Rodenticidal effectiveness of indomethacin baits in warfarin-resistant roof rats (Rattus Rattus) and house mice (Mus Musculus)

Abstract

Deratisation is one of the basic anti-epidemic measures, directed to protect the health of humans and animals. Nowadays, anticoagulants are still the most commonly used rodenticides. In recent years, the problem of development of resistant synanthropic rodents to these agents is becoming more serious. This is the reason for increasing interest in discovering alternative methods for controlling the resistant populations. It is known that some non-steroidal anti-inflammatory drugs (NSAIDs) act as synergists and significantly increase the toxicity of anticoagulant rodenticides, but convincing information on their effectiveness in anticoagulant-resistant rodents is still missing. The aim of the present research is to contribute to solve this problem, by studying the effectiveness of 0.025% indomethacin baits, administered alone and combined with warfarin, in warfarin-resistant wild synanthropic rodents. In the conducted laboratory food tests 36 roof rats (Rattus rattus) and 60 house mice (Mus musculus) were included. A very high toxicity of indomethacin baits in resistant rodents, leading up to 100% mortality, occurring between 24 to 48 hours post acceptance were found. NSAIDs mechanism of action, clinical signs and pathological findings in the intoxicated rodents are discussed. Based on the laboratory conducted tests and scientific data analysis, we conclude that 0.025% indomethacin baits have high effectiveness in anticoagulant-resistant synanthropic rodents and could be used as an alternative method for control of resistant populations