An outbreak of rabbit hemorrhagic disease virus 2 (RHDV-2)-associated disease occurred in the southwestern United States following its first detection in New Mexico in March 2020. The disease spread throughout several states and was diagnosed for the first time in California on May 11, 2020, in a black-tailed jackrabbit (Lepus californicus). The following day, the California Department of Food and Agriculture (CDFA) issued an order banning the entrance into California of several lagomorph species and their products from any state in which the disease had been detected in the last 12 mo. RHDV-2 is a threat to wild lagomorph species in California, including the endangered riparian brush rabbit (Sylvilagus bachmani riparius). Therefore, the California Department of Fish and Wildlife (CDFW) started tracking any mortality event in wild lagomorph populations. As of August 9, 2020, RHDV-2 had been detected in wild and domestic lagomorphs of several counties in southern California that were submitted to the California Animal Health and Food Safety laboratory system by the CDFA or the CDFW. These positive cases included 2 additional black-tailed jackrabbits and 3 desert cottontail rabbits (Sylvilagus audubonii). In addition, the infection spilled over to domestic populations, whereby it was confirmed on July 10, 2020, in a domestic rabbit (Oryctolagus cuniculus).

2020 年 3 月在新墨西哥州首次发现兔出血性疾病病毒 2 (RHDV-2) 相关疾病后，在美国西南部爆发了一次暴发。该疾病蔓延到多个州，并于 5 月在加利福尼亚州首次确诊2020 年 11 月 11 日，在黑尾长耳兔 ( Lepus californicus ) 中。第二天，加州食品和农业部 (CDFA) 发布命令，禁止在过去 12 个月内发现该疾病的任何州的几种兔形目物种及其产品进入加州。RHDV-2 对加利福尼亚的野生兔形目物种构成威胁，包括濒临灭绝的河岸刷兔 ( Sylvilagus bachmani riparius)）。因此，加州鱼类和野生动物部 (CDFW) 开始追踪野生兔形目种群中的任何死亡事件。截至 2020 年 8 月 9 日，已在加利福尼亚州南部几个县的野生和家养兔形动物中检测到 RHDV-2，这些兔形动物由 CDFA 或 CDFW 提交给加利福尼亚动物健康和食品安全实验室系统。这些阳性病例包括另外 2 只黑尾长耳兔和 3 只沙漠棉尾兔 ( Sylvilagus adubonii )。此外，感染蔓延到国内人群，并于 2020 年 7 月 10 日在一只家兔（Oryctolagus cuniculus）中得到证实。