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July 16, 2026
We all look forward to summer, that time of year when we can spend more time outside and less time worrying about things like colds and flu. However, the warm summer months can bring their own infectious disease threats, whether it's ticks, mosquitoes, or foodborne parasites. This week, hosts Chris Dall and Dr. Michael Osterholm discuss some of these summertime infectious disease threats, from the growing Cyclospora outbreak in the US, to new research that suggests the tick-borne allergy alpha-gal syndrome may be under-recognized. They'll also bring you the latest on the Ebola outbreak in the Democratic Republic of the Congo and answer a question about the World Cup.
Links:Workers at an Ebola treatment center in Congo strike over unpaid salaries and bonuses (The Associated Press)What we truly know about the huge US Cyclospora outbreak—and what we don’t (CIDRAP)1 in 4 adults in tick-heavy states test positive for alpha-gal antibodies (CIDRAP)
Resources for vaccine and public health advocacy:Voices for VaccinesFamilies Fighting FluVaccinate Your FamilyShot@LifeMedical Reserve CorpsLearn more about the Vaccine Integrity ProjectMORE EPISODES SUPPORT THIS PODCASTMusic:"Beauty Flow" Kevin MacLeod (incompetech.com)
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Chris Dall: Hello and welcome to the Osterholm Update, a podcast about infectious diseases and public health featuring Dr. Michael Osterholm. Dr. Osterholm is an internationally recognized medical detective and director of the Center For Infectious Disease Research and Policy, or CIDRAP, at the University of Minnesota. In this podcast, Dr. Osterholm draws on over 50 years of experience in infectious disease epidemiology to provide straight talk on the latest infectious disease outbreaks, counter misinformation and disinformation about vaccines, and distill the complex and ever evolving public health threats facing our world. I'm Chris Dall, reporter for CIDRAP news, and I'm your host for these conversations. Welcome back everyone to another episode of the Osterholm Update podcast. After a long winter spent trying to stay warm and dodge respiratory viruses, we all look forward to summer. That time of year when we can spend more time outside and not dwell too much on things like colds and flu. Unfortunately, the warm summer months do bring their own infectious disease threats, from ticks, to mosquitoes, to foodborne parasites. No matter what time of year, there's always something that can make you sick. And this summer, it seems like we're hearing a lot about some of these summertime infectious disease threats, from the growing cyclosporiasis outbreak in Michigan, to new research that suggests the tick borne allergy Alpha-gal syndrome may be under-recognized. We're going to cover a few of these summertime threats on this July 16th episode of the Osterholm update, episode number 213. We'll also bring you the latest on the Ebola outbreak in the Democratic Republic of Congo. Discuss a new survey on Americans perceptions of vaccine myths, answer an ID query on the World Cup and bring you the latest installment of This Week in Public Health History. But before we get started, as always, we will begin with Dr. Osterholm's opening comments and dedication.Dr. Michael Osterholm : Thank you very much, Chris, and welcome back to the podcast family. Thank you so much for joining us. And also thank you for the emails and even the letters I'm getting from you with ideas, suggestions, follow up, etc. It's a wonderful experience to be part of this incredible group. I also want to welcome anyone who may be coming for the first time. I hope we're able to provide you with the kind of information you're looking for. I also welcome your feedback as new thinkers in all of this process, and you may have some ideas that none of us had yet thought about. So let me begin this podcast with a dedication that is one you might say seems somewhat abstract, somewhat distant, and yet very close to our heart. This week, we're dedicating the episode to the people of the Democratic Republic of Congo, and I'm sure most of our listeners are aware of. The DRC has been ravaged by the Ebola outbreak since May. This virus has continued to rage on. While this response struggles to keep up with an ever ongoing outbreak, as we'll discuss later in this episode, dozens of staff people walked out of one hospital in the Ituri province at the center of the outbreak. Workers went on strike over unpaid salaries and bonuses, with one staff member telling The Associated Press they had not been paid for two months. And Ebola is just one of many challenges. The people in the DRC are facing malaria, food insecurity, HIV, tuberculosis and many other public health crises are also impacting the country.Dr. Michael Osterholm : Forced labor and child labor in unsafe conditions are common across cobalt, diamond and gold mines in the country. Political unrest and conflict are widespread, with each crisis compounding on the one that came before. We're thinking of all the people in the DRC. WHO Director General Tedros said last month that the DRC will stop this outbreak because it has stopped numerous Ebola outbreaks before. But Tedros went on to say that "The real measure of success is what we do to prevent the 18th outbreak in the 19th outbreak." Tedros also emphasized the importance of leadership, ownership, partnership and trust. We hope that this type of response picks up swiftly for each and every person impacted on the DRC and beyond. We dedicate this episode to those who are sick and suffering from the Ebola virus, as well as their families and caretakers to those communities who have lost family, friends, colleagues and neighbors, to all the health care workers who have sacrificed themselves on the front lines through a lack of protective equipment, community skepticism, and an absence of pay. This outbreak is heavy on our hearts, and we're thinking of all of you in the DRC.Now, moving on to that light moment in the podcast. For those of you who find this as the nails on the chalkboard moment, give us 30 seconds. I'm happy to report to today on July 16th here in Minneapolis/St. Paul, the morning sunrise is at 5:41 am, the sun set at 8:55 pm. that's a whole 15 hours, 14 minutes, and four seconds of sunlight. But yes, it's true. The loss of sunlight is accelerating, with today losing one minute and 40 seconds of sunlight. I'm happy to report in Auckland, New Zealand, at the Occidental Belgian Beer House on Vulcan Lane, that in fact, today your sun rises at 7:30 am, sunset at 5:23 pm. surely does not match our's, but you are now gaining