An epidemiologist studying diphtheria in Eastern Europe gathers information about the total number of active cases in a given area and the number of new cases in that area over a given time. If an epidemic occurs, which of the following would the epidemiologist notice?

Pathogenicity islands are segments of a pathogen’s chromosome acquired by horizontal gene transfers, such as 

What do these graphs show?  

A key feature of an effective vaccine is that it should

An 11-year-old girl undergoing a routine surgery at a local hospital develops a surgical-wound infection. Even with aggressive treatment, the girl dies. The infection she developed is best known as

Why does fish tend to spoil more rapidly than other meats?

An endemic disease will exhibit

Differences in the access to, use of, and quality of care given to different groups of people is referred to as

The map on the left shows drainage in the Mississippi River drainage basin. The map on the right shows the risk of groundwater nitrate contamination. What is an inference that can be made on the basis of the information presented in these two figures?

Which of the following appendages are thin and flexible and repeatedly extend and retract, giving their bacterial owners a spastic movement called twitching motility?