Inactivation of Hepatitis C Virus Infectivity by Human Breast Milk

J Infect Dis. (2013) doi: 10.1093/infdis/jit519 First published online: September 24, 2013

Stephanie Pfaender1, Julia Heyden1, Martina Friesland1, Sandra Ciesek2, Asim Ejaz3, Joerg Steinmann4, Jochen Steinmann5, Angelika Malarski6, Heribert Stoiber3, Georgios Tsiavaliaris7, Werner Bader8, Gerhard Jahreis6, Thomas Pietschmann1 and Eike Steinmann1,*

+ Author Affiliations

Abstract

Background. Hepatitis C virus (HCV) is spread through direct contact with blood, although alternative routes of transmission may contribute to the global burden. Perinatal infection occurs in up to 5 % of HCV infected mothers and presence of HCV RNA in breast milk has been reported. We investigated the influence of breast milk on HCV infectiousness.

Methods/Results. Human breast milk reduced HCV infectivity in a dose-dependent manner. This effect was species-specific since milk from various animals did not inhibit HCV infection. Treatment of HCV with human breast milk did not compromise integrity of viral RNA or capsids, but destroyed the lipid envelope. Fractionation of breast milk revealed that the antiviral activity is present in the cream fraction containing the fat. Proteolytic digestion of milk proteins had no influence on its antiviral activity whereas prolonged storage at 4 °C increased antiviral activity. Notably, pretreatment with a lipase inhibitor ablated the antiviral activity and specific free fatty acids of breast milk were antiviral.

Conclusion. The antiviral activity of breast milk is linked to endogenous lipase-dependent generation of free fatty acids which destroy the viral lipid envelope. Therefore, nursing by HCV-positive mothers is unlikely to play a major role in vertical transmission.

Received April 17, 2013. Revision received May 29, 2013. Accepted May 30, 2013.

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