Population movements, environmental factors, and infectious disease transmission
Restricted (Penn State Only)
- Author:
- Blake, Alexandre
- Graduate Program:
- Biology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 02, 2023
- Committee Members:
- Nita Bharti, Major Field Member & Dissertation Advisor
Ephraim Hanks, Outside Unit Member
Ottar Bjornstad, Chair & Major Field Represnt
Reka Albert, Outside Field Member
Elizabeth Mcgraw, Program Head/Chair - Keywords:
- infectious diseases
mobility
measles
cholera - Abstract:
- Infectious disease transmission is deeply tied to host mobility and the environment. Transmission can occur when susceptible individuals contact either infectious hosts or environmental reservoirs. For humans, this contact is often the direct result of the mobility of susceptible and infected individuals or the influence of the environment on host mobility and/or pathogen survival. Although these fundamental principles are well known, there is strong spatial heterogeneity in mobility and its drivers. There has also been an exponential increase in mobility in the last 150 years. Many critical features of our environment have changed rapidly during this same time as well. A better understanding of the dynamic interactions between pathogens, host mobility, particularly human mobility, and the environment is necessary to design effective infectious disease control strategy. This dissertation examines these interactions by investigating how mobility and environment influence the dynamics of two diseases: measles and cholera. Measles is a viral disease that infects human hosts exclusively, while cholera is a bacterial disease with an aquatic reservoir. Measles infection, or successful vaccination, leads to life-long immunity. In contrast, for cholera, immunity following infection or successful vaccination is short-lived. These fundamental differences between the two diseases allowed me to focus on specific aspects on the interactions between transmission, mobility, and the environment. I first explore how population mobility influences measles transmission in Niger. I then consider a more complex situation with both population mobility and environmental factors potentially influencing cholera transmission and persistence in the Democratic Republic of Congo (DRC), first in a city and next in a larger metapopulation. I also investigate the data representativeness for estimating population size and mobility in a health vulnerable population, a semi-nomadic population in Namibia. I focus on a modern data stream, mobile phone-based data, that is frequently used to represent mobility in public health efforts. I examine these interactions at various spatial scales using statistical and mechanistic modeling associating surveillance data and geospatial information. My findings emphasize that expanding our understanding of how mobility and environmental factors influence pathogen transmission is critical to improve and adapt infectious disease control strategies. Understanding these interactions is critical to directly target transmission in settings where traditional strategies have consistently produced suboptimal results.