# Microscopic and Molecular Identification of Eimeria Species in Domestic Rabbits (Oryctolagus cuniculus) in Romania

## TL;DR

This study identifies Eimeria species in Romanian rabbits using both microscopy and molecular methods, showing that molecular techniques are more accurate.

## Contribution

The study demonstrates the effectiveness of the ITS-1 molecular marker for accurate identification of Eimeria species in rabbits.

## Key findings

- Microscopy identified ten Eimeria species, while molecular methods detected only four.
- The ITS-1 rRNA gene proved useful for accurate molecular identification of Eimeria species.
- Low DNA quantity in some samples limited PCR detection of all species.

## Abstract

Coccidiosis is a common parasitic disease in rabbits, caused by Eimeria spp. This study analyzed 236 fecal samples from rabbits in Romania, revealing that 77.56% were infested. Microscopic examination identified ten Eimeria species, whereas molecular biology techniques detected only four species. Some species were not detected by PCR due to low DNA quantity. This study demonstrates that the ITS-1 molecular marker is useful for the accurate identification of these parasites in rabbits.

Coccidiosis caused by Eimeria spp. is a parasitic disease with high morbidity that affects various animal species, including rabbits. In rabbits, eleven Eimeria species have been primarily identified through microscopic examination of oocysts; however, this technique has certain limitations that make it challenging to differentiate between Eimeria species. The main objective of this study was to morphologically identify Eimeria species infecting rabbits in Romania, as well as to confirm these identifications using molecular biology techniques, specifically through the ITS-1 rRNA gene. A total of 236 samples were collected from different regions of Romania, of which 77.56% (183/236) tested positive for at least one Eimeria species. The samples were collected from rabbits raised in individual household settings, under various management systems—both in individual cages and in common ground-based enclosures. The areas of origin were chosen randomly, without applying restrictive criteria, specifically to ensure broad representativeness of the farming conditions encountered in practice, regardless of the production system or geographic specificity. The microscopic examination of morphological characteristics identified ten Eimeria species, whereas PCR results confirmed the presence of four species. It was not always possible to identify all the species present in a given sample, likely due to the predominant parasitic load and the DNA quantity of each species. The results of this study confirm that ITS-1 is a useful molecular marker for identifying Eimeria species in domestic rabbits.