Jun 03 2021

Return of the Bird Flu

Remember the bird flu? Avian influenza (H5N1) was first discovered in birds in 1996, with the first human crossover detected in 1997. Since then it has been discovered in 50 countries and is endemic in six. If you are old enough to remember, there was a bit of a bird flu panic back in the late 90s. Fortunately, so far, those fears have not been realized. But it’s important to remember that the bird flu is still around. Even more important is to remember that there are thousands of potentially pandemic viruses in the world.

Avian influenza adapted to infect birds, and mostly spreads through poultry. Bird to human transmission (zoonotic infection) is rare, and usually occurs in those who work in the poultry industry with long term exposure. The virus is very deadly, with a case fatality rate of about 60%. Worldwide there are 700 reported human cases. However, the virus does not spread easily from human to human. Such transmission is very rare, and is not sustainable. This is why the virus has not caused an outbreak or worse among humans. There are also other strains of flu virus that primarily infect birds, such as H10N5. We now have the first report of an H10N5 infection in a human, in a poultry worker in China. Contact tracing did not reveal any other cases.

For now we have experienced rare bird to human zoonotic transmission of flu strains primarily adapted to birds (colloquially “bird flu”) without any significant or sustainable human to human spread. So what’s the concern? As was originally raised by in the 90s, the concern is that every time a virus jumps from an animal reservoir to a human there is the potential that it will either mutate or will combine with another virus to cause a new strain that is highly contagious to humans. It happens, as we are now experiencing with the SARS-CoV-2 virus. So what do we do about it?

The world is freshly confronting this question with the COVID-19 pandemic. It’s pretty clear that our global response to this virus was not optimal, to say the least. It is also clear this is not the last pandemic we will face. If anything, pandemics will likely be coming more often than has historically been the case. Some viruses will be less severe than SARS-CoV-2, but others might be worse. There are several big-picture steps we can take to minimize the probability of new pandemics and their impact.

First, we need to evaluate the animal industry in order to minimize viruses spreading through animals, and monitor industry practices to make sure workers are as safe from infection as possible. Each time a virus crosses to a human we are rolling the dice on whether or not this virus will become more infectious and/or deadly. The possibility of a serious bird flu epidemic or even pandemic, for example, may be small but it is non-zero. We also have to limit all zoonotic infections, which means reviewing locations where high density human populations exist close to wild animal populations. Wild animals, not just domestic animals, can be reservoirs for viruses that already can infect humans, or may acquire that ability through mutation or combination.

We also need for every country to acknowledge that preventing and reacting to pandemics is of global concern. A virus which emerges in one country can affect any other country in the world. That should now be undeniable. There is therefore no justification for the attitude that whatever happens in your country with respect to infectious diseases is your business – it’s the world’s business. Right now the World Health Organization (WHO) is the primary institution by which we have international cooperation to fight things like epidemics and pandemics. The WHO has been and remains critical to fighting COVID-19. Sure, they had their failures as well. That is not a reason to abandon the WHO, but rather to shore it up, to make it into the institution we need, with the resources and authority to prevent or mitigate the next pandemic.

This includes establishing international standards and transparency. For example, I don’t think the “lab leak” theory of how COVID-19 emerged is very likely, but it is not impossible. In any case, we need to enforce international standards for any lab that works with potentially contagious viruses. Lab leaks should be as close to impossible as possible, and there should be a standard transparent response when one possibly occurs. No country should have the ability to hide such a leak, so the world can be confident that it hasn’t.

Finally, there needs to be an immediate international response to study and shut down any outbreaks of potentially new viruses. We lost precious weeks with COVID-19, and now we will never know how much death and disruption we could have prevented. By October 2020 the total cost of the COVID-19 pandemic world-wide was $16 trillion. Obviously prevention, even if very expensive, is cost effective. If we could go back now and spend $100 billion dollars or even a trillion dollars to prevent this pandemic, of course we would. But that’s the thing about prevention – you can’t go back in time. You have to do it before the crisis hits.

This latest bird flu case is just a blip. Itself it is of little concern. But it is a reminder of the overall risk of new zoonotic infections, and that even when the COVID-19 pandemic is completely contained (and we are not there yet) the threat will not be over. Hopefully we will fully learn the lessons from COVID-19.

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