Gut microbiota disturbance during helminth infection: can it affect cognition and behaviour of children?

Abstract

BackgroundBidirectional signalling between the brain and the gastrointestinal tract is regulated at neural, hormonal, and immunological levels. Recent studies have shown that helminth infections can alter the normal gut microbiota. Studies have also shown that the gut microbiota is instrumental in the normal development, maturation and function of the brain. The pathophysiological pathways by which helminth infections contribute to altered cognitive function remain poorly understood.DiscussionWe put forward the hypothesis that gastrointestinal infections with parasitic worms, such as helminths, induce an imbalance of the gut-brain axis, which, in turn, can detrimentally manifest in brain development. Factors supporting this hypothesis are: 1) research focusing on intelligence and school performance in school-aged children has shown helminth infections to be associated with cognitive impairment, 2) disturbances in gut microbiota have been shown to be associated with important cognitive developmental effects, and 3) helminth infections have been shown to alter the gut microbiota structure. Evidence on the complex interactions between extrinsic (parasite) and intrinsic (host-derived) factors has been synthesised and discussed.SummaryWhile evidence in favour of the helminth-gut microbiota-central nervous system hypothesis is circumstantial, it would be unwise to rule it out as a possible mechanism by which gastrointestinal helminth infections induce childhood cognitive morbidity. Further empirical studies are necessary to test an indirect effect of helminth infections on the modulation of mood and behaviour through its effects on the gut microbiota.

Can Parasitic Worms Cure the Modern World’s Ills?

“…Finally, and reminiscent of studies showing that microbial and metabolic alterations in early infancy affect risk of childhood asthma [108], an emerging area of interest is how helminth infection might modulate the gut-brain axis and consequently brain development during pregnancy, a dynamic period for the macrobiome [2,109 ].…”

Modulation of the immune response by helminths: a role for serotonin?

“…Further, the anti-inflammatory benefit of infection with helminth parasites in mouse model systems, may be mediated, at least in part, by gut bacteria [ 132 , 133 ]. Reciprocally, it has been posited that helminth-evoked disturbance of the gut microbiota could affect cognition in children [ 134 ]. A recent study described abundant EC cells in Rhesus macaques with idiopathic colitis who displayed microbial dysbiosis [ 135 ].…”

The essentials of a global index for cognitive function

“…While pharmaceutical management of cognition mostly targets dementia related to ageing and disease, nutraceutical modulation aims to maintain cognition and prevent cognitive decline in healthy individuals. The impact of probiotics on mood has been demonstrated in clinical studies [ 4 ] with gut microbiota dysbiosis having been hypothesized to affect cognitive function [ 5 ]. A variety of phytochemicals including resveratrol, green tea extract, beta carotene, as well as chromium picolinate and antioxidants have supporting clinical evidence that demonstrates improvements in cognition ( Figure 1 ).…”