Covid-19: the laborious search for the origin of the current virus continues

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The authorities are still awaiting the result of the sequencing of 150 samples sent to South Africa. Much information is still lacking to trace its origin. Without having carried out serological tests around patients considered as leads at the start of this wave, the search for patient zero is much broader.

Since the appearance of the virus in the community on March 5, the question of the origin of the virus has arisen. Is it a variant? Or the original? Where is he from ? Who spread it in the community? More than a month later, while the cases in the community are decreasing significantly for the time being, there is still no answer to the question. Why ?

Before determining who is patient zero, we should know what the specificities of the virus circulating in Mauritius are. For now, the authorities are not in the presence of enough information to confirm its origin, where it comes from and, even less, who is the first patient who has infected the others in the community.

Will we ever find out? Hope lies in the 150 samples of the imported and local cases that were sent two weeks ago to the National Institute of Communicable Diseases (NICD), South Africa, for full sequencing. “I hope the report will be informative”, how-and-she, specifying however that the work will not be easy. It is up to us that the authorities hope to discover, with the results of this batch, which was the first patient to arrive in Mauritius with the virus circulating in the community. The logical next step will then be to establish how he escaped quarantine to spread.

One option to trace patient zero would have been to carry out serological tests around patients considered to be leads at the start of this wave, in particular the man who died on his return from India in January, the pilot tested positive or, again, the atypical case who had been treated at ENT on his return from Australia in November, but who subsequently tested positive again. If antibodies had been detected in their relatives, it would have meant that they were infected with Covid-19 and the avenues of research for the first patient would have narrowed.

But with the vaccination campaign that has started, this option no longer holds. If these relatives have been vaccinated, it will be impossible to determine when the antibodies are dated, as those produced by vaccination, especially with Covaxin, may be similar to those created in reaction to the infection. Then, first of all, the viruses of these patients must be sequenced to determine whether the same virus that infected them is circulating.

But even if the origin of the virus and its provenance have not been determined, Dr Catherine Gaud is categorical on one point: “It is not the South African variant, neither English nor Brazilian.” The virus, says the counselor of Prime Minister’s Office (PMO), is not a known strain and not very widespread in the world.

Another established fact, she continues, is that this strain affects young people a little more. “Very young people, even babies”, specifies Dr Gaud.

The current virus is less virulent, in the sense that it causes a very low number of symptomatic cases and does not seem to cause loss of taste and smell. This information was determined on an observation of the situation and not on the genetic information obtained so far.

No change in management

The information sought is important to understanding the second wave. “But that will not change the way of handling the situation”, says Dr Zouberr Joomaye, spokesperson for National Communication Committee.

Moreover, the search for information on the genesis of this second wave did not begin with the sending of these 150 samples. As a reminder, on March 10, Dr Kailesh Jagutpal revealed that a first batch of 40 samples had been sequenced by a local laboratory and subsequently sent to South Africa for cross-checking. “The results do not really match the results of the South African laboratory. We are no longer waiting for results from the local laboratory ”, adds Dr Catherine Gaud. During one of the press conferences, the only information regarding this first batch that had transpired is that the virus currently raging is strain 20B, a categorization too vague to determine anything.

When can we expect to see the light at the end of the tunnel? Dr Catherine Gaud argues that the results of the 150 samples were due to be received last Wednesday, but the NICD is behind schedule. The organization has not communicated any new date for their submission, but authorities hope they will fall early next week. “In medicine, as long as you do not know, it is better to say it clearly, and not to make only one hypothesis”, she adds.