DNA products of a first PCR amplification were used as templates in a second reaction primed by primers that differentiate among strains of a species. The technique has been tested on many pathogens. For example, there are many strains of the common bacteria Escherichia coli, but the strain E. coli 157 causes food poisoning. The Los Alamos technique can quickly identify that particular strain. The technology is not limited to human diseases.
Analysis also can identify the source of diseases in livestock, poultry and plants.
Identifying a disease source or vector is critical to its control. For example, following an outbreak of anthrax in cattle in Norway, analysis showed the Bacillus anthracis strains came from third-world countries. The list of possible source countries matched the list of countries from which the fodder supplement bone meal had been imported. Processing bone meal does not kill notoriously hardy B. anthracis spores. With a likely source of contamination identified, officials in Norway were able to reduce a serious commercial threat.