Correlation of Prevalence of Corona Virus in Sewage with Disease Prevalence in the Netherlands.

[NNadir]

The paper to which I'll refer in this post is this one: Presence of SARS-Coronavirus-2 RNA in Sewage and Correlation with Reported COVID-19 Prevalence in the Early Stage of the Epidemic in The Netherlands. (Gertjan Medema, Leo Heijnen, Goffe Elsinga, Ronald Italiaander, and Anke Brouwer, Environ. Sci. Tech Letters, ASAP June 2020.) It is available as an "as soon as possible" publication and has just been published on line. Like most Covid related scientific papers, this one, provided by the American Chemical Society, of which I am a proud member, is open sourced.

A note: It is well known that some active diseases, for example, polio, can be carried by sewage effluent. My late mother-in-law, one of the last polio victims in the United States, before wide use of the vaccine, contracted the disease after a trip a beach. This paper does not make the claim that this is a mode of transmission, but is rather intended to use an indirect method, the presence of viral RNA in sewage as an estimate of the prevalence of the disease.

From the opening text:

In December 2019, an outbreak of coronavirus respiratory disease (called COVID-19) was detected in Wuhan, China. The outbreak was caused by a new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The outbreak is now widespread, and WHO declared a pandemic on March 11, 2020, when the disease was reported in 114 countries.(1) The primary mode of transmission of SARS-Cov-2 is via respiratory droplets that people produce when they cough, sneeze, or exhale, and the virus may also be spread via fomites.(2) SARS-CoV-2 is 82% similar to the SARS coronavirus that caused an outbreak in 2003. Then, 16%–73% of patients with SARS were reported to have diarrhea in addition to respiratory symptoms,(3) and transmission of SARS through water droplets from faeces via air ventilation systems in Amoy Gardens in Hong Kong was reported.(4) Diarrhea is also reported in a significant proportion of the COVID-19 cases, and recent reports show that SARS-CoV-2 has been detected in stool samples of COVID-19 cases.(5?9) The shedding of SARS-CoV-2 was studied in a cluster of nine cases and was present at 107 RNA copies/stool swab of a gram faeces one week after symptom onset and decreased to 103 RNA copies/swab three weeks after symptom onset.(10) These authors could not detect infectious SARS-CoV-2 in stool samples with high RNA concentrations. Another study(11) reported that in two out of four stool samples with high SARS-CoV-2 RNA concentrations, infective SARS-CoV-2 was detected with cultures combined with electron microscopy. Although it is unlikely that wastewater will become an important transmission pathway for coronaviruses like SARS-CoV-2,(12) increasing circulation of the virus in the population will increase the virus load into the sewer systems of our cities.

A graphic from the paper:



The caption:

Figure 1. Cumulative prevalence of reported COVID-19 cases in the cities that are served by the WWTP from February 27–March 29, 2020.

The full text of the paper, which is again, available, is useful for anyone who is interested in the technology for tracking this sort of thing. Details of the procedure may be found by clicking on the "Supporting Information" link in the paper.

The interesting paper's conclusion:

The testing policy in The Netherlands focused on people with a travel history to Hubei or Italy, people with severe symptoms, and healthcare workers. A study among healthcare workers in The Netherlands indicated that SARS-CoV-2 was already circulating undetected in the community a week prior to February 27, when the first COVID-19 case was reported, suggesting that there is a high prevalence of mild COVID-19 in the community.(25) Recent serological surveys in The Netherlands and elsewhere show that the percentage of people that have been infected with COVID-19 is much higher than reported through clinical surveillance and is in the range of 1%–14%.(26) While absolute estimates of COVID-19 prevalence based on SARS-CoV-2 RNA concentrations in sewage are complex, our data suggest that surveillance of relative changes in SARS-CoV-2 RNA concentrations at the inlet of WWTP over time can serve as a sensitive tool for early warning for increasing virus circulation in the population.

Be safe and healthy.

[soothsayer]

1. I remember early on Fauci I think said it lived

... for days in poop.

And that some places were analyzing sewage to try to track the level of their local outbreak.