公寓長(zhǎng)期閑置,為何驚現(xiàn)新冠病毒?
在中國(guó)廣州市一間無(wú)人居住的公寓衛(wèi)生間里,研究人員發(fā)現(xiàn)了新冠病毒。這表明,空氣中的病原體可能沿著下水管道向上飄浮,與17年前香港SARS病毒大規(guī)模爆發(fā)的情形類似。
中國(guó)疾病預(yù)防控制中心的研究人員本月在《國(guó)際環(huán)境》雜志(Environment International)上發(fā)表的一份研究報(bào)告稱,今年2月,在一間長(zhǎng)期空置的公寓內(nèi)的洗手槽、水龍頭和花灑手柄上均發(fā)現(xiàn)了SARS-CoV-2病毒的痕跡。而在這間被病毒污染的衛(wèi)生間樓下,有五名住戶在不久前被確診感染了新冠病毒。
科學(xué)家對(duì)此進(jìn)行了“現(xiàn)場(chǎng)跟蹤模擬實(shí)驗(yàn)”,以確認(rèn)病毒是否會(huì)通過(guò)馬桶沖力形成的微小氣載顆粒物在污水管道中傳播。他們?cè)诖_診病例住戶樓上10層和12層的衛(wèi)生間里都發(fā)現(xiàn)了這種顆粒物——?dú)馊苣z。2月初,這兩層樓分別出現(xiàn)了兩例確診病例,因此住戶們開(kāi)始擔(dān)心,從糞便中產(chǎn)生的載有新冠病毒的顆粒物可能已通過(guò)下水管道飄進(jìn)自己家中。
這份最新報(bào)告不由讓人回憶起20年前香港私人住宅淘大花園的案例。當(dāng)時(shí),這棟住宅有329位住戶被傳染了嚴(yán)重急性呼吸道綜合征(SARS),部分原因就是有問(wèn)題的污水管道。淘大花園事件造成了42名住戶死亡,是SARS疫情受災(zāi)最嚴(yán)重的社區(qū)。而SARS的罪魁禍?zhǔn)淄瑯邮且环N冠狀病毒。
中國(guó)疾病預(yù)防控制中心環(huán)境與人口健康重點(diǎn)實(shí)驗(yàn)室的科學(xué)家唐宋與同事在報(bào)告中引用了此前未公布的數(shù)據(jù)。報(bào)告稱:“雖然不能排除因?yàn)楣灿秒娞輦鞑ゲ《镜目赡?,但本次研究與2003年香港淘大花園事件的研究結(jié)果一致?!?/p>
澳大利亞昆士蘭科技大學(xué)空氣質(zhì)量與健康國(guó)際實(shí)驗(yàn)室的主任莉迪亞·莫拉斯卡表示,多層建筑內(nèi)的公寓可能通過(guò)共用的廢水系統(tǒng)相連。莫拉斯卡說(shuō),雖然在污水管道中固體和液體會(huì)向下沉降,但管道內(nèi)的氣體通常會(huì)有明顯的氣味,會(huì)通過(guò)沒(méi)有足夠多水的管道向上飄浮。莫拉斯卡沒(méi)有參與本次研究。
莫拉斯卡在接受采訪時(shí)表示:“如果有氣味,意味著空氣已經(jīng)傳播到了不應(yīng)該去的地方?!?/p>
呼吸道飛沫
據(jù)世界衛(wèi)生組織稱,新冠病毒主要通過(guò)呼吸道飛沫傳播,包括飛濺的口水或從鼻腔中噴出的飛沫。但在新冠疫情爆發(fā)的最初幾周,中國(guó)科學(xué)家曾經(jīng)表示在新冠肺炎患者的糞便中發(fā)現(xiàn)了具有傳染性的新冠病毒,也可能在病毒傳播中發(fā)揮了作用。2月,經(jīng)過(guò)對(duì)廣東省73名新冠肺炎住院患者的研究發(fā)現(xiàn),超過(guò)一半患者的糞便病毒檢測(cè)呈陽(yáng)性。
中國(guó)疾控中心的科學(xué)家表示,之前的研究已經(jīng)證明,沖馬桶這一過(guò)程會(huì)從排泄物中產(chǎn)生含有細(xì)菌的氣溶膠。特別是在封閉的、通風(fēng)不暢的空間內(nèi),這些顆粒物能長(zhǎng)時(shí)間懸浮在空中,傳播距離超過(guò)1米(3英尺)。
香港大學(xué)公共衛(wèi)生學(xué)院病毒學(xué)專業(yè)客座教授裴偉士表示,在SARS疫情期間曾經(jīng)出現(xiàn)過(guò)糞便氣溶膠傳播,新冠病毒也可能會(huì)偶爾出現(xiàn)這種情況,這取決于下水道系統(tǒng)。他說(shuō),中國(guó)疾控中心的研究發(fā)現(xiàn)了病毒的痕跡,“這與傳染性病毒是兩回事。但我們不能對(duì)這種病毒傳播的可能性掉以輕心?!?/p>
