Three people have died after a suspected outbreak of hantavirus on a cruise ship in the middle of the Atlantic ocean. At least one other passenger is in intensive care in South Africa.

The World Health Organization announced the deaths in a social media statement on Monday, along with one confirmed case of the rare disease. Authorities are investigating another five suspected cases among passengers travelling on the MV Hondius.

So, what is hantavirus? And why can it be so deadly?

As the investigation unfolds, here’s what we know.

What is hantavirus?

Hantavirus is a rare but severe respiratory illness that can cause severe bleeding, fever and even death.

The virus is spread by rodents, such as mice and rats, mainly through the urine and droppings of infected animals.

Hantavirus does not typically spread from person to person. However, in rare cases it may spread between people.

Globally, there are an estimated 150,000 to 200,000 cases of hantavirus each year.

It is less contagious than airborne viruses such as COVID and influenza, as it typically does not spread from person to person.

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Read more: What is a virus? How do they spread? How do they make us sick?

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What makes it so deadly?

There are two main types of hantavirus, each with different symptoms.

Hantavirus pulmonary syndrome, which affects the lungs, is mainly found in the United States. If a person becomes infected with this type of hantavirus, within days they will likely experience coughing and shortness of breath.

As the illness progresses, they can develop symptoms such as fatigue, fever and muscle aches. They may also get headaches, dizziness, nausea, vomiting and abdominal pain. This is the most deadly kind of hantavirus. Tragically, about 38% of people who develop these symptoms die from the disease.

Hemorrhagic fever with renal syndrome is mainly found in Europe and Asia, but the strain known as the Seoul virus has spread around the world. This form of hantavirus mainly affects the kidneys.

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People usually develop symptoms within two weeks of being exposed to this virus. Early symptoms include severe headaches, abdominal pain, nausea and blurred vision. More advanced symptoms include low blood pressure, internal bleeding and even acute kidney failure. This disease can be caused by different viruses and some are more deadly than others, meaning between 1% and 15% of cases can be fatal.

Unfortunately, there is no specific treatment or cure for either type of hantavirus. However, early medical treatment may increase a person’s chance of survival. This can include using respirators, oxygen therapy and dialysis.

Authorities are still investigating which type of hantavirus the passengers were exposed to.

How did it get on a cruise ship?

In a closed environment such as a cruise ship, there are two possible ways passengers could have contracted hantavirus.

One is being exposed to the virus while on a shore excursion.

The other possibility is that rodents may have entered the ship on cargo, and then spread the disease to passengers through their infected urine or droppings. Other factors such as hygiene standards and food storage practices may have caused the infection to spread more quickly.

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Read more: How do viruses mutate and jump species? And why are ‘spillovers’ becoming more common?

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To contain this suspected outbreak, authorities must first ensure any rodents are safely contained and removed from the ship. They should then monitor all passengers for hantavirus symptoms. The virus is diagnosed with a PCR test, similar to those used to diagnose viruses such as COVID.

Given there is no specific treatment for the disease, authorities must help any infected passengers manage their symptoms. This involves checking that they are breathing normally and their kidneys are functioning properly.

So, how worried should we be?

Although alarming, cases of hantavirus remain are extremely rare. But it can look similar to other respiratory illness, so you should always get symptoms checked. If you’ve been in regions where the virus is found and experience shortness of breath, fever or any other flu-like symptoms, see your GP.

Thomas Jeffries does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

You are more empowered because you get to be seen for who you are.

These are the words of Link*, an online gamer with disability – one of a group of 15 gamers with disability we interviewed as part of our new study, published in the Journal of Disability and Social Justice.

Our study aimed to better understand what online gaming offers people with a disability. And Link’s experience highlights one of its key findings: online gaming acts as a powerful space of empowerment, largely due to participants having control over how they identify within online spaces.

A diversity of gaming experiences

Online gaming does have its problems. These include extremist gaming cultures, exploitative monetisation practices (including gambling-like features), and concerns about addiction.

But the prominence of these narratives can overshadow the diversity of gaming experiences, including the potential of online gaming to cultivate spaces for personal growth and development.

It can also allow people – especially those from marginalised groups – to creatively express their identity in a way they wouldn’t otherwise be able to.

Taking a closer look

We wanted to take a closer look at this in our study by focusing on the empowering impact of online gaming for people with disability – and exploring whether such empowerment extends beyond the online space into other parts of everyday life.

To do this we interviewed 15 people (14 male, 1 female) online. The study focused on young adults aged between 18 and 35 who live with a disability.

The positive impacts of online gaming come from the opportunity online gaming provides to connect to a diversity of people online through shared interests. One of our interviewees, Cloud*, emphasises this point:

There is a lot of disabled-focused communities that have gaming channels and I think it’s great because it brings the community together.

Our research found that the positive influence of online gaming on people’s lives wasn’t just confined to the online space. As Link told us:

I think there can be that confidence boost, especially if you’re good at doing something particular in that game, I think it can give you that sort of translation to the real world.

So, people with disability can take that confidence from online gaming into their daily lives, which is impactful.

The anonymity offered in online spaces allowed participants to construct and express an identity with great control – where a space was created that highlighted other unique parts of their identity, rather than just their disability. As Mario* said:

You can create your own character and just be who you want to be.

This was echoed by Cloud:

Freedom to express yourself and do things that you wouldn’t be able to do in the real world […] You can do whatever you want, you can feel powerful.

