“Worm flu” is the term commonly used by helminthic therapy self-treaters to describe the set of symptoms sometimes experienced in the early stages following inoculation with helminths. The term derives from the fact that many of these symptoms mirror those caused by influenza and can include: fever, cough, respiratory symptoms, chills, muscle or joint ache, fatigue, abdominal pain, diarrhoea, nausea or vomiting.
Worm flu is caused by the immune system’s response to the presence of helminths, especially following their first introduction, and it is largely dose-dependant. It can also re-emerge following the use of supplementary doses that are too large. For this reason, helminthic therapy self-treaters should always begin with small doses and only gradually increase the number of helminths in each subsequent dose. There are dosing guidelines for each species at the following links.
All the therapeutic helminths can cause worm flu, but the hookworm, NA, is the most likely to do this. See the following sections of this site for more details.