#14,896
My thanks to Dr. Ian Mackay for tweeting the link to a study - published in Emerging Microbes & Infections on February 17th - that raises questions over the wisdom of only using nasopharyngeal swabs to test for COVID-19 cases, and warns of alternative routes of spreading.
As we discussed last week in Problematic Lab Testing For The Novel Coronavirus - some patients repeatedly test negative for the virus - even after they become symptomatic.This - along with a suspected lack of test kits - has led to Hubei Province including thousands of clinically diagnosed cases to their confirmed case counts.
The full report is well worth reading, but I've included the Abstract, and a couple of excerpts from the Discussion below. Follow the link to read it in its entirety.
Molecular and serological investigation of 2019-nCoV infected patients: implication of multiple shedding routes
Wei Zhang,Rong-Hui Du,Bei Li,Xiao-Shuang Zheng,Xing-Lou Yang,Ben Hu, show all
Pages 386-389 | Received 04 Feb 2020, Accepted 07 Feb 2020, Published online: 17 Feb 2020
ABSTRACT
In December 2019, a novel coronavirus (2019-nCoV) caused an outbreak in Wuhan, China, and soon spread to other parts of the world. It was believed that 2019-nCoV was transmitted through respiratory tract and then induced pneumonia, thus molecular diagnosis based on oral swabs was used for confirmation of this disease. Likewise, patient will be released upon two times of negative detection from oral swabs.
However, many coronaviruses can also be transmitted through oral–fecal route by infecting intestines. Whether 2019-nCoV infected patients also carry virus in other organs like intestine need to be tested. We conducted investigation on patients in a local hospital who were infected with this virus.
We found the presence of 2019-nCoV in anal swabs and blood as well, and more anal swab positives than oral swab positives in a later stage of infection, suggesting shedding and thereby transmitted through oral–fecal route. We also showed serology test can improve detection positive rate thus should be used in future epidemiology. Our report provides a cautionary warning that 2019-nCoV may be shed through multiple routes.
(SNIP)
Discussion
Within 1 month of the 2019-nCoV disease outbreak, we rapidly developed molecular and serological detection tools. This is the first molecular and serological study on this virus after the initial identification of 2019-NCoV from 7 patients diagnosed with unidentified viral pneumonia [5]. We detected the virus in oral swabs, anal swabs and blood, thus infected patients can potentially shed this pathogen through respiratory, fecal–oral or body fluid routes. In addition, we successfully applied serology test a large population and showed which could greatly improved detection positive rate.
We show that the current strategy for the detection of viral RNA in oral swabs used for 2019-nCoV diagnosis is not perfect. The virus may be present in anal swabs or blood of patients when oral swabs detection negative. In SARS-CoV and MERS-CoV infected patients, intestinal infection was observed at later stags of infection [7–9].
(SNIP)
In summary, we provide a cautionary warning that 2019-nCoV may be transmitted through multiple routes. Both molecular and serological tests are needed to definitively confirm a virus carrier.(Continue . . . )
We've seen similar problems diagnosing MERS cases over the past eight years, including:
AJIC:Intermittent Positive Testing For MERS-CoV
J. Korean Med Sci: Atypical Presentation Of A MERS Case In A Returning Traveler From Kuwait
JIDC: Atypical Presentation Of MERS-CoV In A Lebanese Patient
A Review Of Asymptomatic MERS Cases
