is killing upward of 70 percent of those it infects is killing upward of 70 percent of those it infects is killing upward of 70 percent of those it infects is killing upward of 70 percent of those it infects is killing upward of 70 percent of those it infects is killing upward of 70 percent of those it infects is killing upward of 70 percent of those it infects over 70% is killing upward of 70 percent of those it infects