“…In most of cases, adult fl ukes inhabit the rumen and/ or reticulum without damage (Rolfe et al, 1994), while immature fl ukes are found in the upper small intestine where can cause serious morbidity by protein loss, decrease of milk production and weight, oedema and eventually death (Horak, 1971;Rangel-Ruiz et al, 2003, Rolfe et al, 1994. Studies carried out in Europe (Mage et al, 2002;Cringoli et al, 2004 ;Rinaldi et al, 2005;Díaz et al, 2007;Rieu et al, 2007;Foster et al, 2008;Murphy et al, 2008, González-Warleta et al, 2013 have shown an increased prevalence in the last few years. This should probably been caused by the climate changes with warmer winters and wetter summers that positively infl uenced the life-cycle of the parasite (Gordon et al, 2013).…”