The United States’ Centers for Disease Control and Prevention (CDC) has issued a health alert after the first case of H5N1 avian influenza, or bird flu, seemingly spread from a cow to a human.

A farm worker in Texas contracted the virus amid an outbreak in dairy cattle. This is the second human case in the US; a poultry worker tested positive in Colorado in 2022.

The virus strain identified in the Texan farm worker is not readily transmissible between humans and therefore not a pandemic threat. But it’s a significant development nonetheless.

Some background on bird flu

There are two types of avian influenza: highly pathogenic or low pathogenic, based on the level of disease the strain causes in birds. H5N1 is a highly pathogenic avian influenza.

H5N1 first emerged in 1997 in Hong Kong and then China in 2003, spreading through wild bird migration and poultry trading. It has caused periodic epidemics in poultry farms, with occasional human cases.

Influenza A viruses such as H5N1 are further divided into variants, called clades. The unique variant causing the current epidemic is H5N1 clade 2.3.4.4b, which emerged in late 2020 and is now widespread globally, especially in the Americas.

In the past, outbreaks could be controlled by culling of infected birds, and H5N1 would die down for a while. But this has become increasingly difficult due to escalating outbreaks since 2021.

Wild animals are now in the mix

Waterfowl (ducks, swans and geese) are the main global spreaders of avian flu, as they migrate across the world via specific routes that bypass Australia. The main hub for waterfowl to migrate around the world is Quinghai lake in China.

But there’s been an increasing number of infected non-waterfowl birds, such as true thrushes and raptors, which use different flyways. Worryingly, the infection has spread to Antarctica too, which means Australia is now at risk from different bird species which fly here.

H5N1 has escalated in an unprecedented fashion since 2021, and an increasing number of mammals including sea lions, goats, red foxes, coyotes, even domestic dogs and cats have become infected around the world.

Wild animals like red foxes which live in peri-urban areas are a possible new route of spread to farms, domestic pets and humans.

Dairy cows and goats have now become infected with H5N1 in at least 17 farms across seven US states.

What are the symptoms?

Globally, there have been 14 cases of H5N1 clade 2.3.4.4b virus in humans, and 889 H5N1 human cases overall since 2003.

Previous human cases have presented with a severe respiratory illness, but H5N1 2.3.4.4b is causing illness affecting other organs too, like the brain, eyes and liver.

For example, more recent cases have developed neurological complications including seizures, organ failure and stroke. It’s been estimated that around half of people infected with H5N1 will die.

The case in the Texan farm worker appears to be mild. This person presented with conjunctivitis, which is unusual.

Food safety

Contact with sick poultry is a key risk factor for human infection. Likewise, the farm worker in Texas was likely in close contact with the infected cattle.

The CDC advises pasteurised milk and well cooked eggs are safe. However, handling of infected meat or eggs in the process of cooking, or drinking unpasteurised milk, may pose a risk.

Although there’s no H5N1 in Australian poultry or cattle, hygienic food practices are always a good idea, as raw milk or poorly cooked meat, eggs or poultry can be contaminated with microbes such as salmonella and E Coli.

If it’s not a pandemic, why are we worried?

Scientists have feared avian influenza may cause a pandemic since about 2005. Avian flu viruses don’t easily spread in humans. But if an avian virus mutates to spread in humans, it can cause a pandemic.

One concern is if birds were to infect an animal like a pig, this acts as a genetic mixing vessel. In areas where humans and livestock exist in close proximity, for example farms, markets or even in homes with backyard poultry, the probability of bird and human flu strains mixing and mutating to cause a new pandemic strain is higher.

The cows infected in Texas were tested because farmers noticed they were producing less milk. If beef cattle are similarly affected, it may not be as easily identified, and the economic loss to farmers may be a disincentive to test or report infections.

How can we prevent a pandemic?

For now there is no spread of H5N1 between humans, so there’s no immediate risk of a pandemic.

However, we now have unprecedented and persistent infection with H5N1 clade 2.3.4.4b in farms, wild animals and a wider range of wild birds than ever before, creating more chances for H5N1 to mutate and cause a pandemic.

Unlike the previous epidemiology of avian flu, where hot spots were in Asia, the new hot spots (and likely sites of emergence of a pandemic) are in the Americas, Europe or in Africa.

Pandemics grow exponentially, so early warnings for animal and human outbreaks are crucial. We can monitor infections using surveillance tools such as our EPIWATCH platform.

The earlier epidemics can be detected, the better the chance of stamping them out and rapidly developing vaccines.

Although there is a vaccine for birds, it has been largely avoided until recently because it’s only partially effective and can mask outbreaks. But it’s no longer feasible to control an outbreak by culling infected birds, so some countries like France began vaccinating poultry in 2023.

For humans, seasonal flu vaccines may provide a small amount of cross-protection, but for the best protection, vaccines need to be matched exactly to the pandemic strain, and this takes time. The 2009 flu pandemic started in May in Australia, but the vaccines were available in September, after the pandemic peak.

