Quarterly Cattle Disease Surveillance Report

By Veterinary Laboratories Agency. The report monitors trends in the major endemic cattle diseases in the UK to September 2007.
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Quarterly Surveillance Report GB Surveillance
July-September 2007
Published November 2007


Contents


Introduction to GB Report

Overview
  Factors influencing disease and submission rates
  Notifiable diseases reported
  Farm visit investigations
  Food Safety Incidents

Endemic disease surveillance

Unusual and new diseases

Syndromic disease surveillance – respiratory disease in Q3, 2007

Scanning surveillance for new and emerging disease

Highlights

Analysis of submissions where no diagnosis was reached indicates that there is minimal suspicion of the presence of any new or emerging diseases in the GB cattle population in the third quarter of 2007.

Louping ill was diagnosed in cattle grazing moorland in Cornwall. This zoonotic, tick-borne, viral disease is a risk to cattle and sheep grazing tick-infested areas of extensive grazing.

Roundworm infection of suckler calves, reported in the April-June 2007 report, was confirmed (by Glasgow University) as Toxocara vitulorum infection. A detailed risk assessment of this partially milk-borne, parasitic infection was undertaken. This is the first investigation of this T. vitulorum infection in cattle in GB.

A significant increase in parasitic gastro-enteritis and of lungworm in England and Wales was seen during the quarter compared to the same quarter in 2006. Increases in these diseases in Scotland were less marked and not statistically significant.

There is an increased risk of liver fluke infection in cattle for the next three months.

INTRODUCTION

This is the first cattle surveillance report to be published that combines information from all areas of Great Britain into a single, integrated overview of cattle health across the whole region. It has been made possible through a partnership between Defra, the Scottish Government, the Veterinary Laboratories Agency (VLA) and Scottish Agricultural Colleges Veterinary Services (SAC VS).

A key objective for any cattle disease scanning surveillance system is to increase the likelihood of early detection of important changes in cattle health. Any major disease occurrence, such as the BSE epidemic, or the FMD outbreak of 2001, can have a major impact either by threatening public health and/or animal welfare, or through its economic impact on the agricultural industry and ancillary related industries like tourism across the whole of GB. The possibility of the incursion of exotic diseases, the emergence of a new disease, or changes in known diseases are all risks which scanning surveillance seeks to mitigate. Until now, the surveillance networks north and south of the Scottish border have reported their findings separately, which reduced the likelihood of early detection of important changes in health in this single epidemiological population. The newly unified GB-wide data resource, coupled with new collaborative analytical processes should make detection of all these scenarios both easier and quicker.

The network of 14 VLA Regional Laboratories (RLs) and two Surveillance Centres (at Veterinary Schools) in England and Wales and 8 SAC VS Disease Surveillance Centres in Scotland provides a diagnostic service to private veterinary practitioners across GB. Clinical scanning surveillance information derived from diagnostic samples and carcases is collected and analysed to determine baseline disease levels in the cattle population. The aim is to provide an assessment of the current disease status of the GB cattle population and to warn of potential risks from changing disease trends or new diseases and of zoonotic diseases of human health significance.

Since 1975, diagnostic data from both the VLA and SAC has been merged in the veterinary investigation diagnosis analysis (VIDA) database. This database has been an invaluable source of epidemiological trends for over 30 years, but was limited in the range of data recorded and the analyses available. In 1998, the VLA started to produce a more detailed dataset within FarmFile - a powerful database, linked to the VIDA database, containing a greater amount of descriptive epidemiological data on all submissions and incorporating analysis tools used for disease surveillance purposes. These tools provide automated statistical analysis and built-in “alerters” which highlight statistically significant, and therefore potentially clinically significant, changes in diseases diagnosis and trends enabling more extensive analysis of data for England and Wales from 1999 onwards.

The harmonisation project was initiated in 2006 to allow the extension of FarmFile analysis to cover Scotland as well. This involved the development of a single, standardised data collection system; consistent diagnostic criteria and harmonised recording, which enables the collation of the disease surveillance data from all three countries. This has been achieved by collaboration between staff and disease consultants at the VLA and SAC VS, funded by Defra and the Scottish Government.

Detailed surveillance data from laboratory submissions for all three countries can now be collated, providing a far greater amount of data for analysis and interpretation by disease consultants at a GB level, resulting in improved disease understanding and efficient use of relevant expertise. This should enable action to be taken and resources to be appropriately targeted at an earlier stage than was previously possible, as the dataset is now much more extensive and drawn from the whole cattle population of GB.

The following report is published as a prototype to demonstrate how the data can be collated and some future outputs and analyses. Further analyses will be developed and refined to improve disease surveillance and the health and welfare of the cattle population of GB.

OVERVIEW

Factors influencing disease and submission rates
Many factors combine to influence the patterns of disease in cattle, and the ability to detect changes to these patterns through scanning and active surveillance. They include:

Cattle Demographics

The cattle population in Great Britain (GB) consists of approximately 9.3 million animals (June Census 2006), making it one of the largest in Europe. The map below shows the distribution of the GB cattle population, which for many disease risks constitutes a single epidemiological unit, and the location of the diagnostic laboratories (present in all areas of GB with a large cattle population) that contribute data to this report.

Figure 1
Distribution of Cattle and location of Diagnostic Centres in Great Britain (2006)

Weather and climate

In July, mean temperatures were generally close to or slightly below average. Rainfall was generally well above average, with England & Wales recording over double their average July rainfall and areas around Worcestershire recording over 4 times their average July rainfall.

In August, mean temperatures were generally close to average with most areas having their coldest August for over 10 years and England having its coldest August since 1993. Rainfall ranged from over 150 % of average across parts of NW Scotland to around 50 % of average across some central and northern areas of England.

In September, mean temperatures were close to or slightly above average, with northern Scotland having its coldest September since 1994. Rainfall was generally close to or below average, with southeast and central England receiving only around half of the average September rainfall.

Economics of the cattle industries

Dairy sector


The price of milk was very variable due to differing contractual arrangements. However, the overall increase continued and the July and August averages were 19.65 and 20.70 pence per litre respectively, compared to 17.60 in 2006.

This was reflected in the value of dairy cows, which fluctuated quite widely between £595 and £1,241 each week, an increase over 2006 in which the range for the third quarter was £529 to £889.

Beef sector

The prices of finished beef cattle were very similar to those of the third quarter of 2006, ranging weekly from 206 to 216 pence/kg deadweight. The value of store cattle was also similar to last year, ranging from £389 to £504 per head.

Other influences

Probably the most significant single influence on submissions this quarter was statutory movement restrictions associated with outbreaks of foot and mouth disease in the south of England. Although the periods in which movement of carcases and especially samples to VLA and SAC laboratories was restricted were of short duration, uncertainty and a reduction in veterinary activity on farms very probably reduced submissions significantly.

In the third (July-September) quarter of 2007, there were 10,706 bovine diagnostic submissions, of which 480 included one or more carcases for necropsy (Table 2). Both figures were less those for the third quarter of 2006 – 11,369 and 630 respectively. The proportion of carcase submissions to the total was 4.48% in this quarter and 5.54% in Q3 of 2006.

Table 2
Cattle Diagnostic Submissions in England and Wales and Scotland




Further Reading

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November 2007
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