Clear signs of a pathogenic condition. Depending on the pathogen, they can create damaging conditions including endocrine disturbances (adrenals, thyroid, thymus, androgens, hypothalamus/pituitary etc).
These conditions create massive oxidative stress which cause more damage. Immune shifting (dysregulation which means more immune sensitivity and immune weakening). Liver becomes congested due to the high oxidative stress so toxins become backed up which further stresses the body out.
There are a number of pathogens that can inhabit the gut which is generally the most vulnerable area for infection. parasites can be one variety but there can be others (rogue bacteria, yeast/fungal) and don't forget that parasites including protozoa which are different than worms/flukes.
Remember when you ramp up the metabolic rate because of the infection that nutrients are used up in a higher quantity. Make sure you are getting adequate electrolytes since these will be used up - magnesium is of particular note. B vitamins tend to get used up as well.