Ravinder Sehgal, Dept. of Biology, San Francisco State University
September 09, 2026 | 14h15 | Hybrid Seminar (Zoom Link)
Deforestation driven by the expansion of oil palm plantations is transforming tropical forests at an unprecedented rate, with profound consequences for biodiversity and the transmission of infectious diseases. For more than two decades, we have monitored avian malaria parasites, their mosquito vectors, and wild bird communities in southwestern Cameroon. By comparing sites that have remained relatively intact with forests that have undergone extensive conversion to oil palm plantations, we examine how land-use change has altered vector communities, parasite diversity, and host-parasite interactions over time. Our long-term studies demonstrate that deforestation reshapes mosquito communities and is associated with significant shifts in avian malaria parasite assemblages, while intact forests remain comparatively stable. These findings highlight the complex ecological responses of vector-borne pathogens to anthropogenic environmental change and underscore the importance of long-term datasets for understanding disease dynamics in rapidly changing ecosystems. The seminar will also introduce an emerging frontier in parasite biology: Matryoshka viruses, a recently discovered group of RNA viruses that infect malaria parasites themselves. These hyperparasites add an additional level of biological complexity to host-vector-parasite systems and may influence parasite fitness, transmission, virulence, and evolution. We will present recent discoveries of Matryoshka viruses in avian malaria parasites from California and discuss their potential ecological and evolutionary significance. Together, these studies illustrate how habitat alteration, vector ecology, parasite evolution, and viral hyperparasasitism interact to shape disease processes in natural ecosystems, providing new perspectives on the effects of global environmental change on wildlife health.
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