Back to Search Start Over

Risk Factors for Malformations and Impact on Reproductive Performance and Mortality Rates of Schmallenberg Virus in Sheep Flocks in the Netherlands.

Authors :
Luttikholt, Saskia
Veldhuis, Anouk
van den Brom, René
Moll, Lammert
Lievaart-Peterson, Karianne
Peperkamp, Klaas
van Schaik, Gerdien
Vellema, Piet
Source :
PLoS ONE. Jun2014, Vol. 9 Issue 6, p1-8. 8p.
Publication Year :
2014

Abstract

In Northwestern Europe, an epizootic outbreak of congenital malformations in newborn lambs due to infection with Schmallenberg virus (SBV) started at the end of 2011. The objectives of this study were to describe clinical symptoms of SBV infection, the effect of infection on mortality rates, and reproductive performance in sheep, as well as to identify and quantify flock level risk factors for SBV infections resulting in malformations in newborn lambs. A case-control study design was used, with 93 case flocks that had notified malformed lambs and 84 control flocks with no such lambs. Overall animal seroprevalence in case flocks was estimated at 82.0% (95% CI: 74.3–87.8), and was not significantly different from the prevalence in control flocks being 76.4% (95% CI: 67.2–83.6). The percentages of stillborn lambs or lambs that died before weaning, repeat breeders, and lambs with abnormal suckling behaviour were significantly higher in case flocks compared to control flocks. However, effect of SBV infection on mortality rates and reproductive performance seemed to be limited. Multivariable analysis showed that sheep flocks with an early start of the mating season, i.e. before August 2011 (OR = 33.1; 95% CI: 10.0–109.8) and in August 2011 (OR = 8.2; 95% CI: 2.7–24.6) had increased odds of malformations in newborn lambs caused by SBV compared to sheep flocks with a start of the mating season in October 2011. Other flock-level risk factors for malformations in newborn lambs were purchase of silage (OR 5.0; 95% CI: 1.7–15.0) and flocks with one or more dogs (OR = 3.3; 95% CI: 1.3–8.3). Delaying mating until October could be a potential preventive measure for naïve animals to reduce SBV induced losses. As duration of immunity after infection with SBV is expected to last for several years, future SBV induced congenital malformations are mainly expected in offspring of early mated seronegative animals. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
19326203
Volume :
9
Issue :
6
Database :
Academic Search Index
Journal :
PLoS ONE
Publication Type :
Academic Journal
Accession number :
96860461
Full Text :
https://doi.org/10.1371/journal.pone.0100135