Trauma and starvation have been found to be the major causes of death for most birds, mammals and reptiles in American Samoa.
This is according to a survey by the US Geological Survey's National Wildlife Health Center in Honolulu which began in 2006.
Wildlife found dead in American Samoa is sent to Dr Thierry Work and his team so they can determine their cause of death.
The group has looked at 111 dead animals so far from American Samoa, including bats, turtles and birds.
Dr Work says it is not merely an academic exercise.
"Investigating disease in wildlife is important for two reasons. The first one is it's important for conservation. If the managers know what is killing their wildlife then they can intervene to try to reduce those causes of mortality and help the wildlife recover. And the second reason is some of these wildlife diseases can be transmitted to humans, for instance avian influenza and oftentimes the first indicator that such a disease is in the environment is when you see dead or dying wildlife."