One striking observation is how different the pattern of transmission is in different countries.

ECONOMIST: AIDS

The other cases do not show the sort of transmission pattern that normally gives away a genetic disease yet there is a bigger chance than normal that someone will suffer from Alzheimer's if relatives on his mother's side have also suffered.

ECONOMIST: Trojan DNA

In the new study biostatistician Ira Longini at the Fred Hutchinson Cancer Research Center in Seattle devised a computer model to calculate the probability that such an outbreak pattern could occur without human transmission.

FORBES: Magazine Article