Latest research shows how climate change and the immune reaction of an infected individual could potentially affect the long-term dynamics of parasitic infections.
The study by Penn State University, measured the infection dynamics of soil-transmitted parasites commonly found in rabbits in Scotland, every month for 23 years. The results of the study could potentially lead to some new strategies for the treatment as well as the prevention of infections from related parasites in humans, wildlife as well as livestock.
“Our research shows that how we target treatment for parasite infections — not only in wildlife like the rabbits we studied, but also in humans and livestock — will depend on how the climate changes and whether or not the host can mount an effective immune response,” mentioned Isabella Cattadori, a professor of biology at Penn State as well as a research scientist.
Earlier work in Cattadori’s lab had demonstrted that infections from one of the parasite species included in the study are driven by an immune response in the rabbits, but on the other hand, infections from the other parasite species are not at all controlled, even though the rabbit has an immune response to the parasite.
“Over the course of 23 years, we saw clear evidence of climate warming at our study site in Scotland. The warmer climate leads to increases in the number of soil-transmitted parasites in the pastures where the rabbits live because the parasites can survive longer in the soil,” Cattadori quoted. “With more parasites, there is an increased risk of infection, but how this increased risk affects the severity of the infection in the long term depends on the ability of the host to mount an immune response.”
For the parasite that is not controlled by the immune response of the rabbit, the researchers had observed that there was an increase in the intensity of infections in adult rabbits with climate warming. “Because they can’t clear the infection with an immune response, the rabbits accumulate more and more parasites as they age so that older individuals carry most of the infection in the population,” Cattadori said.
For the parasite that is controlled by the immune response of the rabbit, the researchers did not notice long-term increase with climate warming in the strength of infections in the rabbit population overall. Nevertheless, the severity of infection increased in younger rabbits that had not yet developed a very strong immune response.
“Our research shows that as climates continue to change, we will need to tailor our treatment of parasite infections based on whether or not the host can mount an effective immune response,” Cattadori mentioned. “When the immune response of the host can’t control the infection that tool place, treatment should be focused at older individuals simply due to the reason that they carry the most severe infections. When a host’s immune response could actually control the infection, treatment should be aimed at younger people because they are at the greatest risk.“