糞便氣溶膠流
研究顯示,在淘大花園事件中,一位SARS患者通過(guò)糞便和尿液排出了“超高濃度”的病毒,他的衛(wèi)生間里溫暖潮濕的空氣在通風(fēng)井中形成了一股氣流,將空氣中的病毒傳播到了其他公寓。
中國(guó)疾控中心的研究人員表示,雖然馬桶是日常必需品,但“如果使用不當(dāng),尤其是在醫(yī)院中,它們可能增加糞便生成的氣溶膠傳播。”研究人員引用的流體動(dòng)力學(xué)模擬結(jié)果顯示,在沖馬桶時(shí)“有大量含有病毒的氣溶膠顆粒向上噴出”,導(dǎo)致病毒在室內(nèi)大范圍傳播。
悉尼新南威爾士大學(xué)的全球生物安全教授雷娜·麥金泰爾表示:“研究發(fā)現(xiàn)空氣傳播具有極高的可信度,報(bào)告中詳細(xì)列舉了相關(guān)證據(jù)。”麥金泰爾教授是受邀與中國(guó)疾控中心合作開(kāi)展該項(xiàng)研究的國(guó)際團(tuán)隊(duì)成員之一。
之前的研究證實(shí),在新冠肺炎患者使用過(guò)的馬桶上、醫(yī)院護(hù)士站的空氣中、排氣口等多個(gè)位置都發(fā)現(xiàn)了新冠病毒的基因物質(zhì)。昆士蘭科技大學(xué)的莫拉斯卡表示,糞便氣溶膠流導(dǎo)致人們感染新冠病毒的程度,目前仍是未知數(shù)。
她表示:“有許多不同尋常的情況,可能會(huì)發(fā)生各種各樣的事情?!彼鴧⑴c研究淘大花園事件??茖W(xué)家應(yīng)該研究“異常的情況”,因?yàn)橥ㄟ^(guò)了解這些情況,他們可能發(fā)現(xiàn)“這些情況并不罕見(jiàn)?!保ㄘ?cái)富中文網(wǎng))
在中國(guó)廣州市一間無(wú)人居住的公寓衛(wèi)生間里,研究人員發(fā)現(xiàn)了新冠病毒。這表明,空氣中的病原體可能沿著下水管道向上飄浮,與17年前香港SARS病毒大規(guī)模爆發(fā)的情形類似。
中國(guó)疾病預(yù)防控制中心的研究人員本月在《國(guó)際環(huán)境》雜志(Environment International)上發(fā)表的一份研究報(bào)告稱,今年2月,在一間長(zhǎng)期空置的公寓內(nèi)的洗手槽、水龍頭和花灑手柄上均發(fā)現(xiàn)了SARS-CoV-2病毒的痕跡。而在這間被病毒污染的衛(wèi)生間樓下,有五名住戶在不久前被確診感染了新冠病毒。
科學(xué)家對(duì)此進(jìn)行了“現(xiàn)場(chǎng)跟蹤模擬實(shí)驗(yàn)”,以確認(rèn)病毒是否會(huì)通過(guò)馬桶沖力形成的微小氣載顆粒物在污水管道中傳播。他們?cè)诖_診病例住戶樓上10層和12層的衛(wèi)生間里都發(fā)現(xiàn)了這種顆粒物——?dú)馊苣z。2月初,這兩層樓分別出現(xiàn)了兩例確診病例,因此住戶們開(kāi)始擔(dān)心,從糞便中產(chǎn)生的載有新冠病毒的顆粒物可能已通過(guò)下水管道飄進(jìn)自己家中。
這份最新報(bào)告不由讓人回憶起20年前香港私人住宅淘大花園的案例。當(dāng)時(shí),這棟住宅有329位住戶被傳染了嚴(yán)重急性呼吸道綜合征(SARS),部分原因就是有問(wèn)題的污水管道。淘大花園事件造成了42名住戶死亡,是SARS疫情受災(zāi)最嚴(yán)重的社區(qū)。而SARS的罪魁禍?zhǔn)淄瑯邮且环N冠狀病毒。
中國(guó)疾病預(yù)防控制中心環(huán)境與人口健康重點(diǎn)實(shí)驗(yàn)室的科學(xué)家唐宋與同事在報(bào)告中引用了此前未公布的數(shù)據(jù)。報(bào)告稱:“雖然不能排除因?yàn)楣灿秒娞輦鞑ゲ《镜目赡埽敬窝芯颗c2003年香港淘大花園事件的研究結(jié)果一致?!?/p>
