We don't know how frequently this kind of mutation can appear.

242

By reducing the number of plasmids, we increase the efficiency of virus production.

186

Only one case, and whether that condition was something unique we don't know.

174

We don't know how many more mutations are required. But at this point, we still have some time.

148

Our findings provide a rational explanation for why H 5 N 1 viruses rarely infect and spread from human to human, although they can replicate efficiently in the lungs.

130

Patient 1 had not had any known direct contact with poultry, but had cared for her 21-year-old brother (patient 2) while he had a documented H5N1 virus infection.

107

Application of the new system may be especially advantageous in situations of outbreaks of highly pathogenic avian influenza viruses.

87