Meeting Abstract
Artificial light at night, or ALAN, has become a pervasive anthropogenic stressor for both humans and wildlife over the past century. Although many of the negative impacts of ALAN on health have been documented, the consequences for infectious disease dynamics are largely unexplored. With the recent implementation of broad-spectrum and energy efficient light-emitting diodes (LEDs), the effects of spectral composition of ALAN have also come into question. Previous studies have shown that exposure to low levels of incandescent ALAN extends the infectious period of house sparrows infected with West Nile virus (WNV) without affecting mortality rates. Here, we asked whether altering the spectral composition of ALAN would exacerbate or ameliorate these consequences for house sparrows infected with WNV. We found that exposure to broad-spectrum (3000+5000K) LED ALAN did not affect viral resistance (i.e. inverse of viremia), but this light form increased WNV-induced mortality. As these same individuals died earlier and lost more body mass over time than expected from their viremia, higher mortality under broad-spectrum ALAN may be due to disproportionately higher pathogen-induced damage and/or immunopathology. Conversely, birds exposed to amber-hue (1800K) LED ALAN had significantly lower viremia, and mortality rates similar to natural light exposed controls. This study demonstrates that the spectral composition of ALAN can affect infection outcomes and thus provides insight into utility of particular nighttime lighting methods.
