Which type of rodenticides decrease the clotting ability of blood and are effective after only one feeding?

• A. First-generation anticoagulants
• B. Non-anticoagulant rodenticides
• C. Acute toxicants
• D. Single feeding anticoagulant rodenticides

Answer: (D)

Single-feeding anticoagulant rodenticides are designed to cause coagulopathy after just one meal. They work by blocking the vitamin K cycle, which reduces the production of the vitamin K–dependent clotting factors II, VII, IX, and X. With these factors diminished, blood clotting is impaired, leading to internal bleeding and death from hemorrhage. This class is potent enough that a single ingestion can be lethal, unlike first-generation anticoagulants that require multiple feedings over several days to accumulate a lethal dose. Non-anticoagulant rodenticides act through other toxic mechanisms and do not primarily depress blood clotting, while acute toxicants kill through rapid non–clotting-related processes. So the option describing a single feeding anticoagulant rodenticide best fits the criteria of decreasing clotting ability after one meal.