Zoonoses are infectious diseases that are transmitted from animals to people. The Coronavirus is the fourth pandemic of zoonotic origin of the XXI century. SARS, Avian Flu (H5N1), Swine Flu (H1N1) and now COVID-19.
After the turn of the millennium, the specialists were optimistic. They considered that diseases originating in remote eastern countries, could not affect the West if adequate protocols were established and thanks to its developed health systems and the specialization of its medical professionals.
They were wrong, of course, and the evidence points to this not being the last time. Sarah Gilbert is the scientist leading a 300-person team working on the Oxford-AstraZeneca vaccine. She managed to “advance many of the steps in vaccine development that normally take about five years, and we have done it in four months,” she added.
As one of the more than 136 candidates, their vaccine is one of the few that are in the final clinical phase of studies, the long-awaited Phase 3. In the race to end the pandemic, Gilbert’s development is listed as one of the most advanced in the world.
And now, the English scientist warned that it is possible that there will be more outbreaks of zoonotic origin in the future, due to factors that make viruses spread faster, such as population growth, international travel and deforestation.
The origin of zoonotic infections
The exact origin of COVID-19 is currently unknown, but the scientific consensus suggests that it all started in bats before jumping to another animal that then passed it on to people. Gilbert, from the Jenner Institute in Oxford, said: “Because of the way things have gone in the world, it is more likely that we will have other zoonotic infections that cause outbreaks in the future. Higher population density, more travel, deforestation – all these things make these outbreaks more likely to occur and then something spreads.”
In July, the UN shared a report that warned on precisely this issue, stressing that outbreaks of such infections will continue to rise unless conservation work is done to protect wildlife. The document analyzes the impact of illegal trafficking in protected species, a crime that moves billions of dollars every year and that attracts organized crime because in many countries the penalties with which it is punished are very low.
The transmission of diseases from animals to humans is facilitated, among other causes, by the destruction of the ecosystem and the trade in wild flora and fauna. “The links between the global health crisis and the illegal exploitation of nature have been in the spotlight since it was suggested that “wet markets” selling wild animals, in this case the pangolin, may have facilitated the passing from COVID-19 to humans”, said the director of the UN Office on Drugs and Crime (UNODC), Ghada Waly.
The pangolin – linked by scientists as one of the origins of the Coronavirus – is the most trafficked protected wild mammal in the world because in Asia both its meat and its scales are appreciated for traditional medicine.
Professor Delia Randolph, a veterinary epidemiologist and lead author of the UN report, described a “very clear trend” since the 1930s that showed that 75 percent of emerging human diseases came from wildlife. Destruction of animal habitats forces them to have closer contact with humans, increasing the risk of disease transmission.
According to the WHO, about one billion cases of disease and millions of deaths occur each year from zoonoses, while 60% of infectious diseases that are reported globally have jumped from animals to humans.
On the other hand, Gilbert, who was involved in the development and testing of a universal flu vaccine, also believes that in the future there will be an outbreak of another powerful flu strain, similar to that observed during the 2017-18 season: “There will be another flu pandemic in the future. It will reappear, but we don’t know what subtype of flu it will be”.
The Oxford group “is reaearching on a universal flu vaccine that would work against all types of flu, be it H1N1, H3N3, [or] H7N7.” Creating this one-size-fits-all vaccine, Gilbert added, would mean that “we would not need to know in advance” about the viral subtype. Until now there has not been a universal flu vaccine approved for general use.