"H5N1 is breaking all the patterns we previously knew about bird flu"

70% of emerging human diseases are of animal origin, that is, they are due to pathogens that have managed to make a 'jump' between different species. We have a very close example of this microbiological 'pirouette': SARS-CoV-2, which came from a bat and managed to quickly adapt to humans..

Unfortunately, Covid has not been and will not be the only threat of these characteristics that we will have to face.. The risk of zoonoses will not only not decrease, but will most likely increase in the future, spurred by the climate emergency, globalization and phenomena such as deforestation..

It is remembered by the professor of Microbiology Ignacio López-Goñi, the doctor in Veterinary Medicine Elisa Pérez-Ramírez and the professor in Pharmacy Gorka Orive in Global Health (Ediciones B), a work in which the three experts explain to what extent health is interconnected animal, human and environmental and emphasize that the way to face the challenges that zoonoses will pose in the future is to implement a global health strategy – the so-called 'one health' – that integrates the three aforementioned disciplines..

“Since the Covid pandemic there have been important advances. Above all, at the institutional level, steps have been taken to achieve what we need, that human, animal and environmental health are interconnected, but there is still a long way to go to go from theory to practice,” says Pérez-Ramírez, who gives a clear example of the benefits achieved with a 'one health' strategy.

“With the West Nile virus, surveillance is carried out on mosquitoes, birds and horses, for example in Doñana, where there is circulation of the virus. This surveillance allows for early warning because there is sufficient evidence that three weeks before outbreaks begin to appear in humans, warning signs can already be detected in animals.. “These data would allow us to implement a series of prevention measures to reduce the risks to people.”.

“Human health is still considered a closed field. We still need to do this interconnection exercise, also at an academic level, because it is not in the study plans, there is no talk of 'one health',” says Orive, with whom López-Goñi also agrees..

“It would also be essential for there to be more coordination between the Ministries involved, Health, Agriculture and Environment. An inter-ministerial office is needed to facilitate coordination,” adds the microbiologist, who considers “a mistake that veterinarians do not depend on Health today.”.

The threat of zoonotic flu

If they had to bet on which pathogen is the most adept candidate to star in the next pandemic, all three place zoonotic flu as one of the most palpable threats.

“Flu viruses meet many of the necessary requirements to be considered a pandemic risk,” summarizes Pérez-Ramírez..

The H5N1 subtype, he explains, “is breaking all the patterns that we previously knew about avian flu, affecting on a practically global scale, with mortalities never seen before in species that traditionally did not suffer from the disease and with outbreaks that last all year round.”. Fortunately, it seems that it is still not very effective in the jump to humans, but the powerful epidemiological changes that it has experienced in just over two years place us in a scenario of very great uncertainty.. And putting viruses and uncertainty together is always a little risky,” he reflects..

In this sense, the authors are in favor of closely monitoring the evolution of the virus and minimizing the risks, such as those posed by mink breeding farms, where it has already been shown that reverse zoonoses can occur, that is, contagion. mutual between animals and humans.

“Raising carnivores and, specifically, mustelids at very high densities and with low biosafety measures is a ticking bomb and in recent years we have been having many warnings,” says Pérez-Ramírez..

“With Covid it was already shown not only that humans transmitted it to minks, but that the animals replicated the virus at full speed, generated many adaptation mutations and were capable of returning the infection back to humans.. This was a warning, but we recently had another huge scare with bird flu, with a very large outbreak that occurred on a farm in Galicia. Luckily, the workers were not affected, but the risk was very high.. I don't know what else is needed for action to be taken.. “In my opinion, the risks to public health that these types of farms pose do not at all outweigh the benefits that can be obtained from them.”.

“The mosquito is the most dangerous animal on the planet”

Although they do not occupy these first positions in the pools for a new pandemic, we must also be very attentive to pathogens transmitted by arthropods, specialists say..

“The mosquito is the most dangerous animal on the planet. It causes more than 725,000 deaths each year as it transmits hundreds of pathogens, such as malaria, dengue, yellow fever, chikungunya or the aforementioned West Nile virus..

“Some of these viruses, which seemed very far away to us a few years ago, are already knocking on our door,” they point out.. In Europe, the first case of indigenous dengue was reported for the first time in 2010 and since then several local transmissions of the virus have been detected and experts are closely monitoring them..

The danger of bacterial resistance

Another microbiological threat to which we must pay more attention is that posed by bacterial resistance, says Orive.. “It is a problem that is clearly getting worse and for whose solution we do not have clear tools right now.. And it is essential because if antibiotics stop working, we will be facing a turning point,” he says..

“The proliferation of bacteria resistant to antibiotics represents a major global problem,” adds López-Goñi, who recalls that there are many surgical interventions that depend on antibiotics.. “If antibiotics stop fulfilling their function, they may cure our cancer but we could die from an infection caused by a multi-resistant bacteria”.

Today, it is estimated that around 35,000 people die each year in Spain from complications related to infections caused by multi-resistant bacteria; a problem generated by the abuse of antibiotics for decades in both humans and animals.

Both Orive, López-Goñi and Pérez-Ramírez emphasize that the focus must be placed on the possible solutions available to address the microbiological threats we face..

First of all, they emphasize, it is essential to “invest in scientific research” that allows the development of rapid diagnostic methods and new vaccines and treatments for emerging pathogens..

In addition, they also demand cooperation, both between doctors, veterinarians, biologists, environmentalists, etc., as well as between authorities involved in this area.. And, finally, they also remember that international solidarity is necessary. “It's a global health issue. No one will be safe until we all are.”