A University of Nottingham study is holding freedom from louse infestation responsible for increased allergic reactions. The finding means that the epidemic of allergic disorders in modern, urban people might be due to our having rid ourselves of lice and worms.
As per “hygiene hypothesis” humans’ immune systems evolved to compensate for continual infections with parasitic gut worms, which secrete chemicals that reduce our immune responses. People who are now worm-free have overreactive immune systems, which can lead to asthma and autoimmune disorders.
In the study conducted on wild wood mice, Janette Bradley and her colleagues have found that body louse reduced the readiness of the innate system to mount an immune response.
During the study, the authors conducted post-mortem on the captured mice, assessing their weight, parasite load, and the responsiveness of their spleen cells to substances such as heat-killed listeria and bacteria, which bind receptors of the innate immune system and provoke a measurable reaction.
They found that those mice uninfected with the louse Polyplax serrata showed markedly increased responses to these triggers of innate immune responses, compared to highly-infected animals. This suggests that the parasite is able to exert some kind of immunosuppressive effect, possibly directly by secreting some substance into the mice from its saliva, or indirectly by transmitting bacteria or other pathogens.