sunlight at one minute and eight seconds a day, and in just a few months, you're going to have more sunlight than we have here. One additional comment I just want to make about sunlight is the fact that, of course, from sunlight comes the heat on the earth. I must acknowledge for anyone who has any doubts about climate change, I can tell you, being in Minnesota right now, we have 100 degree temperature in the northern part of the state in the wilderness canoe area, where water temperatures in the lakes have never exceeded the low 70s now are in the high 70s to low 80s. There's a real change in climate here. And so we welcome the light. But we also recognize with this light, we do have another issue that we have to take very seriously. And in the future, that will be a topic for us, because it also has an impact on how some infectious diseases are transmitted.Chris Dall: Mike, we're going to start this episode with the cyclosporiasis outbreak in Michigan and other states. cyclosporiasis tends to be more common in spring and summer, and many states report increases in cases during the summer months. But even the CDC has acknowledged that this appears to be an unusually large outbreak. So, Mike, what causes cyclosporiasis and what is going on with this outbreak?Dr. Michael Osterholm : Well, Chris, this may be the largest outbreak of cyclosporiasis we've seen in this country. Let me just give a brief summary of what this disease is all about. It's an intestinal illness that's caused by the microscopic parasite cyclospora. People become infected by eating or drinking food or water contaminated with the parasite. cyclosporiasis is most commonly linked to fresh produce such as cilantro, basil, lettuce, raspberries, or even imported leafy greens. And finally, contaminated water consumption is also associated with illness. Believe it or not, it doesn't actually transmit directly from human to human, even though humans are the only ones that can be infected by this parasite. What does that mean? It means that once the parasite is excreted out of the human body, it takes at least several days up to two weeks before it matures enough that then, when ingested, can cause infection in the next person. So it means that just being in close contact with someone who is currently infected with the parasite doesn't necessarily put you at any increased risk at all of acquiring it. You have to wait a few days to two weeks before the parasite's excreted by that individual actually become potentially infectious. The symptoms usually begin about one week after exposure and may include frequent watery diarrhea, often very prolonged loss of appetite, weight loss, and sometimes significant weight loss. It includes stomach cramps and bloating, nausea, fatigue, and even low grade fever. Without treatment, symptoms can go on for up to weeks to months. So for anyone who is potentially infected with this parasite now from this outbreak, get treated as soon as possible.Dr. Michael Osterholm : To be diagnosed with cyclosporiasis means a special lab test, that is not normally used, and therefore one that you often have to request from your physician to be tested for. So if you think you're part of this outbreak or you've had prolonged diarrhea that started with acute onset, do consider being tested for cyclosporiasis. The standard treatment is actually very easy. It's an antibiotic combination called trimethoprim sulfa sulfamethoxazole, or often referred to as Bactrim. The treatment is highly effective. People who are allergic to sulfa medications should discuss alternative options with their health care provider, although effective alternatives are more limited. Finally, what is happening with this outbreak? We knew as early as three weeks ago that there was something happening with cyclospora in the United States, particularly in areas like Michigan and Ohio. As of July 15th, the case numbers were estimated to be over 7000. People are realizing, yes, this is a sizable outbreak, given that many cases are likely not yet been tested or have been reported. So in the end, this was an outbreak that surely could involve a number of thousands of people. But let me put this into perspective and comment on why I have such concerns about what's happened with this outbreak. First of all, to many people's surprise, is the fact that one of the most commonly food items consumed in the United States is leafy greens. On an average day, 150 million people will actually consume a leafy green.Dr. Michael Osterholm : I share that number with you only because it gives perspective to talking about a few thousand cases of illness, which are important, very important, particularly if you're one of the cases. But to also give you a sense of the fact that the outbreaks that we're seeing right now are cases are concentrated in Michigan, Kentucky, West Virginia and North Carolina really reflect a very limited distribution of whatever leafy green product is causing this outbreak. We fully expect to see cases of cyclosporiasis this time of year, particularly in travelers around the world, coming back to the United States with the infection. And for a number of states that have reported cases recently, they're not likely part of this outbreak, but rather reflect individuals who are returning with cyclosporiasis from foreign travel. I can speak to at least several states west of the Mississippi, where all the cases that they have reported have nothing to do with the outbreak. And it's notable that in this outbreak that we should suspect a produce item being involved. Why? Again, the experience of dealing with many of these outbreaks in the past is that kids often are underrepresented in cases involving produce. They're just not big produce eaters. And in this outbreak, about 5% of the cases to date have occurred in individuals 20 years of age and younger. They make up over 25% of the nation's population. This is not unusual to see that underrepresentation, and should almost be a first signal to you that you're dealing with a type of produce related outbreak.Dr. Michael Osterholm : I also add that the geographic location of cases is really important in terms of trying to solve the outbreak. Some product was distributed 4 to 6 weeks ago in this country, and matching that up against the distribution of the various produce items surely can be helpful in getting a clue as to what might have caused the outbreak. I'm quite convinced at this point that this outbreak is really over. Now, that may surprise some people to hear me say that as case numbers continue to pour in. But let me put this into perspective first. From the time that someone becomes infected with this