Hey there, welcome to Paging Dr. Gupta. Every week, we have been trying to pay attention to what you're seeing, what you are feeling, and the questions you have about your own health. So today, we're going to answer questions about a story that's been unfolding at sea, a hantavirus outbreak. It's been happening on a cruise ship in the Atlantic. It started last week when a cruise on a long voyage made headlines after three passengers died and a handful of others got sick. There was a lot of action over this weekend as passenger evacuations took place, so we're going to have a full update for you at the end of this episode. But first, let's get to your questions. My producer Jennifer is back with us, so what are listeners curious about?

Hey Sanjay. Yes, listeners have been really curious and a bit concerned about the hantavirus. They want to know what's going on and how worried we all should be.

Well, first of all, I want to say the hantavirus outbreak is a developing story. I have covered outbreaks for the last 25 years. I know things can change, and they can change quickly. They can change every day as we learn more and more. So let's get into it after this short break.

Okay, welcome back. We are talking about the hantavirus outbreak on a small cruise ship. Let me give you a few details that maybe you haven't heard. First of all, the cruise ship is the MV Hondius. It is said not to be a traditional cruise ship but more of an expedition vessel where passengers get to visit some of the world's most remote islands and see wildlife. There were about 150 people on board, including 17 Americans. Now, it originated in Argentina, April 1st. Making its way to the Antarctic and then making its way north in the Atlantic. And that's when it started to run into trouble. People began to get sick. And according to the World Health Organization, passengers fell ill between April 6 and April 28. Again, it departed April 1. People started to get sickness between April 6 and 28. Keep these dates in mind, because they are relevant here. The symptoms they had included fever, gastrointestinal symptoms, rapid progression to pneumonia, acute respiratory distress syndrome, and then shock. And then as of this recording on Monday evening, there have been at least nine cases, seven confirmed and two probable of hantavirus infections from the ship. Three passengers have died, including a couple from the Netherlands. The man sadly died on board the ship on April 11th. The wife then collapsed at an airport in South Africa, as she was trying to fly home to the Netherlands. She was taken to a nearby hospital and she died there. Now, going back to those dates again, this couple was believed to have possibly been exposed before they boarded the ship. A German woman then died on board the ship, her death is a confirmed hantavirus case. And then again, as I mentioned, six additional confirmed or suspected cases among passengers and crew. Here's a few things you need to know. On April 24th, about 30 passengers, including seven from the United States, disembarked the ship in St. Helena. That's a remote island in the South Atlantic Ocean. This was part of a scheduled disembankment before hantavirus was confirmed aboard the ship. So yes, people had gotten sick, but they weren't sure what it was at the time these passengers disembarked. Those passengers live in several states, Arizona, California. Georgia, Texas, and Virginia, as well as other countries. What's happening now is public health officials have been working to track them down for testing and monitoring.

So Sanjay, can you explain a bit about hantavirus and what is the Andes strain?

This is a group of viruses that are spread mainly by rodents through their bodily fluids and their feces How does infection happen? Well humans often become infected when they inhale particles from dry rodent droppings. I know, it's kind of gross. Typically, it happens when someone tries to dispose of rodent dropings by sweeping them up. That may cause the particles to become airborne and the most common hantavirus in the United States is spread by the deer mouse. Humans can also become infected by touching contaminated objects and then touching their mouth or nose. Hantavirus can also spread through rodent bites or scratches, though that is actually pretty rare. Now, one hantivirus strain, the Andes strain, is native to South America. It was first discovered in 1995, and it's really the only one known to spread from person to person. Again, rarely. This is the strain that scientists believe might be responsible for the outbreak on the cruise ship. In fact, we know now that four of the five sick cruise ship patients is confirmed to be infected with the Andes strain of the virus. Again, what makes this outbreak unique is that the evidence points to it being caused by this particular strain of hantavirus, which is known to have had limited spread between people in the past. Health authorities are reporting this information after sequencing the virus from some of those that have been infected.

Okay, we have a question from Emily in New York, and she wants to know if this is likely to turn into a pandemic.

