One health toxicology: expanding perspectives and methods to assess environmental contaminants

Abstract

The discipline of One Health is founded on the principal that environmental health, animal health, and human health are interconnected. Although the field has been largely focused on zoonotic diseases, examining concepts such as toxicology under a One Health lens can offer a more holistic and preventative approach to research and implementation and, in particular, how fish-based diets may be involved with One Health outcomes. Here we present three general case studies that demonstrate new approaches to investigating One Health toxicology. In Chapter One we show how Arctic canids can be used as environmental sentinels for human health. We discuss three separate canid studies; in the first we find that Arctic foxes can act as sentinels of Arctic contaminants due to their foraging plasticity, in the second we examine the use of fish-fed sled dogs as a model for the effects of a fish-based diet on contaminants exposure and gene transcription, and in the third we develop the sled dog as a model for particulate matter air pollution in the Fairbanks North Star Borough. In Chapter Two we utilize the Steller sea lion, a nonmodel organism, as a sentinel for the effects of fish-based diet mercury exposure induced whole-genome changes in gene transcription (RNA-Seq). Using newly developed informatics tools we assemble a de novo transcriptome and examine large scale changes in gene expression related to mercury exposure and other One Health uses. This approach is extremely adaptable and has the potential to be applied across numerous non-model organisms and contaminants. We also applied a microbial mining algorithm to our RNA-Seq data and found evidence for a hemotropic Mycoplasma spp. in one of our samples. In Chapter Three we examine sources of mercury exposure for pregnant women from La Paz, Baja California Sur, Mexico. We found mercury concentrations to be generally low among the examined fish species and staple foods. While typical dietary assessments rely on recall surveys and questionnaires, we found that examining chemical biomarkers of diet including stable isotopes of carbon and nitrogen are critical in dietary risk assessment. Taken together these three investigations offer valuable lessons and techniques which can be applied to the field of One Health toxicology; especially to those fish diet based systems.