Centre for Animal Production and Health, Food Futures Institute, Murdoch University, South Street, Murdoch, Western Australia, 6150, Australia.
Nossal Institute for Global Health, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, 3010, Australia.
BMC Vet Res. 2022 Mar 19;18(1):109. doi: 10.1186/s12917-022-03211-w.
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.
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.
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.
弓形虫在全球范围内导致绵羊繁殖损失，包括澳大利亚。初产母羊的繁殖性能通常低于成熟、多产的母羊，如果在怀孕期间感染弓形虫，年轻的母羊更容易免疫幼稚，因此更容易受到生殖疾病的影响。本研究的目的是使用前瞻性队列研究评估澳大利亚南部感染弓形虫对初产母羊繁殖性能的影响。这将为澳大利亚绵羊的弓形虫靶向控制策略提供信息。
在澳大利亚南部的 28 个农场中，使用间接 ELISA 检测到 16/28 个农场存在弓形虫血清阳性。初产母羊的弓形虫血清阳性率（1.1，95%置信区间（CI）0.6，1.8）明显低于成熟、多产的母羊（8.1，95%CI 6.0，10.5；P<0.001）。在未能产羔的 1097 头妊娠初产母羊中，有 11/1097（1.0，95%CI 0.5，1.7）和 161 头已确认中期流产的初产母羊中，有 1/161（0.6，95%CI 0.1，2.9）确认了在妊娠和产羔期间发生了弓形虫血清转化。
在妊娠期间检测到弓形虫血清转化的频率较低，以及对弓形虫的血清阳性率较低，表明在澳大利亚南部广泛地理区域的农场中，弓形虫病并不是初产母羊繁殖损失的重要原因。
