According to the June 2011 Agricultural Census, there were 3.93 million turkeys in the UK, compared to 3.89 million in 2010, which is an increase of approximately one per cent.

In January 2010, the National Control Programme for the control of Salmonella in turkeys was introduced across the European Union. The NCP includes breeding and fattening turkey flocks. Data originating from the National Control Programme in 2011 can therefore only be compared to those from 2010.

As described in the chapter on chickens, two different systems of reporting are used in this chapter and therefore the interpretation of the results has to be done bearing this in mind.

• Incidents are defined as the first isolation and all subsequent isolations of the same Salmonella serovar from an animal, group of animals or their environment on a farm within a defined time period (usually 30 days). An incident can therefore involve more than one flock and/or house sampled at the same time and occasionally, in the case of turkeys, subsequent crops from the same house or premises. The first part of this chapter describes incidents and includes samples originating from statutory surveillance, voluntary surveillance, investigations into clinical disease and investigations carried out under the Zoonoses Order.
  
  
• The second part of this chapter describes results obtained within the National Control Programmes (NCPs), i.e. results from statutory surveillance. Results from the NCPs are reported to the European Commission in a way that ensures that every flock with a Salmonella-positive result is counted. Numbers of positive flocks reported within the NCP are therefore expected to differ from the number of reported incidents. Some flocks may be positive for more than one serovar, in which case they are still only counted once as positive flocks, but were counted as more than one incident. This also applies if there is a long interval between positive tests within a single flock.

The number of turkey submissions to AHVLA/SAC laboratories (for all reasons, including Salmonella) in 2011 was 515, compared to 604 in 2010 and 240 in 2009. The increase in the number of submissions between 2009 and 2010 was associated with the introduction of the National Control Programme for Salmonella in turkeys at the beginning of 2010. The decrease in submission numbers between 2010 and 2011 was due in part to a fall in the number of diagnostic submissions.

A total of 282 Salmonella incidents were reported from turkeys in 2011. This compares to 239 incidents in 2010 (an increase of 18.0 per cent), 73 incidents in 2009 and 57 incidents in 2008. The more than three-fold increase in the number of incidents between 2009 and 2010 can be explained by the introduction of the National Control Programme for Salmonella in turkeys, which involves more sensitive and regular testing of both breeding and fattening flocks and is likely to have led to the identification of positive flocks which otherwise might not have been detected through voluntary surveillance or from diagnostic submissions.

The total number of incidents were distributed among the following categories according to the reason for submission:

• statutory surveillance: 258 (91.5 per cent)
• voluntary surveillance: 21 (7.5 per cent)
• investigations of clinical disease: 2 (0.7 per cent)
• investigations under the Zoonoses Order: 1 (0.4 per cent)

The number of incidents originating from statutory surveillance increased from 218 in 2010 to 258 in 2011 due to the introduction of the National Control Programme.

Fifteen different serovars of Salmonella enterica were isolated in 2011, accounting for 271 of the 282 incidents. Seven incidents involved untypable Salmonella enterica strains and four incidents involved Salmonella enterica rough strains.

Salmonella Derby was the most common serovar in turkeys in 2011, accounting for 42.9 per cent of all incidents, followed by S. Kedougou (19.5 per cent of all incidents), S. Kottbus (12.8 per cent of all incidents) and S. Newport (8.2 per cent of all incidents). S. Derby has been the top or second most common serovar in turkeys since 2005. S. Virchow, which had been isolated from one turkey holding in 2010, was isolated again from the same holding in 2011. S. Panama, a serovar normally associated with pigs, which was last isolated from turkeys in 1989, was isolated from one turkey fattening holding in 2011. S. Reading, another pig related serovar, which had last been seen in turkeys in 1997, was isolated from a breeding flock in 2011. Monophasic strains of S. Typhimurium with the antigenic formula S. 4,[5],12:i:- were isolated for the first time since the introduction of the NCP in British turkey flocks in 2011. These strains are now included in the target set by the European Union under the National Control Programme following the recommendations made by the European Food Safety Authority (EFSA).

There has been little change in the ranking of serovars between 2007 and 2011, with S. Derby, S. Kedougou and S. Kottbus being the most common serovars. S. Enteritidis was not seen in turkeys in 2011, and has not been reported since 2004. The prevalence of S. Typhimurium, which was the most common serovar in 2006 (21.3 per cent of incidents), has reduced considerably over the past five years and accounted for only 1.4 per cent of all incidents in 2011. Four incidents of S. Typhimurium were reported in 2011, two of which were DT8, one was DT30 and one was DT104. A list of phage types of S. Typhimurium observed in turkeys over the past five years is shown in the report.

National Control Programme for Salmonella in Fattening and Breeding Turkeys

The United Kingdom National Control Programme for Salmonella in fattening and breeding turkeys came into effect on 1 January 2010 and has been implemented to comply with Regulation (EC) No 2160/2003 and Regulations (EC) No 584/2008. These Regulations are aimed at the protection of public health by the reduction in levels of Salmonella along the turkey food chain. Monophasic strains of S. Typhimurium with the antigenic formula S. 4,[5],12:i:- are included in the Salmonella programme reduction target together with S. Enteritidis and S. Typhimurium.

