Rapid test reliably identifies smallpox virus

NEW YORK (Reuters Health) - A real-time, sensitive and specific test for the detection of smallpox virus (also known as variola virus) has been developed in Spain.

It may be of value in the event that smallpox is used as a biological weapon, its developers say.

Smallpox once killed millions of people around the world. The virus killed 30 percent of those infected and left others scarred for life. It was eradicated by a global vaccination program led by the World Health Organization in 1979.

A research team, headed by Dr. C. G. Fedele of the Instituto de Salud Carlos III, in Madrid, describes the investigational test in the December issue of the Journal of Clinical Microbiology.

The test identifies a specific DNA sequence found in all known variola virus genomes but in no other similar viruses.

Fedele's team proved the specificity of the method using DNA from other infectious agents that are considered when making a differential diagnosis of smallpox.

"In multiple assays, 100 copies of variola virus DNA were regularly detected; however, 10 copies were detected in some experiments," the researchers report.

The results obtained, they conclude, suggest that the assay is "rapid, sensitive, specific and suitable" for the identification of smallpox virus and avoids false-negative results in a single reaction tube.

SOURCE: Journal of Clinical Microbiology, December 2006.