Munita M P, Rea R, Bloemhoff Y, Byrne N, Martinez-Ibeas A M, Sayers R G
Animal and Grassland Research and Innovation Centre (AGRIC), Teagasc, Moorepark, Fermoy, County Cork, Ireland; Biological Sciences, Cork Institute of Technology, Bishopstown, Cork, Ireland.
Biological Sciences, Cork Institute of Technology, Bishopstown, Cork, Ireland.
Prev Vet Med. 2016 Nov 1;134:16-25. doi: 10.1016/j.prevetmed.2016.09.024. Epub 2016 Sep 28.
Completion of the F. hepatica lifecycle is dependent on suitable climatic conditions for development of immature stages of the parasite, and its snail intermediate host. Few investigations have been conducted regarding temporal variations in F. hepatica status in Irish dairy herds. The current study aimed to conduct a longitudinal study examining annual and seasonal trends in bulk milk seropositivity over six years, while also investigating associations with soil temperature, rainfall and flukicide treatment. Monthly bulk milk samples (BTM) were submitted by 28 herds between March 2009 and December 2014. In all, 1337 samples were analysed using a Cathepsin L1 ELISA. Soil temperature, rainfall and management data were obtained for general estimating equation and regression analyses. A general decrease in milk seropositivity was observed over the six year study period and was associated with an increased likelihood of treating for liver fluke (OR range=2.73-6.96). Annual and seasonal analyses of rainfall and F. hepatica BTM status yielded conflicting results. Higher annual rainfall (>1150mm) yielded a lower likelihood of being BTM positive than annual rainfall of <1000mm (OR=0.47; P=0.036). This was most likely due to farmers being more proactive in treating for F. hepatica in wetter years, although a 'wash effect' by high rainfall of the free living stages and snails cannot be ruled out. Higher seasonal rainfall (>120mm), however, was associated with increased ELISA S/P% values (Coefficient=9.63S/P%; P=0.001). Soil temperature was not found to influence F. hepatica to the same extent as rainfall and may reflect the lack of severe temperature fluctuations in Ireland. Flukicides active against both immature and mature F. hepatica were approximately half as likely to record a positive F. hepatica herd BTM status than a flukicide active against only the mature stage of the parasite (OR≅0.45; P<0.01). This study highlights the importance of examining both annual and seasonal F. hepatica data, which can vary significantly. Additionally, it highlights the progress that can be achieved in fluke control by application of a continuous BTM monitoring program.
肝片吸虫生命周期的完成取决于适宜的气候条件，以利于该寄生虫未成熟阶段及其中间宿主蜗牛的发育。关于爱尔兰奶牛群中肝片吸虫感染状况的时间变化，此前很少有研究。本研究旨在开展一项纵向研究，考察六年期间全脂牛奶血清阳性率的年度和季节性趋势，同时调查其与土壤温度、降雨量及杀吸虫剂处理之间的关联。2009年3月至2014年12月期间，28个牛群每月提交全脂牛奶样本（BTM）。总共使用组织蛋白酶L1酶联免疫吸附测定法（ELISA）分析了1337个样本。获取土壤温度、降雨量及管理数据用于广义估计方程和回归分析。在为期六年的研究期间，观察到牛奶血清阳性率总体呈下降趋势，且这与治疗肝吸虫的可能性增加相关（比值比范围为2.73至6.96）。对降雨量和肝片吸虫BTM感染状况的年度和季节性分析得出了相互矛盾的结果。年降雨量较高（>1150毫米）时，BTM呈阳性的可能性低于年降雨量<1000毫米时（比值比=0.47；P=0.036）。这很可能是因为在多雨年份农民更积极地治疗肝片吸虫，不过高降雨量对自由生活阶段和蜗牛的“冲刷效应”也不能排除。然而，季节性降雨量较高（>120毫米）与ELISA S/P%值升高相关（系数=9.63S/P%；P=0.001）。未发现土壤温度对肝片吸虫的影响程度与降雨量相同，这可能反映出爱尔兰缺乏剧烈的温度波动。对未成熟和成熟肝片吸虫均有效的杀吸虫剂记录到肝片吸虫牛群BTM呈阳性的可能性约为仅对寄生虫成熟阶段有效的杀吸虫剂的一半（比值比≅0.45；P<0.01）。本研究强调了同时考察肝片吸虫年度和季节性数据的重要性，这些数据可能有显著差异。此外，它突出了通过实施持续的BTM监测计划在吸虫控制方面所能取得的进展。
