Molecular and Environmental Toxicology Center and Zoology Department, University of Wisconsin-Madison, 1300 University Avenue, 1530 MSC, Madison, WI 53706, USA.
Toxicology. 2010 Feb 28;269(1):81-8. doi: 10.1016/j.tox.2010.01.010. Epub 2010 Jan 22.
Public health agencies utilize aerial insecticides to interrupt an active West Nile virus (WNV) transmission cycle, which may expose WNV-infected birds to these agents. Although resmethrin has been considered benign to birds, no studies have evaluated whether the environmentally employed form of resmethrin with PBO synergist (synergized resmethrin (SR)) can suppress avian immunity to WNV infection and enhance a bird's host competence. Recognizing that wild birds confront toxicological stressors in the context of various physiological states, we exposed four groups (n=9-11) of 9-week-old chickens (Gallus domesticus) to drinking water with either SR (three alternate days at 50 microg/l resmethrin+150 microg/l piperonyl butoxide), CORT (10 days at 20mg/l to induce subacute stress), the combination of SR and CORT, or 0.10% ethanol vehicle coincident with WNV infection. Compared to controls, SR treatment did not magnify but extended viremia by 1 day, and depressed IgG; CORT treatment elevated (mean, 4.26 log(10)PFU/ml) and extended viremia by 2 days, enhanced IgM and IgG, and increased oral virus. The combination of SR and CORT increased the number of chickens that shed oral virus compared to those treated with CORT alone. None of the chickens developed a readily infectious viremia to mosquitoes (none >or=5 log(10)PFU/ml), but viremia in a CORT-exposed chicken was up to 4.95 log(10)PFU/ml. Given that SR is utilized during WNV outbreaks, continued work toward a complete risk assessment of the potential immunotoxic effects of SR is warranted. This would include parameterization of SR exposures with immunological consequences in wild birds using both replicating (in the laboratory) and non-replicating (in the field) antigens. As a start, this study indicates that SR can alter some immunological parameters, but with limited consequences to primary WNV infection outcome, and that elevated CORT mildly enhances SRs immunotoxicity in chickens.
公共卫生机构利用空中杀虫剂来中断西尼罗河病毒（WNV）的活跃传播周期，这可能使感染 WNV 的鸟类接触到这些药剂。尽管雷锁辛已被认为对鸟类无害，但尚无研究评估环境中使用增效剂胡椒基丁醚的雷锁辛（增效雷锁辛（SR））是否可以抑制鸟类对 WNV 感染的免疫力，并增强鸟类的宿主易感性。认识到野生鸟类在各种生理状态下都会面临毒理学应激源，我们让四组（每组 9-11 只）9 周龄的鸡（Gallus domesticus）连续 10 天饮用含 SR（每隔三天 50 微克/升雷锁辛+150 微克/升胡椒基丁醚）、CORT（20 毫克/天诱导亚急性应激）、SR 和 CORT 组合或 0.10%乙醇的水，同时感染 WNV。与对照组相比，SR 处理没有放大但延长了 1 天的病毒血症，并降低了 IgG；CORT 处理使病毒血症升高（平均 4.26 对数 10 病毒颗粒/ml）并延长了 2 天，增强了 IgM 和 IgG，并增加了口腔病毒。与单独用 CORT 处理的鸡相比，SR 和 CORT 的组合增加了口腔排毒的鸡的数量。没有一只鸡对蚊子产生易感染的病毒血症（均<5 对数 10 病毒颗粒/ml），但暴露于 CORT 的鸡的病毒血症高达 4.95 对数 10 病毒颗粒/ml。鉴于在 WNV 爆发期间使用了 SR，因此有必要继续进行 SR 对免疫毒性潜在影响的全面风险评估。这将包括使用实验室中的复制抗原和现场的非复制抗原，对 SR 暴露与免疫后果之间的参数进行参数化。作为一个开始，这项研究表明，SR 可以改变一些免疫学参数，但对原发性 WNV 感染结果的影响有限，而升高的 CORT 轻度增强了 SR 在鸡中的免疫毒性。
