Detecting signals of chronic shedding to explain pathogen persistence: Leptospira interrogans in California sea lions.

摘要: Identifying mechanisms driving pathogen persistence is a vital component of wildlife disease ecology and control. Asymptomatic, chronically infected individuals are an oft-cited potential reservoir infection, but demonstrations the importance chronic shedding to at population-level remain scarce. Studying using commonly collected data hampered by numerous challenges, including short-term surveillance that focuses on single epidemics acutely ill individuals, subtle dynamical influence relative more obvious epidemic drivers, poor ability differentiate between effects population prevalence vs. intensity duration in individuals. We use Leptospira interrogans serovar Pomona California sea lions (Zalophus californianus) as case study illustrate how these challenges can be addressed. Using leptospirosis-induced strands measure incidence, we fit models with without shedding, different seasonal determine time-scale over which detectable interactions drivers needed explain outbreak patterns. Chronic enable L. interrogans within lion population. However, was only apparent when included least two outbreaks intervening inter-epidemic trough during fadeout transmission most likely. Seasonal transmission, opposed recruitment susceptibles, dominant driver seasonality this system, both factors had limited impact long-term persistence. show temporal extent have dramatic inferences about processes, where failure identify short- ecological cascading impacts understanding higher order phenomena, such