parasite, anywhere from several up to 14 days after exposure, then they become sick. People often will persist for several days, at the very least before they'll seek medical care for diarrheal illness, That's something we've documented in many outbreaks. Testing often takes a week or more for results to come back. Now I'm up into the 20 some days post-exposure. Well, at that point you might get reported as a case and that would be great. But knowing that the exposure was weeks before, how does that relate to my statement? The outbreak is almost over. Whatever product caused this, and we surely have reason to suspect several types of produce items are involved. It turns out that that product obviously lived its shelf life as a perishable food item, unlike some products where you may keep them on the shelf for days or months with produce, that's not the case.Dr. Michael Osterholm : It literally blows through the food distribution system, and when it's gone, it's gone. Typically, leafy greens for the time of the year that we were seeing. The first cases of cyclosporiasis often come from south of our border, particularly Mexico. And when they're harvesting product in Mexico, they'll harvest a large field, completely exhausting it. So it's not producing product for some time yet to come and move on to other fields. And it could only be one of those fields that's contaminated with whatever it is as a result of sewage overflow, flooding, whatever. But the bottom line is this is a type of food item that comes into the system, does its damage quickly and leaves the system in terms of its actual availability. But the outbreak is a residual tale. And I think that's what's happening right now. We will continue to see new cases reported. We will continue to hear about individuals who are quite ill. Please get tested so you can get treated. But in a sense the outbreak is over. And I also base that on having worked up a number of cyclosporiasis and other foodborne pathogen outbreaks where you can actually document clearly that the actual outbreak was likely to wane after a certain period of time based on the type of vehicle. So again, a perishable food item. So by the time you hear this podcast, I really do believe that transmission has ended in this country from the product and that we'll go through another 3 or 4 weeks of increasing case numbers as these late cases get reported, but do not conclude that the outbreak is still happening.Dr. Michael Osterholm : Now, why is that important? Because in the end, we're all interested in how do we prevent this from happening? And one of the things that's happened with this outbreak is there has been a total lack of public relations leadership from any of our federal agencies. The CDC and the FDA have had virtually no comments. And only on Tuesday of this week did the CDC finally issue what's called a health alert network, a Han. This is actually a document that is supposed to be sent out to public health agencies in the first instance, suggesting a possible outbreak that was not done four weeks ago. And in this particular document, again, there is really a lack of clear evidence that there is some summary of cases, but lacking really any interpretation, as I just shared with you. Geographic differences, the differences in age and so forth, that could help you understand what was going on. And so the public was left to its own design to find out what do I do? I'm just hearing about this 24 over seven in the media. And this is where I had a real problem is the media. The media basically sensationalized this outbreak. And what I mean by that, I'm not saying that 7000 or more cases aren't important, but they basically continued to interview individuals who had no real experience in foodborne outbreak evaluation or in particular, for cyclosporiasis. And they would come up with recommendations saying, for example, "wash your lettuce."Dr. Michael Osterholm : Well, they had no idea what we know about the disinfection of produce and specifically leafy greens. And it turns out that it's extremely difficult to do. And the idea that I first heard on CNN, and they've repeated it many times, as well as other sources "Buy head lettuce, cut the first 2 to 3 leaves off and then wash it." Do you know that there are no data that supports that? That in fact would prevent the transmission of cyclospora by doing that? Also, it turns out that bagged lettuce, which is sold at retail grocery stores, not the bag lettuce that goes into restaurants, which is a much larger commodity product. But the bags that you see in grocery stores, they actually go through a wash that is more effective at reducing any kind of pathogen, including cyclospora. And those bagged lettuce recommendations that come from the science community actually say, do not wash your product in that kitchen from that bag because you have a greater likelihood of contaminating that product with contamination that's in your kitchen than it is from the bag lettuce itself. And yet we heard people say, don't eat lettuce. Now come on, this is a health food that we all want to basically embrace. And when you have 150 million servings a day, you know that it's an important part of our diet. Well, we're telling people, don't eat lettuce for everybody. West of the Mississippi were less than 5% of the cases in this country reside.Dr. Michael Osterholm : That population surely was not involved with this outbreak. And yet the lack of clarity made people think if you lived in the 50 states, you were at some risk for developing cyclosporiasis just simply not the case. So my recommendation is that when this outbreak is over with that we actually have a hot wash or a real review of what happened. Why do we have state health departments putting out information that's not scientifically correct, as the Michigan Department of Health has done repeatedly about ways to protect yourself from getting infected with this particular parasite. And the information system they provided on leafy green disinfection just was not based in science. What do we do about the media that continues to basically hype these cases, that continues to hype means of disinfecting your products, something we all want to know, but in fact, they're not the scientifically sound recommendations that if they had interviewed academic, trained researchers who have spent many years researching how to make produce safer, they would have found very, very different results. And finally, we even had one individual that went so far as to say, oh boy, this probably is water borne when you look at so many cases are congregated in southeastern Michigan, northwestern Indiana. It may be as water. They