All flocks of 250 or more breeding turkeys and 500 or more fattening turkeys are included in the National Control Programme unless, in the case of fattening turkey flocks, they are exempted according to Regulation (EC) No. 2160/2003 under Article 1.3, i.e. birds produced for private domestic consumption, or where there is only direct supply of small quantities of products to the final consumer or to local retail establishments directly supplying the primary products to the final consumer. Each fattening flock is sampled at least once close to the time of slaughter of individual slaughter batches, whilst the breeding flocks are sampled several times during the course of their lives and a minimum of every three weeks during the laying periods.

The NCP is enforced by The Control of Salmonella in Turkey Flocks Order 2009 (CSTO) which came into force in England on the 1st January 2010. There is separate national legislation for Scotland and Wales with close collaboration throughout the development of the legislative proposals and implementation.

An EU-wide baseline survey on the prevalence of Salmonella in turkey flocks which was conducted in 2006/07. The Community-observed prevalence of Salmonella-positive fattening flocks was 30.7 per cent (3.8 per cent for S. Enteritidis/S. Typhimurium) and of breeding flocks was 13.6 per cent (1.7 per cent for S. Enteritidis/S. Typhimurium). In the United Kingdom, the weighted prevalence of Salmonella-positive fattening flocks was 32.2 per cent (4.6 per cent for S. Enteritidis/S. Typhimurium) and for breeding flocks was 4.4 per cent (0.5 per cent for S. Enteritidis/S. Typhimurium). Following this survey an EU-wide Member State target was set for both breeding and fattening turkeys of less than 1 per cent of flocks positive for S. Enteritidis and/or S. Typhimurium by the end of 2012. Detailed survey results are published on the EFSA website.

Positive flocks identified in the NCP for fattening turkeys

In Great Britain, 478 fattening turkey flocks, originating from 93 individual holdings, were positive for Salmonella spp. No fattening turkey flocks were positive for S. Enteritidis (SE). Two fattening turkey flocks, on one holding, were positive for S. Typhimurium (STM). Four fattening turkey flocks on four separate holdings were positive for the monophasic S. Typhimurium strain S. 4,12:i:- and one flock from another holding was positive for S. 4,5,12:i:-. Therefore, a total of seven flocks tested positive for regulated serovars. 287 flocks tested positive for S. Derby, 83 for S. Kedougou, 41 for S. Kottbus, 40 for S. Newport, 20 for S. Indiana, one for S. Panama, one for S. Virchow, and 13 involved untypable isolates (five of which were positive for S. 6,8:e,h:-, two for S. 13,23:i:-, five for S. O Rough:f,g:-, and one for S. O Rough:g,m,s:-).

There was little difference in the number of flocks positive for Salmonella spp. in 2011 compared to 2010. In 2010, 473 flocks were reported positive for Salmonella spp. compared to 478 in 2011. In 2010, four flocks were reported positive for S. Typhimurium compared to two flocks positive for S. Typhimurium plus five flocks positive for monophasic strains of S. Typhimurium in 2011. S. Derby was the most prevalent serovar in both years, even though the number of positive flocks was lower in 2011 (287 flocks) compared to 2010 (330 flocks). S. Kedougou, S. Kottbus and S. Newport were the second, third and fourth most prevalent serovars in both years respectively. S. Indiana, which had only been reported from one flock in 2010, was found in 20 flocks in 2011 and was therefore the fifth most prevalent serovar in 2011.

The prevalence for all Salmonella serovars in fattening turkeys in Great Britain during 2011 was 16.49 per cent (478/2,898). The prevalence for regulated serovars was 0.24 per cent (7/2,898).

Positive flocks identified in the NCP for breeding turkeys

In Great Britain, 29 turkey breeding flocks were reported as positive for Salmonella spp. No turkey breeding flocks were positive for S. Enteritidis, S. Typhimurium or monophasic strains. Fifteen flocks tested positive for S. Senftenberg, seven flocks tested positive for S. Kottbus, three flocks tested positive for S. Derby, two flocks tested positive for S. Montevideo, one flock tested positive for S. Bardo and one flock tested positive for S. Mbandaka.

All S. Senftenberg isolates originated from samples taken at the hatchery, whereas S. Kottbus and S. Derby isolates originated from both hatchery and holding samples. S. Montevideo, S. Bardo and S. Mbandaka isolates were all from samples taken at the holdings.

The number of breeding flocks positive for Salmonella spp. in 2011 was higher than in 2010. In 2010, a total of seven flocks were reported positive for Salmonella spp. compared to 29 in 2011. In 2010, four flocks were reported positive for S. Derby, two flocks for S. Bovismorbificans and one flock for S. Montevideo. In 2011, 15 flocks were positive for S. Senftenberg and seven flocks were positive for S. Kottbus, neither of which were reported from breeding flocks in 2010. The number of flocks positive for S. Derby was similar in both years (four flocks in 2010 versus three flocks in 2011).

The prevalence for Salmonella spp. in breeding turkeys in 2011 was 12.29 per cent (29/236). The prevalence for regulated serovars was 0 per cent (0/236).

Further Reading You can view the full report by clicking here. To read the chapter on Salmonella in chickens, click here. To read the chapter on Salmonella in feeds and feedingstuffs, click here.

September 2012