Pathogen Perspectives

Put on a coat. Dry your hair. Don’t sit on that toilet seat. Green snot means antibiotics. And if food hits the floor, you have five seconds. But how much of the infectious-disease wisdom we inherited from our parents is actually true? In this episode of Infectious Dose, we put some of the classics under the microscope: whether being cold can really make you sick, what green mucus actually tells us, why fever isn’t a good measure of how sick someone is, whether public toilet seats deserve their reputation, what the five-second rule gets wrong, and why a case of head lice does not require decontaminating your entire house. It turns out many of these myths started with perfectly reasonable observations. The problem came when generations of parental anxiety tried to explain the biology. Mom wasn’t necessarily wrong about what she saw. She was just wrong about the rhinovirus waiting for you on the porch. Want to dig into the science behind this episode? You’ll find the full companion blog post, including annotated citations and links to the research, at InfectiousDose.com. While you’re there, you can also sign up for Field Notes, the free Infectious Dose newsletter, for more infectious-disease stories, outbreak updates, and curiosities between episodes.

In this Outbreak Watch, we return to the outbreaks and signals we’ve been tracking...and several have changed.  New genomic evidence is revealing the hidden early months of the DRC’s Bundibugyo Ebola outbreak, while Uganda has successfully ended transmission across the border. New World screwworm is worsening in Sonora as cattle imports into Arizona resume, and COVID-19 is climbing again across the South amid changes to how CDC categorizes and displays wastewater activity. We also check in on measles, Cyclospora, H5 avian influenza, Vibrio vulnificus, mpox, Oropouche, and other signals on the board—and close the loop on the quarantined riverboat near Kinshasa. Full citations in companion blog post at Infectious Dose. Subscribe to Field Notes to continue the conversation around episodes and weekly outbreak updates. 

Somebody's roommate's cousin definitely knows the person this happened to. This month on Outbreak After Dark, pull up a chair for an evening of infectious-disease urban legends. Heather investigates the infamous “Welcome to the World of AIDS” story and infected-needle scares, whether you can really get crabs from a toilet seat, and the long-running warning about fatal leptospirosis from rat urine on soda cans. Each story gets a Campfire Verdict as we separate genuine biology from folklore and ask what happens when something that could happen gets transformed into a story people swear happened. Then Heather and her unusually quiet cardboard cohost, CK, play Construct a Contagion, building an infectious-disease urban legend from scratch and testing their creation against real microbiology. Because possible, plausible, and proven are three very different things. Citations and resources can be found in the companion blog post at Infectious Dose.

What changes when the sun goes down? In the final episode of From Sunrise to Starlight, we're heading down a summer trail as dusk gives way to darkness, following the microbes—and the vectors and hosts that carry them—into the night. We'll explore why different mosquitoes keep different schedules, how ticks find hosts, what wildlife encounters actually mean for zoonotic disease risk, and how artificial light can alter nighttime ecology. Then we'll emerge from the woods beside a dark lake, turn off the flashlight, and look up. Because infectious-disease risk isn't simply about which pathogens are present. It's about encounters: where they happen, when they happen, and how microbes, vectors, hosts, and human behavior come together. Night Hike: Following Microbes Into the Dark closes our August journey from the first light of morning to a lake beneath the stars. All citations in the companion blog post at Infectious Dose. 

It’s afternoon in our journey From Sunrise to Starlight, and we’re spreading out the picnic blanket. This week, we’re following the hidden microbial pathways running through a summer meal. From farms and kitchens to the cooler, the blanket, and eventually us. We’ll explore how foodborne pathogens such as Salmonella, Listeria, Cyclospora, and norovirus reach our food, what happens as the cooler warms, and how hands, utensils, flies, ants, and even a shared bag of chips can turn a picnic into a transmission network. Plus: Does the five-second rule work? Can ants actually contaminate your food? Is mayonnaise really the problem with potato salad? And when the picnic is over, which leftovers should come home? Pull up a corner of the blanket. Lunch is served. See companion blog post for citations. Subscribe to Field Notes to continue the conversation.

The guy in the white house signed a new executive order changing federal childhood vaccine policy. So what actually changed and what does it mean for families? In this bonus Booster Dose episode, Heather separates the executive order itself from claims made during its announcement and break down what we know right now. She covers the new categories of childhood vaccine recommendations; the proposal to separate MMR into individual measles, mumps, and rubella vaccines; the directive calling for childhood immunizations to be administered at separate medical visits “to the maximum extent feasible”; potential effects on vaccine access and insurance coverage; what states can—and don’t have to—do in response; and what parents should know about upcoming vaccination appointments. She also addresses claims he made about MMR safety, the amount of vaccine children receive, giving multiple vaccines at once, and autism and point you toward previous Vaccine Safety Files episodes for deeper dives into the evidence. This policy is still developing. This episode reflects what we know as of August 10, 2026. Relevant Vaccine Safety Episodes: Measles and MMR Too Many Too Soon? Vaccines & Autism  

Ebola nears 4,000 confirmed cases in the Democratic Republic of the Congo, New World screwworm continues circulating in Texas, and the U.S. cyclosporiasis outbreak is expanding. In this Outbreak Watch, we look at what has changed and what the evidence actually tells us, including why there’s currently no evidence that mutation explains the severity of the Ebola outbreak and why wildlife surveillance may be crucial to understanding screwworm transmission. Then we zoom out for Global Signals and Surveillance Milestones: Chile’s nationwide hantavirus response, H5 avian influenza, Oropouche virus, a 30-year measles high in the United States, and rising Hansen’s disease cases in Florida. All Citations in companion blog post at the website. Subscribe to the free Field Notes newsletter to continue the conversation around the weekly episodes. 

