Hepatic ultrasound in a population with high incidence of invasive amoebiasis: evidence for subclinical, self-limited amoebic liver abscesses.

About 10% of successfully treated amoebic liver abscesses (ALA) do not completely resolve and can be detected by ultrasound as typical residual liver lesions. The frequency of these residues should be an indicator for the prevalence of ALA in a given population, and may help to solve the question whether non-clinical, self-healing ALAs occur. We have performed hepatic ultrasound in 1036 adult individuals living in a high-risk area for ALA in Central Vietnam and identified typical ALA residual lesions in about 1.2% of the subjects. As expected, these lesions were associated with positive amoeba serology and were found in 11.9% of individuals with a previous ALA history. However, more than 50% of the residues were identified in individuals who had never developed symptoms suspected for ALA and who never received any ALA specific treatment, suggesting that subclinical, self-limited hepatic amoeba abscesses truly exist.