# Molecular Investigation of Eimeria spp. Infection in Weaned Dairy Calves in Thessaly, Greece, and Associated Risk Factors

## TL;DR

This study investigates Eimeria infections in weaned dairy calves in Greece, finding high prevalence and identifying risk factors like young age and poor hygiene.

## Contribution

The first molecular investigation of Eimeria spp. in weaned dairy calves in Thessaly, Greece, with detailed risk factor analysis.

## Key findings

- 46.3% of samples showed Eimeria infection, with Eimeria bovis and Eimeria zuernii being the most common.
- Mixed infections occurred in 51.0% of positive cases.
- Calves under 60 days old had 2.15 times higher odds of infection, and poor hygiene practices increased risk.

## Abstract

This study presents the first molecular investigation into the prevalence and risk factors of Eimeria spp. infection among weaned dairy calves in Thessaly, Greece. Utilizing a cross-sectional design, 665 fecal samples were collected from 35 intensive dairy cattle farms and analyzed via genus-specific PCR and species-specific multiplex PCR targeting the internal transcribed spacer 1 (ITS-1) region. The overall molecular prevalence was found to be 46.3%, with Eimeria bovis (24.7%) and Eimeria zuernii (14.0%) emerging as the most prevalent species. Mixed infections were common, occurring in 51.0% of the positive cases. Multivariable analysis revealed that dairy calves aged less than 60 days had 2.15 times higher odds of infection compared to older calves. Environmental factors also significantly influenced infection rates, specifically ground flooring, the use of immovable/concrete water troughs and infrequent cleaning of floors, feeders and water troughs. These results highlight the high burden of pathogenic Eimeria in dairy cattle herds of Thessaly, Greece, and underscore the importance of integrating rigorous hygiene protocols with age-targeted management to control bovine coccidiosis.