'So the short answer is no. And there's sort of three primary reasons that scientists talk about this being low risk. One is something known as the reproductive number. That means if someone has it, how many people are they likely to spread it to in the future? And with this, if you look at the overall average during outbreaks, it's about 1.19, okay, 1.19. When COVID was at its peak transmission, the numbers were somewhere between two and four, so more than double that. So that's one reason they don't expect this to be something that's going to become widespread. Second of all, we know that people can only transmit this virus during a very short infectious window, and that is typically when they are sick, really sick, and that's typically one to two days. Keep in mind, again, with COVID, people could spread that virus even before they developed symptoms. And then third of all, I think it's really important is that this virus, this Andes virus, its genome was first sequenced back in 1996. And when they compare that genome sequencing to 2018 and then again to 2026, it really hasn't changed much. It's a pretty stable genome. Remember again with COVID, all those variants, it was mutating near constantly, especially in that first year. Now, I will say that what makes this a little bit tricky is that the Andes virus does have a long incubation period. That means the time between exposure to the virus and when someone first begins to show symptoms, that's typically 14 to 17 days, but it can also be as long as eight weeks. So just think about that. Someone starts to get sick and then they have to sort of think about what they were doing two months earlier, what the exposures may have been. This long interval makes tracking down people who may have been exposed particularly difficult. But that's the incubation period. The good news, again, is that the infectious period, the window for transmission appears to be pretty short, about a day or so. We know a lot about this Andes virus due to an outbreak that occurred in 2018. It's kind of an incredible story. A man walks into a birthday party. He is sick at the time. He has fever. He is symptomatic. He spreads the Andes virus to five people, and then some of them spread it to others and so on and so, and at the end of this super spreader event, 11 people have died and 34 people were infected. That gives you some idea of the real world transmission of this virus. But importantly, there were 80 healthcare workers that took care of those patients and none of them got sick. None of them tested positive. Very, very important. I think it sort of makes two points. First of all, just with simple protective measures, like masks, people were able to avoid getting infected, even though they were caring for patients who were clearly sick. And second of all that narrow infectious window. Many of these patients that went to the hospital, they may have gone to the hospitals at a time when they were no longer contagious. I will say again that just about every major medical organization, the World Health Organization, CDC. Doctors, they're saying that, look, this is not something they are particularly worried about, and I think for the reasons we just outlined. Dr. Lucille Blumberg, an infectious disease specialist, former deputy director of the National Institute for Communicable Diseases in South Africa, said simply, "This not COVID. This is really not COVID, it's not even influenza. This is an unusual person-to-person event, and it might have happened because of the closed environment on a ship." Ships are places where viruses can spread, we know that. Carlos del Rio, my colleague at Emory, he says that I tell people that I'd be more concerned about getting in my car or crossing the street and having an accident than getting hantavirus, okay? So hopefully that assuages, alleviates some of your concerns, but when we come back, we'll tackle more of your questions.

Okay, I hear that it's time for another question. Jennifer, what other questions do we have?

Okay, so Amelia from Woodbridge, Virginia wants to know, what are all the signs and symptoms? What treatments are available for hantavirus at the moment?

'Okay, symptoms can initially be flu-like, headache, fever, but as the disease becomes more severe, there are two types of severe illness that it may develop into, depending on the strain of the virus that someone is exposed to. Certain strains seem to be more prevalent in different parts of the world. So the kind of virus that's found in the Americas, that typically causes Hantavirus Pulmonary Syndrome, lung features. So again, initially flu-like, Fatigue, fevers, chills and aches. But then shortness of breath, tightness in the chest, lungs start to fill with fluid. After exposure, symptoms again can take a while to develop, but sadly nearly 40% of those who do develop respiratory symptoms will die of this infection. There's another kind that's primarily found in Europe and Asia that can cause hemorrhagic fever with renal syndrome. That means the kidneys. So people again develop headaches, abdominal pain, nausea, but then they may develop low blood pressure, internal bleeding, and kidney failure, and in those cases up to 15% of cases are fatal. Big question a lot of people ask, obviously, is there a cure or even a treatment for hantavirus? Short answer is no. We don't have a vaccine or specific antivirals for the viruses. Patients are typically treated with hydration, rest, and what is known as symptomatic treatment. They treat the symptoms. When people have bad lung problems, sometimes they may be placed on something known as ECMO, extracorporeal membrane oxygenation. That basically means, Hey, look, the lungs simply aren't working. They take the blood outside the body, oxygenate it, and then put it back inside the body. It's obviously very extreme, but that's what they do to try and keep someone alive. But there is no specific cure.

