Preliminary study of the mechanism of action of ethanamizuril against Eimeria tenella

Systemic Caryospora-like coccidiosis in a clutch of hatchling red-eared slider turtles (Trachemys scripta elegans)

Caryospora-like organisms (CLOs) form a clade of at least 11 genotypes of related coccidia that can cause epizootic mortality in marine turtles. The biology, transmission, host species range, and host cell tropism of these organisms are still largely unknown. The goal of this study was to characterize the host cell tropism, pathologic and ultrastructural features, and phylogeny associated with the first report of a mortality event due to CLO in the freshwater red-eared slider turtle (Trachemys scripta elegans). Sudden mortalities within a clutch of captive-raised red-eared slider hatchlings (n = 8) were recorded, and deceased animals had severe segmental to diffuse, transmural, fibrinonecrotic enterocolitis and multifocal to coalescing hepatic necrosis, among other lesions associated with numerous intracytoplasmic developing stages of intralesional coccidia. Among the different developmental stages, merozoites were ultrastructurally characterized by an apical complex. A pan-apicomplexan polymerase chain reaction (PCR) yielded a 347 bp-amplicon matching the Schellackia/Caryospora-like clade with 99.1% identity to the US3 strain from green sea turtles (Chelonia mydas) and 99.1% identity to Schellackia sp. Isolate OC116. Surviving hatchlings were treated with toltrazuril sulfone (ponazuril) but were subsequently euthanized due to the risk of spreading the parasite to other chelonids in the collection. The ponazuril-treated hatchlings (n = 4) had mild proliferative anterior enteritis, with few intraepithelial coccidia in one hatchling confirmed as CLO by PCR. This is the first report of Caryospora-like coccidiosis in non-cheloniid turtles, highlighting the relevance of this disease as an emerging highly pathogenic intestinal and extra-intestinal form of coccidiosis of turtles with potential cross-species infectivity.

Safety pharmacology assessment of Ethanamizuril, a novel triazines coccidiostat

In the current study, to support the safety pharmacology assessment of Ethanamizuril as a new potent anticoccidial agent of triazine compounds, the effects of Ethanamizuril on the central nervous system, cardiovascular system and respiratory system were investigated. Using locomotor activity test, climbing behavior test and nembutal subthreshold hypnotic test at each time point after oral administration of Ethanamizuril to mice, the effects on the central nervous system were evaluated. An assessment of Ethanamizuril effects on the cardiovascular and respiratory system were performed by the use of a telemetry system in conscious beagle dogs. The results showed that the treatment of Ethanamizuril had no effects on motor activity, behavioral changes, coordination, and sensory/motor reflex responses in mice. There were also no changes in heart rate, blood pressure, and electrocardiogram at all doses and each time points in beagle dogs. Our data suggested that Ethanamizuril showed no adverse effects on the central nervous system, cardiovascular system, and respiratory system.