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.