The role of nitric oxide in helminthoses

Nitric oxide (NO) is a small gaseous molecule produced mainly by activated macrophages, but some other cells as well, in reaction to an infection. Since late 80s, when the effect of NO on schistosomes was demonstrated, many experiments have been conducted examining both the effect of NO on other helminths and its role in helminthoses. In vitro experiments center mainly upon direct effects of NO on helminths - loss of motility and viability in particular. On the other hand, in vivo studies focus on the course of infection and pathological changes in hosts. However, in vitro and in vivo data do not always corroborate. Moreover, the effects of NO differ not only across helminth genera but also for developmental stages of the same parasite.