Alrightk, Winta from Tempe, Arizona, wants to know if this hantavirus strain can mutate and become even more contagious.

'Yeah, this is an important question. What we know about this virus is limited. I just want to start with that. There's been thousands of cases around the world, but maybe only about 300 cases of human-to-human transmission of the virus. But one thing again to point out is that it was first sequenced back in 1996 and then again in 2018, and they find very little difference between the genomic sequence over that time period and even as compared to now. So that's the good news, potentially. This virus seems to be pretty stable. COVID, again, was mutating all the time that first year in particular. Now, I will say as the virus spreads more and more, and that may happen, the chance for mutations goes up. So we have to keep monitoring this, following this and making sure we're continuing to test people and sequence the virus if they find it in people. In other words, based on the little we do know, it does not appear to mutate a lot unlike COVID or influenza, but we do have to continue keeping an eye on it. All right, time for one more question.

Okay, our last question is from Rosh. They're writing from a New York City suburb, and they want to know if they should be stressed about getting the virus after finding a field mouse and its droppings. They told us that their adult son did sweeping after vacuuming, and then the next day wiped down surfaces sitting near the bottom shelf. From what Rosh has read, this is all the wrong moves. No mask either. They had the mouse in the mouse trap and used a thin plastic bag to discard it. What do you think?

'Okay, well, one of the most important parts of this listener's question is that she's from New York. That is not common in New York, the vast majority of cases that have happened in the United States have been west of the Mississippi. They tend to occur in places where people and rodents coexist. Obviously, there's rodents in New York, but we're talking about truly coexist, most commonly in rural areas and agricultural settings. Here in the United States, it's not the common house mouse that carries hantavirus. It's actually something known as the deer mouse, more commonly seen in the wild. Yes, they can end up in houses and cabins and people can get exposed to feces, urine, and saliva. And again, the risk comes from cleaning or touching, sweeping a barn, for example, that can waft the droppings up into the air. And in the Unites States, the first outbreak wasn't recognized until 1993. And it happened in the Four Corner States area. So Rosh, you live in a suburb of New York City. Answer is you probably don't need to be stressed about getting this from a mouse. But for everyone out there who may be worried about this a bit, CDC says the best way to protect yourself is to keep rodents out of the house. Seal any gaps or holes in your home. Keep your food well-sealed. Put garbage in thick containers with tight lids. When cleaning rodent droppings, use gloves. Spray the waste with a bleach solution. And then wait for five minutes before wiping the area with paper towels. Dispose of all that safely. If you do ever get sick, seek early medical care. If you have symptoms, stay away from other people. That should be an obvious one by now. Okay, I hope that helps. Hope that answers some of the questions. And I did want to give you an update. As of Monday evening, 18 passengers from the MV Hondius are back in the United States and are being monitored at medical units. Sixteen of those people are at the University of Nebraska Medical Center, including at least one who tested positive But all of them are asymptomatic, none of them or showing any symptoms. Two others have been transferred to Emory University in Atlanta. One of them is experiencing symptoms. The other is a close contact, health officials said, while stressing again that the virus does not spread easily. As for the Hondius itself, the ship left the Canary Islands after the carefully managed evacuation of all of its passengers. It set sail with the remaining crew members for Rotterdam in the Netherlands, where the ship will then be disinfected. That's all the time we have for today's episode. Keep the questions coming. If there's something health related you've been wondering about, send it to us. We might answer it next week. Record a voice memo. Email it to pagingdrgupta@cnn.com. That's pagingdrgupta@cnn.com or give us a call at 470-396-0832 and leave a message.