African green monkey origin of the atypical cytopathic 'stealth virus' isolated from a patient with chronic fatigue syndrome.

Background: A cytomegalovirus-like 'stealth virus' had previously been isolated from a patient with the chronic fatigue syndrome (CFS).

Objective: To determine the original derivation of this virus.

Study Design: DNA sequencing of cloned regions of the virus was performed and the sequences were compared using BLASTN and FASTA analyses against the entire GenBank database.