Despite significant advances in molecular biology and immunology, electron microscopy (EM) continues to be useful for morphologic identification of infectious microbes in body fluid and cultured specimens from humans and experimental animals. Morphologic identification using negative stain and/or thin-section EM is often a primary tool in public health investigations, followed by immunologic, molecular, or cultured isolation. Difficulties encountered are usually related to the length of time between specimen (e.g. stool) collection and preparation for EM and/or handling and shipping conditions. Another negative mitigating factor may be multi-lab interventions prior to arrival. Appropriate specimen collection, storage, and handling prior to attempts to identify the agent are important factors for successful identification.

Barrier-control guidelines called “Universal Precautions for Laboratories“ have for many years been recommended by U.S. and international health services organizations. The guidelines are based on the premise that safe work sites result from a combination of engineering controls, management policies, work practices, and, when required, prompt medical intervention.