Quantification of porcine circovirus type 2 (PCV-2) within- and between-pen transmission in pigs

Free access article

Issue		Vet. Res. Volume 39, Number 5, September-October 2008


Number of page(s)		13
DOI		http://dx.doi.org/10.1051/vetres:2008020
Published online		17 April 2008
How to cite this article		Vet. Res. (2008) 39:43

How to cite this article: Vet. Res. (2008) 39:43
DOI: 10.1051/vetres:2008020

Quantification of porcine circovirus type 2 (PCV-2) within- and between-pen transmission in pigs

Mathieu Andraud¹, Béatrice Grasland¹, Benoît Durand², Roland Cariolet¹, André Jestin¹, François Madec¹ and Nicolas Rose¹

¹ AFSSA-site de Ploufragan, B.P. 53, 22440 Ploufragan, France
² AFSSA-site de Maisons-Alfort, 23 avenue du Général de Gaulle, Maisons Alfort Cedex, 94706, France

Received 19 October 2007; accepted 10 April 2008; published online 17 April 2008

Abstract - PCV-2 within- and between-pen transmission was quantified by estimating the daily transmission rate $\beta$ and the basic reproduction ratio (R₀) using a stochastic SEIR (Susceptible, Exposed, Infectious, Removed) model fitted on experimental data. Within-pen transmission was quantified by using four groups of eight SPF (specific pathogen-free) pigs (four infected and four susceptible pigs having direct contact). Between-pen transmission was studied in two groups of 16 SPF pigs (eight infected and eight susceptible pigs having indirect contact (10 cm distance)). Pigs were monitored twice a week (blood samples) and were tested for PCV-2 antibodies (ELISA test) and viral genome load in sera (real-time PCR). Transmission parameters $\beta_{\rm within}$ and $\beta_{\rm between}$ were estimated using a maximum likelihood method and the duration of infectiousness, to compute R₀, was estimated with a parametric survival model. Different assumptions were made to determine the end of infectiousness (seroconversion, seroconversion and decline in viral genome load, permanent infectiousness). $R_{0[\rm within]}$ (8.9 (5.1-15.4)) was greater when the end of infectiousness was assumed to be related to both seroconversion and a decline of PCV-2 genome load in sera (average duration of infectiousness = 32 days) compared with only seroconversion as the indicator of recovery ( $R_{0[\rm within]}$ = 5.5 (3.3-9.0)). Whatever the assumption, between-pen R₀ (0.58 (0.23-1.47)) was always significantly lower than within-pen R₀. Only $\beta_{\rm within}$ was sensitive to the assumption on end of infectiousness and decreased with increasing duration of infectiousness. These results showed that PCV-2 transmission is influenced by contact structure that appears worth being taken into account in an epidemic model.

Key words: PCV-2 / pigs / transmission / modelling

Corresponding author: m.andraud@afssa.fr

© INRA, EDP Sciences 2008

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.

Quantification of porcine circovirus type 2 (PCV-2) within- and between-pen transmission in pigs

In 2011, Veterinary Research will move to BioMed Central www.veterinaryresearch.org