Infections and immunological factors.
A number of viral, bacterial or parasitic infections have been found in some cases of ME/CFS (e.g., herpes viruses, enteroviruses, B. burgdorferi, mycoplasmas, G. lamblia).15 Based on clinical observation, the use of long-term antibiotics, anti-parasitics or antiviral therapy may be beneficial in patients where the presence of pathogens has been confirmed.
Although initial results of some new drug therapies for various viral infections in ME/CFS appear promising,85-89 treatment protocols are often complex and remain untested in controlled trials. In addition, adverse reactions, the development of drug resistance, and costs are significant concerns. Referral to a specialist who has experience in testing and therapeutic interventions for these subgroups of patients may be helpful. [my bolding]