Post by Admin on Mar 11, 2023 20:18:09 GMT
The Huanan Seafood Wholesale Market in Wuhan was the early epicenter of the COVID-19 pandemic
Pandemic epicenter
As 2019 turned into 2020, a coronavirus spilled over from wild animals into people, sparking what has become one of the best documented pandemics to afflict humans. However, the origins of the pandemic in December 2019 are controversial. Worobey et al. amassed the variety of evidence from the City of Wuhan, China, where the first human infections were reported. These reports confirm that most of the earliest human cases centered around the Huanan Seafood Wholesale Market. Within the market, the data statistically located the earliest human cases to one section where vendors of live wild animals congregated and where virus-positive environmental samples concentrated. In a related report, Pekar et al. found that genomic diversity before February 2020 comprised two distinct viral lineages, A and B, which were the result of at least two separate cross-species transmission events into humans (see the Perspective by Jiang and Wang). The precise events surrounding virus spillover will always be clouded, but all of the circumstantial evidence so far points to more than one zoonotic event occurring in Huanan market in Wuhan, China, likely during November–December 2019. —CA
Abstract
Understanding how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019 is critical to preventing future zoonotic outbreaks before they become the next pandemic. The Huanan Seafood Wholesale Market in Wuhan, China, was identified as a likely source of cases in early reports, but later this conclusion became controversial. We show here that the earliest known COVID-19 cases from December 2019, including those without reported direct links, were geographically centered on this market. We report that live SARS-CoV-2–susceptible mammals were sold at the market in late 2019 and that within the market, SARS-CoV-2–positive environmental samples were spatially associated with vendors selling live mammals. Although there is insufficient evidence to define upstream events, and exact circumstances remain obscure, our analyses indicate that the emergence of SARS-CoV-2 occurred through the live wildlife trade in China and show that the Huanan market was the epicenter of the COVID-19 pandemic.
On 31 December 2019, the Chinese government notified the World Health Organization (WHO) of an outbreak of severe pneumonia of unknown etiology in Wuhan, Hubei Province, China (1–4), a city of ~11 million people. Of the initial 41 people hospitalized with unknown pneumonia by 2 January 2020, 27 (66%) had direct exposure to the Huanan Wholesale Seafood Market (hereafter, “Huanan market”) (2, 5, 6). These first cases were confirmed to be infected with a novel coronavirus, subsequently named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and were suffering from a disease later named coronavirus disease 2019 (COVID-19). The initial diagnoses of COVID-19 were made in several hospitals independently between 18 and 29 December 2019 (5). These early reports were free from ascertainment bias because they were based on signs and symptoms before the Huanan market was identified as a shared risk factor (5). A subsequent systematic review of all cases reported to China’s National Notifiable Disease Reporting System by hospitals in Wuhan as part of the joint WHO-Chinese “WHO-convened global study of origins of SARS-CoV-2: China Part” (hereafter, “WHO mission report”) (7) showed that 55 of 168 of the earliest known COVID-19 cases were associated with this market. However, the observation that the preponderance of early cases were linked to the Huanan market, alone, does not establish that the pandemic originated there.
Sustained live mammal sales during 2019 occurred at the Huanan market and three other markets in Wuhan, and included wild and farmed wildlife (8). Several of these species are known to be experimentally susceptible to SARS-related coronaviruses (SARSr-CoVs) such as SARS-CoV (hereafter, “SARS-CoV-1”) and SARS-CoV-2 (9–11). During the early stages of the COVID-19 pandemic, animals sold at the Huanan market were hypothesized to be the source of the unexplained pneumonia cases (12–19) (data S1), consistent with the emergence of SARS-CoV-1 from 2002 to 2004 (20), as well as other viral zoonoses (21–23). This led to the decision to close and sanitize the Huanan market on 1 January 2020, with environmental samples also being collected from vendors’ stalls (7, 12, 24) (data S1).
