Eimeria

Eimeria is a genus of obligate intracellular protozoan parasites belonging to the phylum Apicomplexa. These parasites are not a molecular target or receptor in the traditional pharmacological sense, but rather an organism that causes the disease coccidiosis, primarily in livestock such as poultry, cattle, sheep, and goats. The parasite invades and multiplies within the intestinal epithelial cells of its host, leading to significant damage. This infection manifests as diarrhea, weight loss, dehydration, reduced feed efficiency, and can result in high mortality, causing substantial economic losses in the agricultural industry. Control strategies involve anticoccidial drugs and vaccines, which target various stages of the parasite's complex life cycle. However, the widespread and continuous use of these drugs has led to significant challenges, including the development of drug resistance in Eimeria species and concerns about drug residues in animal products.

Other names

CoccidiaApicomplexan parasite

Drugs targeting Eimeria, known as anticoccidials, exert their effects through various mechanisms. Ionophores (e.g., monensin, lasalocid) act on membrane function, destroying the parasite during its motile stages (sporozoites and merozoites) by interfering with ion transport. Chemical anticoccidials have diverse mechanisms; for instance, ethopabate inhibits nucleic acid synthesis by acting as an antagonist of folic acid or its precursor, PABA. Amprolium inhibits co-factor synthesis, specifically acting as a thiamine analogue. Quinolones like decoquinate inhibit the parasite's energy metabolism, particularly mitochondrial respiration. Sulphonamides also inhibit co-factor synthesis. These drugs can be coccidiostatic, halting parasite development, or coccidiocidal, killing the parasite. Vaccines, another control measure, stimulate the host's immune response to the parasite.