A summer morning at the lake is about swimming, skipping stones, dragonflies, and family memories, but it's also the perfect opportunity to explore one of nature's most fascinating invisible ecosystems. In this episode, we're diving beneath the surface of freshwater lakes to discover how microbes respond to changing environmental conditions throughout the day. We'll discuss: Why swimmer's itch is caused by a confused bird parasite—not dirty water How cyanobacterial (blue-green algae) blooms develop and why not all blooms are toxic The real story behind Naegleria fowleri, the so-called "brain-eating amoeba," and why infections remain extraordinarily rare How sunlight, temperature, wind, and wildlife shape lake microbial communities How public health agencies monitor recreational waters The growing role of citizen science in protecting lakes and rivers Whether you're a swimmer, paddler, angler, pet owner, or simply someone who loves spending time outdoors, this episode will give you a new appreciation for the remarkable—and mostly unseen—life beneath the water's surface. All citations and resources in the companion blog post on the website. Subscribe to the free weekly newsletter, Field Notes, to continue the conversation around each episode.

Medicine. Contraband. Comfort. Step inside a hidden 1920s speakeasy where the jazz is live, the whiskey is illegal, and one of the most surprising chapters in medical history unfolds. During Prohibition, physicians could legally prescribe medicinal whiskey for illnesses ranging from pneumonia and influenza to pain and "nervous exhaustion." At the same time, bootleggers, pharmacists, lawmakers, and patients were all navigating a confusing world where the same bottle could be medicine, commodity, or contraband. In this immersive Outbreak After Dark episode, Heather and Kate explore: Why doctors prescribed medicinal whiskey before antibiotics How Prohibition reshaped medical practice Patent medicines and the blurred line between treatment and marketing Industrial alcohol and the tragic consequences of denaturing What these stories reveal about medicine, evidence, and human behavior Join us for an evening of jazz, secret passwords, and one of the most unusual intersections of infectious disease and American history. Full citations and more at the website. Subscribe to the Field Notes newsletter to continue the conversation and get updates on outbreaks and a peek behind the scenes.

For much of history, entering a hospital could be one of the most dangerous decisions a person could make. Patients survived injuries and operations only to die from infections acquired in the very places meant to heal them. In this final episode of our Turning Points in Infectious Disease series, we explore the revolution that transformed hospitals from centers of disease transmission into institutions designed to prevent infection. Follow the stories of Ignaz Semmelweis, Louis Pasteur, Joseph Lister, and Florence Nightingale as medicine gradually uncovered the invisible world of microbes and reshaped healthcare around one revolutionary idea: the safest infection is the one that never happens. We'll also explore why healthcare-associated infections still occur today and what this history teaches us about the ongoing challenge of translating scientific evidence into everyday practice. Check out the companion blog post at the website for full, annotated citations , historical images, and more. And subscribe to the free weekly newsletter, Field Notes, to continue the conversation, get updates on outbreaks and the infectious disease signals Heather is paying attention to, and get a peek behind the scenes.

In this edition of Outbreak Watch, we provide a current briefing on the major outbreaks unfolding now, including Ebola in the Democratic Republic of the Congo and Uganda, New World screwworm in the United States, and the rapidly growing U.S. cyclosporiasis outbreak. Along the way, we answer the questions listeners are asking most. We also examine several emerging signals, including H5 avian influenza in mammals, the potential for Vibrio vulnificus infections this summer, and why surveillance systems are just as important as laboratories when it comes to detecting outbreaks before they become national emergencies. As always, you'll find annotated references, official dashboards, and links to additional resources in the companion blog post at InfectiousDose.com. If you want the free, weekly companion newsletter to the episodes, Field Notes, subscribe here.

For most of human history, epidemics were something people endured—not prevented. Smallpox alone killed hundreds of millions of people, leaving survivors scarred, blinded, or forever changed. But hidden within that devastation was a remarkable observation: those who survived rarely became sick again. In this episode, we explore the centuries-long journey from variolation to vaccination, following the observations of physicians, the experiences of milkmaids, the bold experiment of Edward Jenner, and the scientific breakthroughs that transformed an idea into one of medicine's greatest achievements. We'll also trace how Jenner's work inspired generations of scientists, eventually leading to vaccines against countless other diseases and the global eradication of smallpox. This episode is part of our July series, Turning Points in Infectious Disease, exploring the discoveries that fundamentally changed humanity's relationship with disease. This week, we examine the moment prevention became possible. For the full list of annotated citations, historical images, and additional resources, visit the companion blog post at InfectiousDose.com. And while you're there, subscribe to Field Notes, our free weekly newsletter featuring an expanded conversation about the episode, outbreak updates, infectious disease signals I'm keeping an eye on, and behind-the-scenes notes from Infectious Dose.

