Quails are susceptible to avian coccidiosis, which causes significant economic loss to the quail industry worldwide. However, the morphological comprehension of Eimeria species in quails in Vietnam remains inadequate. The study aimed to identify Eimeria species in infected quails and to survey the prevalence of Eimeria species in Japanese quails in the Mekong Delta, Vietnam by using the flotation technique. Identification of Eimeria species was conducted based on morphological indices of oocysts and sporocysts, combined with sporulation time observation by using a light microscope. The infected quails were highlighted at 46.10% positive with coccidiosis. The prevalent species were morphologically characterized as Eimeria bateri, E. tsunodai, E. uzura, and E. fluminensis.  Young chicks were easily infected with Eimeria at early development from the second week to the fourth week of age reaching the highest rate of infection 77.33%. Eimeria bateri was identified as the most predominant species, but E. tsunodai was the most pathogenic in surveyed quails, accounting for 67.95% and 46.67% of coccidiosis infection, respectively. These results indicated that quails were highly susceptible to coccidiosis, highlighting the urgent need to implement effective prophylaxis in quail farms.

To Cite This Article: Tran NHB, Khang NTK, Tien LA, Tien NTM, Chuc NT and Hung NH 2025. First report of morphological identification and prevalence of Eimeria species in Japanese quails (Coturnix coturnix japonica) in Mekong Delta of Vietnam. Pak Vet J. http://dx.doi.org/10.29261/pakvetj/2025.259