Toxicity of pyrethroids and repellency of diethyltoluamide in two deltamethrin-resistant colonies of Triatoma infestans Klug, 1834 (Hemiptera: Reduviidae).

Abstract

The aim of the currrent investigation was to evaluate (a) the toxicity of three pyrethroids (deltamethrin, lambda-cyhalothrin, and tetramethrin); (b) the effect of these insecticides on the locomotor activity; and (c) the repellent effect of N,N-diethyl-m-toluamide (DEET) on two deltamethrin-resistant strains of Triatoma infestans from Argentina (El Chorro and La Toma), and one susceptible strain. The resistance ratios (RRs) obtained for the La Toma strain were: > 10,769, 50.7, and > 5.2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The RRs for the El Chorro strain were: > 10,769, 85.8, and > 5.2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The hyperactivity usually caused by the three pyrethroids was in both the deltamethrin-resistant strains compared to the susceptible reference strain. No differences were observed in the repellent effect of DEET between the three groups. These results indicate that the deltamethrin-resistant insects have a cross resistance to lambda-cyhalothrin and tetramethrin, and are also resistant to the first symptom of pyrethroid poisoning (hyperactivity). However, the sensorial process related to DEET repellency does not appear to be altered.

• Authors: Valeria Sfara, Eduardo N Zerba, Raúl A Alzogaray
• Journal: Memorias do Instituto Oswaldo Cruz (Mem Inst Oswaldo Cruz) Vol. 101 Issue 1 Pg. 89-94 (Feb 2006) ISSN: 0074-0276 [Print] Brazil
• PMID: 16699715 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Insect Repellents
• Insecticides
• Pyrethrins
• DEET

Topics

• Animals
• DEET
• Insect Repellents
• Insecticides (toxicity)
• Lethal Dose 50
• Motor Activity (drug effects)
• Nymph (drug effects)
• Pyrethrins (toxicity)
• Triatoma