1.   The cause of the disease continues to elude researchers.

2.   A cure or vaccine continues to elude researchers for reasons that have more to do with scientific complexity than with venality or cupidity.

3.   But a true understanding of mental illness continues to elude researchers.

4.   But the precise cause continued to elude researchers.

5.   He was convinced, however, that his experience in the operating room gave him insight into cancer growth that eluded researchers who never left the laboratory.

6.   But the way that clock signals the rest of the body to follow the daily cycle has eluded researchers.

7.   The cause of narcolepsy has eluded researchers, Stimulant drugs help some victims but can cause side effects.

8.   The cause of the disease has eluded researchers.