Local adaptation of parasite off-host stages

Human-caused changes are affecting the environment in ways that challenge many organisms, including parasites. Many of these parasites are exposed to the environment (as environmental or “off-host” stages) while waiting to encounter the next host. Longer survival ability in the environment is clearly an advantage, as the chances for transmission increase. Indeed, numerous parasites evolved strategies to survive prolonged periods using specialized structures to resist drying, heating or freezing. However, evolving such structures, or physiological mechanisms that aid survival, is costly, and these costs may be traded-off with the quantity or quality of transmission stages, or other fitness related characteristic of the parasite. The effects of climate change on the off-host stage of a parasite have received little attention. I want to focus on how the parasite, in its off-host stage, adapts to its local external environment and whether this adaptation comes at the cost of being maladapted to external environments. My aim is to understand the implications of parasite local adaptation to the external environment, and its impact on disease spread. To this end, I want to write a review, split into two parts. In the first part, I want to understand how different parasites in different environments protect themselves against environmental stress. I will use this data in the second part to link stress factors to forms of protection. The insights gained from this review will not only guide me to streamline my own laboratory research on this topic, but also have important implications for disease control in general.