For much of history, disease claimed more soldiers than combat. In this episode of Infectious Dose, we trace the evolution of military preventive medicine—from the Revolutionary War to the present day—and explore how armies came to view infectious disease as an operational threat rather than an unavoidable consequence of war. We'll follow the story through George Washington's smallpox inoculation campaign, Florence Nightingale's sanitation reforms during the Crimean War, Walter Reed and William Gorgas's fight against yellow fever, the development of military vaccination programs, the adenovirus outbreaks that reshaped recruit health, COVID-19 aboard the USS Theodore Roosevelt, and the ongoing influenza outbreak among military trainees at Lackland Air Force Base. It's the story of how prevention became strategy—and why the invisible enemy continues to shape military readiness today. Companion blog post with all citations and resources at Infectiousdose.com Subscribe to the free, weekly Infectious Dose newsletter, Field Notes. 

In the mid‑20th century, ranchers across the southern United States watched livestock being literally eaten alive by a flesh‑eating parasite: New World screwworm. This episode tells the story of how an entomologist’s “absurd” idea helped eradicate screwworm from North America, and why that victory is suddenly back in the spotlight as new cases appear in Texas in 2026. We follow the parasite’s biology, the development of the Sterile Insect Technique, the massive binational infrastructure that kept screwworm at bay until it was gutted last year, and the quiet, ongoing work of prevention that most people never see. Along the way, we explore what this outbreak can teach us about public health systems, maintenance versus one‑time “wins,” and why some of the most important turning points in infectious disease are really long‑term commitments. Companion blog post with annotated citations and resources at infectiousdose.com. Subscribe to Heather's free, weekly newsletter, Field Notes, to continue the conversation beyond each episode, get outbreak updates, and see behind the scenes of Infectious Dose. 

June's Summer Rain series wraps up with a tribute to Gulf Coast mosquitoes. In this episode of Outbreak After Dark, Heather and Kate explore the anatomy of a mosquito bite—from the moment a female mosquito detects carbon dioxide to the itch that keeps you awake long after she's gone. Topics include: • How mosquitoes find humans • Why only female mosquitoes take blood meals • The surprising anatomy hidden inside a mosquito's proboscis • Why mosquito bites itch • Histamine, nerves, and the science of scratching • Why some people attract more mosquitoes than others • Mosquito-borne diseases and changing mosquito ranges • Practical mosquito prevention tips Plus: a Galveston mosquito disaster and an unexpectedly heated discussion about the plural of proboscis. Recipes for Night Hum, Wheal & Fizz, Grilled Proboscides, and Afterbite are available in the accompanying blog post at infectiousdose.com Subscribe to the free weekly newsletter, Field Notes.

Outbreak Watch returns with updates on three unfolding biological events and the systems responding to them. This week: • The Bundibugyo Ebola outbreak in the Democratic Republic of the Congo becomes the largest on record as contact tracing, clean water access, and response operations face growing challenges. • The Andes hantavirus outbreak linked to the MV Hondius cruise ship is behaving as expected, providing an important lesson in what successful containment looks like. • New World screwworm detections in the United States highlight ongoing debates about surveillance, preparedness, and the challenges of responding to an emerging threat when critical systems must be rebuilt. In this episode, we explore visibility, uncertainty, and the operational realities that shape outbreak response long before most people hear about it. For weekly outbreak updates, subscribe to the free Infectious Dose newsletter, Field Notes, at infectiousdose.com

You can smell rain before it arrives. The air changes. The wind shifts. And somehow, before the first drop falls, you already know a storm is coming. In this immersive episode of Infectious Dose, we explore the science behind that experience. We'll follow a summer storm from distant rain clouds to the microbes living beneath our feet, uncovering the roles of petrichor, geosmin, and the remarkable biology behind one of nature's most beloved scents. Along the way, we'll explore why humans are so sensitive to the smell of rain, how storms become tied to memory, and why a single breath of cool air before a summer downpour can transport us years into the past. Part science story. Part sensory journey. Part summer rain.  Experience audio of a real summer storm from Heather's patio Part of our June series: Stories of Summer Rain. Citations in companion blog post at Infectiousdose.com Sign up for the free weekly newsletter, Field Notes

In this episode of Infectious Dose, Heather explores one of the strangest allergic conditions modern medicine has ever identified: a syndrome in which a tick bite can trigger an allergy to mammalian meat weeks, months, or even years later. Why do symptoms often appear in the middle of the night instead of immediately after a meal? How did a cancer drug help scientists solve the mystery? Where does the alpha-gal molecule come from, and why do ticks seem uniquely capable of triggering this unusual immune response? Join us as we follow the trail from the woods to the dinner table and unravel the science behind alpha-gal syndrome. In this episode: • What alpha-gal syndrome is and how it develops • The surprising role of the Lone Star tick • The cancer drug clue that helped solve the mystery • Why reactions are delayed for hours after eating • Diagnosis, testing, and common misconceptions • Living with AGS and preventing future tick bites • Separating evidence from conspiracy theories Part of our June series, Stories of Summer Rain, this episode explores how warm, wet environments shape the ecosystems around us—and how those ecosystems can unexpectedly shape our health. Referenced resources and scientific citations are available at InfectiousDose.com. Subscribe to Field Notes, the free Infectious Dose newsletter, for weekly Outbreak Watch updates and additional resources.

