What a case of Hantavirus looks like

Added: 2026-05-12

[00:00:00]Hi Dr. Bernard here. I am going to cover a case  of Hantavirus that was published in Literature in 2025. From the same country where it appears  the 2026 cruise ship incident originated from.

[00:00:10]I am going to cover it as written, and give you  perspective of how we would see this case as if it came through our hospital. I will tell you  a little bit about hantavirus, and why I don’t think overt panic is warranted in context of the  2026 cruise ship incident. And I’ll just tell you my personal advice right now, it’s very simple  and everyone should have been living it anyways: 1) wash your hands often. Before and after  you eat. After meeting with people. And do it as the first thing when you get home. Wash  them thoroughly, for twenty seconds, and do it twice in succession. Think as if you’re a surgeon  and you’re about to do surgery on someone. 2) if you feel sick, and/or have a fever, stay at home.  And 3) if you have trouble breathing, go to the hospital. Simple rules for life in general, I  highly recommend them. JB is a 52-year-old man presenting to the emergency room sweaty and  nauseous. He had hypotension. Hypo meaning low. Tension referring to blood pressure. Low  blood pressure. And he had a fever. When doctors measured his blood oxygen saturation, it was 89%.  Under 90 needs emergency medical attention because it means that the body is suffocating. They  see him sitting there confused, obtunded, and unaware of where he was. These symptoms suggest  his brain is starving of oxygen and something terrible is happening. A chest X-ray reveals his  lungs are filled with fluid. This prevents the oxygen exchange from the air, into his blood,  explaining why he’s suffocating. A blood test confirms he has hypoxemia. Ox referring to oxygen.  And -emia meaning presence in blood. Low oxygen presence in blood. It’s not just low saturation,  the oxygen actually isn’t there. But why is that fluid in his lungs? He might be volume overloaded.  Water has flooded his body and has no where else to go other than to squeeze into his lungs. Or his  lung blood vessels have been leaking. Or there’s an infection in his lungs. Some of these will take  time to confirm. But doctors need to do something NOW. JB was given supplemental oxygen. Air is  only 21% oxygen. Vastly increasing the amount of oxygen per inhalation should ameliorate some  of the hypoxemia. And this buys some time. But as the hours pass, it stops working. JB’s oxygen  saturation decreases. Something very bad is happening to him. And it’s happening very quickly.  And, it’s getting worse. He’s transferred to the intensive care unit. JB is sedated. A tube is  placed down his throat so that a machine can breathe for him. But as the hour passes, JB  goes into shock. His blood pressure suddenly drops even more. This means that blood can’t  get to all of his organs. But most importantly, it cant get in to his brain. If oxygen already  wasn’t getting into his brain adequately because he had hypoxemia, then, adding severe hypotension  on top means that there’s seconds to minutes left before his brain suffers permanent damage..  Because oxygen makes energy production happen in cells. Normal blood flow and breathing helps  clear out the wastes produced by brain cells.

[00:03:01]When that mechanism no longer functions, JB’s  brain will cease to exist. 2 medicines were immediately given. The first one constricts his  blood vessels and forces his heart to beat harder.

[00:03:11]The second one tells his kidneys to hold on  to water. These should push his blood pressure higher. But it wasn’t enough. Shortly after  his ICU admission, JB stops making urine. His kidneys have completely shut down. Doctors had  to hook him up to a dialysis machine so that the body waste that would have been urine, can be  filtered out of him. A chest CT scan confirms JB has pulmonary edema. This is the fluid that’s  in his lungs. And there seems to be more now than when he presented to the emergency room. But this  higher resolution scan gives more insights. It kind of looked like JB had a fungal infection.  But this was borderline. If it isn’t fungus, then for sure what’s happening isn’t a typical  infection. Other parts of his lungs had collapsed.

[00:03:53]Doctors start him on multiple antimicrobial agents  to cover a wide variety of pathogens. It’s still not clear that this is absolutely an infection.  But if it is, one of these could start working some, and buy time to figure out why this much  fluid has flooded into his lungs. They write a list of problems, and they need to rule each one  out to make a diagnosis of what’s wrong, so that they can treat him properly. Hey quick question.  Have you learned something from this video so far?