actually went so far as to say, oh, I would only drink bottled water right now. What a ridiculous recommendation. And one again, if I'm in the public, I'm trying to understand what I can do to protect myself and my family.Dr. Michael Osterholm : So I went out and bought bottled water. So the bottom line message for this outbreak investigation is it will be solved. We will know exactly how it happened. We will understand why the distribution of product was as it was and therefore defined where the outbreak really was. But I hope we also learned we learned the fact that we do not have a monolithic U.S. food supply in terms of distribution of, particularly things like leafy greens. And don't make recommendations for one outbreak in one area of the country for the whole entire country where we had a problem, it was bad and we surely needed to make recommendations for that area. But to tell people in California, where there's no evidence at all that this outbreak has had any impact, not to eat lettuce, that just, to me, is a really irresponsible position to take in public health. So we'll keep you posted on this outbreak. You can test me on the issue as this outbreak over with when we report back in two weeks and let you know what's happening with case numbers, surely by 3 to 4 weeks out, it'll be over with. And at this time, all I can say is that we want to find ways to eat healthy foods. When you eat a food item that gives you cyclosporiasis, that's not healthy. We surely want to do everything we can to minimize that. But at this time, we must strongly consider the opportunity to do this review of what happened in this outbreak and learn from it.Chris Dall: And Mike, are there any practical tips for our listeners to help them avoid cyclosporiasis?Dr. Michael Osterholm : The most obvious thing to avoid is contaminated produce. But how do you know? Well, as I already pointed out, I believe that the product that caused this outbreak is already through the food system. It's gone. Quite honestly, we could have an entire country of produce and leafy greens right now that are free from cyclospora. I don't know that, but it surely is possible. What I would tell you to do if you're not eating in one of the high risk areas like parts of Michigan, Ohio, Kentucky, West Virginia, or North Carolina, I would say your risk is no different today for developing cyclosporiasis than it was some 8 to 10 months ago. No different even in those areas where the outbreak occurred. It may not be different, but you can still, if you want, take some precautions. I think you're going to find it interesting when the final results do come out where it was a very specific type of produce that was involved, and it was delivered to very specific locations, meaning that restaurants versus retail grocery stores, where the type of product that you consumed may be a specialty product that came from another country, which was not part of the main grocery store sales area.Dr. Michael Osterholm : We'll find all that out. Having said that, I think for most of the country, the leafy green products have returned back to their high level of safety. Now, people may challenge me on that, but I want to present this as a challenge to you. If we're consuming 150 million servings of leafy greens a day in this country, if it was such an unsafe product, we'd be having lots of outbreaks week after week after week after week. And we don't. We surely do have outbreaks, and they can surely be a challenge. But the frequency with which leafy greens get contaminated and cause an outbreak is actually limited. That doesn't help anyone listening to this podcast who right now can't get more than five feet away from their bathroom. And so my professional heart is extended to you and I hope you get treated soon. What a challenge. But for the vast majority of consumers in this country, I do not think that this parasite poses a significant risk at this time.Chris Dall: When we talk about tick borne illnesses, the first thing that comes to mind is Lyme disease. But there's another tick borne illness called Alpha-gal syndrome, which can give people a dangerous allergy to red meat and dairy products. A recent study published by the CDC found that in five states with high rates of Alpha-gal syndrome, nearly 25% of adults tested positive for antibodies associated with the condition. Mike, what can you tell our listeners about Alpha-gal syndrome?Dr. Michael Osterholm : Thanks, Chris. This topic clearly has been getting a lot of attention this summer, especially given in the recent years as we've seen an increase in tick exposures and an expanded geographic region for those ticks. Alpha gal syndrome refers to a condition where a bite of a tick, specifically the lone star tick, can trigger an allergy to galactose alpha one three, which is the sugar found in mammalian derived animal products but not found in humans or other related primates. During a lone star tick bite, Alpha-gal and other molecules in the tick, saliva can stimulate the immune system to produce what we call Ige antibodies against Alpha-gal. Over weeks to months, some people may develop alpha gal syndrome, while others remain sensitized without developing symptoms. When an individual with an established allergy eats red meat that contains alpha gal sugars, they may experience symptoms like hives, swelling, GI symptoms, and in some cases, even anaphylaxis. While there is no permanent cure for Alpha-gal syndrome, it can successfully be managed through strict dietary avoidance medication and preventing future tick bite. In many cases, the allergy can naturally decline or go away completely over a period of 1 to 2 years if you manage to avoid getting bitten by ticks again. In terms of the dietary avoidance, the primary way to prevent an allergic reaction is to avoid consuming the alpha gal sugar molecule found in mammals. In terms of mammalian meat, we're talking about completely eliminating beef, pork, lamb, venison, goat, and rabbit. Safe alternatives include poultry, such as chicken and turkey, fish and seafood. Avoidance of dairy products. Avoid milk, cheese, butter and yogurt if you are highly sensitive. Around 5 to 20% of people with Alpha-gal syndrome react to dairy. And finally, gelatin and animal byproducts. Check the labels carefully for gelatin, lard and tallow.Dr. Michael Osterholm : Gelatin is commonly found in gummy candies, marshmallows, and some dessert. In terms of medical treatment for reactions. Because reactions can be delayed by 2 to 6 hours after eating. Keeping rescue medications on hand is really quite crucial. Your doctor may very well prescribe for you epinephrine. In addition, alpha