In this episode of Infectious Dose, Heather explores the infectious disease risks that follow hurricanes, tropical storms, and flooding events. Learn how severe weather changes exposure pathways for pathogens already present in our environment and why recovery can create unique health challenges long after the rain stops. Topics include: • Floodwater and wound infections • Vibrio vulnificus and coastal flooding • Leptospirosis and rodent exposure • Mold and respiratory risks during cleanup • Mosquito blooms after heavy rainfall • Food and water safety after power outages • Building an infectious disease-informed hurricane preparedness kit Plus: A free downloadable Infectious Disease Hurricane Preparedness Guide with checklists, safety tips, emergency reference formulas, and a personal medical information worksheet. Download in companion blog post at Infectious Dose. The storm isn't always the biggest health risk. Sometimes it's the week after. Subscribe to the free Infectious Dose newsletter, Field Notes, here.   

Introducing Outbreak Watch by Infectious Dose. When major outbreaks evolve quickly, Heather will occasionally release these extra episodes featuring timely updates and systems-focused analysis. In this first Outbreak Watch episode, we examine the rapidly escalating Bundibugyo Ebola outbreak in eastern DRC and Uganda alongside the continuing Andes hantavirus cluster linked to the MV Hondius cruise ship. We break down the latest WHO numbers, why Ebola transmission is accelerating through conflict-affected mining corridors, what new genomic and geospatial analyses reveal about the outbreak’s spread, and why public-health responders are struggling to contain it amid violence and instability. We also discuss the newest hantavirus cases emerging internationally weeks after passengers returned home, why the slow appearance of additional cases is expected for Andes virus, and how this cluster has already affected global biocontainment logistics. Finally, we look at the U.S. decision to send exposed Americans to a quarantine facility in Kenya instead of bringing them home for monitoring and treatment — and what that reveals about confidence in domestic public-health systems. Pathogens don’t create emergencies in isolation. They exploit the vulnerabilities we leave open for them.

A nurse in Louisiana receives an HIV diagnosis that doesn’t make sense. No clear exposure. No obvious source. And eventually, investigators begin to suspect something far more disturbing. In this episode of Outbreak After Dark, Heather and Kate explore the real case that brought forensic virology into the courtroom for the first time. Through genetic sequencing and phylogenetic analysis, scientists traced the relationships between viruses to help prosecutors build a criminal case against a physician accused of intentionally infecting his former partner. How can a virus become evidence? What can viral evolution reveal? And how do you explain that science to a jury? This is the story of the case that asked whether a virus could testify. Topics include: Forensic virology Viral mutation and transmission Scientific evidence in criminal court Daubert standards The Richard Schmidt case And because this is Outbreak After Dark, there’s also a menu: • Chain of Custody cocktail • Cold Case File mocktail • Trace Evidence Bites • Gel Run Layers dessert All recipes and citations in the companion blog post at infectiousdose.com Subscribe to the free weekly newsletter, Field Notes, to continue the conversation.

A new Ebola outbreak is unfolding in Central Africa — this time caused by Bundibugyo ebolavirus. As cases rise in the Democratic Republic of the Congo and Uganda, fear and misinformation are spreading too. In this episode, we break down: What Ebola actually is How Ebola spreads — and how it doesn’t Why healthcare workers and caregivers are at highest risk What happens inside the body during Ebola infection Why Ebola outbreaks amplify through strained systems The latest updates on the 2026 Bundibugyo outbreak Newly released genomic data suggesting a possible new spillover event Hot Zone Hotline for listener questions This episode also explores the human side of Ebola outbreaks: caregiving, fear, stigma, survival, and the difficult realities faced by affected communities. Companion blog post with transcript, references, outbreak updates, and photographs from the 1995 Kikwit outbreak: Infectious Dose Subscribe to the free weekly newsletter, Field Notes, for outbreak updates and behind-the-scenes context.

Last week, the central question surrounding the MV Hondius outbreak was whether Andes virus was spreading person-to-person at all. This week, the evidence shifted. In Part 2 of Hantavirus on the High Seas, we revisit the major questions from last week’s episode and examine what new genomic data, case timelines, and public-health guidance now suggest about the outbreak. We break down what changed, what remains uncertain, and why the public conversation around “airborne” spread, “prolonged close contact,” and precautionary public-health measures became so messy in real time. Topics include: Updated case timeline and international spread New genomic sequencing analysis Evidence supporting likely person-to-person transmission Why “person-to-person” does not automatically mean “pandemic-level spread” The difference between scientific evidence and public-health operations WHO’s new technical guidance for disembarkation and quarantine The Tristan da Cunha military medical deployment The International Hantavirus Society’s updated statement Why outbreak language became so contentious after COVID This episode is less about headlines and more about learning how scientific understanding evolves while an outbreak is still unfolding. Subscribe to weekly Field Notes to continue the conversation Companion blog post with annotated citations at infectiousdose.com