[00:04:20]If you have and you aren’t subscribed yet, I’d  really appreciate it if you did subscribe and come back to see the video that I post next month  too. I’ve made one video a month on average, every month since 2017. This is my fun time hobby,  and I make these to teach about medicine through stories. It’s one of the best ways that we teach  clinically. I make these and it’s genuinely one of the highlights of my day. I’m thankful for the  opportunity to make these for you. Appreciate you.

[00:04:44]JB was previously healthy. He had just come back  from a trip in Argentina, before experiencing a fever for 7 days. These are important to know,  because theres only a couple things that this could be. It’s not a previously known chronic  disease. And fever means, this could be an infection. That involves fluid in the lungs. That  means, this could be pneumonia. The problem is, pneumonia usually comes with a productive cough.  He didn’t have that. And when he was tested for respiratory bacteria and viruses, they all came  out negative. So, this isn’t pneumonia. Fever also could mean inflammation. If not pneumonia  infection, then, maybe this is autoimmune. The immune system attacking the body. Shortly after  ICU admission, JB’s kidneys failed. That could be the immune system attacking it. When that  happens, the immune system can also attack the lungs simultaneously. And this pulmonary  capillaritis, -itis meaning inflammation. Capill from capillary which is the small blood vessels in  the lungs, and pulmonary referring to the lungs, can result in diffuse alveolar hemorrhage. Alveoli  being the air sacs surrounded by capillaries where oxygen exchanges into the blood. The bleeding  would be the fluid that’s flooded into his lungs.

[00:05:52]And the bleed would be getting worse coinciding  with his kidneys suddenly shutting down in the intensive care unit. But the reason this why  this isn’t likely, is because nothing indicated that JB had autoimmune disease. Blood test didn’t  say it. Past medical history didn’t show it. So, this was unlikely, leaving one final problem.  JB had fluid in both lungs. Without evidence of pneumonia, this means that his lung blood vessels  were leaking. He fell into shock when he arrived to the ICU. Both of these together, suggest viral  infection. And given that he had recently been in Argentina before he had the fever, this suggests  one virus that wasn’t tested for when doctors look at pneumonia, because it doesn’t cause  pneumonia, rather, it suffocates the person by flooding their lungs with fluid. This one is  called hantavirus. In the intensive care unit, doctors order serologic and molecular testing  for hantavirus. This is not a standard test, because, this is not a common problem in most  places on this side of the earth. And it came out positive. What is hantavirus? The original  name was Hantaan Virus. From the Hantan River in Korea. This exact location tells us how this  was re-discovered in modern English. In 1951, United Nations troops stationed by the Hantan  River started reporting an epidemic hemorrhagic fever that would end in kidney failure. At the  time, they didnt know what it was that caused it, and they didnt know how it was happening.  27 years later, Dr Ho Wang Lee was able to identify what caused that hemorrhagic fever,  and he found out, it was a virus that’s first hosted in infected rodents, before being passed  on to humans. He named this the Hantaan Virus. It looks like it had been described and alluded to in  ancient Chinese texts from thousands of years ago, describing inflammatory fever diseases that  ended in kidney and lung disease. For sure, this appears to have been a known entity to locals  for centuries. When scientists looked closer, they found that this virus had been circulating  around much wider area than previously thought.

[00:07:51]Korea, China, Japan, Russia, and getting as far  as Scandanavia. And when we started developing the technology to sequence genomes, we found out that  many viruses in different geographic locations were genetically similar to Hantaan Virus. They  were related, though, just slightly different.

[00:08:07]And this is where the Hantavirus family comes  from. One reason why theres distinction among family members here, is that the illness caused by  each virus can be a little bit different. Overall, they either cause kidney failure, or, they cause  cardiopulmonary failure, like in JB’s case. And, at least during the time of Dr Ho Wang Lee,  it was found that most all of the viruses in the family were transmitted to humans through  airborne particles of infected rodent feces.

