NICD’s breakthrough in culturing coronavirus takes SA a step closer to cracking it

Scientists at the National Institute for Communicable Diseases (NICD) have come face-to-face with the local SARS-CoV-2 virus, and independent scientists believe this breakthrough is significant as it brings local scientists one step closer to enhancing South Africa’s capacity to develop diagnostics and anti-viral compounds.

The successful isolation and capturing of the virus was achieved by culturing the virus in a high biocontainment facility, the NICD’s biosafety level 3 (BSL3) laboratory, one of the most advanced integrated high and maximum facility on the African continent.

The successful isolation of the virus was confirmed by observing changes in the cell lines used to grow the virus, called a cytopathic effect (CPE). The NICD explained that confirmation this was indeed SARS-CoV-2 was done by specific diagnostic molecular assay, with the cultured virus spotted and photographed under a high-powered electron microscope.

The virus particle of SARS-CoV-2, with a “crown” of peplomers, characteristic of the coronavirus genus, was cultured from a South African Covid-19 patient. The capacity to culture SARS-CoV-2 from local Covid-19 cases was developed in the past few weeks by Professor Janusz Paweska and his team at the NICD.

“It will allow scientists to better understand the basic virology and pathogenicity of this novel coronavirus and enhance South Africa’s capacity to develop diagnostics and antiviral compounds,” the institute said in a statement.

The scientists added that there was also the possibility of using laboratory-grown virus for the local development of inactivated or live attenuated Covid-19 vaccines and contribute to effective disease prevention and control.

Professor Glenda Davison, head of the biomedical sciences department at Cape Peninsula University of Technology and honorary senior lecturer at the University of Cape Town, said this was “exciting work”.

She said the isolation of the virus was an important breakthrough for South Africa as the structure of the virus and how it operates could now be studied in more detail.

“One important advantage of growing the virus in a laboratory is that scientists can now perform experiments which may lead to the development of a Covid-19 vaccine,” she said.

Dr Atiya Mosam, an independent public health medicine specialist, said this meant the NICD scientists had managed to isolate the local strain of the virus.

She said this was a significant development because as viruses spread, they mutated and may therefore behave differently to the original. For example, they could be more or less contagious.

“Therefore knowing what the local strain is allows us to study the virus and the way it transmits and infects people, which can give us insight into the measures that we need to take,” Mosam said.

Unmasking the enemy

By studying the virus, scientists can answer many questions regarding diseases, for example how the virus causes the disease, but also work to develop and evaluate antivirals to treat infections and vaccines to prevent infection.

This means taking samples that contain the virus and then manipulating it in the laboratory to “draw” the virus from the sample. Viruses are essentially parasites and need live cells to multiply and, in the laboratory, this natural infection process can be mimicked in order to allow a virus to reproduce.

Scientists can then culture it (this means grow more of the virus) by providing artificially the cells that a virus would need to replicate.

According to the NICD, the SARS-CoV2 virus is on average 120 nanometres in diameter and, to compare, a human hair is between 80,000 and 100,000 nanometres wide.

– siphom@citizen.co.za

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