Absorption host factors, role

The level of infection in a host has a direct effect on the carbohydrate content of cestodes (796) and has been shown by Henderson (317) to affect glucose absorption by H. diminuta in vitro (Fig. 5.1). These are manifestations of the crowding effect, reported in Raillietina, H. microstoma, H. nana and, most notably, H. diminuta (697), which results in an inverse correlation between worm size and increasing population density. Competition for host dietary carbohydrate presumably plays a role in the crowding effect, but the phenomenon is complex and a number of other factors are probably involved (348, 697, 979, 980). This phenomenon is addressed further in Chapter 9. 

Colonic microbiota could now be considered as a microbial organ placed within a host organism. In addition to the obvious role of the intestine in the digestion and absorption of nutrients, the human G1 tract contains a huge collection of microorganisms. Microbiota has not been fully described, but it is clear that the human gut is home for an ecosystem of around 10 -10 " bacterial cells. As a whole, the microorganisms that live inside humans are estimated to outnumber human cells by a factor of ten. And the microbiome represents overall more than 100 times the human genome [78]. 

---