[00:08:34]You inhale them, and then it gets you. However,  there was a pivotal discovery that linked the Americas with these Eurasian hantavirus species.  On May 14, 1993, a 19 year old man was driving through the Four Corners to go to his fiancee’s  funeral, when suddenly, he couldn’t breathe. He had no known health problems. He was a marathon  runner. He stopped at a local gas station because regular people back then didn’t have cell phones  back then, and he called for help. An ambulance arrives, but, before it does, he collapses  because he can’t breathe. In the emergency room, they find that fluid had filled into his lungs.  And within minutes of arriving to the hospital, he’s not alive anymore. This didn’t make sense.  Someone this young and healthy shouldn’t pass away like this. New Mexico Office of the Medical  Investigator was contacted. And the investigator at the time was totally shocked. Because, a  few weeks earlier, another young woman nearby had also passed away in the same manner. She  was previously healthy too, but then suddenly, she had trouble breathing. Collapsed. And then it  was over. At autopsy for both patients, doctors noticed that there was nothing structurally wrong  with their lungs. They just suddenly filled with fluid, and then their lives were over. Something  very bad was happening. That 19 year old man’s fiancee. He was going to her funeral. Why did  she pass away? Investigators found out that she was only 21. She had passed away only a few  days earlier. She was also a marathon runner like her fiancee and previously healthy. During  her autopsy, a different doctor who was present.

[00:09:59]He immediately remembered a recent consultation  that he was a part of, involving 2 more young, previously healthy adults who collapsed  after suddenly not being able to breathe, and then subsequently passed away. Both of those  patients also had unexplained pulmonary edema.

[00:10:14]New Mexico Department of Health sent a letter to  Arizona, Colorado, New Mexico And Utah, because it appeared there was an occult illness happening  right at the border. And they received responses: multiple cases of a mysterious illness that all  presented the same way in previously healthy patients, had been reported all around the Four  Corners. And even worse, it was 80% mortality. CDC was asked for help. They tested autopsy samples  for gene samples of various pathogens. And it was here where they saw something that had been  never seen before. Public health officials went to homes of the deceased. They found rodents  in and nearby the buildings. They collected them. Tested them. And found these rodents had  the same pathogen genetic material, that these patients did at autopsy, meaning that something  was passed on. When they were able to grow it, they discovered a virus, that was a previously  un-described species of hantavirus. This is the first time a cluster of infections was formally  described in the western hemisphere. But there was a problem. Infected small animals were the only  known vectors to hantavirus known at the time.

[00:11:18]And massive quantities of small animals, enough  to mutate an entirely new species of hantavirus, can’t easily get from Asia to New Mexico, meaning,  this species, had always been here. But why was it showing up in 1993? Not too far from the Four  Corners, there were persistent rains all over the midwestern United States in 1993. The rivers  that feed into the Mississippi River started overflowing. And after several months, the water  became so much that the Mississippi River itself flooded. This was the one of the worst floods in  US history. But where did that rain come from? And what does it have to do with hantavirus? On July  16, 1990, there was a magnitude 7.8 earthquake in the Philippines. Two weeks after the quake,  local residents reported steam was coming from a nearby volcano. Over the next several months,  successive earthquakes were felt until April 2, 1991 when that volcano Mount Pinatubo erupted.  It sent 20 megatons of Sulfur Dioxide into the atmosphere, and triggered a volcanic winter. The  global temperature dropped half a degree celsius for 2 years into 1993. This created abnormal  conditions for excessive precipitation in North America causing a river flood. But also, the Four  Corners also had massively increased rains. And this is where it connects to hantavirus. In  spring of 1993, a sudden influx of biologists came into the Four Corners region to study.  The rodent population had exploded by 10 times, because there was an increase in local  vegetation due to increased rain. Public health officials at first didnt realize this.  But once they made the connection, they realized: with more rodents, it means there was more chance  for rodents to get infected. And more chance for an infected-rodent-associated-disease  to be transmitted to locals. Meaning, hantaviruses had already existed in North America.  It’s just that we hadn’t directly observed it yet for multiple reasons. In 2025, a high profile case  of Sin Nombre hantavirus was reported. That’s the one from the 1993 outbreak. Betsy Arakawa, wife of  Gene Hackman, had passed away in her home in New Mexico, while his dementia had progressed to the  point where he didn’t realize what was happening.

