Coccidiostats

Coccidiostats are drugs used to prevent or control coccidiosis, a disease caused by protozoan parasites of the genus Eimeria that infect the intestinal tract of a variety of animals, especially poultry. They are commonly added to feed or drinking water as feed additives or veterinary medicines to reduce parasite replication, intestinal damage, and production losses.

Coccidiostats can be broadly categorized into ionophore antibiotics and non-ionophore agents. Ionophores, such as monensin, lasalocid, narasin, and salinomycin, disrupt ion transport across parasite membranes, while non-ionophore compounds include amprolium, decoquinate, diclazuril, and toltrazuril, which interfere with essential metabolic processes of the parasites. These agents are generally used prophylactically to maintain gut health and performance, though some compounds may also have therapeutic uses under veterinary guidance.

In practice, coccidiostats are routinely incorporated into poultry feeds and, in some cases, used in cattle, sheep, goats, and rabbits. Management typically involves rotation of different coccidiostats or combining drug use with vaccination to delay resistance. Regulatory frameworks require adherence to labeled dosages and withdrawal periods to ensure drug residues do not enter meat or eggs.

Resistance and safety considerations are important; improper or continuous use can select for resistant Eimeria strains and reduce efficacy. Some ionophore coccidiostats can be toxic to non-target species, notably horses, highlighting the need for correct handling and species-specific guidance.