were seen.

MYCOPLASMAS: Submissions October – December 2007 in pigs:

Nothing new has been found in the porcine Mycoplasma field.

44 samples from 19 cases were submitted to the group. M. hyopneumoniae was identified twice from lungs, M. hyorhinis was detected 9 times from lungs. M. hyosynoviae was identified in one sample source not stated. Unusually an isolate that gave a 100% match by 16S rDNA sequencing to Acholeplasma oculi was detected from a joint sample. Also one sample from a pig lung gave a close match to M. bovirhinis by 16S rDNA sequencing, M hyorhinis was detected in another lung sample from the same animal.

PIG-RELATED QUARTERLY SUBMISSIONS: (Provisional fourth quarter 2007 data)

The fourth quarter of 2007 showed no significant changes compared with the previous quarters, although the total of submissions were down in the fourth quarter compared with the first. This is a reflection of the continual economic pressure on farmers and the significant reduction in both size and in particular the numbers of units.

Analysis of ‘main clinical sign’ reported with diagnostic submissions did not indicate any major changes during this fourth quarter compared with the average for the whole of 2007.

Differential diagnosis of PMWS and/or ileitis was one of the most common reasons for submissions.

Further Reading

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February 2008