Although head lice can be readily infected with R. prowazekii and B. quintana and later disseminate these virulent organisms in their feces, thus having the potential to be vectors of these pathogens under optimal epidemiologic conditions, e.g. during outbreaks of epidemic typhus, no reports can be found that in the absence of body lice, head lice could act as vectors under field conditions. In experimental work conducted with head and body lice, the humoral immune response of both lice, following bacterial challenge was examined and it was shown that both exhibited an increased immune response to Staphylococcus aureus but little to Escherichia coli. However, head lice exhibited a significantly higher phagocytotic activity against E. coli than body lice, suggesting that the reduced phagocytotic activity in body lice could be responsible, in part, for their increased vector competence. It is concluded that head lice are poor biological vectors of human diseases and accordingly of little relevance from the epidemiologic point of view of these diseases. Mumcuoglu KY, Is the Head Louse, Pediculus humanus capitis Vector of Human Diseases?
Last date updated on June, 2014