A hantavirus outbreak linked to a cruise ship has triggered fear, speculation, and growing debate online about whether the virus could be spreading person-to-person. But what do we actually know right now? In this episode, Heather breaks down the current hantavirus cruise cluster through the lens of science communication and uncertainty. Rather than focusing only on the facts of the outbreak, this episode explores a bigger question: What does trustworthy, imperfect outbreak communication sound like when the evidence is still coming in? Topics include: the timeline of the current cruise ship cases why the first infection almost certainly occurred before boarding the difference between hantavirus “airborne” transmission and viruses like measles what we know about Andes virus and rare person-to-person spread how outbreak investigations work in real time and why “we haven’t ruled it out” is not the same thing as “this is happening” Heather also introduces a practical framework for understanding outbreak communication. This episode is about resisting panic, avoiding false certainty, and rebuilding a clearer understanding of how science works when the story is still unfolding. Heather will also be following the outbreak with updates in her free, weekly newsletter, Field Notes. Subscribe at the link if you want to join the conversation. All citations in the companion blog post at infectiousdose.com

Imagine getting sick in the 1700s—before microbes were discovered, before antibiotics, and before infection had a clear cause. In this Outbreak After Dark episode, we explore the strange, unsettling, and sometimes surprisingly insightful treatments used to fight disease in the pre-germ theory era. From bloodletting and mercury to tobacco smoke enemas and malariotherapy, these practices reflect a time when medicine was working without seeing the real enemy. Along the way, we also uncover the rare moments when history got it almost right—and how those moments helped shape the science we trust today. Don't forget to sign up for my free weekly newsletter Field Notes, to continue the conversation around each episode. Transcript and annotated citations in companion blog post at infectiousdose.com 

There’s a virus you probably already have. Epstein–Barr virus infects nearly 95% of adults worldwide. For many, it shows up once—fatigue, a sore throat, maybe a diagnosis of mononucleosis—and then disappears. But EBV doesn’t disappear. It stays, establishing lifelong infection inside B cells—the very cells responsible for immune memory. Most of the time, the immune system keeps it under control. But EBV is not passive. It shifts between latency and reactivation, adapts to immune pressure, and in some cases contributes to cancer and chronic disease. In this episode, we explore: How EBV infects epithelial cells and B cells The molecular mechanisms that allow it to persist for life Latency, reactivation, and immune system control Why EBV is linked to cancers like Hodgkin lymphoma and nasopharyngeal carcinoma How host genetics and viral variation shape disease risk And what new research suggests about finally preventing infection This isn’t just a story about a virus. It’s a story about what happens when infection never truly ends. Want to go deeper? Field Notes is my free, weekly newsletter where I expand on one key idea from each episode. It’s not a summary—it’s a shift in perspective. Subscribe here. Annotated citations are in the companion blog post at infectiousdose.com

Murine typhus is a flea-borne bacterial infection that continues to circulate in parts of the United States, particularly in urban and suburban environments. But it’s often missed—because its symptoms are nonspecific, its rash may be subtle or absent, and it doesn’t fit the diagnostic patterns clinicians expect. In this episode, we explore: How murine typhus is transmitted (and why fleas matter more than you think) The role of urban ecology, including opossums, rodents, and flea vectors What happens biologically when Rickettsia typhi infects endothelial cells Why these infections are frequently misdiagnosed or overlooked This is not just an episode about typhus—it’s about how recognition fails, and what that means for the diseases hiding in plain sight. Also in this episode, introducing Field Notes, the new, free email newsletter companion to the episodes - not a recap, but what stays with Heather after the episodes. Issues are sent mid-morning after episodes drop. Sign up on the website if you want to receive Field Notes.  Companion blog post with transcript and all citations is at infectiousdose.com  

One year in, Heather steps back to reflect on what this podcast has become—and what changed along the way. What started as a focus on clear, accurate science grew into something more layered: an exploration of how trust, systems, and lived experience shape the way people understand infectious disease. It also opened the door to creative storytelling, immersive formats, and conversations that challenged her own assumptions. This episode includes a few short clips from the past year—moments that capture the range of the show, from unsettling to unexpected to quietly funny. If you want to keep following those threads a little further, Heather is starting a free, weekly companion called Field Notes—a place to sit with one idea from each episode and see where it leads. The first issue arrives with next week's episode.  Whether you’ve been listening from the beginning or just found your way here, thank you so much for listening. We're glad you’re here. Companion blog post at Infectiousdose.com

You’re about to step inside a BSL-4 lab. Not a tour. Not an explanation. An experience. You’ll move through clearance. Suit up. Connect to air. And cross the threshold into one of the most controlled environments in the world. Inside, the work is methodical. Quiet. Precise. And everything you think you know about these labs… starts to shift. Put your headphones on. And step inside. More information and resources can be found at infectiousdose.com.

