# Presentation: 675054

## BSE: World update

- FDA TSE Advisory Committee
- Gaithersburg, MD
- September 18, 2006
- Lisa A. Ferguson, DVM
- Senior Staff Veterinarian
- USDA, APHIS, Veterinary Services

## Total BSE cases worldwide

- Cumulative total – greater than 189,000 cases
- Greater than 96% in United Kingdom
- Greater than 89% occurred in 1996 and before
- OIE website lists current reported totals:
- _[www.oie.int](http://www.oie.int/)_

## EU monitoring - 2005

- Total of 10,113,559 bovine tests
- 1.5 million risk animals,  8.6 million healthy slaughter
- 561 positive (448 in risk/suspect, 113 healthy sltr)
- Number of cases decreased by 35% from 2004
- Overall prevalence in tested animals decreased by 29%

## EU monitoring - 2005

- Reductions and increasing age of positive cases indicate success of control measures
- Analysis by year of birth of positive animals
- Peak of exposure appears well defined in some Member States
- France, Ireland – 1995
- Germany, Belgium, Italy, Netherlands – 1996
- TSE monitoring in small ruminants
- 614,864 tests in sheep/goats, 959 positives
- No confirmed BSE cases in small ruminants

## EU monitoring

| Year | Total positives | Risk/
suspect | Healthy slaughter |
| --- | --- | --- | --- |
| 2001 | 2,153 | 1,859 | 279 |
| 2002 | 2,126 | 1,839 | 287 |
| 2003 | 1,364 | 1,089 | 265 |
| 2004 | 865 | 699 | 166 |
| 2005 | 561 | 448 | 113 |

## BSE in Canada

- Surveillance:  targeted surveillance since 1991

| Year | Total # samples | Positive |
| --- | --- | --- |
| 2003 | 5,727 | 2* |
| 2004 | 23,550 | 0 |
| 2005 | 57,768 | 2 |
| 2006 (to 9/8/06) | 38,147 | 5 |

- *one case detected in US

## BSE in Canada

- Epidemiological summary – January 2006
- Geographic cluster theory
- “Cluster” of rendering/feed/livestock production – feed distribution
- Links between cases
- Will update this work

## BSE in Japan

- First identified in 2001
- Feed ban imposed after diagnosis
- Surveillance primarily in clinically normal animals at slaughter until more recently

| Year | Cases |
| --- | --- |
| 2001 | 3 |
| 2002 | 2 |
| 2003 | 4 |
| 2004 | 5 |
| 2005 | 7 |
| 2006 (to date) | 7 |

## BSE Surveillance in the US

- Active surveillance since 1990
- Targeting population where disease is most likely to be diagnosed – most efficient
- Assumption if we cannot find disease in targeted – or most likely – population, even more unlikely to be found in non-targeted population
- Use data obtained to extrapolate information about broader cattle population

## BSE – Targeted Surveillance

**Non-ambulatory animals**
**Dead stock**
**Field CNS Cases and on-farm suspects**
**Veterinary Diagnostic Laboratory data**
**Public health laboratories**
**Ante-mortem condemns at slaughter**

## Enhanced BSE Surveillance

- Total tests conducted since June 1, 2004 – through August 2006:
- >785,000
- 2 positives identified during this effort

## BSE Enhanced Surveillance Sample CollectionJune 2004 – August 2006

## OIE Standards for BSE SurveillanceMay 2005

- Weighted points system
- Sample points classified to four surveillance streams:
- Clinical suspect
- Casualty slaughter
- Fallen stock
- Healthy slaughter.

## OIE Point Values

- Points can be accumulated over 7 years

## OIE Point Distribution

## BSE Prevalence in the United States

- Estimate using two methods:
- BSurvE model
- Bayesian Birth Cohort model
- Sensitivity analyses
- Conclusion:
- BSE prevalence is less than 1 infected animal per 1 million adult cattle.
- Most likely values (with upper and lower 90% confidence levels)
- BSurvE - 7 (3,24) infected animals in adult cattle population
- BBC – 4 (1,8) infected animals in adult cattle population

## Ongoing BSE Surveillance Plan

- Launched August 28, 2006
- Approximately 40,000 samples per year
- Continue to monitor the status of U.S. cattle
- Able to detect increasing BSE prevalence

## Ongoing BSE Surveillance

- Sample size calculation, based on analysis of enhanced surveillance data and BSurvE model
- More sensitive design prevalence of 1 case per 1 million adult cattle
- BSurvE used to estimate sample numbers and points
- 3,000,000 analytical points necessary
- Average 9.5 analytical points per sample in enhanced
- Assume higher average points, require approximately 40,000 samples per year

## www.aphis.usda.gov