Significant familial differences in the frequency of
abortion and Toxoplasma gondii infection within
a flock of Charollais sheep

Morley, EK; Williams, RH; Hughes, JM; Terry, RS; Duncanson, P; Smith, JE; Hide, G

Abstract

A study was carried out to investigate the frequencies of abortion and congenital Toxoplasma gondii infection within 27
families (765 individuals) of a pedigree Charollais sheep flock maintained on a working farm in Worcestershire, UK, since
1992. Pedigree lambing records were analysed to establish the frequency of abortion for each family. The frequency of
congenital infection was determined for each family by PCR analysis of tissue samples taken from newborn lambs. Atotal of
155 lambs were tested for congenital T. gondii infection, which were all born during the study period 2000–2003. Significant
differences in the frequency of abortion between sheep families within this flock were observed with frequencies ranging
between 0% and 48% (P<0.01). Significantly different infection frequencies with T. gondii were also observed for different
families and ranged between 0% and 100% (P<0.01). Although the actual cause of each abortion was not verified, a highly
significant positive correlation was found to exist between the frequency of abortion and the frequency of T. gondii infection
in the same families (P<0.01). The data presented here raise further questions regarding the significance of congenital
transmission of T. gondii within sheep populations, the possible successive vertical transmission of T. gondii within families
of sheep, and the potential role of inherited genetic susceptibility to abortion with respect to T. gondii infection. This work
invites further study into the epidemiology of ovine toxoplasmosis and may have implications for sheep husbandry methods
in the future.
Key words: Toxoplasma gondii, ovine, toxoplasmosis, congenital, transmission, pedigree, sheep.

Citation

a flock of Charollais sheep. Parasitology, 131, 181-185. https://doi.org/10.1017/S0031182005007614

• Journal Article Type: Article
• Publication Date: Jan 1, 2005
• Deposit Date: Jun 10, 2010
• Publicly Available Date: Apr 5, 2016
• Journal: Parasitology
• Print ISSN: 0031-1820
• Publisher: Cambridge University Press (CUP)
• Peer Reviewed: Peer Reviewed
• Volume: 131
• Pages: 181-185
• DOI: https://doi.org/10.1017/S0031182005007614
• Publisher URL: http://dx.doi.org/10.1017/S0031182005007614