These comments speak to the limitations people with disability experience in society while also demonstrating how powerful online gaming can be. They reiterate the importance of having agency around how you identify made possible through the anonymity that online gaming provides. As Cloud puts it:

[Online gaming] has allowed me to feel like I’m just a normal human being who can interact with anyone and be a part of a community.

A sense of expressing identity freely and confidently without feeling isolated and judged. Ultimately, that is empowering.

Playing without limitation

Notwithstanding the narratives of harm, it’s important that people with disability have full inclusion in the online gaming world in terms of access and adaptability, which includes accessible interfaces and devices.

However, it is important to note that accessible options can be quite costly, especially adaptive controllers.

Gaming is a permanent fixture in our lives. It can have profound benefits for people with disability by helping them construct their full identity. We should ensure people with disability can play without limitation and showcase their empowered selves.

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*Names have been changed for privacy reasons.

The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.

Each animal species has an optimal temperature at which it can metabolise food and its immune system can best fight off pathogens.

As our recent research shows, temperature directly affects the immune systems of vertebrates – regardless of how they moderate their own body temperatures. At first, slightly hotter temperatures actually give many animal immune systems a boost. But when temperatures get still hotter, conditions favour pathogens – organisms which cause disease.

This is a real problem, given many pathogens found in warmer areas are likely to expand their range as the climate changes.

The good news: learning more about how temperatures affect animal immune systems gives us new options, such as using “frog saunas” to help frogs fight off the lethal chytrid fungus.

How do animals maintain body temperatures?

Different types of vertebrates have very different ways of maintaining an optimal body temperature.

Mammals and birds are endotherms. In cold conditions, they can keep their body temperature close to optimal by burning energy stored as fat. Animals such as reindeer are able to live in temperatures as low as -40°C while keeping their core body temperature at 38-40°C.

At the other extreme are snakes, lizards and other poikilotherms – so-called “cold blooded” animals who rely on the environment to modify their temperature. If they’re too cold, they seek the sun. If too hot, they seek the shade.

Regardless of the method, the goal is the same: keep body temperature as close to optimal as possible.

Pathogens have temperature preferences too

Pathogens are very diverse. Some prefer hotter conditions and others cooler. For some, high temperatures can stop them replicating. But for others, heat is great. The lethal Ebola virus replicates best at 41°C.

The rhinoviruses which cause the common cold prefer the slightly cooler temperatures (33°C) found in human airways.

In birds, outbreaks of lethal H5N1 avian influenza have been shown to come shortly after a large sudden drop in temperatures.

The fungus causing devastating white-nose syndrome in bats likes colder temperatures of 12-16°C. When bats hibernate, their body temperatures drop and their immune response isn’t as strong. This is when the fungus can invade.

Most fish species are poikilotherms. If they move into water colder than their optimal, their immune defences are lowered and they’re more susceptible to pathogens such as viral haemorrhagic septicaemia virus or the bacteria Flavobacterium psychrophilum causing coldwater disease.

Frogs and other amphibians are now declining globally. A major cause is the disease chytridiomycosis caused by the chytrid fungus. The disease is implicated in at least 90 extinctions. This fungus lives in water or damp soil and prefers the cold. As the world heats up, the fungus will likely gain access to new water bodies – and amphibian hosts.

Researchers found leopard frogs (Rana yavapaiensis) living in warmer water were infected less than those in colder water. Australian researchers are now building “frog saunas” which let infected frogs kill off the infection.

How does temperature affect animal immune systems?

When an animal’s body temperature is lower than optimal, it can’t mount as strong an immune defence against specific pathogens. Interestingly, we found this effect only seems to impair specific defences, while the animal’s innate defences aren’t affected.

Ground squirrels and many other species can go into short hibernation periods known as torpor. In this state, their metabolism slows down, body temperature drops and reduces numbers of cells and molecules responsible for specific immune defences circulating. In most cases, the lower body temperature also stops pathogens from replicating. Once an animal leaves the torpor state and its body warms up, its specific immune responses bounce back.

How does this work? When temperatures fall, changes take place in the physical structure of the molecules necessary to mount a specific defence against a pathogen, making an immune response impossible. For instance, the major histocompatibility complex, a key immune molecule found in almost all vertebrates, loses the ability to bind to other immune system molecules in the cold.

Heat acts differently. Humans and all other endotherms can induce a fever, which means the immune system raises the body temperature to stop an invading bacterium, virus or other pathogen from replicating. Fevers put most pathogens at a disadvantage and triggers specific immune responses. But too much heat is a problem, as it can stress the body or even kill. Luckily, special molecules called heat shock proteins can buffer cells against heat and help restore the proteins needed to induce a specific immune response.

Lizards, fish and other poikilotherms can’t increase their own body temperature. Instead, when they get an infection, they employ “behavioural fever” – moving to warmer environments to boost their immune response.

Can we use this to protect species?

Knowledge of how temperature affects animal immune systems lets us plan new ways of protecting threatened species.

We can use heat or cold to change body temperatures and trigger immune responses, or to stop pathogens replicating.

But as climate change intensifies, rapid temperature changes will bring many unwelcome changes for animals. Heat-loving pathogens such as malaria will expand their range, as will cold-hating parasites such as ticks. Milder winters in Canada and the United States, for instance, are letting winter ticks survive the cold. These blood-sucking parasites are now killing many young moose.

The more we understand about how temperatures and animal immune systems intersect, the better we are placed to help animals whatever is to come.

Brian Dixon receives funding from the Natural Sciences and Engineering Research Council of Canada

Julie Old does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.