1.   At the lab, researchers infected volunteers with cold viruses while subjecting them to cold temperatures.

2.   Researchers infected nine monkeys with a live attenunated vaccine.

3.   She was further persuaded last spring, she said, when researchers infected monkeys by injecting extract of mad-cow brains.

4.   The researchers infected healthy mice with brain tissue from cattle with mad cow disease, or bovine spongiform encephalopathy.

5.   The results were striking because the researchers infected the mice with a different strain of HIV than they used to develop the HIV-vaccine, Sarin said.

6.   After breeding mice without this gene, the researchers infected them and a group of normal mice to the influenza virus and the Coxsackie virus.