The plague doctor: a symbol of fear, medicine, and mystery. But were they really the heroes we imagine—or something more complicated? In this Outbreak After Dark episode, we explore the real history behind the iconic beaked mask. From medieval theories of “bad air” to the rise of quarantine systems and early public health policy, we follow the evolution of plague response—and the role of the doctors at its center. Along the way, we unpack: What plague doctors actually did (and didn’t do) Why their treatments were mostly ineffective How quarantine emerged as one of the few strategies that worked The rise of epidemic bureaucracy—and what it meant for ordinary people Why the plague doctor image still resonates today This episode also explores the emotional reality behind the mask—both in the past and in modern medicine—and asks a deeper question: What does care look like when distance becomes necessary? 🔥 Plus: our themed Masks & Miasma snack break, with recipes and all citations in the blog post at infectiousdose.com  

What if the biggest misunderstandings about vaccine safety aren’t just about the science—but about how the system communicates it? In this updated guided tour of the Vaccine Safety Series, Heather maps the episodes that break down how vaccines are tested, monitored, and evaluated—and where communication and institutional failures have contributed to confusion and mistrust. This episode is designed to help you navigate the series—whether you’re new, revisiting key topics, or looking for the right episode to share with someone who has questions. Because understanding the science matters. But understanding the system matters too. Where to go next in the Vaccine Safety Series: 👉 Too Many Vaccines Too Soon? — Understanding the childhood vaccine schedule 👉 Expecting Protection — Vaccines during pregnancy 👉 The Wakefield Story — How misinformation took hold All citations in the blog posts at infectiousdose.com

When we talk about misinformation in public health, we usually imagine social media, conspiracy theories, or individuals misunderstanding science. But what if some of the most influential misinformation starts somewhere else? In this episode of Infectious Dose, Heather speaks with biomedical researcher Dr. Mark Ungrin about how scientific ideas move through institutional systems and why correcting errors can be surprisingly difficult once they become embedded in policy. They discuss: Why “human error” is often a misleading explanation for systemic failures How flawed studies can shape public health guidance Why institutional hierarchies can make correcting mistakes difficult The role of evidence-based medicine in shaping policy decisions Why transparency and accountability are essential for rebuilding public trust This conversation explores how misinformation can emerge from institutional processes themselves — and why understanding those systems is critical for responding more effectively to future pandemics and biological threats. 👉Dr. Ungrin's Talk: Science, Pseudoscience and Public Policy https://whn.global/science-pseudoscience-and-public-policy/ Transcript and sources at infectiousdose.com

Mpox isn’t just a headline from 2022. In this episode, we explore what scientists have learned about mpox since the global outbreak — from how the virus moves through the body to why its lesions can be so painful. We break down the biology of orthopoxviruses, the surprising role of human immune enzymes in shaping viral evolution, and the emergence of a new lineage known as clade Ib that researchers are watching closely. We also look at the bigger picture: wildlife reservoirs, genomic surveillance, vaccine strategies, and the global inequities that shape how outbreaks unfold. Mpox is not the most transmissible virus, nor the most lethal. But it offers a clear window into how zoonotic diseases evolve — and what happens when global attention fades while transmission continues. Topics covered: Mpox symptoms and pathogenesis How the virus spreads APOBEC3 mutations and viral evolution Clade Ib and emerging lineages Wildlife reservoirs and spillover Vaccines, antivirals, and public health response Global inequity in outbreak response See blog post at Infectiousdose.com for all citations.

What if attraction isn’t entirely yours? In this Outbreak After Dark episode, Heather, Kate, and Sam gather around the campfire to explore the parasites, fungi, and viruses that manipulate behavior in the name of survival. We’re talking: Toxoplasma gondii, the parasite that dampens rodents’ fear of cats The lancet liver fluke, which turns ants into grazing bait Ophiocordyceps, the real-life “zombie ant” fungus Baculoviruses that liquefy caterpillars from the treetops Hairworms that drive crickets into water Limb-altering trematodes that make frogs easier prey Insect viruses that disrupt courtship songs and pheromones And the global rise of antifungal-resistant Candidozyma (Candida) auris Then we turn the lens toward humans. Do gut microbes influence mood and attraction? Are pheromones real? What happens to your microbiome when you kiss someone? (Answer: about 80 million bacteria exchange in ten seconds.) This episode blends behavioral ecology, evolutionary strategy, fungal cautionary tales, and just enough snack-fueled chaos to keep it campfire-worthy. Because love isn’t always sweet. Sometimes it’s optimized. 🔥 Recipes for Parasite Punch, Symbiosis Spritz, Zombie Ant Tapenade Toasts, and Courtship Clusters are available on infectiousdose.com.

Nipah virus scares virologists, and for good reason. It infects endothelial cells and neurons. It can cause fatal encephalitis. It spreads from bats to humans, and sometimes between people. So why does it keep burning out? In this episode of Infectious Dose, we examine: Henipavirus biology and receptor usage (ephrin-B2/B3) Why neurotropism drives severity Why outbreaks are small but deadly Why R₀ remains low What would actually have to change for Nipah to go pandemic Why spillover keeps recurring in Kerala And why survival does not always mean full recovery This is a grounded look at pandemic thresholds — not panic headlines. Preparedness requires vigilance not hysteria. All citations in the companion blog post at infectiousdose.com

Syphilis is back—and it never really left. In this episode, we break down how a curable, preventable infection is resurging to cause a public health crisis across the U.S., and globally, especially among pregnant people and newborns. We unpack the science behind Treponema pallidum, the public health failures driving the crisis, and why trust in health systems is still broken—from Tuskegee to today. Plus: what you need to know about testing, treatment, and why a shot of penicillin makes all the difference. Sources at Infectiousdose.com

This short, standalone episode is a statement of ethics. It explains why this podcast will not remain silent in the face of state violence, the dismantling of public health, and the normalization of harm against vulnerable people. It clarifies the ethical boundaries that guide the work behind Infectious Dose: that science is for everyone, but cruelty, authoritarianism, and the protection of abuse are not neutral positions. This episode is not a scientific explainer and not an invitation to debate. It exists to make clear where this podcast stands, why silence is not an option, and why evidence, accountability, and human rights are inseparable from public health.

