Understanding how social, environmental, and etiological factors shape (re)emerging infectious disease outbreaks

Emerging infectious diseases (EIDs), over 60% of which are zoonotic, represent a growing threat to human health, development, and ecological stability. Their emergence is shaped by complex interactions among environmental change, human activity, and social vulnerability, particularly in low-resource settings. This dissertation investigates the ecological, social, and environmental determinants of EID risk through three integrated studies.

The first chapter examines public health communication in two geographically and socially vulnerable island communities: Shahpori Island, Bangladesh, and Gaya Island, Malaysia. Both face high burdens of vector-borne diseases yet have limited access to healthcare and surveillance systems. While awareness was generally low, residents of Gaya Island demonstrated significantly greater knowledge and preventive behaviors. Factors such as education, age, and marital status emerged as significant predictors of disease knowledge. Inadequate understanding on mosquito ecology highlights the urgent need for culturally tailored, community-based interventions.

The second chapter presents a systematic meta-analysis of global risk factors for human anthrax. The analysis reveals that occupational exposures such as handling infected carcasses, butchering moribund animals, and consuming contaminated meat greatly increase infection risk. These behaviors are often rooted in poverty, limited veterinary infrastructure, traditional practices, and inadequate public health outreach. Addressing these structural drivers is essential for effective anthrax prevention and control, especially in endemic rural settings.

The third chapter uses ecological niche modeling to project current and future climatic suitability for 14 bat species identified as putative reservoir hosts of Nipah virus. Based on WorldClim climate data and Maxent modeling under SSP245 and SSP585 scenarios for 2021–2040 and 2041–2060, the models predict substantial shifts and expansions in climatically suitable habitats. These changes signal increasing risk of zoonotic spillover in new areas, reinforcing the importance of climate-sensitive surveillance and early warning systems.

Together, these studies integrate communication research, epidemiological synthesis, and spatial modeling to inform a One Health approach to EID prevention. The findings emphasize the urgency of climate-informed surveillance, risk communication, and cross-sectoral preparedness strategies for vulnerable populations.