Sonoda Ivan Vieira, Dias Letícia Sena, Bezerra Cláudia Mendonça, Dias João Carlos Pinto, Romanha Alvaro José, Diotaiuti Liléia
Instituto de Pesquisas René Rachou, Fiocruz, Belo Horizonte, MG, Brasil.
Mem Inst Oswaldo Cruz. 2010 May;105(3):348-52. doi: 10.1590/s0074-02762010000300019.
After controlling Triatoma infestans in Brazil, other species of triatomine that were considered minor in the transmission of Chagas disease became important. The persistence of Triatoma brasiliensis in Northeastern Brazil, associated with reinfection of domestic environments recently sprayed with pyrethroids, may be a signal of susceptibility alteration of this species to this insecticide. Specimens of T. brasiliensis from the municipality of Tauá, state of Ceará, were captured before and one year after spraying. They were submitted to bioassays using deltamethrin. The LD50 ranged from 0.19-0.33 ng of deltamethrin/nymph. The resistance ratio among samples from Tauá varied from 1.16-1.79 in the samples captured before the spraying and 1.00-1.74 in the samples captured one year after spraying, demonstrating that the two populations were equally susceptible to deltamethrin. The small difference in susceptibility between the two captures suggests that T. brasiliensis obtained in the second capture are from new invasions of the domestic environment and that the insecticide did not select resistant individuals. Therefore, it is suggested that T. brasiliensis control be carried out supplementing the regular use of pyrethroids with complementary measures, such as improvement of the dwellings and health education.
在巴西对骚扰锥猎蝽进行控制后，其他曾被认为在恰加斯病传播中不太重要的锥蝽种类变得重要起来。巴西锥蝽在巴西东北部持续存在，且与近期喷洒拟除虫菊酯的家庭环境再次感染有关，这可能表明该物种对这种杀虫剂的易感性发生了改变。从塞阿拉州陶阿市采集的巴西锥蝽样本，在喷洒前和喷洒一年后分别进行捕获。对其进行了使用溴氰菊酯的生物测定。半数致死剂量范围为0.19 - 0.33纳克溴氰菊酯/若虫。陶阿市样本在喷洒前的抗性比率在1.16 - 1.79之间，喷洒一年后的样本在1.00 - 1.74之间，表明这两个种群对溴氰菊酯的易感性相同。两次捕获的易感性差异较小，表明第二次捕获的巴西锥蝽来自新侵入家庭环境的个体，且杀虫剂并未选择出抗性个体。因此，建议在控制巴西锥蝽时，在常规使用拟除虫菊酯的基础上辅以补充措施，如改善居住环境和开展健康教育。