RSV is one of the most common respiratory viruses — and a leading cause of hospitalization in young children worldwide. In this solo episode, I explain what RSV is, how it spreads, and what illness typically looks like in babies, children, and adults. We cover when RSV can be managed at home, how to recognize breathing-related red flags, when to go to the ER or call an ambulance, and what supportive care actually helps. The episode also looks at the current RSV landscape, including rising cases in parts of the U.S. and new prevention tools — maternal vaccination and long-acting monoclonal antibodies — that are dramatically reducing severe RSV disease in infants. Clear, practical, and evidence-based. https://www.healthychildren.org/English/health-issues/conditions/chest-lungs/Pages/RSV-When-Its-More-Than-Just-a-Cold.aspx

Spiders inspire some of our deepest fears—but are they actually as dangerous as we think? In this Outbreak After Dark episode, Heather, Sam, and Kate dig into the real science behind spiders, venom, and so-called “spider bites,” separating evidence from exaggeration. Along the way, they unpack persistent myths, medical misattribution, and why spiders loom so large in outbreak lore—despite rarely being the culprit. Creepy? Yes. Deadly? Usually not. Welcome to Outbreak After Dark. Editor's Note: While this episode leans into humor and fear, spiders play an important ecological role and are rarely a danger to humans.  See companion blog post at infectiousdose.com for full transcript and references.

What are biological weapons—and what are they not? In this episode, Heather is joined by bio-risk consultant and biodefense researcher Conor Browne for a grounded, reality-based conversation about biological weapons, biodefense, and why public discourse around these topics so often goes wrong. Together, they unpack what actually defines a biological weapon, why intent and delivery matter, and how real historical programs differ from the conspiratorial narratives dominating social media and politics. They explore state and non-state capabilities, the real constraints involved in weaponization, and why most pathogens—even deadly ones—are not practical weapons. The conversation also tackles some of today’s most misunderstood ideas, including gain-of-function research, lab accidents versus deliberate release, dual-use research of concern (DURC), and the limits of attribution when outbreaks occur. Along the way, Conor explains why sloppy language isn’t just misleading—it can actively undermine public health and national security. This episode is a clear-eyed look at biological threats without fear-mongering, designed to replace panic with understanding and precision. Topics covered include: What actually qualifies as a biological weapon Why dangerous pathogens ≠ weapons Historical bioweapons programs and what they really looked like State vs. non-state actor capabilities Why lab accidents are not weapons Gain-of-function research, DURC, and political distortion How misinformation increases real biological risk

In this episode of Infectious Dose, Heather McSharry talks with Terry Virts—retired NASA astronaut, Air Force colonel, and candidate for Congress in Texas—about what happens when leadership ignores science. Drawing on his experience in aviation, spaceflight, and risk analysis, Terry discusses the real-world consequences of sidelining evidence in public health, climate, and emergency preparedness. The conversation covers COVID-era misinformation, vaccines, measles outbreaks, healthcare access in Texas, and the dismantling of scientific institutions. The episode also explores the parallels between spaceflight safety systems and high-containment biosafety labs—highlighting why science-based leadership isn’t optional when lives are on the line. 🔗 A full transcript PDF is available in the companion blog post at InfectiousDose.com. And Terry's campaign website is: https://www.terryvirts.com/ Follow Terry: @AstroTerry on Insta/Twitter/Bluesky and astro_terry on Threads Follow Heather: @pathogenscribe on Insta/Twitter/Bluesky/Threads

This week in “Seasonal, Not Safe,” we confront the truth about influenza in 2025–2026. It’s not “just the flu.” From the tragic stories of children lost to fast-moving infections, to the science of how influenza spreads, mutates, and turns deadly — this episode explores what’s really happening this season. We break down the rise of Subclade K, current global flu patterns, new U.S. vaccine policy controversies, and what makes the flu virus so evasive. Plus: how antiviral medications work, why vaccination rates are falling, and what’s coming next in the push for a universal flu vaccine.  All citations and updates available in companion blog post at infectiousdose.com

This New Year’s Eve episode isn’t about resolutions — it’s about a reset. In Still Curious: A New Year’s Reset (Without Resolutions), Heather reflects on a difficult year for science, public health, and trust, and makes the case for curiosity as a quieter, steadier way forward. Rather than focusing on optimism or big promises, this episode explores what it means to pause, to stay engaged without burning out, and to carry curiosity into the new year even when certainty feels loud. The episode closes with a gentle midnight mantra for anyone listening alone, early, or in need of calm at the turn of the year. Companion blog post at infectiousdose.com

