# Evidence of in Utero Anti-Neospora caninum Antibody Production in Paired Sow and Umbilical Cord Blood Samples

## TL;DR

This study found evidence that piglets can produce antibodies to Neospora caninum while still in the womb, suggesting the parasite may contribute to reproductive issues in pigs.

## Contribution

The study provides the first evidence of in utero anti-Neospora caninum antibody production in stillborn piglets, indicating potential fetal immune response to the parasite.

## Key findings

- Anti-Neospora caninum IgG and IgM antibodies were detected in umbilical cord blood samples, indicating in utero immune response.
- Antibody detection was more common in smaller farms, possibly due to lower biosecurity.
- The presence of antibodies in umbilical cord blood suggests Neospora caninum may contribute to reproductive disorders in swine.

## Abstract

Neosporosis, caused by Neospora caninum, is a major protozoal disease responsible for reproductive disorders and economic losses in livestock. Swine are susceptible to N. caninum infection, as evidenced by serological and experimental studies, but the impact of natural infection on reproduction failure remains poorly defined. The objective of this study was to investigate N. caninum transplacental transmission in naturally infected sows by detecting an active fetal immune response in their stillborn piglets. Paired maternal blood and umbilical cord blood (UCB) samples were collected from 247 sows and stillborn piglets across 39 farrow-to-finish farms in mainland Greece. Sera were tested for anti-N. caninum IgG and IgM antibodies using an indirect fluorescence antibody test. An IgG and IgM seropositivity for N. caninum of 8.91% and 3.64%, respectively, was reported in sows, while lower percentages of IgG and IgM antibodies (3.24% and 0.81%, respectively) were detected in UCB samples. Overall, antibodies were detected in 4.05% of UCB samples, indicative of in utero antibody production. Positive samples were more frequently encountered on smaller farms with up to 250 sows, possibly due to lower biosecurity standards. The detection of antibodies in UCB resulting from the fetal immune response to intrauterine N. caninum infection is indicative of the potential involvement of N. caninum parasitism in reproductive system disorders. Testing of UCB for the presence of anti-Neospora antibodies elucidates the dynamics of parasite transmission within the farm and provides evidence for the implementation of more efficient biosecurity and preventative measures.