澳大利亞昆士蘭科技大學(xué)空氣質(zhì)量與健康國(guó)際實(shí)驗(yàn)室的主任莉迪亞·莫拉斯卡表示,多層建筑內(nèi)的公寓可能通過(guò)共用的廢水系統(tǒng)相連。莫拉斯卡說(shuō),雖然在污水管道中固體和液體會(huì)向下沉降,但管道內(nèi)的氣體通常會(huì)有明顯的氣味,會(huì)通過(guò)沒(méi)有足夠多水的管道向上飄浮。莫拉斯卡沒(méi)有參與本次研究。
莫拉斯卡在接受采訪時(shí)表示:“如果有氣味,意味著空氣已經(jīng)傳播到了不應(yīng)該去的地方?!?/p>
呼吸道飛沫
據(jù)世界衛(wèi)生組織稱,新冠病毒主要通過(guò)呼吸道飛沫傳播,包括飛濺的口水或從鼻腔中噴出的飛沫。但在新冠疫情爆發(fā)的最初幾周,中國(guó)科學(xué)家曾經(jīng)表示在新冠肺炎患者的糞便中發(fā)現(xiàn)了具有傳染性的新冠病毒,也可能在病毒傳播中發(fā)揮了作用。2月,經(jīng)過(guò)對(duì)廣東省73名新冠肺炎住院患者的研究發(fā)現(xiàn),超過(guò)一半患者的糞便病毒檢測(cè)呈陽(yáng)性。
中國(guó)疾控中心的科學(xué)家表示,之前的研究已經(jīng)證明,沖馬桶這一過(guò)程會(huì)從排泄物中產(chǎn)生含有細(xì)菌的氣溶膠。特別是在封閉的、通風(fēng)不暢的空間內(nèi),這些顆粒物能長(zhǎng)時(shí)間懸浮在空中,傳播距離超過(guò)1米(3英尺)。
香港大學(xué)公共衛(wèi)生學(xué)院病毒學(xué)專業(yè)客座教授裴偉士表示,在SARS疫情期間曾經(jīng)出現(xiàn)過(guò)糞便氣溶膠傳播,新冠病毒也可能會(huì)偶爾出現(xiàn)這種情況,這取決于下水道系統(tǒng)。他說(shuō),中國(guó)疾控中心的研究發(fā)現(xiàn)了病毒的痕跡,“這與傳染性病毒是兩回事。但我們不能對(duì)這種病毒傳播的可能性掉以輕心。”
糞便氣溶膠流
研究顯示,在淘大花園事件中,一位SARS患者通過(guò)糞便和尿液排出了“超高濃度”的病毒,他的衛(wèi)生間里溫暖潮濕的空氣在通風(fēng)井中形成了一股氣流,將空氣中的病毒傳播到了其他公寓。
中國(guó)疾控中心的研究人員表示,雖然馬桶是日常必需品,但“如果使用不當(dāng),尤其是在醫(yī)院中,它們可能增加糞便生成的氣溶膠傳播?!毖芯咳藛T引用的流體動(dòng)力學(xué)模擬結(jié)果顯示,在沖馬桶時(shí)“有大量含有病毒的氣溶膠顆粒向上噴出”,導(dǎo)致病毒在室內(nèi)大范圍傳播。
悉尼新南威爾士大學(xué)的全球生物安全教授雷娜·麥金泰爾表示:“研究發(fā)現(xiàn)空氣傳播具有極高的可信度,報(bào)告中詳細(xì)列舉了相關(guān)證據(jù)?!丙溄鹛柦淌谑鞘苎c中國(guó)疾控中心合作開(kāi)展該項(xiàng)研究的國(guó)際團(tuán)隊(duì)成員之一。
之前的研究證實(shí),在新冠肺炎患者使用過(guò)的馬桶上、醫(yī)院護(hù)士站的空氣中、排氣口等多個(gè)位置都發(fā)現(xiàn)了新冠病毒的基因物質(zhì)。昆士蘭科技大學(xué)的莫拉斯卡表示,糞便氣溶膠流導(dǎo)致人們感染新冠病毒的程度,目前仍是未知數(shù)。
她表示:“有許多不同尋常的情況,可能會(huì)發(fā)生各種各樣的事情?!彼鴧⑴c研究淘大花園事件??茖W(xué)家應(yīng)該研究“異常的情況”,因?yàn)橥ㄟ^(guò)了解這些情況,他們可能發(fā)現(xiàn)“這些情況并不罕見(jiàn)?!保ㄘ?cái)富中文網(wǎng))
The discovery of coronavirus in the bathroom of an unoccupied apartment in Guangzhou, China, suggests the airborne pathogen may have wafted upwards through drain pipes, an echo of a large SARS outbreak in Hong Kong 17 years ago.
