LCMV is a zoonotic pathogen coming from hamsters and mice with a poorly studied role in human chronic disease. Some strains (ARM) cause an acute and some (Cl13, Docile) a persistent chronic disease in mice. http://emedicine.medscape.com/article/220796-overview http://en.wikipedia.org/wiki/Lymphocytic_choriomeningitis "The virus seems to be relatively resistant to drying and therefore humans can become infected by inhaling infectious aerosolized particles of rodent urine, feces, or saliva, by ingesting food contaminated with virus, by contamination of mucus membranes with infected body fluids, or by directly exposing cuts or other open wounds to virus-infected blood. The only documented cases of transmission from animals have occurred between humans and mice or hamsters." "Some cases of LCM become chronic, potentially resulting in hydrocephalus. Other organs, especially the testes, heart, and joints, may be involved. Cardiac involvement is typical of viral myocarditis." "LCMV infection is more common in young adults, although illness may occur in any age group" "Infection is most common in the fall." "Diagnosis is subject to methodological shortcomings in regard to specificity and sensitivity of assays used. For this reason, LCMV may be more common than is realized." I also found a paper in Russian that refers to some scientific data from 1930s that says that LCMV can cause persistent chronic incapacitating disease in humans: http://www.adventus.info/medicine/infect/061.php "flu-like forms are common, with symptoms of encephalitis, encephalomyelitis (!), polyradiculoneuritis and visceral manifestations" "the slow form of infection is characterized by an acute onset, fever, meningeal symptoms. After an acute phase is over, it can be succeeded by a phase of seeming improvement with weakness, vertigo, ataxia, fatigue, headache, memory loss, psychological problems, cranial nerves lesions. Sometimes the disease lingers for several, up to 10, years, can be accompanied by pareses and paralyses, and ends fatally." I haven't found if there are diagnostic tests commercially available. I've heard CDC's Special Pathogen Branch does it in the US, and I have no idea about Europe. The virus also serves as a model for viral research, and there's an interesting B-cells CD27 blocking treatment strategy reminiscent of CD20 blocking with Rituximab: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2118404/ Also, a lot of us PWCs have high serum TNF-alpha, and CD27 is a tumor necrosis factor receptor, so perhaps this model may be worth further studying. Overall, do you think LCMV may be an underlying factor in a subset of ME cases?