Plague is a virulent zoonosis, vectored by fleas, posing danger to black-tailed prairie dogs (BTPDs) (Cynomys ludovicianus), black-footed ferrets (Mustela nigripes), and humans in North America. During prior research, a fipronil grain bait (0.005%) applied at rates of 1-½ cup/burrow, reduced flea abundance by > 95–100% when applied three times February–March in northern Colorado. The objective of the current study was to determine the efficacy of fipronil bait against fleas in northern Colorado at reduced application rates (½ cup/burrow) and frequencies (1–2 applications). The field study was conducted in Larimer county, Colorado USA between June-November 2018. Three test plots were selected: two treatment plots (1 vs. 2 fipronil bait applications) and one untreated control. Fipronil was applied at a rate of ½ cup (~95 g)/burrow. Fleas were collected from captured BTPDs and swabs of active burrows prior to bait application and up to 134-days post-treatment. A total of 203 BTPDs and 210 active burrows were sampled. Within the treatment plots, no fleas were collected from BTPDs up to 134-days post-treatment (100% efficacy). Five fleas were recovered from burrows within the one-application plot (<40-days post-application) with efficacy ranging from 97.1 to 100%. No fleas were recovered from burrows within the two-application plot. We caution that while fleas were present within the control plot throughout the study, abundances were low. The efficacy results are supported by those of prior field research conducted in South Dakota and suggest that fipronil bait may be applied at lower rates and frequencies than initially proposed, with potential to sustain flea removal >4-months.

鼠疫是一种致命的人畜共患病，由跳蚤传染，对黑尾土拨鼠（BTPD）（Cynomys ludovicianus），黑脚雪貂（Mustela nigripes）构成危险），以及北美的人类。在先前的研究中，氟虫腈谷物诱饵（0.005％）以1-½杯/穴的速率施用，当在2月至3月在科罗拉多州北部施用3次时，跳蚤丰度降低了95-100％以上。当前研究的目的是确定在减少的施用量（1/2杯/穴）和频次（1-2次施用）下，氟虫腈诱饵对科罗拉多州北部的蚤的功效。现场研究于2018年6月至11月在美国科罗拉多州拉里默县进行。选择了三个试验区：两个处理区（1对2氟虫腈诱饵施用）和一个未经处理的对照。以每杯1/2杯（〜95 g）的速率施用Fipronil。在诱饵施用之前和治疗后长达134天，从捕获的BTPD和活性洞穴拭子中收集蚤。总共采样了203个BTPD和210个活动洞穴。在治疗地块内，直到治疗后134天（100％的功效）都未从BTPD中收集到跳蚤。在一次施用地块（施用后<40天）内从洞穴中回收了五只跳蚤，功效为97.1至100％。在两次施用的土地上，没有从洞穴中找到跳蚤。我们提醒您，尽管在整个研究中对照区内都存在跳蚤，但丰度却很低。功效结果得到了在南达科他州进行的先前田间研究的支持，并表明氟虫腈诱饵的施用频率和频率可能比最初提出的要低，并且有可能将蚤的清除时间维持在4个月以上。在一次施用地块（施用后<40天）内从洞穴中回收了五只跳蚤，功效为97.1至100％。在两次施用的土地上，没有从洞穴中找到跳蚤。我们提醒您，尽管在整个研究中对照区内都存在跳蚤，但丰度却很低。功效结果得到了在南达科他州进行的先前田间研究的支持，并表明氟虫腈诱饵的施用频率和频率可能比最初提出的要低，并且有可能将蚤的清除时间维持在4个月以上。在一次施用地块（施用后<40天）内从洞穴中回收了五只跳蚤，功效为97.1至100％。在两次施用的土地上，没有从洞穴中找到跳蚤。我们提醒您，尽管在整个研究中对照区内都存在跳蚤，但丰度却很低。功效结果得到了在南达科他州进行的先前田间研究的支持，并表明氟虫腈诱饵的施用频率和频率可能比最初提出的要低，并且有可能将蚤的清除时间维持在4个月以上。我们提醒您，尽管在整个研究中对照区内都存在跳蚤，但丰度却很低。功效结果得到了在南达科他州进行的先前田间研究的支持，并表明氟虫腈诱饵的施用频率和频率可能比最初提出的要低，并且有可能将蚤的清除时间维持在4个月以上。我们提醒您，尽管在整个研究中对照区内都存在跳蚤，但丰度却很低。功效结果得到了在南达科他州进行的先前田间研究的支持，并表明氟虫腈诱饵的施用频率和频率可能比最初提出的要低，并且有可能将蚤的清除时间维持在4个月以上。