[00:13:28]She very likely, felt ill for days after her  first exposure, and then suddenly couldn’t breathe. And it was found to be hantavirus. It is  endemic in this region of the country. Finding her case is a legacy of this direct observation  of hantavirus in the region. But in 1993, this region still wasn’t quite aware of it. And  why? Well, this is not a densely populated part of the country. If cases had shown up in the  past, they were probably one-offs that were hard to identify without multiple cases showing  a pattern. You can see it happening in realtime as the 1993 outbreak was unfolding at first from  the 19 year old man. It would have looked like people suddenly collapsing for no reason. But  with 10x more rodents in an area than normal, clusters of cases will draw attention, and allow  investigators to connect ideas. But when it was identified in 1993, scientists wanted to know,  is this North American species different than the hantaviruses found in Asia? And if South America  has different small animal species, and this virus is transmitted through infected animals, is  it possible that South America has different hantaviruses too? And the answer to both was yes.  Argentina. 1995. 2 people in a rural area in the south (El Bolson) suddenly stopped breathing. At  autopsy, doctors found hantavirus genetic material in the lungs and the liver. When they compared it  to known hantaviruses, it was distinct. They named this one the Andes Virus. This was interesting  because, if this was spread by infected rodents, well, South American rodents are different from  North American ones. And while they didn’t know which rodent could transmit this Andes virus  at the time, it wasn’t very long until they found out that Andes Virus can be transmitted from  human to human in a small cluster of infections in the same town where the virus was first found the  year earlier. This brings us to 2026. A group of people boarded a cruise ship in Argentina. Near  where Andes Virus is known to be. 5 days later, one of the passengers started feeling ill. And  5 more days later, he wasn’t alive anymore. No one knew what happened. When the ship arrives at  St Helena island 13 days later, on April 24th, his body was examined at the hospital. His wife,  who accompanied his body, wasn’t feeling well. The next day, she took a flight from St Helena island  to Johannesburg, South Africa. When she lands, she collapses at the airport, and then passes  away. The cruise company hadn’t confirmed that these deaths were related to a medical situation  onboard that boat. But the same day when the wife passes away, another passenger on the boat  becomes ill. He’s evacuated to South Africa, and admitted into the Intensive Care Unit. 5 days  later, on May 2nd, another passenger on board the ship, has difficulty breathing, before suddenly  passing away. From the patient still alive in South Africa, doctors are able to confirm that  he has hantavirus. World Health Organization is contacted, and they were able to identify 7  total cases of hantavirus onboard the ship, and including the deceased as of early May 2026.  And it was here where WHO was able to confirm, this was Andes Virus. This is the one that can  be transmitted human to human, and evidence was already mounting before it was confirmed that this  was the causative agent. Started from Argentina.

[00:16:40]The ship’s doctor, who would tend to those who  feel ill, started getting sick himself and had to disembark the ship to get medical treatment.  Andes virus is a different hantavirus species than what JB likely suffered. The reason we know this  is because Argentina has multiple hantaviruses unique to different regions. Andes Virus comes  predominantly from the south. JB got sick in the north. But despite all of this, the illness  is still more or less the same, in that there’s a sudden cardiopulmonary collapse that follows a  period of time where the patient will feel sick.

[00:17:14]So that’s why it’s important for you to get  medical attention immediately if you feel sick, especially during times when alarm bells for  hantavirus have been raised in your local area. There is no direct medicine to give for  hantavirus cardiopulmonary syndrome as of the time I am publishing this. It’s supportive care.  It’s the tube down JB’s throat for the machine to breathe for him. If that doesn’t work, then it’s  redirecting his blood to a machine that oxygenates it for him and pumps it back into his body. Over  time, it’s known that the body does eventually clear out the virus, taking out the fluid that  fills into the lungs, and allowing the person to be able to breathe once again, normally. And  all of this is possible if the person sought and received the correct care in time. So there’s  a few things here to know. Some people are concerned, and rightly so, about the 2026 cruise  ship outbreak. Because there’s passengers who disembarked the boat after the announcement that  someone had died on board. I haven’t been on a cruise for a long time, but I can’t imagine if I  would be ok knowing that there’s a dead body on the ship for my vacation for 2 weeks before anyone  does anything about it. Where are they keeping the body? Is it in the room next to mine? I hope  not. But if this virus can transmit from human to human, and that virus was circulating among  the passengers, and there are passengers who left early, is it possible that they could be spreading  it out to everyone around them in their hometown?

