题目选项分析

An unknown simian virus recently killed off nearly half the human population of a remote jungle town. Because the disease spread at an alarming rate—victims usually exhibited signs within 8 hours of exposure, and many died within 36 hours—the simian virus, if an outbreak occurs again, is likely to cause more deaths than has any other previous virus.

Which of the following pieces of information most effectively calls into question the validity of the conclusion?

【选项】Viruses tend to be most destructive in densely populated areas, oftentimes spreading amongst thousands of people before any quarantine can be put in place.