Determining the epicenter of the COVID-19 pandemic at the neighborhood level rather than at the city level could help to resolve whether SARS-CoV-2 had a zoonotic origin, similar to SARS-CoV-1 (20). In this study, we obtained data from a range of sources to test the hypothesis that the COVID-19 pandemic began at the Huanan market. Despite limited testing of live wildlife sold at the market, collectively, our results provide evidence that the Huanan market was the early epicenter of the COVID-19 pandemic and suggest that SARS-CoV-2 likely emerged from the live wildlife trade in China. However, events upstream of the market, as well as exact circumstances at the market, remain obscure, highlighting the need for further studies to understand and lower the risk of future pandemics.
Results
Early cases lived near to and centered on the Huanan market
The 2021 WHO mission report identified 174 COVID-19 cases in Hubei Province in December 2019 after careful examination of reported case histories (7). Although geographical coordinates of the residential locations of the 164 cases who lived within Wuhan were unavailable, we were able to reliably extract the latitude and longitude coordinates of 155 cases from maps in the report (figs. S1 to S8).
Although early COVID-19 cases occurred across Wuhan, most clustered in central Wuhan near the west bank of the Yangtze River, with a high density of cases near to, and surrounding, the Huanan market (Fig. 1A). We used a kernel density estimate (KDE) to reconstruct an underlying probability density function from which the home locations for each case were drawn (25). Using all 155 of the December 2019 cases, the location of the Huanan market lies within the highest density contour that contains 1% of the probability mass (Fig. 1B). For a KDE estimated using the 120 cases with no known linkage to the market, the market remains within the highest density 1% contour (Fig. 1C). The clustering of COVID-19 cases in December around the Huanan market (Fig. 1, B and C, insets) contrasts with the pattern of widely dispersed cases across Wuhan by early January through mid-February 2020 (Fig. 1, D and E), which we mapped using location data from individuals who had used a COVID-19 assistance channel on Sina Weibo, a Chinese social media platform (26). Weibo-based data analyses showed that, unlike early COVID-19 cases, by January and February, many of the sick individuals who sought help resided in highly populated areas of the city, particularly in areas with a high density of older people (Fig. 1E and figs. S9 and S10).
www.science.org/doi/10.1126/science.abp8715
Pandemic epicenter
As 2019 turned into 2020, a coronavirus spilled over from wild animals into people, sparking what has become one of the best documented pandemics to afflict humans. However, the origins of the pandemic in December 2019 are controversial. Worobey et al. amassed the variety of evidence from the City of Wuhan, China, where the first human infections were reported. These reports confirm that most of the earliest human cases centered around the Huanan Seafood Wholesale Market. Within the market, the data statistically located the earliest human cases to one section where vendors of live wild animals congregated and where virus-positive environmental samples concentrated. In a related report, Pekar et al. found that genomic diversity before February 2020 comprised two distinct viral lineages, A and B, which were the result of at least two separate cross-species transmission events into humans (see the Perspective by Jiang and Wang). The precise events surrounding virus spillover will always be clouded, but all of the circumstantial evidence so far points to more than one zoonotic event occurring in Huanan market in Wuhan, China, likely during November–December 2019. —CA
Abstract
Understanding how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019 is critical to preventing future zoonotic outbreaks before they become the next pandemic. The Huanan Seafood Wholesale Market in Wuhan, China, was identified as a likely source of cases in early reports, but later this conclusion became controversial. We show here that the earliest known COVID-19 cases from December 2019, including those without reported direct links, were geographically centered on this market. We report that live SARS-CoV-2–susceptible mammals were sold at the market in late 2019 and that within the market, SARS-CoV-2–positive environmental samples were spatially associated with vendors selling live mammals. Although there is insufficient evidence to define upstream events, and exact circumstances remain obscure, our analyses indicate that the emergence of SARS-CoV-2 occurred through the live wildlife trade in China and show that the Huanan market was the epicenter of the COVID-19 pandemic.
