Författare: Adam Taylor Professor of Anatomy Lancaster University

Oscar-winning actor Gene Hackman and his wife Betsy Arakawa were found dead, along with their pet dog, at their home in Santa Fe, New Mexico in February 2025, sparking intense online speculation about the cause of death.

In March, New Mexico’s chief medical examiner, Dr Heather Jerrell, announced that Hackman, who was in the advanced stages of Alzheimer’s disease, died from hypertensive and atherosclerotic cardiovascular disease – a combination of high blood pressure and a buildup of plaque in the arteries. Arakawa, however, died around a week before her husband from hantavirus pulmonary syndrome – an infection transmitted to humans from rodent faeces, urine and saliva.

It’s unknown how Arakawa contracted hantavirus. Usually, (farmers and forestry workers) are most at risk of exposure to infected rodents.

There are at least 38 recognised species of hantavirus across the world, 24 of which cause disease in humans. It’s considered a rare virus but it’s also likely to be underdiagnosed in many areas of the world because the initial symptoms can be mistaken for cold and flu-like viral infections.

Hantaviruses are typically divided into “old-world” and “new-world” types. Old world hantaviruses are found in Europe and Asia, including the puumala hantavirus, which uses the bank vole as its host, and the Hantaan virus and Seoul virus, carried by the striped field mouse and the common brown rat. These hantaviruses cause haemorrhagic fever with renal syndrome (HFRS) – bleeding from various areas of the body and varying degrees of kidney impairment. Estimated to affect 150,000 people annually, this condition is usually reversible. Some patients may develop nephropathia epidemica – a milder form of the virus.

New world hantaviruses, found in North and South America, result in hantavirus pulmonary syndrome (HPS), which tends to be more severe than HFRS. It affects the lungs and heart, impairing the delivery of oxygen around the body. In North America, the most common type of hantavirus is the sin nombre virus spread by the deer mouse. In South America the andes virus, often carried by the long-tailed pygmy rice rat, is most common.

Hantavirus transmission

The disease is caused by inhaling rodent faeces, urine or saliva – often from disturbing rodent nests and droppings while cleaning. More rarely, hantavirus is transmitted by bites and scratches from infected animals.

A small number of studies have documented human-to-human spread of the andes strain in South America, but a systematic review of the research didn’t find enough evidence of human-to-human transmission.

The incubation period of hantavirus is relatively long, typically two to three weeks, but can be as long as six weeks. This may be why cases are underreported – patients may forget the potential exposure event. Diagnosis is usually based on symptoms and history, although laboratory tests can detect antibodies to hantavirus in human serum.

The virus causes a change in the permeability of the cells that line blood vessels so that fluid leaks out in places it shouldn’t, such as the lungs and kidneys. It also reduces the number of platelets in the blood, reducing blood clotting so that blood leaks from organs and vessels. The hantavirus also appears to prevent apoptosis – when the body kills cells in response viral infection – so the body is unable to get rid of infected cells as efficiently, which prolongs the virus.

The severity of the virus depends on a number of factors, including age and genetic predisposition. People over the age of 70 are most likely to die of hantavirus, while some human leukocyte antigens– the immune system markers that check which cells belong in your body and which do not – show an increased risk of severe disease.

It isn’t known how long immunity following hantavirus infection lasts, but immunoglobulin G antibodies – a type of protein that helps the body fight infections from viruses and bacteria – are likely to protect against subsequent symptomatic infection from the same strain. However, given the large number of hantavirus species, having had one form would be unlikely to protect against catching a different form.

Symptoms

Infection with either old or new world strains start with similar viral symptoms: fever, headache, fatigue, muscle pains, abdominal issues including nausea, vomiting, diarrhoea and abdominal pains. The old and new strains have different disease progression. Both strains should be treated promptly to reduce risk of death.

In old-world infections leading to HFRS, patients move from the generic symptoms to low blood pressure and then reduced urinary output. Patients may need dialysis to protect the kidneys. Those infected will then experience increased urinary output to clear the excess fluid collected in the previous stage of the disease. Finally, patients enter the convalescent phase with fatigue and muscle pains.

In HPS from new-world hantavirus strains, symptoms usually appear within eight weeks of exposure. Three to five days of generic symptoms are followed by rapid deterioration as fluid fills the lungs making breathing difficult. Many patients require mechanical ventilation such as extracorporeal membrane oxygenation – a kind of life support where blood is pumped outside of the body to a heart-lung machine. In the final stage of the disease, urine output will increase significantly as the body attempts to expel excess fluid. With early treatment, most people with HPS fully recover with no lasting effects – but mortality rate can be as high as 40%.

Treatments

Treatment is targeted towards symptom management with oxygen therapy. Antiviral medication ribavirin has shown in trials to be more beneficial for HFRS than HPS. A hantavirus vaccine trailed in South Korea generated a good immune response and was well tolerated for prevention of HFRS but wider results are unclear.

As always, prevention is better than cure and the most effective way to prevent hantavirus infection in humans is to keep surroundings free from rodents. But, this is easier said than done – so cleaning with disinfectant is essential to ensure areas are free of rodent fluids and faeces. Allow disinfectant or bleach to soak the area for at least five minutes before cleaning with absorbent materials. Gloves and a mask, of course, should be worn at all times. Läs mer…

The human body has evolved to shield its vital organs, from the brain’s hard skull and meninges to the ribs and sternum protecting the heart and lungs. Even abdominal structures are safeguarded by muscular layers. In contact sports, understanding these vulnerabilities can give competitors the edge, allowing them to take down an opponent with a knockout or submission.

