RAPID: Understanding SARS-CoV2 transmission through a novel continuous monitoring system

冠状病毒SARS-CoV-2（严重急性呼吸道综合征-冠状病毒-2）是COVID-19的病因，与之前已知通过呼吸道分泌物、飞沫、直接或间接接触传播的类似冠状病毒相关的有限流行相比，其传播率更高。最近的一项研究表明，SARS-CoV-2可以在不锈钢、塑料、玻璃和纸板等各种表面上存活数小时，这表明传播也可以通过受污染的表面发生。SARS-CoV-2是否可以通过气溶胶传播仍存在争议。因此，重要的是要了解感染者多久开始散发病毒，以及他或她多久将感染传播给与他们直接或间接接触的另一个人。为了解决这些主要问题，该项目将利用一种新型的非侵入性监测系统，该系统可以提供有关疾病进展的重要信息，并使用小鼠模型对疾病分期，结果和传播进行新的见解，该小鼠模型已被设计为具有人类受体，这是允许病毒进入人类气道细胞的关键。监测系统可以连续捕获疾病相关数据，例如体温、头-身距离、活动模式和呼吸声。获得的数据将用于确定与疾病发作和进展相关的有意义的模式。为了确定直接接触（DC）和间接接触（IC）之间的差异，将感染和未感染动物组饲养在同一笼（DC）或由可渗透隔板（IC）隔开的相邻笼中。这一新的信息将为进一步的研究打开大门，可以研究更多的实验因素，实现更人性化的终点。此外，新的SARS-CoV-2 -小鼠传播模型可以应用于其他传染病。该原理验证项目的目标是在小鼠模型中通过直接或间接接触（DC或IC）产生有关SARS-CoV-2传播率，频率和疾病进展的新信息。预计获得的结果将提供基本的洞察力，以了解感染者多久开始散发病毒，以及他或她多久将感染传播给与他们直接或间接接触的另一个人。该项目的目标将使用表达ACE 2受体的hACE 2（人血管紧张素转换酶2）转基因小鼠和一个非侵入性和连续监测系统（CMS）来实现，该系统设计用于多传感器数据收集，可以捕获几种外部表型，包括体温，头体距离，活动模式，呼吸声等，以表征感染性疾病的进展。已经开发了用于时间序列分解和分类的算法，可以识别与疾病分期相关的有意义的模式。该项目假设新型CMS可用于更好地表征SARS-CoV-2传播时间、频率，并研究DC和IC小鼠间传播模型之间的疾病进展变异性。 将以两个具体目标来检验这一假设。第一个目标是量化SARS传播时间，频率，以及由此产生的疾病进展动力学在DC小鼠到小鼠的传播模型。这一目标将通过用SARS-CoV-2感染每笼两只圈养的hACE 2转基因小鼠中的一只来实现，之后将连续监测动物21天。将使用真实的时间数据分析来确定其它未感染hACE 2小鼠的疾病发作（病毒传播），所述其它未感染hACE 2小鼠与感染小鼠圈养在同一笼中并且具有DC。第二个目标是在IC小鼠间传播模型中量化SARS传播时间、频率和疾病进展。这一目的将通过将未感染的hACE 2小鼠圈养在笼中来实现，笼中具有将它们与感染的hACE 2小鼠分开的可渗透隔板。在这两个目标中，道德率都将量化。组织将从安乐死的动物中收集，以测量组织病毒载量，组织病理学，并通过免疫组织化学（IHC）染色检测组织病毒抗原。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The coronavirus SARS-CoV-2 (severe acute respiratory syndrome–coronavirus-2), which is the cause of COVID-19, has a higher transmission rate compared to previous limited epidemics related to similar coronaviruses that are known to be transmitted by respiratory secretions, droplets, direct or indirect contacts. A recent study documented that SARS-CoV-2 can remain viable for several hours on various surfaces such as stainless steel, plastic, glass, and cardboards, suggesting that transmission can also happen through contaminated surfaces. Controversies remain whether SARS-CoV-2 can be transmitted through aerosols. Therefore, it is important to understand how soon an infected person starts shedding the virus, and how soon he or she transmits the infection to another person who is in direct or indirect contact with them. To address these major questions, this project will utilize a novel non-invasive monitoring system that can provide important information about the disease progression and new insights on disease staging, outcomes, and transmissions using a mouse model that has been engineered to have the human receptor that is key to allowing the virus to enter cells lining human airways. The monitoring system can continuously capture disease related data such as body temperature, head-body distance, activity patterns and breathing sounds. The data obtained will be used to identify meaningful patterns associated with disease onset and progression. To determine the difference between direct contact (DC) and indirect contact (IC), infected and uninfected animal groups will be housed in the same cage (DC) or in adjoining cages separated by a permeable partition (IC). This novel information will open the door for further studies where a greater number of experimental factors can be investigated, enabling more humane endpoints. Furthermore, the novel SARS-CoV-2 - mouse transmission models can be applied to other contagious diseases. The goal of this proof-of-principle project is to generate novel information about the SARS-CoV-2 transmission rate, frequencies and, disease progression through direct or indirect contact (DC or IC) in murine models. Results obtained are expected to provide fundamental insight into how soon an infected person starts shedding the virus, and how soon he or she transmits the infection to another person who is in direct or indirect contact with them. The project’s goal will be accomplished using hACE2 (human angiotensin-converting enzyme 2) transgenic mice expressing the ACE2 receptor and a non-invasive and continuous monitoring system (CMS) designed for multi-sensor data collection that can capture several external phenotypes, including body temperature, head-body distance, activity patterns, breathing sounds, and others to characterize infectious disease progression. Algorithms have been developed for time-series decomposition and classification that can identify meaningful patterns associated with disease staging. The project hypothesizes that the novel CMS can be used to better characterize the SARS-CoV-2 transmission time, frequencies, and to study disease progression variability between DC and IC mice-to-mice transmission models. The hypothesis will be tested with two specific aims. The FIRST aim is to quantify the SARS transmission time, frequencies, and resulting disease progression dynamics in a DC mice-to-mice transmission model. This aim will be achieved by infecting one of the two housed hACE2 transgenic mice per cage with SARS-CoV-2, after which the animals will be continuously monitored for 21 days. Real time data analysis will be used to determine disease onset (viral transmission) for other uninfected hACE2 mice, which are housed in the same cage and have DC with the infected mice. The SECOND Aim will quantify the SARS transmission time, frequencies, and disease progression in an IC mice-to-mice transmission model. This aim will be accomplished by housing uninfected hACE2 mice in cages with a permeable partition separating them from infected hACE2 mice. In both aims, the morality rate will be quantified. Tissues will be collected from euthanized animals to measure tissue viral loads, tissue pathogenesis by histology, and to detect tissue viral antigens by immunohistochemistry (IHC) staining.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.