Tuberculosis has much slowe progressr than the major haemorrhagic fevers. It can take weeks to months, or even years to become obvious. This means that more people will be infected before the outbreak is apparent, and they will be spread out more geographically. TB is not as dramatic but may kill more people over a long time. Since the bacterium is endemic it will be more difficult to prove culpability unless a sample of the original bacterium can be obtained.