Questions have been raised about whether there could be something different about this strain of Ebola that makes it more contagious than previous ones. Researchers are doubtful, but Thomas W. Geisbert, an Ebola expert at UTMB, said it was important to keep an open mind about the possibility. During vaccine tests expected to start next month in monkeys, he said, he and his colleagues will monitor infected animals to see if they develop unusually high virus levels early in the disease that might amplify its infectiousness.