Summary: Our brains obtain information from sick people, eliciting changes in our physiology and immune response. Observing images of ill people triggers activation of the immune system.
Source: Chapman University
Surrounded by coworkers who are sniffling and sneezing?
You may not be able to ask for sick leave preemptively, but your body is already bracing for battle, says Patricia C. Lopes, assistant professor of biological sciences at Chapman University’s Schmid College of Science and Technology.
Lopes studies how our bodies and behaviors change once we become sick.
“Our physiology, particularly the immune system — the system that protects the body from invaders — is tightly regulated,” says Lopes. “Once we become sick, our physiology can drastically change to support recovery from the disease.”
Lopes’ article in the British Ecological Society journal Functional Ecology “Anticipating infection: How parasitism risk changes animal physiology” highlights research showing that there are scenarios in which our physiology changes prior to becoming sick, when disease risk is high.
“In other words,” Lopes, explains, “our brains can obtain information from diseased people and then elicit changes to our physiology. For example, observing images of sick people can already trigger activation of the immune system.”
From a big picture perspective, this means that parasites affect our lives much more than previously considered, because they are already affecting our physiology even before they invade us, she says.
“How this ability to change physiology before getting sick helps animals cope with, or recover from disease is not well known, but could have major impacts on how diseases spread, and on how we care for and study sick humans and other sick animals,” Lopes says.
Anticipating infection: How parasitism risk changes animal physiology
Uninfected animals can attempt to prevent parasitism in many ways. Behavioural avoidance of parasitized conspecifics, for instance, is documented in several species.
Interactions with parasitized conspecifics can also, however, lead to physiological changes in uninfected animals, an effect that is much less well studied, and consequently, less well understood. The way in which exposure to parasitism risk changes the physiology of uninfected animals and the impacts of those changes on animal fitness remain a significant gap in knowledge.
Determining how the disease environment experienced by animals impacts their physiology, survival and reproduction has major implications for our knowledge of how parasites affect populations beyond their consumptive effects. If the physiological changes triggered in uninfected animals help reduce disease burden or speed up recovery from disease, they can have cascading effects on disease dynamics; therefore, they are important to study and understand.
In this perspective, I highlight studies in vertebrates and invertebrates that demonstrate the existence of these responses. I also consider how these responses may be adaptive and instances when they should occur. Finally, I briefly discuss the importance of studying these responses in relation to animal welfare, human health, disease dynamics and experimental design.