Traces of SARS-CoV-2 were detected in February on the sink, faucet and shower handle of a long-vacant apartment, researchers at the Chinese Center for Disease Control and Prevention said in a study published this month in Environment International. The contaminated bathroom was directly above the home of five people confirmed a week earlier to have COVID-19.
The scientists conducted “an on-site tracer simulation experiment” to see whether the virus could be spread through waste pipes via tiny airborne particles that can be created by the force of a toilet flush. They found such particles, called aerosols, in bathrooms 10 and 12 levels above the COVID-19 cases. Two cases were confirmed on each of those floors in early February, raising concern that SARS-CoV-2-laden particles from stool had drifted into their homes via plumbing.
The new report is reminiscent of a case at Hong Kong’s Amoy Gardens private housing estate almost two decades ago, when 329 residents caught severe acute respiratory syndrome, or SARS, in part because of faulty sewage pipelines. Forty-two residents died, making it the most devastating community outbreak of SARS, which is also caused by a coronavirus.
“Although transmission via the shared elevator cannot be excluded, this event is consistent with the findings of the Amoy Gardens SARS outbreak in Hong Kong in 2003,” Song Tang, a scientist with the China CDC Key Laboratory of Environment and Population Health, and colleagues wrote in the study, which cited unpublished data from the health agency.
Apartments in multistory buildings may be linked via a shared wastewater system, said Lidia Morawska, director of the International Laboratory for Air Quality and Health at Australia’s Queensland University of Technology. While solids and liquids descend the network, sewer gases -- often detectable by their odor -- sometimes rise through pipes in the absence of sufficient water, said Morawska, who wasn’t part of the research team.
“If there’s smell, it means that somehow air has been transported to where it shouldn’t go,” Morawska said in an interview.
Respiratory Droplets
SARS-CoV-2 spreads mainly through respiratory droplets -- spatters of saliva or discharge from the nose, according to the World Health Organization. Since the first weeks of the pandemic, however, scientists in China have said infectious SARS-CoV-2 virus in the stool of COVID-19 patients may also play a role in transmission. A February study of 73 patients hospitalized with the coronavirus in Guangdong province found more than half tested positive for the virus in their stool.
Previous research has shown that toilet flushes can generate germ-laden aerosols from the excreta, the China CDC scientists said. Those particles can remain in the air for long periods and be dispersed over distances of more than 1 meter (3 feet), particularly in confined, poorly ventilated spaces.
Fecal aerosolization occurred with SARS, and it’s possible that it may rarely occur with SARS-CoV-2, depending on sewage systems, said Malik Peiris, chair of virology at the University of Hong Kong’s School of Public Health. The China CDC study found traces of virus, “which is not the same thing as infectious virus,” he said. “But one has to keep the possibility in mind.”
Fecal Plume
In the Amoy Gardens case, warm, moist air from the bathroom of a SARS patient excreting “extremely high concentrations” of virus in feces and urine established a plume in an air shaft that spread the airborne virus to other apartments, research showed.
Although toilets are a daily necessity, they “may promote fecal-derived aerosol transmission if used improperly, particularly in hospitals,” the China CDC researchers said. They cited a fluid-dynamics simulation that showed a “massive upward transport of virus aerosol particles” during flushing, leading to large-scale virus spread indoors.
“The study finds high plausibility for airborne transmission and outlines the evidence in great detail,” said Raina MacIntyre, professor of global biosecurity at the University of New South Wales in Sydney, who was part of an international team invited to collaborate with China CDC on the study.
Previous investigations confirmed that SARS-CoV-2 genetic material was found on toilets used by COVID-19 patients, in the air in hospital nurses’ stations, on air outlet vents, and multiple other sites. The extent to which fecal aerosol plumes are infecting people with the SARS-CoV-2 virus isn’t known, said Queensland’s Morawska.
“There are lots of situations where things happen and are pretty unusual,” said Morawska, who was part of a team that studied the Amoy Gardens contagion. Scientists should investigate the “unusual situations” because, by understanding them, they may find “they’re not that unusual.”