[00:18:33]That’s a question everywhere in the news right  now. It is possible. And the only real experience that is known about this comes from southern  Argentina, in the 1996 case cluster, and a second one that happened in 2018. One person had gotten  infected. They were ill while at a birthday party.

[00:18:50]And people at the birthday party who sat close  to this person, subsequently got sick 17-24 days afterwards. One of these people had a very active  social life and went on to infect 6 more people before he was symptomatic. And 16 days after  symptom onset, this person stopped breathing, and it was over. His wife had a fever while  attending his wake. And 10 people who came into close contact with her during the wake became  ill 14 and 40 days afterwards. And in total, there were 34 people getting infected and 11 deaths  from this 2018 outbreak. Something important to note from this: no healthcare worker who treated  the infected patients got infected themselves.

[00:19:30]And medical teams are exposed to (almost) every  bodily fluid possible during treatment. They did have protective equipment on, but it wasn’t  uniform. Keep in mind, we’re speculating whether or not the human to human transmission comes from  saliva droplets and other body fluids. Some of the transmission described between patients in  this paper is a little ambiguous, for example, this patient, is reported as his daughter.  This method of transmission is a valid topic to bring up. However, I hope something in here  was reported incorrectly. And also simply saying hi. Very possible Andes Virus can be transmitted  through saliva droplets like sneezes, but we just dont know enough right now. What we do know, is  that the difference between this and 2020, is that back in 2020, we had never seen that before. It  was kind of similar to something we saw in 2002, but also not really. And the unknown part in the  very early months of the year was the scary part.

[00:20:25]But this Andes Virus, has been known for 30 years.  The 1996 and the 2018 cases demonstrated that the virus had no mutations in that time period.  And it looks like in the 2026 situation, it hasn’t changed much, again. Thats not to say it  wont change going forward. But we can only act on the information that we have now. If it changes,  then adjust accordingly. The point of this is that we know what to do in the cases of hantavirus.  And it’s good that the alarms have been raised so that should a case come through, the medical team  will know what to look for. What is particularly dangerous is when the medical team doesn’t know  what they’re looking for and diagnose hantavirus as something else, like a pulmonary embolism,  atypical pneumonia, or pulmonary capillaritis.

[00:21:07]That’s why I showed the differential diagnosis in  JB’s case. This is unlike January through April of 2020, where that pathogen really was something  new. This isn’t new. We’ve known about it for decades in America, millennia in Asia. This is a  data point that one should be aware of. Take note of. You should take the precaution of making sure  your hands are clean by washing after you come home. Wash your hands before you eat. If you feel  sick and have a fever, stay at home. And if you really don’t feel well, go to the hospital. This  is your datapoint. And those are actions for you to take. Because now the whole world knows about  hantavirus, should someone actually have trouble breathing that descends to sudden cardiopulmonary  collapse, they are more likely to get the right care that they need, than compared to before the  time this hantavirus cruise ship story came out.

[00:21:54]Doing those 3 things and paying attention are  all the brain power I personally will dedicate to this. And that’s my humble recommendation to you  as well. For JB, he was in the intensive care unit for 40 days. During this time, his respiratory  function and blood pressure gradually improved.

[00:22:09]His kidneys were able to completely recover.  After physical therapy and rehabilitation, JB was able to make a full recovery. This is  what a hantavirus cardiopulmonary case looks like. All hantaviruses that cause this syndrome  more or less look like this. The renal hemorrhage version that’s found in Asia looks a little  bit different. But the 2026 cruise ship one is the cardiopulmonary one. When one gets the right  treatment in time, they can make a full recovery.

[00:22:37]And good thing that we’re able to raise the alarm  bells now, so that should any patient present to any given hospital with similar symptoms like JB,  which are fever, confusion, shortness of breath, with low oxygen saturation and hypoxemia with  a fever AND they may have had prior contact with someone who had hantavirus, the hospital  should be able to order the right tests (they still would need to rule other things out just  in case) in the right time so that they can deliver the correct care to that patient. Just  based on the information we have at the time I am publishing this, I am not overly panicked  about this. Be mindful. Have it in the back of your mind. Take your necessary precautions, and  continue on. Take care of yourself. And be well.