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:

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:

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