Lisa Brown, Ph.D.

Research Areas

Education

• Louisiana State University, Ph.D.
• University of Louisiana at Monroe, M.S.
• University of Texas at Tyler, B.S.

Publications

1. Lynch A, Mauricio M, Palomino Y, Brown LD. Male and female cat fleas (Ctenocephalides felis) differ in bacterial control, survival, and circulating hemocyte responses following systemic challenge. 2026. Insects.
2. Singer C, Palomino Y, Brown LD. Chemical modulation of IMD signaling in the cat flea (Ctenocephalides felis) reveals reduced antimicrobial activity in vitro without corresponding effects on bacterial infection in vivo. 2026. Current Research in Insect Science.
3. Brown LD. From acquisition to transmission: revisiting Bartonella henselae infection in the cat flea (Ctenocephalides felis). 2026. Vector-Borne and Zoonotic Diseases.
4. Zellner PN, Njoroge E, Lynch A, Brown LD. Physiology of the cat flea (Ctenocephalides felis) gut: digestive enzymes, pH, and intestinal barrier integrity. 2026. Journal of Medical Entomology.
5. Weber K, Karnik D, Brown LD. Transcriptional induction of the IMD signaling pathway and associated antibacterial activity in the digestive tract of cat fleas (Ctenocephalides felis). 2024. Parasites & Vectors.
6. Muñoz M, Lin N, Lin R, King B, Brown LD. Immune defense mechanisms against a systemic bacterial infection in the cat flea (Ctenocephalides felis). 2022. Journal of Invertebrate Pathology.

Funding

Current Grants

1. National Center for Veterinary Parasitology (PI): Prior Doxycycline Exposure as a Determinant of Bartonella henselae Acquisition and Persistence in the Cat Flea ($25,000)
2. NOAA (Co-PI): Neonicotinoid Presence in Coastal Waters and Potential Impacts on the Eastern Oyster ($150,000)
3. NIH R16 (PI): Ecological Immunology of a Flea Vector ($674,500)

Research Projects

1. Immune Defenses of Blood-Feeding Insects: Blood-feeding insects encounter a wide range of microorganisms while acquiring the nutrients necessary for survival and reproduction. Our research investigates how cat fleas (Ctenocephalides felis) recognize and respond to microbial challenges, with particular emphasis on the immune defenses of the digestive tract and the interactions between local and systemic immunity. We examine antimicrobial signaling pathways, reactive oxygen species, antioxidant defenses, and cellular immune responses to understand how fleas maintain physiological balance while limiting microbial infections. By identifying the mechanisms that regulate these responses, our work advances our understanding of insect immunity and the biological factors that influence vector competence.
2. Pathogen Acquisition and Transmission by Flea Vectors: Fleas are important vectors of bacterial pathogens that affect human and animal health. Our research focuses on the interactions between fleas and flea-associated bacteria, particularly Bartonella henselae, the causative agent of cat-scratch disease. We investigate how pathogens survive the physiological and immunological challenges of the flea digestive tract, establish persistent infections, and potentially disseminate within the insect. Current projects examine how blood meal digestion, oxidative stress, and host immune responses influence bacterial survival and persistence. Understanding these interactions may reveal biological mechanisms that shape pathogen transmission and identify new opportunities to reduce the spread of flea-borne diseases.
3. Environmental Stressors and Immune Function in Eastern Oysters: Environmental contaminants and infectious diseases pose significant challenges to the health and sustainability of coastal ecosystems. Our research examines how environmental stressors, particularly neonicotinoid insecticides, influence immune function and disease susceptibility in the Eastern oyster (Crassostrea virginica). We investigate the effects of chemical exposure on oyster immune defenses and their responses to microbial pathogens, including Vibrio bacteria. Complementary studies explore immune gene expression and naturally occurring infections in wild oyster populations. This work seeks to better understand how environmental conditions influence disease resistance in marine invertebrates and to provide information relevant to shellfish health, aquaculture, and coastal ecosystem management.

Research Group

Undergraduate Students

• Sienna Williams
• Ashley Conde

Graduate Students

• Abby Subler
• Sriya Jupalli