This month’s Outbreak After Dark is a special holiday episode — and a heavier one. In A Consumption Christmas Carol , we reimagine Dickens’ classic ghost story through the real epidemic that haunted Victorian London: tuberculosis. Long before antibiotics, TB shaped daily life, art, poverty, and policy — romanticized in parlors, devastating in tenements, and deadly across all social classes. Guided by familiar spirits of past, present, and yet to come, we trace how tuberculosis was misunderstood, aestheticized, and ultimately revealed as an airborne infectious disease — one that remains among the world’s deadliest today. This episode blends historical storytelling, medical science, and reflection on why some diseases never truly stay in the past. Because this is a weightier story, we close the episode gathered by the fire for a post-Carol decompression — sharing snacks, drinks, behind-the-scenes thoughts, and space to process the history together. 🕯️ Outbreak After Dark is the after-hours storytelling series of Infectious Dose, where science, history, and a little gothic atmosphere meet.  This episode is an original reimagining inspired by Charles Dickens’ A Christmas Carol.

This episode was updated in March 2026 to explicitly frame the hepatitis B birth dose controversy through a systems-level lens — examining how evidence-based vaccine policy can be destabilized when institutional safeguards are removed, and why recognizing those failures is essential to restoring public trust. This episode unpacks everything you need to know about hepatitis B and the life-saving vaccine that helps prevent chronic liver disease and liver cancer later in life. From the biology of the virus to the science behind the birth dose, we explore how this vaccine works, why it’s given so early, and what’s at stake now that ideology is overriding evidence in U.S. vaccine policy. We also confront a dangerous shift in public health: the dismantling of expert-driven systems in favor of anti-vaccine rhetoric. The result isn’t just political—it’s personal. And it puts newborns at risk. In this episode: How hepatitis B infects the liver and evades the immune system Why newborns are uniquely vulnerable to chronic infection The history and science behind the universal birth dose What the ACIP overhaul means for public trust and public health Vaccine safety, ingredients, and long-term effectiveness Debunking the most common lies circulating on social media All citations are in the blog post for this episode at infectiousdose.com

This episode was updated in March 2026 to clarify that the analysis presented already reflects the systems-level framework used throughout this vaccine safety series — examining what the claim gets right, where institutional safeguards failed, and what evidence would actually be required to support the claims being made.  A leaked FDA memo sparked headlines claiming the COVID vaccine killed children — but the memo included no evidence, no data, and no scientific analysis. In today’s episode, Heather unpacks what the memo actually said, why experts across the field immediately rejected its conclusions, and how vaccine safety is truly evaluated. She explains the real risks of COVID in kids, from MIS-C to long COVID, and why misinformation from inside federal agencies threatens public trust and puts families at risk. Clear, compassionate, and evidence-driven, this episode gives parents the clarity they deserve. NOTE: All sources are cited in the blog post for this episode at infectiousdose.com

There’s more to your favorite winter rituals than nostalgia. In this episode, we dive into how centuries of winter traditions—across Europe, Asia, Africa, and the Americas—offered accidental protection against infectious diseases. From citrus in stockings to cloves in mulled wine, from kimchi to candlelight, we trace how ancient practices around food, air, warmth, and cleaning helped communities stay healthier in the harshest season. Learn how: Spices like cinnamon, ginger, and clove helped preserve food and reduce pathogens Fires, feasts, and fermentation doubled as primitive infection control Cleaning rituals and seasonal isolation slowed the spread of disease Modern public health can still draw lessons from these old traditions We also address how today’s world—sealed homes, global travel, and misinformation—has changed the game, and why clear science is more important than ever. 🎙️ Plus: a discussion of the recent HHS decision under Robert F. Kennedy Jr. to remove the statement “vaccines do not cause autism” from federal pages—and why this political move contradicts decades of scientific evidence. See the corresponding blog post at infectiousdose.com for all citations.

In this Outbreak After Dark episode, we revisit Thanksgiving’s origin story through the lens of infectious disease. Heather, Sam, and Kate dive into the epidemics that devastated Indigenous nations before the Pilgrims ever arrived, the microbial mismatches between Old World and New, and the narratives that still distort how we talk about “the First Thanksgiving.” It’s a campfire conversation that blends history, science, myth-busting, and respect for the communities whose histories were altered by plague long before the feast. All episode citations and recipes are in the blog post at infectiousdose.com

This week’s episode dives into the roots of the global antimicrobial resistance crisis. How did routine cuts, UTIs, and pneumonias become untreatable? What systems helped superbugs evolve — and why is the problem accelerating worldwide? We explore the science, the policies, the failures, and the future of drug-resistant microbes in A Prescription for Pestilence: The Global Spread of Antimicrobial Resistance. NOTE: All cited references are linked in the blog post for this episode at infectiousdose.com

Rift Valley fever is back — and it’s hitting harder than it has in years. In this episode, we trace the 2025 outbreak from Mauritania to Senegal, explore how the virus hides between rainy seasons, and reveal what scientists have learned from unexpected hotspots in Tanzania. From mosquitoes and livestock to people and policy, this is Rift Valley fever: when the rains bring life and loss. Don't miss today's (Nov 12, 2025) free webinar on RVF: The World Health Organization is hosting a free EPI-WIN webinar at 1pm CET, which is 7pm EST called “Rift Valley Fever and Community Protection: Gaps, Needs and Priorities,” and it brings together experts from WHO, Senegal, and Rwanda.