Systemic and local immune responses in sheep after Neospora caninum experimental infection at early, mid and late gestation

Abstract

Neospora caninum is an obligate intracellular protozoan parasite considered as one of the leading infectious causes of abortion in cattle worldwide [1, 2]. Neosporosis is generally asymptomatic in non-pregnant cows; however, the consequences of either primo infection or recrudescence in pregnant cattle may be foetal death or the delivery of a still-born calf or a congenitally infected calf, either healthy or exhibiting nervous clinical signs [3]. It has been agreed that these outcomes depend greatly on the period of gestation in which infection occurs [4]. Several mechanisms have been proposed to lead to foetal death, such as damage directly caused by parasite proliferation in placental and foetal tissues or the immunological imbalance in the placenta [2, 5].