Infection and Immunity

Abstract

Invasive capacity refers to the capacity of certain pathogens to invade the organism and to grow and multiply within the organism. Some pathogens can directly invade human body, such as leptospira, filariform larva of ancylostoma, and schistosome cercaria. Some gain their access to human body via digestive or respiratory tract, followed by their adherence to the intestinal or bronchial mucosal surfaces and then invasion into histiocytes to produce toxins and cause diseases. Such pathogens include Shiga bacillus and tubercle bacillus. Viral pathogens usually gain their access to cells after their binding to receptors on the cell surface. Some pathogens with weak invasive capacity gain their access to human body via wounds, such as bacillus tetani and rabies virus.