gal can be found in non-food products. Always verify ingredients with your doctor or pharmacist. Such as medications. Gelatin capsules derived from animals and certain inactive binders can trigger reactions. Personal care products such as lotions, soaps, and cosmetics containing collagen, keratin, or glycerin may cause skin irritation. Finally, the key piece is preventing future tick bites. Preventing new tick bites, particularly from the Lone Star tick, is vital. New bites introduce more Alpha-gal saliva into your bloodstream, which spikes your antibody level and resets or worsens the allergy. Use EPA registered bug sprays containing Deet or picaridin on your skin. Treat your outdoor clothing and gear with permethrin. As I mentioned earlier, increasing human exposure to ticks has contributed to the growing concern about tick associated illnesses like Lyme disease or leucosis, anaplasmosis and Alpha-gal syndrome. To better characterize the burden of Alpha-gal seroprevalence in the population, a team led by the CDC screened for antibodies against the sugar in 3000 residual blood donor samples collected in 2024 and 2025 across ten states. The findings from the study suggest that in five states with the highest prevalence of Lone Star ticks namely Arkansas, Kentucky, Missouri, Tennessee and Virginia, about 24% of the adults were estimated to carry Alpha-gal antibodies. The study found that men were more likely than women to be seropositive. Antibody prevalence increased with age, and people living in less densely populated counties were more likely to test positive.Dr. Michael Osterholm : However, the authors rightly point out that just testing zero positive does not mean that those individuals have the allergy, and that many people may be sensitized by tick exposures without developing symptoms. It's an ongoing challenge to distinguish exposure from actual disease for clinicians and public health officials. These findings underscore the importance of pairing laboratory testing with clinical symptoms when evaluating patients for Alpha-gal syndrome, and for the rest of us, it's another reminder that tick bite prevention is an increasingly important part of staying healthy outdoors. One last note that I'd like to make was something that was shared with me by Doctor Brooks Edward, a cardiologist and professor of medicine at the Mayo Clinic who previously directed the William J. Liebig Center for Transplantation and Clinical Regeneration. He said, and I quote, I did want to point out about a nuance that the general public usually doesn't address, but I think it's very interesting and sort of important. We all have naturally occurring alpha gal IgG, IgG, IgM and IGA antibodies, and only the IgG seems to result in the meat allergy. The human IgG expression probably results from the gut microflora and its natural alpha gal expression. I don't know why the non-ige expression does not seem to cause issues with meat allergies. He went on to say the IgG is, however, especially relevant to xenotransplantation, where all mammals, including swine, express alpha gal antigens except the Old world monkeys, apes and humans. Our IgG results in hyperactive rejection with naturally occurring pig organs. Knowing this, the animals used for xenotransplantation are now genetically modified to remove the alpha gal expression. I guess it's one of the benefits of genetically modified technology.Chris Dall: Now to those other summertime pests mosquitoes. Mike. The CDC recently noted that the U.S. has reported the most cases of the mosquito borne West Nile virus disease in people since 2004. Do we have any sense of what's driving this uptick?Dr. Michael Osterholm : I'll start first by acknowledging that the number of cases reported by CDC is likely a really major underestimation of the true number of infections. Approximately 20% of West Nile infections in humans are symptomatic, and less than 1% result in the severe neurologic symptoms for which testing would typically be sought from medical providers. I say that not to undermine the public health importance of West Nile, but to highlight that this virus is likely much more widespread than our surveillance data might suggest. As far as the recent uptick in cases, it's likely that weather is playing a major role. We talked about the El Nino in previous episodes in the context of hantavirus, but it can actually play a large role in disease transmission for a number of viruses West Nile included with El Nino. The United States experiences warmer winters and, in many locations, increased precipitation. This is relevant for mosquito borne viruses, in particular because the warmer weather increases survivorship of the adult Culex mosquitoes over the winter season and into the spring. The Culex mosquito, which breeds in temporary bodies of water such as waters in ditches or spillover water from floods. With this, the weather then does have a big impact on what the mosquito population will look like. So what happens in the springtime with these mosquitoes? Well, baby birds hatch and birds are the primary reservoir for the West Nile virus. Hatchlings are confined to their nest because they can't fly yet, so they're easy targets for the mosquito. Mosquito bites the bird and just the virus, and then go on to transmit West Nile when they then eventually bite the next host, which very well may be a human.Dr. Michael Osterholm : El Nino also brings hotter temperatures in the summertime, as well as increased likelihood of heavy rainfall. Combined, those conditions are literally the perfect breeding ground for mosquitoes. So in addition to El Nino increasing survivorship of mosquitoes over the winter, it can also accelerate mosquito breeding and therefore increase the number of vectors that can transmit West Nile. Long story short, Chris, it's all about the weather. Now, our listeners might be wondering what they can do to protect themselves from West Nile. The best preventive measure is avoiding mosquito bites altogether. People can use an EPA registered insect repellent. Wear loose long sleeved shirts and long pants when outside, and stay indoors during peak mosquito hours, which is between dusk and dawn. Mosquitoes breed in stagnant water, so emptying or covering sources of standing water, such as planters, birdbaths and clogged gutters, can limit the number of mosquitoes around the home. West Nile is also only one of many vector borne diseases that circulate this time of year. So preventing mosquito bites goes a long way in preventing a multitude of infectious diseases. It's still early in the season, and we promise to keep our listeners informed about any important updates as we learn