Repository logo
  • Log In
    New user? Click here to register.Have you forgotten your password?
University College Dublin
    Colleges & Schools
    Statistics
    All of DSpace
  • Log In
    New user? Click here to register.Have you forgotten your password?
  1. Home
  2. College of Health and Agricultural Sciences
  3. School of Veterinary Medicine
  4. Veterinary Medicine Research Collection
  5. Effect of changes in testing parameters on the cost-effectiveness of two pooled test methods to classify infection status of animals in a herd
 
  • Details
Options

Effect of changes in testing parameters on the cost-effectiveness of two pooled test methods to classify infection status of animals in a herd

Author(s)
Messam, Locksley L. McV.  
O'Brien, Joshua M.  
Hietala, Sharon K.  
Gardner, Ian A.  
Uri
http://hdl.handle.net/10197/10174
Date Issued
2010-05-01
Date Available
2019-04-29T08:18:26Z
Abstract
Monte Carlo simulation was used to determine optimal fecal pool sizes for identification of all Mycobacterium avium subsp. paratuberculosis (MAP)-infected cows in a dairy herd. Two pooling protocols were compared: a halving protocol involving a single retest of negative pools followed by halving of positive pools and a simple protocol involving single retest of negative pools but no halving of positive pools. For both protocols, all component samples in positive pools were then tested individually. In the simulations, the distributions of number of tests required to classify all individuals in an infected herd were generated for various combinations of prevalence (0.01, 0.05 and 0.1), herd size (300, 1000 and 3000), pool size (5, 10, 20 and 50) and test sensitivity (0.5-0.9). Test specificity was fixed at 1.0 because fecal culture for MAP yields no or rare false-positive results. Optimal performance was determined primarily on the basis of a comparison of the distributions of numbers of tests needed to detect MAP-infected cows using the Mann-Whitney U test statistic. Optimal pool size was independent of both herd size and test characteristics, regardless of protocol. When sensitivity was the same for each pool size, pool sizes of 20 and 10 performed best for both protocols for prevalences of 0.01 and 0.1, respectively, while for prevalences of 0.05, pool sizes of 10 and 20 were optimal for the simple and halving protocols, respectively. When sensitivity decreased with increasing pool size, the results changed for prevalences of 0.05 and 0.1 with pool sizes of 50 being optimal especially at a prevalence of 0.1. Overall, the halving protocol was more cost effective than the simple protocol especially at higher prevalences. For detection of MAP using fecal culture, we recommend use of the halving protocol and pool sizes of 10 or 20 when the prevalence is suspected to range from 0.01 to 0.1 and there is no expected loss of sensitivity with increasing pool size. If loss in sensitivity is expected and the prevalence is thought to be between 0.05 and 0.1, the halving protocol and a pool size of 50 is recommended. Our findings are broadly applicable to other infectious diseases under comparable testing conditions.
Other Sponsorship
Johne's Disease Integrated Project
Type of Material
Journal Article
Publisher
Elsevier
Journal
Preventive Veterinary Medicine
Volume
94
Issue
3-4
Start Page
202
End Page
212
Copyright (Published Version)
2010 Elsevier
Subjects

Cost-effectiveness

Pooled testing

Mycobacterium avium s...

Retesting

Cattle Diseases

DOI
10.1016/j.prevetmed.2010.01.005
Language
English
Status of Item
Peer reviewed
ISSN
0167-5877
This item is made available under a Creative Commons License
https://creativecommons.org/licenses/by-nc-nd/3.0/ie/
File(s)
Loading...
Thumbnail Image
Name

Pooling_Article_sub2_final.pdf

Size

699.33 KB

Format

Adobe PDF

Checksum (MD5)

16148d44d7764e448cb31c7847d5ff5f

Loading...
Thumbnail Image
Name

Pooling_Article_Tables_sub2_final.pdf

Size

289.59 KB

Format

Adobe PDF

Checksum (MD5)

fa6c2e6cf5e3d4b123357a74587267a7

Owning collection
Veterinary Medicine Research Collection

Item descriptive metadata is released under a CC-0 (public domain) license: https://creativecommons.org/public-domain/cc0/.
All other content is subject to copyright.

For all queries please contact research.repository@ucd.ie.

Built with DSpace-CRIS software - Extension maintained and optimized by 4Science

  • Cookie settings
  • Privacy policy
  • End User Agreement