Toxoplasma gondii is not an important contributor to poor reproductive performance of primiparous ewes from southern Australia: a prospective cohort study

Abstract

Background Toxoplasma gondii causes reproductive losses in sheep worldwide, including Australia. The reproductive performance of primiparous ewes is typically lower than for mature, multiparous ewes, and younger ewes are more likely to be immunologically naïve and therefore more susceptible to reproductive disease if T. gondii infection occurs during pregnancy. The aim of this study was to assess the impact of infection with T. gondii on the reproductive performance of primiparous ewes in southern Australia using a prospective cohort study. This will inform the need for targeted control strategies for T. gondii in Australian sheep. Results Toxoplasma gondii seropositivity using indirect ELISA was detected at 16/28 farms located across southern Australia. Apparent seropositivity to T. gondii was lower in primiparous ewes (1.1, 95% confidence interval (CI) 0.6, 1.8) compared to mature, multiparous ewes (8.1, 95% CI 6.0, 10.5; P < 0.001). Toxoplasma gondii seroconversion during the gestation and lambing period was confirmed for 11/1097 (1.0, 95% CI 0.5, 1.7) of pregnant primiparous ewes that failed to raise a lamb, and 1/161 (0.6, 95% CI 0.1, 2.9) primiparous ewes with confirmed mid-pregnancy abortion. Conclusions Low frequency of detection of T. gondii seroconversion during gestation and low frequency of seropositivity to T. gondii suggests that toxoplasmosis was not an important contributor to reproductive losses in primiparous ewes on farms located over a wide geographical area in southern Australia.

Seroprevalence of Specific Antibodies to Toxoplasma gondii, Neospora caninum, and Brucella spp. in Sheep and Goats in Egypt

“…In the same study, seroconverting to T. gondii had no significant impact on the loss of pregnancy [ 52 ]. Similarly, in another region of the world, only about 1.6% of lost lambs were attributed to T. gondii in a prospective cohort study in primiparous ewes from southern Australia, albeit at an overall much lower seroprevalence than in our study [ 53 ]. Moreover, in a study performed with breeding ewes from Mexico, seroprevalence for T. gondii (61.96%) and N. caninum (15.22%) was similar to our study, and T. gondii seroprevalence was not associated with a history of abortion, but N. caninum seroprevalence was [ 54 ].…”

Seropositivity to Campylobacter and association with abortion and lamb mortality in maiden ewes from Western Australia, South Australia and Victoria

“…Abortions, stillbirths and polyarthritis associated with Chlamydia pecorum were identified in a subset of farms from WA. 27,30 Exposure of ewes to Toxoplasma gondii, 37 Neospora caninum 25 and Coxiella burnetii 26 were identified on farms in this study, but there was no evidence that these were important contributors to foetal and lamb mortality in these flocks. Further investigations using data from this study will include multivariable analysis to evaluate the relative importance of different pathogens on reproductive performance.…”