Departamento de Parasitología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Apartado Postal 70483, México D.F., 04510, Mexico.
Vet Parasitol. 2011 Jan 10;175(1-2):73-9. doi: 10.1016/j.vetpar.2010.09.034. Epub 2010 Oct 8.
The aim of the present work was to study the dynamics of Fasciola hepatica natural infection in ovines, caprines, bovines and two mollusc species, Lymnaea (Fossaria) humilis and Lymnaea (F.) bulimoides, from 2004 to mid 2007 under normal farm management conditions, and the relation to climate changes. The study was performed in a research centre in the plateau of Mexico. Temperature and rainfall were registered every month, as well as the number and intensity of infection in livestock and molluscs, as determined by coprology and direct observation/cercariae release, respectively. The first two years mammals were treated with clorsulon/ivermectin because the animals were harbouring concomitant intestinal nematode infections and this was the available drug combination. During the second period treatment was with triclabendazole. The temperature ranged from around cero to 30 °C, except during September 2005 to January 2006, when a cold climate prevailed. The rainfall augmented every year in July-August, and slightly in April, 2006. Lymneid snails appeared during or immediately after the rainfall peaks of 2004 and 2006, while few L. humilis and no L. bulimoides were present during the same period of 2005, probably because it was cold. A total of 15564 cercariae were released from molluscs during the wet time of 2004, 76 during 2005 and 368 in 2006. Several peaks of infection in mammals were observed, most occurring up to 4 months after the snails had disappeared. As expected, the weather had strong impact on snails and then on livestock infection. Also, treatment given to livestock was related to reduced cercarieae release five months later. Therefore, the combination of treatment and inspection of snails in the biotopes where the livestock graze may facilitate control of fasciolosis under current farm management.
本研究旨在 2004 年至 2007 年中期，在正常的农场管理条件下，研究肝片形吸虫在绵羊、山羊、牛和两种软体动物（Fossaria）humilis 和 Lymnaea（F.）bulimoides 中的自然感染动态，并探讨其与气候变化的关系。该研究在墨西哥高原的一个研究中心进行。每月记录温度和降雨量，以及通过粪便检查和直接观察/尾蚴释放分别确定的家畜和软体动物的感染数量和强度。前两年，由于动物同时感染肠道线虫，使用氯舒隆/伊维菌素对哺乳动物进行治疗，这是当时可用的药物组合。在第二个时期，使用三氯苯达唑进行治疗。温度范围在 0 摄氏度左右到 30 摄氏度之间，除了 2005 年 9 月至 2006 年 1 月的寒冷气候期间。降雨量每年 7 月至 8 月增加，2006 年 4 月略有增加。2004 年和 2006 年的降雨高峰期出现了 Lymneid 蜗牛，而 2005 年同期只有少量的 L. humilis 和没有 L. bulimoides，可能是因为天气寒冷。2004 年的潮湿时期共从软体动物中释放了 15564 条尾蚴，2005 年释放了 76 条，2006 年释放了 368 条。在哺乳动物中观察到了几次感染高峰，大多数发生在蜗牛消失后 4 个月内。正如预期的那样，天气对蜗牛和随后的家畜感染有很大的影响。此外，五个月后对家畜进行的治疗与尾蚴释放减少有关。因此，在当前的农场管理下，在牲畜放牧的生物区系中对蜗牛进行治疗和检查的组合可能有助于控制肝片吸虫病。
