Episode 602: How Bartonella Hijacks the Brain’s Immune System: Linking Infection and Neurodegeneration – Dr. Janice Bush

Overview This special episode of the Tick Boot Camp Podcast was recorded live at the 2nd Annual Alzheimer’s Pathobiome Initiative (AlzPI) and PCOM Symposium in collaboration with Pathobiome Perspectives. Hosted by Ali Moresco in partnership with Nikki Schultek, Executive Director of AlzPI, this series expands the Tick Boot Camp mission of exploring infection-associated chronic illness (IACI)—including Lyme and other tick-borne infections—to the global Alzheimer’s and neuroimmunology research community. Tick Boot Camp co-founders Matt Sabatello and Rich Johannesen partnered with Ali and Nikki to showcase scientists exploring the microbial and immune mechanisms behind neurodegeneration. This episode features Dr. Janice Bush, a PhD candidate at North Carolina State University’s College of Veterinary Medicine, whose research under world-renowned Bartonella expert Dr. Edward Breitschwerdt investigates how Bartonella bacteria alter gene expression in the brain’s immune cells. Guest Janice Bush, DVM, PhD Candidate College of Veterinary Medicine, North Carolina State University (NCSU) Dr. Janice Bush began her career in veterinary medicine, where she observed a striking overlap between illnesses in pets and their human owners—particularly those linked to vector-borne infections like Bartonella. Now completing her PhD under Dr. Edward Breitschwerdt, she focuses on Bartonella henselae, the bacterium behind Cat Scratch Disease, and its ability to infect human microglial cells—the brain’s resident immune defenders. Her presentation, “Bartonella-Infected Human Microglial Cells: Transcriptional Changes Associated with Chronic Neurologic Disorders,” revealed how this stealth pathogen triggers widespread gene dysregulation linked to Alzheimer’s disease, psychiatric symptoms, and neurodegenerative processes. Key Discussion Points Dr. Bush explains how Bartonella infection reprograms human microglia, the brain’s innate immune cells, leading to hundreds of genes being upregulated or suppressed—affecting energy metabolism, mitochondrial function, cell signaling, and immune communication. These cellular changes mirror those observed in chronic neurological and psychiatric disorders, providing a potential mechanistic link between infection and long-term neurodegeneration. She describes Bartonella’s sophisticated immune evasion strategy, including its ability to hijack cellular machinery and increase production of interleukin-10 (IL-10)—an anti-inflammatory cytokine that suppresses immune response, allowing the bacteria to persist undetected. This mechanism may explain why patients experience cyclic flares and remissions, and why Bartonella can linger silently for years. Dr. Bush’s findings suggest that even short-term infections can produce measurable transcriptional changes in brain immune cells within 48 hours. If such infections persist for months or years, they may set the stage for neurodegenerative disease, particularly when combined with other pathogens or environmental factors. “If one intracellular pathogen can cause this many changes in two days, imagine what happens over months or years. Bartonella may be the spark that primes the brain for neurodegeneration.” — Dr. Janice Bush Why It Matters Dr. Bush’s research offers a groundbreaking look at how a common, underrecognized infection may drive neuroinflammation and neurodegeneration. Her work bridges veterinary medicine, infectious disease, and neurology—revealing how pathogens once dismissed as minor or self-limiting may alter the brain’s immune landscape. By demonstrating that Bartonella can infect and manipulate microglial cells, she provides critical biological evidence linking vector-borne disease and cognitive decline, paving the way for future diagnostic and therapeutic innovation. About the Event This interview was recorded at the 2nd Annual Alzheimer’s Pathobiome Initiative (AlzPI) and Philadelphia College of Osteopathic Medicine (PCOM) Symposium, held October 3, 2025, at Ohio University in Dublin, Ohio. The event gathered more than 20 leading researchers exploring how microbes, the microbiome, and immune dysregulation contribute to Alzheimer’s, dementia, and infection-associated chronic illness (IACI). The Tick Boot Camp Podcast, in partnership with Ali Moresco and Nikki Schultek, documented these conversations to connect the chronic Lyme, infectious disease, and Alzheimer’s research communities. This episode is part of Tick Boot Camp’s AlzPI collaboration series. Learn More Learn more about the Alzheimer’s Pathobiome Initiative (AlzPI) Listen to Tick Boot Camp Podcast episodes, including Episode 406: Pathobiome – An Interview with Nikki Schultek and Episode 101: The Young Gun – An Interview with Alex (Ali) Moresco discussed in this interview.