Ashley Hazel: Stanford UniversityPopulations that are dependent upon physical environments for their immediate livelihoods utilize subsistence strategies that are both well adapted to predictable environmental variability (e.g., seasonality) and resilient to unpredictable shocks (e.g., drought). Livelihood strategies that entail high degrees of mobility typically have temporal and spatial heterogeneities in social contact, which influences infection dynamics for pathogens that require prolonged or repeated contact for transmission, such as sexually transmitted infections (STIs) or tuberculosis.
In this talk, I present my work on the epidemiology of two STIs—HSV2 and gonorrhea—among a group of semi-nomadic pastoralists in Kaokoveld Namibia, where sexual-partner concurrency functions not just as an STI risk factor but, crucially, as an ecological strategy. I find that extreme geographical remoteness is associated with a higher HSV2 (viral) transmission rate. In contrast, ephemeral population density and social aggregation are associated with higher gonorrhea (bacterial) prevalence. Furthermore, both predictable and unpredictable climate variation influenced sexual-networks, which has important implications for the impending effects of climate change.