In 1959 Hadlow, a veterinarian, visited a medical exposition in England where Carlton Gajdusek posted pathological slides of autopsied Kuru brains and a clinical description of the illness. He realized that Gajdusek's slides and clinical descriptions were almost identical to an illness that he had been studying in sheep (Scrapie). It was well known that Scrapie was a transmissible, infectious illness. In his paper Hadlow postulated several landmark ideas:

1) Kuru was similar to Scrapie.

2) Kuru was transmissible.

3) Hadlow also suggested that to demonstrate transmissibilty one should inject brain tissue from Kuru victims into chimp brains since they are so closely related to humans.

4) He also noted that many months or years might be required before disease would be recognizable in non-human primates.

All of Hadlow's assertions were later confirmed.

(Thanks to Juan Weiss for this reference and its interpretation.)