I just read about the death of 6 recently arrived tamarin monkeys at the Oregon Zoo. While I am by no means a veterinarian, the mysterious death of lower primates should make every infectious disease physician's ears perk up.
The reason why unexplained outbreaks--epizootics--in lower primates are so important stems from the fact that if a pathogen is able to infect a monkey or chimpanzee, there is a good chance that it has the ability to infect humans, as all primates are genetically similar.
In fact, preventing these diseases from spilling over--a concept made popular by David Quammen's book--into humans has become a major focus of interest in the emerging infectious diseases world.
Integral to this paradigm is the simple concept of "One Health," a viewpoint that recognizes that physicians and veterinarians have many of the same goals and that situational awareness of diseases of interest occurring in animal populations is crucially important to the task of safeguarding human health from infectious disease threats. Monitoring sentinel animal populations such as primates, bats, and poultry for infectious diseases can provide clues allowing some degree of predicting the pathogens on the cusp of jumping into humans to be possible. Similarly, monitoring human populations that have exposure to these species, such as bushmeat hunters and poultry workers, can provide early evidence of cross-species infections before a wider outbreak occurs. In fact, such monitoring would likely have shown HIV in its early years as an agent almost exclusively infecting bushmeat hunters and bushmeat preparers.
While these monkeys, who were in quarantine because of their recent arrival, may have died from something common and not on par with the events detailed in Hot Zone, their deaths cannot be taken lightly and the cause should be determined. As a non-veteranarian it is difficulty to speculate on causes of death, but ruling out an infectious disease is paramount.
Update: Seems like travel-related shock may have been the etiology.