In the laboratory, he identified the most common lethal pneumococcal strains, or serotypes.

HIV-1 is the most common and pathogenic strain of the virus.

Studies have also shown that the most common strain of bacteria found in dental plaque may cause blood clots.

"The common strain is my love for Western civilization," he said.

Of course, there were vaccines for the more common strains of the disease, but it seemed as if a new strain developed every week.

And that's the common strain, from welding yourself into your apartment on 13th Street to Hamas.

Research continues in many countries abroad to develop vaccines against the most common strains and to find better ways of controlling the disease.

If avian flu combines with a more common human strain, the results could be devastating.

But vaccines are available that protect against the common strains of the bacterium.

Genotype 1 is the most common strain in the United States.