Head and neck

In many sports, a blow to the head is a quick route to a knockout (KO). Strikes to the side of the head can lead to KOs — and sadly, sometimes death. These blows can rupture vital blood vessels around the brain, triggering rapid bleeding that causes instant symptoms or slowly compresses the brain, leading to a coma and eventual death.

Blows to the chin are usually much more effective for an instant KO. They can generate significant force by rotational acceleration through the brain tissue. They may also result in “diffuse axonal injury”, where the force generated causes long nerves in the brain to stretch or tear.

The neck is often exploited in mixed martial arts (MMA) and jiu-jitsu. The rear-naked choke is one of the more effective, taking 8.9 seconds to render an opponent unconscious. This choke cuts off blood flow to the brain through the two main carotid arteries, which each deliver up to 590ml of blood to the brain per minute.

It takes just nine seconds to render someone unconscious with a rear naked choke.
Marco Crupi/Shutterstock

Unconsciousness from the heart stopping beating can occur in as little as eight seconds. Arteries running through the neck to the brain are also susceptible to direct trauma in combat sports, potentially leading to paralysis or even death.

Nerves and bones

The legs are a key target in combat sports, such as muay thai and MMA. Low kicks to the outside of the thigh and buttock area target the sciatic nerve – the largest nerve in the body. The sciatic nerve supplies muscles on the back of your leg and bottom of your foot.

Although this nerve is rarely permanently injured in most sports, repeated trauma can cause numbness, weakness or paralysis of the muscles it supplies.

Another target is a branch of the sciatic nerve called the common peroneal nerve. It sits underneath a bony bulge on the outside of your leg just below the knee. Repeated targeting of this nerve can result in the inability to stand because the foot drops and the person can’t sense its position or inability to move the affected foot.

Because of the direction of kicks to this area, almost 60% of muay thai fighters report contracture (shortening) of their calf (gastrocnemius) muscle, in response to repeated trauma.

Armbars and ankle locks are also rapid ways to bring things to an end. Armbars involve trapping the arm in such a way that the elbow is in the hyper-extended position, trying to force it beyond straight. On the back of the joint is a large bony bulge called the olecranon, which prevents over-extension.

If an opponent doesn’t “tap out”, the joint cavity and tissues of the elbow sprain or tear or the radius or ulna break.

Ankle locks are often described as one of the most painful locks. This is because, when done properly, it hyper-extends the ankle joint and compresses the achilles tendon, which is the largest and thickest tendon in the body and has many sensory receptors for pressure.

This is further exacerbated because many of the nerves passing through the ankle have little or no protection from muscle or connective tissues and there are 11 ligaments that support the ankle, all now having excessive forces stretch through them.

Abdomen

Attacking the abdomen is common in combat sports as it’s an easier target to hit than the head. There are two blows to this area that can end a fight. Blows to the liver and to the spleen.

The liver sits on the right, protected by the ribs. But hitting the body over or just below this area can send shock waves into the liver that result in instant crippling pain because of the large number of critical nerves that sit behind it. These nerves are responsible for important functions including monitoring organ status and blood vessel diameter.

Some of these punches can result in death from internal bleeding. The liver receives a huge volume of blood: 25% of the heart’s output. Any significant injury can tear the liver, causing fatal blood loss.

A blow to the liver causes extreme pain and can end a fight.
Zuma Press, Inc/Alamy Stock Photo

The left side can have similar consequences, tucked behind the lower ribs at the back on this side is the spleen, a soft and blood-filled organ which is often silently or subtly torn by blunt-force trauma, such as car accidents, contact sports or broken ribs.

It often gives no or vague symptoms and can bleed slowly after the initial injury occurrence, resulting in collapse or death a few hours after the event.

The heart

Commotio cordis is a rare cause of sudden death, occurring most commonly in young male athletes who are struck in the chest. It occurs in the absence of visible heart damage.

This trauma causes a fatal interruption to the electrical activity of the regular heartbeat. The reason that all chest blows don’t result in this outcome is because it is believed to have to happen at a specific part of the electrical conduction through the heart – called the T-wave, which usually accounts for about 1% of the heartbeat cycle time. The T-wave increases with exercise, which is why commotio cordis is usually seen in exercising young athletes.

For commotio cordis to occur, the impact must generate roughly 50 joules of energy, which is roughly equivalent to a baseball travelling at about 40mph.

The illegal stuff

Most of the above blows are allowed in most combat sports. However, some things that occur during fights aren’t. Punching the back of the head – so-called rabbit punches are banned because they can snap the cervical vertebrae at the top of the neck and potentially the spinal cord, which can have significant lifelong injuries, or even death.

Likewise, groin strikes are banned too, they can prevent people from having children and are incredibly painful because of the vast number of highly sensitive nerves that supply that area in men and women.

While reading this may make you wince, it also brings a newfound respect for those athletes who train and repeatedly put themselves through a gruelling regime in these true contact sports. Läs mer…