27 JUL 2020SAVE | EMAIL | PRINT | PDF Some scientists feel that the current Covid-19 pandemic, which has already infected more than 16-million and killed more than 600,000 worldwide, is only a dress rehearsal for an even bigger pandemic.Professor Robert Bragg, researcher in the Department of Microbial, Biochemical and Food Biotechnology, and Professor Aliza le Roux, assistant dean: natural and agricultural sciences and associate professor: zoology and entomology at the University of the Free State (UFS), warn about future pandemics, saying that humans’ interaction with animals and lack of learning from the past are the reasons for this.
Another researcher, Dr Martin Nyaga, senior lecturer/ researcher: next generation sequencing (NGS), agrees with Bragg and Le Roux about new viruses and says viruses will keep emerging due to their general nature.
More pandemics might be on the cards
“There is a feeling among some scientists that this could just be a dress rehearsal for the real big pandemic. Many virologists, including me, have been predicting an influenza pandemic for many years. Mankind has been warned about the coming pandemics for many years, but people seem to want to listen only when they are in the midst of a pandemic.
“The bird-flu virus, Influenza H5N1, has a mortality rate of around 60-65%, but it has not yet developed human-to-human transmission. If it does, we could be in for a really serious pandemic,” says Bragg.
Humans’ need for affordable meat on a regular basis is creating the perfect breeding ground for more diseases like this. “This means our demand for meat is driving cheaper and less controlled agricultural practices, cramming more animals into smaller spaces, feeding them less and less natural fodder.
“Remember mad cow disease? Have you seen chicken batteries? We should not blame ‘exotic’ eating practices, but look at our own. If we could see eating meat as a ‘treat’ and not a daily ‘right’, we can reduce pressure on the environment and reduce the speed at which another zoonotic virus can evolve,” says Le Roux.
Nyaga says that more viruses are possible in other organisms as well. “In as much as research on viral particles continues, more outbreaks are possible within not only the coronavirus domain, but also any other class of organisms. The ever-changing nature of viruses, mainly due to mutations and other mechanisms of genetic diversity, could occur through chain of transmission, including via the intermediate hosts. This kind of antigenic mutations could make the general population vulnerable due to lack of immunity against the new strains of emerging strains or completely novel viruses.”
Origin of SARS-CoV-2 and other diseases
According to Bragg, the previous coronavirus that led to SARS and caused major concerns, also started in a wet food market in China – just like Covid-19. That virus was traced to a civet cat meat. This virus had a very high mortality rate but could only be transmitted when a person showed clinical signs. Therefore, measuring the temperature of people was useful and beneficial.
“There are many other examples of serious human pandemics which was spread from animals to humans. Another good example is the Ebola virus, which has also been traced to people eating bats in Africa. Yet another example is HIV, which is believed to have spread to man as a result of the consumption of chimpanzee meat.
“The most serious has been the 1918 Spanish flu, which started off in pigs and spread to man. All of these have to do with the mistreatment of animals by man.“
Learning from past pandemics
Le Roux says past pandemics can teach us how to respond from a public health perspective. “If we found treatments that worked before, we can use that as a starting point for current treatments. But if we can’t even control human behaviour (learning from past mistakes), think of how much more challenging it is to develop a vaccine against a virus that is so adaptable.”
Prof Bragg adds: “Mankind should also have learned lessons from the 1918 pandemic, but man is notoriously slow at learning lessons from the past. Each generation wants to make their own mistakes. One can only draw parallels from the people who defined lockdown regulations in 1918 to celebrate the end of the First World War and the demonstrations currently underway in the USA.
“The celebrations in 1918 caused more deaths than have occurred during the four years of the First World War. I predict that within a week or two, the number of cases and mortalities in the USA (and around the world) are going to skyrocket,” says Bragg.
Knowing the animals involved
Nyaga explains that identification of the source (reservoir hosts) and the intermediate host(s) is crucial in devising strategies, including palliative measures and designing drugs or vaccines against a potential pathogenic agent such as SARS-CoV-2. This will help in understanding the genomic dynamics and likely immunological responses that could be triggered along the chain of transmission to humans, and more importantly, how the compounds in the therapies can terminate the different stages of viral replication.
Le Roux says she is not sure if a vaccine would be developed based on knowledge of a host species, but there is the possibility that (depending on the species) we can use some of the host’s antibodies to develop our own antibody therapies. “But generally, the knowledge can help more long-term planning on how to avoid future host shifts to humans. If we know where the virus originated, we can study that species or group of species better, and understand how the mutations occurred, etc. It would help us with future prevention more than current mitigation, I think.”
Research in the fight against Covid-19
According to the experts, various research efforts are afoot on the control of the disease. These range from the development of a vaccine, development of antiviral drugs, and the development of monoclonal antibodies or antibody fragments. Research is also needed on improved, faster, and cheaper diagnostic tests to test for the presence of the virus as well as for the detection of antibodies against the virus in people. This last test is needed to demonstrate the efficacy of vaccines as well as people in the population who have recovered from the virus.
Bragg says research on the epidemiology of the virus is also needed. How far it can spread and how long it can survive are critical questions, particularly when talking about social distancing. Much of the current information is based on guesswork. “Worldwide, research efforts are gaining an understanding of the virus and how it is causing disease in humans. If you think that this virus was unknown before December 2019, mankind has very quickly learned a lot about this virus and there are many very interesting articles coming out on what receptors the virus binds to and how the virus causes damage to the host and overcomes the host defence mechanisms.”
Nyaga says while the understanding of SARS-CoV-2 and Covid-19 is still in its infancy, results are already emerging on the molecular dynamics and immunological perspectives of the virus. With the characterisation of the genomic sequences of the virus, it has been possible to design several vaccines, including the inactivated virus, viral vectors, nucleic acid-based and protein-based vaccines. A good number of them are currently under clinical trials for possible WHO qualification towards global use. “Just recently, a clinical trial on one of these vaccines, called ‘the South African Ox1Cov-19 Vaccine VIDA-trial’, was on schedule locally to be championed by the University of the Witwatersrand, Johannesburg,.”
According to him, effective prevention essentially requires an in-depth understanding of the clinical severity of Covid19, the extent of transmission and infection, and the efficacy of treatment options in order to accelerate the development of diagnostics and treatment options.
Bragg says that the socio-economic impact of the virus is very serious at this stage. The final number of human cases and fatalities are still a long way from completion. This virus is going to be with us for quite some time and the mortality rate in some countries with high levels of HIV and TB could become very high.