Crossley Lucy, Findlay-Wilson Stephen, Easterbrook Linda, Kennedy Emma, Salguero Francisco J, Mackay Kim, Graham Victoria, Fotheringham Susan, Dowall Stuart
UK Health Security Agency (UKHSA), Porton Down, Salisbury, Wiltshire, SP4 0JG, UK.
J Gen Virol. 2025 Jul;106(7). doi: 10.1099/jgv.0.002125.
Mpox (formerly known as monkeypox) virus (MPXV) is the zoonotic pathogen of mpox disease in humans. Its increasing emergence outside of its endemic area has heightened the importance of investigating the virus' prevalence and maintenance in sylvatic reservoirs. The common brown rat () can inhabit almost anywhere in the UK, posing a threat to zoonotic transmission to humans. Two independent studies were carried out; the first investigated the susceptibility of brown rats to MPXV infection with a clade IIb mpox strain via two challenge routes: intranasal and intradermal. The second study considered the transmission of MPXV between challenged and naïve brown rats. All animals were asymptomatic to mpox disease, although enzyme-linked immunosorbent assay (ELISA) confirmed subclinical infection in challenge groups. In the susceptibility study, reverse transcription PCR (RT-PCR) detected mpox DNA in the lung tissue and throat swabs within the intranasally inoculated group, in addition to viable virus observed from the intranasal throat swabs. In contrast, no virus was detected in either tissues or swabs in the intradermally inoculated group or control group. RT-PCR results from the transmission study detected mpox DNA in tissues and throat swabs taken from challenged animals. Viable virus was observed from tissues and swabs of intranasally challenged animals with infectious titres of ~10-10 TCID per millilitre. ELISA assays in the transmission study showed replicable results compared to the first susceptibility study in directly challenged animals alongside evidence of seroconversion in co-housed naïve animals. In conclusion, brown rats are susceptible to MPXV infection, as they have been demonstrated to maintain viable virus in the absence of clinical signs. Viral transmission of MPXV from infected rats to naïve rats was not observed by RT-PCR, although naïve rats did show antibody responses when exposed to infected rats indicating exposure to virus.
猴痘（原称猴天花）病毒（MPXV）是人类猴痘疾病的人畜共患病原体。它在其流行区以外越来越多地出现，这凸显了调查该病毒在野生宿主中的流行情况和维持机制的重要性。普通褐鼠（ ）几乎可以栖息在英国的任何地方，对人畜共患病传播给人类构成威胁。开展了两项独立研究；第一项研究通过鼻内和皮内两种攻毒途径，调查了褐鼠对IIb分支猴痘毒株MPXV感染的易感性。第二项研究考虑了MPXV在攻毒褐鼠和未接触过病毒的褐鼠之间的传播情况。所有动物对猴痘疾病均无症状，尽管酶联免疫吸附测定（ELISA）证实攻毒组存在亚临床感染。在易感性研究中，逆转录聚合酶链反应（RT-PCR）在鼻内接种组的肺组织和咽拭子中检测到猴痘DNA，此外，从鼻内咽拭子中观察到活病毒。相比之下，皮内接种组和对照组的组织或拭子中均未检测到病毒。传播研究的RT-PCR结果在攻毒动物采集的组织和咽拭子中检测到猴痘DNA。从鼻内攻毒动物的组织和拭子中观察到活病毒，感染滴度约为每毫升10-10组织培养感染剂量（TCID）。传播研究中的ELISA检测结果与第一项针对直接攻毒动物的易感性研究相比具有可重复性，同时在同笼饲养的未接触过病毒的动物中也有血清转化的证据。总之，褐鼠对MPXV感染易感，因为已证明它们在没有临床症状的情况下能维持活病毒。虽然未接触过病毒的褐鼠在接触感染大鼠时确实显示出抗体反应，表明接触过病毒，但RT-PCR未观察到MPXV从感染大鼠向未接触过病毒的大鼠的病毒传播。
