The anthelmintic activity and toxicity of 2,2-dichlorovinyl dimethyl phosphate (dichlorvos) in equines.

This study investigated the effectivity and safety of 2,2-dichlorovinyl dimethyl phosphate (dichlorvos) in controlling internal parasite infections in equines. The researchers found that the substance was successful in treating various parasites but had minimal effect on certain larvae and stomach worms. Overdoses caused temporary symptoms that faded after 96 hours.

Introduction and Background

• This research focused on studying the anthelmintic activities of a chemical substance known as 2,2-dichlorovinyl dimethyl phosphate, commonly referred to as dichlorvos.
• The goal was to assess how effective and safe dichlorvos was in getting rid of internal parasites in horses (equines). These parasites have the potential to cause severe health issues in equines.

Research Findings

• The study found that the use of dichlorvos, at a concentration of 31 mg/kg body mass, effectively cleared various types of adult parasites, specifically strongyles, Oxyuris equi, Parascaris equorum, Probstmayria vivipara and Gasterophilus spp bots.
• However, the same substance and concentration showed no impact on 4th stage larvae of Trichonema spp, and the stomach worms, Draschia megastoma and Habronema spp.

Effects of Overdose

• The researchers also tested the effects of a 10- and 20-times therapeutic dose of dichlorvos that calculates to 310 and 620 mg/kg body mass respectively.
• Findings show that overdosing led to certain transient clinical signs, indicating a possible state of discomfort or illness in the horses. However, these signs disappeared 96 hours after the dosage was administered.

Implications and Conclusion

• This study provides valuable insights on the efficacy and safety of using dichlorvos as an anthelmintic drug in equines.
• Dichlorvos appears to be an effective treatment against several types of parasites, but ineffective for others, suggesting that its use might need to be combined with other treatments for a full spectrum of parasite control.
• The temporary effects of an overdose highlight the need to administer the correct dosage for the health and safety of the animals.