On 31 December 2019, the Chinese government notified the World Health Organization (WHO) of an outbreak of severe pneumonia of unknown etiology in Wuhan, Hubei Province, China (1–4), a city of ~11 million people. Of the initial 41 people hospitalized with unknown pneumonia by 2 January 2020, 27 (66%) had direct exposure to the Huanan Wholesale Seafood Market (hereafter, “Huanan market”) (2, 5, 6). These first cases were confirmed to be infected with a novel coronavirus, subsequently named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and were suffering from a disease later named coronavirus disease 2019 (COVID-19). The initial diagnoses of COVID-19 were made in several hospitals independently between 18 and 29 December 2019 (5). These early reports were free from ascertainment bias because they were based on signs and symptoms before the Huanan market was identified as a shared risk factor (5). A subsequent systematic review of all cases reported to China’s National Notifiable Disease Reporting System by hospitals in Wuhan as part of the joint WHO-Chinese “WHO-convened global study of origins of SARS-CoV-2: China Part” (hereafter, “WHO mission report”) (7) showed that 55 of 168 of the earliest known COVID-19 cases were associated with this market. However, the observation that the preponderance of early cases were linked to the Huanan market, alone, does not establish that the pandemic originated there.
Sustained live mammal sales during 2019 occurred at the Huanan market and three other markets in Wuhan, and included wild and farmed wildlife (8). Several of these species are known to be experimentally susceptible to SARS-related coronaviruses (SARSr-CoVs) such as SARS-CoV (hereafter, “SARS-CoV-1”) and SARS-CoV-2 (9–11). During the early stages of the COVID-19 pandemic, animals sold at the Huanan market were hypothesized to be the source of the unexplained pneumonia cases (12–19) (data S1), consistent with the emergence of SARS-CoV-1 from 2002 to 2004 (20), as well as other viral zoonoses (21–23). This led to the decision to close and sanitize the Huanan market on 1 January 2020, with environmental samples also being collected from vendors’ stalls (7, 12, 24) (data S1).
Determining the epicenter of the COVID-19 pandemic at the neighborhood level rather than at the city level could help to resolve whether SARS-CoV-2 had a zoonotic origin, similar to SARS-CoV-1 (20). In this study, we obtained data from a range of sources to test the hypothesis that the COVID-19 pandemic began at the Huanan market. Despite limited testing of live wildlife sold at the market, collectively, our results provide evidence that the Huanan market was the early epicenter of the COVID-19 pandemic and suggest that SARS-CoV-2 likely emerged from the live wildlife trade in China. However, events upstream of the market, as well as exact circumstances at the market, remain obscure, highlighting the need for further studies to understand and lower the risk of future pandemics.
Results
Early cases lived near to and centered on the Huanan market
The 2021 WHO mission report identified 174 COVID-19 cases in Hubei Province in December 2019 after careful examination of reported case histories (7). Although geographical coordinates of the residential locations of the 164 cases who lived within Wuhan were unavailable, we were able to reliably extract the latitude and longitude coordinates of 155 cases from maps in the report (figs. S1 to S8).
Although early COVID-19 cases occurred across Wuhan, most clustered in central Wuhan near the west bank of the Yangtze River, with a high density of cases near to, and surrounding, the Huanan market (Fig. 1A). We used a kernel density estimate (KDE) to reconstruct an underlying probability density function from which the home locations for each case were drawn (25). Using all 155 of the December 2019 cases, the location of the Huanan market lies within the highest density contour that contains 1% of the probability mass (Fig. 1B). For a KDE estimated using the 120 cases with no known linkage to the market, the market remains within the highest density 1% contour (Fig. 1C). The clustering of COVID-19 cases in December around the Huanan market (Fig. 1, B and C, insets) contrasts with the pattern of widely dispersed cases across Wuhan by early January through mid-February 2020 (Fig. 1, D and E), which we mapped using location data from individuals who had used a COVID-19 assistance channel on Sina Weibo, a Chinese social media platform (26). Weibo-based data analyses showed that, unlike early COVID-19 cases, by January and February, many of the sick individuals who sought help resided in highly populated areas of the city, particularly in areas with a high density of older people (Fig. 1E and figs. S9 and S10).
www.science.org/doi/10.1126/science.abp8715