 Background: On the basis of immunological considerations and in vitro trials on co-infections there is strong reason to suspect a detrimental effect of helminth infection on the course of HIV. The immunological answer very efficiently evoked by helminth infection is aimed at hijacking and suppressing the immune system in order to suit the requirements of the specific helminth. This permits helminths to cause chronic infection, often persisting over years and allowing some infecting worms to grow to several centimetres of length within their host. However, this immune modulation also affects non-related antigens for example HIV which would actually require a different line of immunological action. 