Ascaris: The Neglected Parasite

Co-infection with other pathogens is a common occurrence in Ascaris-infected individuals and it is generally accepted that co-infection is not inconsequential to the host. Interactions in the immune responses generated to each pathogen can, in certain situations, alter the pathogenesis and progression of a co-infecting pathogen in an Ascaris-infected host. There is also some evidence that co-infection can impact on the transmission potential of co-infecting pathogens in an Ascaris-infected host. In this chapter we review some of the general principles of co-infection and discuss how Ascaris co-infection may interact with the human immunodeficiency virus and malaria in co-infected hosts. We also explore some of the hypothetical effects co-infection may have on Ascaris infection, in particular with respect to the success of larval migration and the maintenance of adult nematodes in the gastrointestinal tract.