SARS-CoV-2 is transmitted via contact and via the air between ferrets

Abstract

bioRxiv preprint SARS-CoV-2, a coronavirus that newly emerged in China in late 2019 1,2 and spread rapidly 12 worldwide, caused the first witnessed pandemic sparked by a coronavirus. As the pandemic 13 progresses, information about the modes of transmission of SARS-CoV-2 among humans is critical 14 to apply appropriate infection control measures and to slow its spread. Here we show that SARS-15 CoV-2 is transmitted efficiently via direct contact and via the air (via respiratory droplets and/or 16 aerosols) between ferrets. Intranasal inoculation of donor ferrets resulted in a productive upper 17 respiratory tract infection and long-term shedding, up to 11 to 19 days post-inoculation. SARS-18 CoV-2 transmitted to four out of four direct contact ferrets between 1 and 3 days after exposure 19 and via the air to three out of four independent indirect recipient ferrets between 3 and 7 days 20 after exposure. The pattern of virus shedding in the direct contact and indirect recipient ferrets 21 was similar to that of the inoculated ferrets and infectious virus was isolated from all positive 22 animals, showing that ferrets were productively infected via either route. This study provides 23 experimental evidence of robust transmission of SARS-CoV-2 via the air, supporting the 24 implementation of community-level social distancing measures currently applied in many 25 countries in the world and informing decisions on infection control measures in healthcare 26 settings 3 . In late December 2019, clusters of patients in China presenting with pneumonia of unknown etiology 29 were reported to the World Health Organization (WHO) 1 . The causative agent was rapidly identified 30 as being a virus from the Coronaviridae family, closely related to the severe acute respiratory 31 syndrome coronavirus (SARS-CoV) 2,4,5 . The SARS-CoV epidemic affected 26 countries and resulted in 32 more than 8000 cases in 2003. The newly emerging coronavirus, named SARS-CoV-2 6 , rapidly spread 33 worldwide and was declared pandemic by the WHO on March 11, 2020 7 . The first evidence 34 suggesting human-to-human transmission came from the descriptions of clusters among the early 35 cases 8,9 . Based on epidemiological data from China before measures were taken to control the 36 spread of the virus, the reproductive number R0 (the number of secondary cases directly generated 37 from each case) was estimated to be between 2 and 3 10-12 . In order to apply appropriate infection 38 control measures to reduce the R0, the modes of transmission of SARS-CoV-2 need to be elucidated.39 Respiratory viruses can be transmitted via direct and indirect contact (via fomites), and through the 40 air via respiratory droplets and/or aerosols. Transmission via respiratory droplets (> 5 μm) is 41 mediated by expelled particles that have a propensity to settle quickly and is therefore reliant on 42 close proximity between infected and susceptible individuals, usually within 1 m of the site of 43 expulsion. Transmission via aerosols (< 5 μm) is mediated by expelled parti...

SARS-CoV-2 neutralizing human antibodies protect against lower respiratory tract disease in a hamster model

“…This suggests that treatment may protect against disease in the lungs but not virus transmission from the nose. Recent studies have shown that SARS-CoV-2 can transmit between animals via both direct contact and air 13,15,25 .…”

Intranasal exposure of African green monkeys to SARS-CoV-2 results in acute phase pneumonia with shedding and lung injury still present in the early convalescence phase

“…Both small animal models and nonhuman primates (NHP) may prove valuable in triaging the most promising medical countermeasures prior to use in humans. Hamsters and ferrets are currently being used as immunocompetent small animal models of COVID-19 [3][4][5] while several NHP models have been quickly developed [6][7][8][9][10][11][12]. Among the nonhuman primate models evaluated the African green monkey (AGM) appears to best recapitulate the most salient features of human COVID-19 [10][11][12].…”

Might SARS‐CoV‐2 Have Arisen via Serial Passage through an Animal Host or Cell Culture?

“…Further support for the possibility that serial passage through lab ferrets or throughout mink farms played a role in the genesis of this novel coronavirus is provided by a preprint that notes the obvious ease with which it passes through the air between ferrets, since SARS-CoV-2 was transmitted through the air to three out of four indirect recipient ferrets monitored for airborne passage of the novel coronavirus. [42] It seems reasonable to think that SARS-Cov-2's apparent affinity for ferrets and minks should lead to an investigation of mink farms in the Hubei province were the novel coronavirus was discovered, since a viable pathway for its emergence could be infected bats defecating on commercial mink farms, which would loosely parallel the emergence of MERS-CoV from herds of camels following putative fecal contamination by local bats. [43] The prospect that serial passage through lab animals or on commercial farms may have played a role in the creation of SARS-CoV-2 is also raised by an April 2020 preprint, which appears to have been retracted after Chinese authorities implemented the censorship of any papers relating to the origins of the novel coronavirus.…”