more. But I feel confident we are going to be talking a lot more about this topic, particularly in the months of August and September.Chris Dall: I want to turn now to the Ebola outbreak in the Democratic Republic of Congo. The outbreak in DRC currently stands at 1963 cases and 719 deaths as of Tuesday. And a senior W.H.O. official recently told Reuters that four out of every five cases has no connection to an existing case, which suggests there's a lot of undetected transmission going on. In addition, Congolese health workers have gone on strike over poor working conditions. Mike, while there is some hopeful news to report, it seems like this outbreak could go on for a very long time.Dr. Michael Osterholm : Chris, you are absolutely right, and I am very concerned about where this situation is headed. As you noted, as of Tuesday morning, there has been a total of nearly 2000 confirmed cases and over 700 confirmed deaths in the outbreak so far. Those numbers are growing daily, and the fact that so many cases don't have a known contact with another Ebola patient means the spread is far exceeding what we're seeing in the confirmed case numbers. It's notable that a story in The Associated Press declared this as, quote, the fastest growing Ebola outbreak in history, unquote. This may be in part due to the milder symptoms that some patients with bundibugyo virus experience compared to other strains. Some may take the outbreak less seriously because they know someone who experienced relatively mild symptoms and recovered at home. Others may assume their symptoms are caused by something else, like malaria, and therefore not take the appropriate precautions to protect against transmitting the virus to others. In some ways, this is not unlike what we saw with the Omicron strain of COVID. People with milder symptoms were out in their workplaces and social settings rather than staying home being ill. This means more virus is circulating in the community overall. So while the likelihood of mortality from a single case declined, the higher number of overall infections will result in an increase in hospitalizations and deaths.Dr. Michael Osterholm : All of this is to say this outbreak is growing quickly, and we really don't have a strong grasp on the extent to which the virus is spread. It's very possible that this outbreak could be among the worst we've ever seen with Ebola. And I know I'm not alone in that concern. In more hopeful news, I do want to share that trials for a vaccine, a prophylactic medication and a treatment are soon to be underway. The vaccine trial will be taking place at Oxford to assess immune responses in 50 people who were given the vaccine. The prophylactic trial will assess whether the antiviral drug or designer results in the risk of developing bundibugyo virus and those who have come in contact with patients. The treatment trials involve two medications, an antiviral drug called remdesivir, which may sound familiar to some as it was used to treat COVID, and a monoclonal antibody treatment called MBP 134, which contains two proteins engineered to neutralize the virus. About 1200 patients will be enrolled in the trial and will receive either both treatments remdesivir alone. Mbp 134 alone or neither treatment, meaning that they would only receive supportive care. These treatments have shown promise in animal models, but more data are needed to understand their efficacy in human patients. Additionally, even if these treatments are effective, there are still significant barriers ahead. Both treatments are administered intravenously.Dr. Michael Osterholm : The MBP MBP134 as a one time infusion and remdesivir for ten days. This presents a high burden in an area with an already overwhelmed healthcare infrastructure. This brings me to the next point I want to cover. Chris, the healthcare worker strike is a really important issue. After alleging not being paid for multiple months, staff at an Ebola treatment hospital in Ituri walked off the job last week. In addition to these payment issues, workers have also faced attacks from community members who oppose the Ebola response. It is no question that working conditions, as well as the risk of Ebola exposure, are contributing to fatigue, fear and burnout among health care workers. And as of last week, an estimated 112 healthcare workers have become infected and 32 have died during the outbreak. And that number is likely to grow as transmission continues. The bottom line is that while there is some hope ahead with these clinical trials, things are still likely going to get a lot worse before they get better. To those who are working hard to mitigate the outbreak and treat patients, we can never thank you enough for your courageous and critically important effort. We will continue to keep you all updated as the outbreak progresses. In the meantime, I urge you to all check out the CIDRAP news coverage of the issue to stay informed between episodes.Chris Dall: Now for our ID query. On the June 18th episode of the podcast, we discussed the potential public health threats posed by the World Cup, which will wrap up this Sunday. A few listeners have written to ask if any World Cup associated disease clusters or outbreaks have been reported. Mike, what can you tell them?Dr. Michael Osterholm : I want to start by saying what a joy it has been to see so many soccer fans from around the globe gathering across North America to support their teams and countries, whether you're a soccer fan or not. Over the past month, we've seen fans unite and form unexpected friendships over their shared love of the beautiful game, a universal language. During such tense times, both here at home and across the world, the tournament has been a breath of fresh air from the Scots taking over Boston to the bond form between the Algerian fans and the people of Lawrence, Kansas, and to the friendships formed between the Korean and Mexican fans ahead of their team's group stage match. This month has provided so many uplifting moments and stories of connection and kindness. I know so many people will be sad to hear the final whistle on Sunday. A month ago, Chris, you asked me about my concerns heading into the World Cup, and I think my answer may have surprised some listeners. I noted that while 6.5 million people gathering and cheering in close quarters provides potential for disease transmission, 6.5 million is not an unusual number of visitors for us to have in our country at a given time. Remember, I noted that in 2024 we had have 60 million visitors total. There was not a particular pathogen I was concerned about with the arrival of these spirited fans. I was actually more concerned