Global Warming and Parasitic Diseases of Livestock

Writing in Trends in Parasitology, Morgan and Wall (2009) state that "global climate change predictions suggest that far-ranging effects might occur in population dynamics and distributions of livestock parasites, provoking fears of widespread increases in disease incidence and production loss." However, they indicate that "just as development rates of many parasites of veterinary importance increase with temperature, so [too] do their mortality rates [increase]." And they further add that "temperature will also affect mortality indirectly through the action of predators, parasitoids, pathogens and competitors, whose development and abundance are also potentially temperature sensitive," so that, in the end, "the net effect of climate change could be complex and far from easily predicted."

In perusing the subject in greater detail, as they elucidate some of the many complexities involved, the two UK researchers indicate that "several biological mechanisms (including increased parasite mortality and more rapid acquisition of immunity), in tandem with changes in husbandry practices (including reproduction, housing, nutrition, breed selection, grazing patterns and other management interventions), might act to mitigate increased parasite development rates, preventing dramatic rises in overall levels of diseases." However, because "optimum mitigation strategies will be highly system specific and depend on detailed understanding of interactions between climate, parasite abundance, host availability and the cues for and economics of farmer intervention," as they characterize the situation, they conclude "there is a need for research that considers likely effects of climate change and mitigation strategies in terms of the whole host-parasite system, including anthropogenic responses, and not just in terms of parasite population dynamics."