Neospora caninum is one of the more-efficient transplacentally-transmitted organisms. The goal of the present study was to investigate the pathologic and immunologic changes that occur at the materno-fetal interphase in pregnant BALB/c mice infected with N. caninum at mid-gestation. Parasite DNA was detected in feto-placentary units 3 days post-infection (PI). On day 7 PI, the DNA detection level and parasite burden were significantly higher in the placentas than in the fetuses, which may indicate that the parasite is mainly multiplying in the placenta during the initial infection. In the spleens of infected dams, we observed an increase in IFN-γ, IL-10, and IL-4. However, only IL-4 was upregulated in placentas from the infected dams; this may enhance susceptibility to N. caninum at the materno-fetal interphase and favor transmission to the progeny. Finally, an increase in TNF-α expression in nested–PCR-positive placentas combined with necrosis may compromise the viability of the fetuses.

Besnoitia besnoiti was isolated from a skin biopsy of a chronically infected cow from central Spain. Zoites released from macroscopic cysts were adapted to its culture in vitro on a MARC-145 cell monolayer. Tachyzoites produced in vitro were either cryopreserved or used for genomic DNA isolation. A 2206 nt sequence containing 18S ribosomal RNA gene, internal transcribed spacer 1 (ITS1), and a partial sequence of 5.8S ribosomal RNA gene was amplified by PCR and sequenced. This sequence showed a 99–100% identity to 18S, ITS1, and 5.8S sequences of B. besnoiti published in databases. After analysis by transmission and scanning electron microscopy of isolated bradyzoites and tachyzoites, it was observed that their ultrastructural morphology coincided with B. besnoiti . The isolate characterized in this study was identified as B. besnoiti on the basis of the disease produced, molecular characteristics, and morphology. The B. besnoiti isolate was denoted as BbSpain-1; it is the first isolate obtained and characterized in Spain and one of the first European isolates adapted to grow in vitro. The isolation and in vitro production of this B. besnoiti isolate offers a good opportunity to study general aspects of bovine besnoitiosis, including epidemiology, pathogenesis, and diagnosis of this re-emergent disease.

Neospora caninum , a recently recognized protozoan parasite of animals, is considered to be a major cause of bovine abortion worldwide. Although its life cycle is not completely known, recent studies suggest that the sexual stage occurs in dogs. The prevalence of sexual reproduction in N. caninum , however, is unknown. We investigated the ability of 3 N. caninum isolates (NC-1, NC-SweB1, and NC-Liverpool) to propagate asexually for approximately 250 parasite generations in a cell line in which they had not been cultured previously. The malthusian parameter of fitness was estimated for each isolate from 10 independent replicates of tachyzoites at the beginning as well as at the end of the experimental period. Derived and ancestral values for mean fitness were compared both within and among NC-1, NC-SweB1, and NC-Liverpool isolates. Results showed a significant increase in mean fitness for the 3 N. caninum isolates at the end of the experimental period. These findings indicate that N. caninum can adapt to new environmental conditions without the help of sexual recombination, supporting the idea that this parasite has, at least potentially, the capacity for maintaining clonal propagation in nature.

Neospora caninum is a cyst-forming coccidian that mainly affects bovines, although Neospora infection has also been described in other domestic and wild ruminant species. Serum samples from 78 alpacas ( Vicugna pacos ) and 73 llamas ( Lama glama ) at a unique dilution of 1:50 tested by indirect fluorescent antibody test (IFAT) were further analyzed serologically by IFAT and Western blot in both ruminant species to avoid cross-reactions with closely related coccidian parasites and to confirm the existence of N. caninum –specific antibodies. IFAT titers ranging between 1:50 and 1:800 were found. When using Western blot, N. caninum tachyzoite–specific immunodominant antigens with apparent molecular weights of 17–18, 34–35, 37, and 60–62 kDa were also recognized, although some sera with 1:50 IFAT titers proved not to have N. caninum –specific antibodies. As expected, higher IFAT titers were associated with higher anti– N. caninum reactivity in Western blot. This report documents for the first time the presence of N. caninum infection in adult alpacas and llamas from Peru.