Infectious Diseases of Marine Mammals as Sentinels of Ecosystem Health in the Neotropics

Long-lived aquatic animals, such as marine mammals, can be exposed to several environmental threats. With a wide variety of lifestyles, from large intercontinental migration to long-living coastal residents, charismatic megafauna are recognized as sentinels for ecosystem health at different ecological levels. Infectious diseases can cause unusual mortality events as well as sudden individual mortalities. Cases of morbillivirus in cetaceans and influenza virus in pinnipeds have caused unusual mortalities in recent decades in the northern hemisphere, and now, a highly pathogenetic influenza is causing massive mortality in marine wildlife in Latina America (LATAM). An increase in stranding events and mortalities has been reported worldwide and in LATAM; however, the limited possibilities to respond to stranding events in LATAM have left more questions in the cases of massive marine animal strandings. In this chapter, we will focus on an extensive literature review of the importance of charismatic marine mammals and their role in the determination of ecosystem health with a focus on LATAM. Finally, we will provide some examples of emerging diseases on marine mammals and the effect of several threats on their dynamics, opening questions about the effect of multiple threats on the conservation of these ecosystem sentinels.