about a lack of centralized, coordinated effort or even support from the federal government to be prepared to detect and respond in case of any outbreaks.Dr. Michael Osterholm : Much of these efforts have fallen on individual host cities, states and also the incredible important group led by Doctor Rebecca Katz at Georgetown University, who have stepped up to lead monitoring and detection efforts throughout the tournament with no federal funding. Rebecca and her team have been running the Health Security Operations Center in collaboration with MedStar health. The team monitors wastewater data and travel data, as well as less obvious sources such as social media, to identify potential outbreaks and respond accordingly. One example of the work that the operation center started was when Caitlyn Jenner, who leads your local epidemiologist And is working with the operation center during the World Cup efforts. Notice several social media posts about gastrointestinal illness in Seattle. She notified the wastewater team, who identified a spike in adenovirus in Seattle, and that they were able to notify state and local public health departments about the uptick. The Operations Center releases a report each weekday that includes risks near any host city or team base camp. Overall, the operations center has not identified any major disease outbreaks or clusters. There has been an uptick in adenovirus activity in Seattle, as I mentioned, and an uptick in hepatitis A wastewater detections in several cities. But it seems that so far, the World Cup has not been the superspreader event that many people were fearing it would be.Chris Dall: Mike. There was a recent KFF poll that found that fewer than 1 in 10 U.S. adults firmly believed in any of the vaccine myths they've heard, like the false claim that the MMR vaccine causes autism, but about 30% expressed some uncertainty about these myths. Kff analysts dubbed this group the Malleable Middle. Is this good news or bad news?Dr. Michael Osterholm : I'd say the answer is mostly good news, but it comes with a warning sign. What's striking about this new poll from KFF is that despite years of misinformation about vaccines, fewer than 1 in 10 Americans firmly believe any of the major vaccine myths, including the long debunked claim that the MMR vaccine causes autism. That suggests that the most extreme forms of vaccine misinformation have not been fully embraced by the public. But the more revealing finding is that roughly 30% of adults fall into this malleable middle. These are people who aren't committed vaccine skeptics, but they're also not fully convinced by the scientific evidence. They often respond that vaccine myths are probably true or probably false, reflecting on certainty rather than conviction from a public health perspective. That uncertainty is both encouraging but also concerning. It's encouraging because people in the malleable middle are still persuadable. They're not hardened believers in conspiracy theories. In fact, Cfse analysis suggests that confusion, rather than deep ideological opposition, determines most of their opinions. That's especially important because even among parents who delay or skip childhood vaccinations, uncertainty is more common than strong belief in vaccine myths. In other words, many hesitant parents may still be reachable through trusted information and conversations. I say it is also concerning because the uncertainty can and is still influencing behavior. We know childhood vaccination rates are slipping. Mmr coverage among US kindergartners fell to under 93% in the 2024-25 school year below the 95% level typically needed for strong community protection against measles.Dr. Michael Osterholm : More Concerningly. This is not an evenly distributed 93%. There are many schools and counties with vaccination rates under 50%, leaving them highly vulnerable to disease transmission. At the same time, measles outbreaks have surged, with 30 outbreaks already reported in 2026 following a record 48 outbreaks in 2025 as vaccination rates declined. Even modest levels of doubt can translate into more parents delaying shots and more communities becoming vulnerable to outbreaks. The poll also provides clues about what may help adults who have a trusted healthcare provider are significantly less likely to believe or lean towards believing vaccine myths. Conversely, people who regularly rely on social media or AI tools for health information are more likely to endorse these myths. That suggests that the challenge isn't simply misinformation itself. It's whether people have access to trusted sources that can answer questions and build confidence. So if you're looking for a takeaway from this poll, here's mine. Americans don't seem to have a widespread firm belief in vaccine myths. Contrary to what it may feel like at times, but we do have a substantial problem with vaccine uncertainty. This uncertainty matters. The encouraging part is that people in the middle are still open to evidence. That challenge is reaching them before confusion turns into vaccine refusal, and before declining vaccination rates lead to even more preventable disease outbreaks.Chris Dall: Now that we've spent most of this podcast telling our listeners about summertime infectious disease threats, Mike, can we give them some good news on those wintertime threats? COVID-19 flu and respiratory syncytial virus.Dr. Michael Osterholm : Chris, I love good news. Fortunately, we have another short and sweet respiratory update today. Wastewater levels for all three viruses remain very low. We may be seeing the early signs of COVID-19 wastewater concentrations increasing in the west and northeast, but the increases are minimal. Influenza and RSV activity remains low and decreasing or stable across every metric. The one metric we're keeping an eye on is for COVID-19 emergency room department visits, where we have seen slight increases for less than one year old and 1 to 4 year old age groups. We'll keep an eye on this and keep you updated in the coming weeks.Chris Dall: Now it's time for this week in public health history. Mike, what are we commemorating this week?Dr. Michael Osterholm : Chris, this week's public health history segment is one of remembrance, not of celebration. Next week on July 24th marks the 54th anniversary since the Washington Star newspaper broke the story on the Tuskegee Experiment, a syphilis experiment which withheld diagnosis and treatment of black men in Alabama over multiple decades. While news of the experiment first broke in 1972, the actual experiment dates back 40 years earlier in 1932. The US Public Health Service partnered with Tuskegee Institute