herpes- n. a disease that causes painful spots on the ski

plague – n. a change in brain tissue that occurs in Alzheimer's disease

clog – v. to slowly form a block in (something, such as a pipe or street) so that things cannot move through quickly or easily

impressive - adj. deserving attention, admiration, or respect

scream – v. to shout loudly

symptoms –n. a change that shows that a disease is present

bystander – n. someone who is uninvolved in an incident but comes to watch the police or ambulance

microbe – n. an extremely small living thing that can only be seen with a microscope