First the unvarnished fact, without the slightest intention of grabbing brownie points. A scientific letter was published last week in the “Lancet Gastroenterol Hepatol Journal” that reported results of the presence of coronavirus in respiratory and faecal samples confirmed by real time reverse transcription polymerase chain reaction (RT-PCR). Respiratory and faecal samples could be collected from 74 of 98 patients infected with Covid-19 (76% of patient group). Respiratory swabs remained positive for 15.4 days from symptom onset. Faecal samples were positive in 41 (55%) of 74 patients and remained positive for 27.9 days, while the respiratory swabs remained positive for only 16.7 days after first symptom onset. Simply put patients infected with Covid -19 had virus in their stools by an average 11 days more than in their respiratory swabs . However,45% of patients had negative faecal samples, that is almost half of the patients did not have their guts infected with Covid-19. Some crucial observations pointed out by the researchers need to be emphasised; presence gastrointestinal symptoms was not associated with faecal viral positivity; severity of disease was not associated with extended duration of virus in faeces; but importantly there was an association of faecal virus with anti-viral treatment.
The authors of the letter suggest that routine stool sample testing should be done by RT-PCR even after respiratory samples become negative. But they concede that do not know whether the virus in stool is viable based upon RT-PCR testing; and that no case of transmission has been reported by the faecal-oral route with Covid-19 : “which might suggest that infection via this route is unlikely in quarantine facilities, in hospital, or while under self -isolation.” Further studies are obviously needed to to determine viability and infectivity of Covid-19 in faeces. Based upon this scientific letter the plausible conclusions we can draw are the Covid-19 virus is present for more days in faeces, but little is known of the viability and infectivity of this virus. Crucially the letter does NOT mention transmission of Covid-19 by flies anywhere.
The news report by Hindustan Times today quoting a famous Bollywood celebrity therefore comes a surprise. The Hindustan Times elaborates “If the house fly sits on this excreta and then on some food particles and spread the disease.” It is possible this is a hacked tweet. It certainly is not based on any scientific peer reviewed publication. Hindustan Times provides a reference but this is a comment on recommendations for stool transplant from prospective donors, who should be screened for typical Covid-19 symptoms within the previous month, travel to areas infected by Covid -19 or close contact with an infected person. If any of the above are present such a donor must have confirmation by RT-CRP testing. The recommendations would be applicable to all types of donors. Incidentally faecal microbiota transplantation is now successfully being used in the management of recurrent Clostridoides difficile infection.
The study cited by Hindustan Times is not on faecal-oral transmission of Covid-19 but does provide a reference of a study (yet to be proof read) on 73 patients infected with Covid-19 virus. Of the 73n patients about half were stool postive for a duration ranging from 1 day to 12 days. About 23% patients persisted with positive stool samples after respiratory samples had become negative. The authors note that their study provides evidence of gut infection and its “possible” faecal-oral route transmission. Entry into the gastrointestinal tract is by ACE 2 receptors present in the stomach, duodenum and rectum. The CDC recommendation that once a patient has 2 consecutive negative respiratory samples can be considered disease free may not hold because of extended presence of the virus in the gut. But again this paper too does not dare to make specific extrapolations on infectivity by this route.
The global pandemic has brought the planet to standstill. Economies across the world are getting brutally battered. Scientists are scrambling to provide answers. There have been mixed signals regarding the new disease in almost every country. Understandably people are under extremes stress; but it is exactly in such times that we have hold our nerves. It is imperative that we keep our wits about us and gather information from peer reviewed publications in scientific journals. Newspaper headlines albeit interesting could be quite misleading or worse add to the confusion. Never before has the lay public needed to pay more attention (only) to qualified scientists; this hold good for any country, but especially for us in India. Celebrities for all their laudable efforts in disseminating information may inadvertently add to the chaos. We cannot afford a Mr. Idris Elba staring into the camera in all seriousness to announce that he is infected with Covid -19 with his wife (Covid-19 negative) next to him. Obviously Mr. Elba, good enough to be in the James Bond loop for years, is completely unaware that he is sending the wrong message, or he is quite sure he will not transmit the virus to his wife. Silence was never more golden.
The Indian ministry of health has a website up with daily bulletins on the do’s and dont’s regarding the Covid-19 virus.