to study the effects of untreated syphilis in black men. There were about 600 black men who were persuaded into becoming a part of the experiment, 400 of which already had syphilis and 200 who did not. Researchers did not collect informed consent from any of the participants, and many people within the community thought it was a special government health care program. About 200 of these black men were purposely left untreated and suffered side effects, even after penicillin was discovered as a cure for syphilis in 1945. This violates every medical and public health principal to ensure no harm to study participants. It is standard practice that, should an effective treatment become available during the course of a clinical trial, participants be offered the treatment even if it would invalidate or limit study results.Dr. Michael Osterholm : Over 100 participants died from the disease or subsequent complications, and dozens of partners and children of participants were also affected. Investigative reporter Jean Heller of The Associated Press was the first to break the news. Public outcry followed suit, and three months later the study was shut down. A year later, the NAACP filed a class action lawsuit for survivors, reaching a $10 million settlement in 1974. The US government did not issue a formal apology until over 20 years later during the Clinton administration. Clinton's apology read: "What was done cannot be undone. But we can end the silence. We can stop turning our heads away. We can look you in the eye and finally say, on behalf of the American people, what the United States government did was shameful. And I am sorry to our African American citizens. I'm sorry that your federal government orchestrated a study so clearly racist." The grave consequences of the Tuskegee experiment have gone on to fuel understandable distrust between the black community and the medical establishment, even today. It's critical we don't shy away from histories like these, and look forward towards providing the most ethical and equitable care for all people. Tuskegee is a glaring reminder of that.Chris Dall: Mike, what are your take home messages for today?Dr. Michael Osterholm : Well, thanks, Chris. Three messages. First, let me focus on the cyclospora outbreak. I believe that there should be a really comprehensive hot wash after the outbreak is over to understand what went right and what went wrong. This is not to point fingers at people for failing, but I believe that this outbreak investigation lacked a lot in terms of messaging, in terms of execution and understanding what is causing the outbreak. Only through a review of events like this are we in a position to get better. Point two, Ebola is a slow moving, catastrophic infectious disease tsunami. And when I mean by slow moving, it doesn't mean that there's not a lot of active transmission in that community. But I see this unfolding for months and months ahead. And finally, breathe the air. We're still in good shape. It's wonderful when I can feel the confidence in COVID, influenza, and RSV not being the main culprits in any one given day in my life. And right now, the air we're breathing surely gives us that possibility.Chris Dall: And Mike, what's your closing song for this episode?Dr. Michael Osterholm : Well, Chris, I have to say, this was a particularly difficult choice today. There is so much right now that feels so painful in this world when it comes to infectious diseases. We decided we needed something positive. So we chose a song by Kacey Musgraves, "Rainbow." It was released as the fifth and final single from Musgraves third studio album in February 2019. Musgraves co-wrote the song with Shane McAnally and Natalie Hemby. Its release coincided with her performance at the 61st annual Grammy Awards. This song holds great significance for Musgraves for several reasons, but by far the most important one was it was the last song her grandmother heard her write and was played at her funeral, and she also noted she hoped the song would be an anthem for those facing adversity, such as those in the LGBT community. I share with you a happy song, a positive song, a way to end this podcast today with a smile. Here it is. Kacey Musgraves: "Rainbow"When it rains, it pours. But you didn't even notice. It ain't raining anymore. It's hard to breathe. When all you know is the struggle of staying above the rising water line. Well the sky has finally opened. The rain and wind stopped blowing. But you're stuck out in the same old storm again. You hold tight to your umbrella. But darling, I'm just trying to tell you that there's always been a rainbow hanging over your head. You could see what I see. You'd be blinded by the colors. Yellow, red and orange and green. And at least a million others. So tie up the boat, take off your coat and take a look around. Because the sky has finally opened. The rain and wind stopped blowing. But you're stuck out in the same old storm again. You hold tight to your umbrella. Well, darling, I'm just trying to tell you that there's always been a rainbow hanging over your head. Oh, tie up the boat, take off your coat and take a look around. Everything is all right now. Because the sky has finally opened. And the rain and wind stopped blowing. But you're stuck out in the same old storm again. Let go of your umbrella. Cause darlin, I'm just trying to tell you. That there's always been a rainbow hanging over your head. Yeah, there's always been a rainbow hanging over your head. It'll be all right. Kacey Musgraves.Thank you again for joining us. I hope we were able to give you some of the kind of information you're looking for. And hopefully we clarified any confusion that might be occurring with some of these events over the course of the next weeks. I only anticipate that things are going to get more complicated with infectious diseases and for that matter, the whole world. Now is the time for us to remember how important it is to be kind, to be thoughtful, to care. I hope you have a great two weeks. Enjoy your summer. Thank you, thank you, thank you.Chris Dall: Thanks for listening to the latest episode of the Osterholm update. If you enjoyed the podcast, please subscribe, rate and review wherever you get your podcasts. And be sure to keep up with the latest infectious disease news by visiting our website, CIDRAP.umd.edu. This podcast is supported in part by you, our listeners. The Osterholm Update is produced by Sydney Redepenning, Elise Holmes and Ruby Guthrie. Our researchers are Cory Anderson, Meredith Arpey, Leah Moat, Emily Smith, Clare Stoddart, Angela Ulrich and Mary VanBeusekom.
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