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

Abstract

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.