Secondary poisoning

Secondary poisoning, or relay toxicity, is the poisoning that results when one organism comes into contact with or ingests another organism that has poison in its system. It typically occurs when a predator eats an animal, such as a mouse, rat, or insect, that has previously been poisoned by a commercial pesticide. If the level of toxicity in the prey animal is sufficiently high, it will harm the predator.

Mammals susceptible to secondary poisoning include humans, with infants and small children being the most susceptible. Pets such as cats and dogs, as well as wild birds, also face significant risk of secondary poisoning.

PesticidesEdit

Various pesticides such as rodenticides may cause secondary poisoning.[1] Some pesticides require multiple feedings spanning several days; this increases the time a target organism continues to move after ingestion, raising the risk of secondary poisoning of a predator.

Pesticide Type Classification Target Oral Toxicity Feedings Secondary Risk to Mammals Secondary Risk to Birds
Warfarin Anticoagulant Hydroxycoumarin Rodenticide Moderate Multiple Low Minimal
Bromadiolone Anticoagulant Hydroxycoumarin Rodenticide High Single Moderate Moderate
Difethialone Anticoagulant Hydroxycoumarin Rodenticide High Single Moderate Highest
Brodifacoum Anticoagulant Hydroxycoumarin Rodenticide Highest Single Highest Highest
Chlorophacinone Anticoagulant Indandione Rodenticide High Multiple Highest Minimal
Diphacinone Anticoagulant Indandione Rodenticide High Multiple Highest Moderate
Bromethalin CNS other Rodenticide High Single Low Low
Fluoroacetate Metabolism other Rodenticide Highest Single High Highest
Zinc phosphide other other Rodenticide High Single Minimal Low

ReferencesEdit