CONTROLS AND PRACTICES
What steps did industry and regulators take, and when did they take them relative to the emergence of BSE? Table 3 provides
a brief chronology of some of the main events. It also shows that other countries did not immediately implement feed controls
that the UK enacted starting in 1988, despite the devastation experienced in the UK cattle industry as a result of the BSE
epidemic. For example, Canada implemented some rules only in July 2003, after finding a BSE-positive cow in May, and the US
fully implemented these controls in February 2004, after finding a BSE-positive cow in December 2003.18,23-24
The US response lag is notable, since cattle move freely across the US-Canadian border.
To guide public policy and government spending, the meaning of this data must be evaluated in a broader context. Logically,
relative risks should guide resource allocations and decisions, but not all diseases are created equal: some affect small
children, some are highly infectious, and some, such as vCJD, create much pain and suffering. Each of these factors is a reason
to increase the relative investment in surveillance and prevention.
Food-borne diseases cause an estimated 76 million illnesses each year, including 325,000 hospitalizations, and 5,000 deaths,
according to CDC.32,33
As of March 2004, about 155 vCJD cases have occurred worldwide. Society must decide how much money to allocate to improving
meat safety as regards TSE compared to E. coli 0157: H7, Listeria, and other infections that have already caused hospitalizations and thousands of deaths in the US alone.34 It can be argued that preventing the entry of a new disease into North America is worth expending disproportionate resources;
likewise, it is necessary to focus limited resources to maximize the impact on public health. Policy makers have difficult
choices to make, and the stakes are high. What should be done, and what can we afford?
What happens when we approach the TSE conundrum from the viewpoint of reducing risk to consumers? The following factors appear
to have increased BSE and vCJD risk:
- There are large-scale movements and intermingling of livestock, feed, and semen, permeating the national food supply. For
example, in tracing the peers of one cow, hundreds of animals at more than 15 locations had to be destroyed.26,35
- Meat is processed in large batches, meaning that any consumer eating one hamburger comes in contact with meat from a large
number of cattle, increasing the per-event risk of exposure.
- Automation of meat processing has increased the risk that spinal cord or brain could contaminate ground meat.
What actions should be considered, in addition to those already mandated by the EU, US, and Canadian authorities, to reduce
potential health risk in humans? There are a number of options:
- Set up smaller or closed herds in defined geographic areas to contain any infections in a smaller population, and decrease
shipping of animals and mixing of herds.
- Stop all animal rendering and all cross-species feeding, the activities that are thought to have created the risks. But what
should be done with the waste?
- Test all cows older than 30 months for BSE before allowing them into the food chain, thus focusing resources on the highest-risk
animals. This practice is used in the UK and Japan and is under discussion in the US. The difficulty lies in storing large
quantities of meat to wait for test results.
- Increase general surveillance for BSE by testing more animals. This is being implemented in Canada and the US and will be
helpful in defining risk and guiding public policy.
- Consider reduction in batch sizes of feed and meat products, and improve feed traceability. Reducing batch sizes would expose
fewer people to infected meat if an infected animal entered the food chain. Additionally, since feed likely is the causative
agent, knowing what feed is used where could allow more targeted sampling when an infected cow is found. At present, it is
not possible to trace feed.
- Lastly, more effective cleaning procedures, combined with dedicated equipment, would reduce the opportunity for cross-contamination
between high- and low-risk feeds.