Validation of Inactivation Methods for Arenaviruses.

Several of the human-pathogenic arenaviruses cause hemorrhagic fever and have to be handled under biosafety level 4 conditions, including Lassa virus. Rapid and safe inactivation of specimens containing these viruses is fundamental to enable downstream processing for diagnostics or research under lower biosafety conditions. We established a protocol to test the efficacy of inactivation methods using the low-pathogenic Morogoro arenavirus as surrogate for the related highly pathogenic viruses. As the validation of chemical inactivation methods in cell culture systems is difficult due to cell toxicity of commonly used chemicals, we employed filter devices to remove the chemical and concentrate the virus after inactivation and before inoculation into cell culture. Viral replication in the cells was monitored over 4 weeks by using indirect immunofluorescence and immunofocus assay. The performance of the protocol was verified using published inactivation methods including chemicals and heat. Ten additional methods to inactivate virus in infected cells or cell culture supernatant were validated and shown to reduce virus titers to undetectable levels. In summary, we provide a robust protocol for the validation of chemical and physical inactivation of arenaviruses in cell culture, which can be readily adapted to different inactivation methods and specimen matrices.

Sexual transmission of Zika virus in Germany, April 2016.

Zika virus (ZIKV), an emerging mosquito-borne flavivirus, causes a mild dengue fever-like illness but has recently been associated with neurological disease and severe birth defects. The virus is currently causing a large epidemic in the Americas. Here, we report a male-to-female sexual transmission of ZIKV in Germany in April 2016, following travel to Puerto Rico of the male patient, demonstrated by subsequent seroconversions and molecular identification of identical virus sequences from both patients.