To reduce the risk of a pandemic, we must identify how H5N1 is spreading to so many mammalian species, what new wild bird pathways pose a risk, and monitor for early signs of outbreaks and illness in animals, birds and humans. Economic compensation for farmers is also crucial to ensure we detect all outbreaks and avoid compromising the food supply.

C Raina MacIntyre, Professor of Global Biosecurity, NHMRC L3 Research Fellow, Head, Biosecurity Program, Kirby Institute, UNSW Sydney; Ashley Quigley, Senior Research Associate, Global Biosecurity, UNSW Sydney; Haley Stone, PhD Candidate, Biosecurity Program, Kirby Institute, UNSW Sydney; Matthew Scotch, Associate Dean of Research and Professor of Biomedical Informatics, College of Health Solutions, Arizona State University, and Rebecca Dawson, Research Associate, The Kirby Institute, UNSW Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Have you ever heard something that others cannot – such as your name being called? Hearing voices or other noises that aren’t there is very common. About 10% of people report experiencing auditory hallucinations at some point in their life.

The experience of hearing voices can be very different from person to person, and can change over time. They might be the voice of someone familiar or unknown. There might be many voices, or just one or two. They can be loud or quiet like a whisper.

For some people these experiences are positive. They might represent a spiritual or supernatural experience they welcome or a comforting presence. But for others these experiences are distressing. Voices can be intrusive, negative, critical or threatening. Difficult voices can make a person feel worried, frightened, embarrassed or frustrated. They can also make it hard to concentrate, be around other people and get in the way of day-to-day activities.

Although not everyone who hears voices has a mental health problem, these experiences are much more common in people who do. They have been considered a hallmark symptom of schizophrenia, which affects about 24 million people worldwide.

However, such experiences are also common in other mental health problems, particularly in mood- and trauma-related disorders (such as bipolar disorder or depression and post-traumatic stress disorder) where as many as half of people may experience them.

Why do people hear voices?

It is unclear exactly why people hear voices but exposure to prolonged stress, trauma or depression can increase the chances.

Some research suggests people who hear voices might have brains that are “wired” differently, particularly between the hearing and speaking parts of the brain. This may mean parts of our inner speech can be experienced as external voices. So, having the thought “you are useless” when something goes wrong might be experienced as an external person speaking the words.

Other research suggests it may relate to how our brains use past experiences as a template to make sense of and make predictions about the world. Sometimes those templates can be so strong they lead to errors in how we experience what is going on around us, including hearing things our brain is “expecting” rather than what is really happening.

What is clear is that when people tell us they are hearing voices, they really are! Their brain perceives voice experiences as if someone were talking in the room. We could think of this “mistake” as working a bit like being susceptible to common optical tricks or visual illusions.

Coping with hearing voices

When hearing voices is getting in the way of life, treatment guidelines recommend the use of medications. But roughly a third of people will experience ongoing distress. As such, treatment guidelines also recommend the use of psychological therapies such as cognitive behavioural therapy.

The next generation of psychological therapies are beginning to use digital technologies and virtual reality offers a promising new medium.

Avatar therapy allows a person to create a virtual representation of the voice or voices, which looks and sounds like what they are experiencing. This can help people regain power in the “relationship” as they interact with the voice character, supported by a therapist.

Jason’s experience

Aged 53, Jason (not his real name) had struggled with persistent voices since his early 20s. Antipsychotic medication had helped him to some extent over the years, but he was still living with distressing voices. Jason tried out avatar therapy as part of a research trial.

He was initially unable to stand up to the voices, but he slowly gained confidence and tested out different ways of responding to the avatar and voices with his therapist’s support.

Jason became more able to set boundaries, such as not listening to them for periods throughout the day. He also felt more able to challenge what they said and make his own choices.

Over a couple of months, Jason started to experience some breaks from the voices each day and his relationship with them started to change. They were no longer like bullies, but more like critical friends pointing out things he could consider or be aware of.

Gaining recognition

Following promising results overseas and its recommendation by the United Kingdom’s National Institute for Health and Care Excellence, our team has begun adapting the therapy for an Australian context.

We are trialling delivering avatar therapy from our specialist voices clinic via telehealth. We are also testing whether avatar therapy is more effective than the current standard therapy for hearing voices, based on cognitive behavioural therapy.

As only a minority of people with psychosis receive specialist psychological therapy for hearing voices, we hope our trial will support scaling up these new treatments to be available more routinely across the country.

We would like to acknowledge the advice and input of Dr Nadine Keen (consultant clinical psychologist at South London and Maudsley NHS Foundation Trust, UK) on this article.

Leila Jameel, Trial Co-ordinator and Research Therapist, Swinburne University of Technology; Imogen Bell, Senior Research Fellow and Psychologist, The University of Melbourne; Neil Thomas, Professor of Clinical Psychology, Swinburne University of Technology, and Rachel Brand, Senior Lecturer in Clinical Psychology, University of the Sunshine Coast

This article is republished from The Conversation under a Creative Commons license. Read the original article.