Experimental caprine neosporosis: the influence of gestational stage on the outcome of infection

Abstract

Here, we assessed outcome of experimental infection by Neospora caninum in goats intravenously inoculated with 106 tachyzoites of the Nc-Spain7 isolate at 40 (G1), 90 (G2) and 120 (G3) days of gestation. Infected goats had fever between 5 and 9 days post inoculation (dpi); all were seropositive at the time of abortion/birth. Foetal death occurred in G1 from 10 to 21 dpi (n = 7) and in G2 from 27 to 35 dpi (n = 4). Goats in G2 also had seropositive stillbirth (n = 1) and healthy kids (n = 2). G3 goats (n = 7) had 3 seropositive and 3 seronegative weak kids, and 2 seronegative healthy kids. Parasite DNA detection in placentomes was 100% in G2, 85.7% in G3 and in G1 was detected only in placentomes from the goats with foetal losses from 17 dpi (100%). Parasites were detected in foetal/kid brain (>85.7%) and liver (≥50%) of G2 and G3, and in G1 after 17 dpi (100%). The highest parasite loads were detected in the placentomes of G1 from 17 dpi and G2, and in foetal tissues of G1 from 17 dpi and G3. Multifocal necrotic lesions were observed in the placentas of the three groups, but they were larger and more frequent in G1 and G2. Similar lesions were observed in foetal tissues, but they were more frequent in G3. These findings suggest that, as observed in cattle and sheep, the clinical consequences of N. caninum in pregnant goats are dependent in part on the time of gestation when animals were infected.Electronic supplementary materialThe online version of this article (doi:10.1186/s13567-016-0312-6) contains supplementary material, which is available to authorized users.

Placental lesions associated with abortion and stillbirth in goats naturally infected by Neospora caninum

“…However, these lesions differ in intensity from those presented here, since they were described as mild lesions (Porto et al 2016). The differences in the intensity of these placental lesions could be due to differences regarding the N. caninum strains, since Porto et al (2016) used a strain derived from cattle in Spain, and the goats from the present study were naturally infected with strains circulating in Brazil. In addition, the inoculation route and number of inoculated parasites may explain the differences regarding placental lesions observed in the present study and those reported by Porto et al (2016).…”

“…Similarly, non-purulent necrotic placentitis was described in goats experimentally infected (Porto et al 2016). However, these lesions differ in intensity from those presented here, since they were described as mild lesions (Porto et al 2016).…”

“…Similarly, non-purulent necrotic placentitis was described in goats experimentally infected (Porto et al 2016). However, these lesions differ in intensity from those presented here, since they were described as mild lesions (Porto et al 2016). The differences in the intensity of these placental lesions could be due to differences regarding the N. caninum strains, since Porto et al (2016) used a strain derived from cattle in Spain, and the goats from the present study were naturally infected with strains circulating in Brazil.…”

“…The differences in the intensity of these placental lesions could be due to differences regarding the N. caninum strains, since Porto et al (2016) used a strain derived from cattle in Spain, and the goats from the present study were naturally infected with strains circulating in Brazil. In addition, the inoculation route and number of inoculated parasites may explain the differences regarding placental lesions observed in the present study and those reported by Porto et al (2016). The placental lesions in experimentally infected goats were more prominent in early and mid-gestational stage (Porto et al 2016).…”

“…Placental lesions in cows experimentally infected with N. caninum are characterized by necrosis of the mesenchymal and trophoblast cells associated with a mixed inflammatory infiltrate (Caspe et al 2012). Similarly, in experimentally infected goats with the Nc-Spain7 strain, multifocal necrotic placentitis has been described in different gestational ages (Porto et al 2016). However, placental lesions in naturally infected goats are poorly characterized.…”