Researchers at the Johns Hopkins Bloomberg School of Public Health recently demonstrated that proteomic mass spectrometry has the potential to be applied for this purpose. Using a two-step process, researchers successfully separated, purified and concentrated a norovirus surrogate from a clinical sample within a few hours. Nanospray mass spectrometry was used to demonstrate the feasibility of detecting norovirus particles in the purified concentrates.
Human norovirus is responsible for an estimated 23 million cases of gastrointestinal illness in the United States each year. This pathogen is a particular problem aboard cruise ships. The researchers believe that their mass spectrometric method could potentially be used for biodefense and public health preparedness as a tool for rapidly detecting norovirus--a category B bioterrorism agent--and other viral public health threats. The study is published in the April 2006 edition of Applied and Environmental Microbiology.
In simplified terms, mass spectrometry is essentially a scale for weighing molecules. A laser turns a sample into ionized particles, which are then accelerated in a vacuum toward a detector. The time lapsed prior to registering on the detector helps researchers determine the mass--or weight--of the particles. By targeting characteristic particles, or peptides, belonging to the viral coat protein, the virus can be positively identified by matching the results to entries in genetic databases.
In the Hopkins study, the researchers analyzed a stool sample treated with virus-like particles, which closely resemble norovirus but are noninfectious. Using mass spectrometry, the researchers were able to detect the norovirus capsid protein down to levels typically found in clinical specimens fro