Figure 3 is a histogram showing the number of stools that tested positive for Campylobacter each month between 2010 and 2014, by type of test performed. The types of test include polymerase chain reaction, culture, or both polymerase chain reaction and culture. A line shows the total percent positivity for Campylobacter. Prior to late 2013, all specimens were positive by culture alone. After polymerase chain reaction was introduced in late 2013, the total number of tests positive and percent positivity increased, and approximately one third of specimens were positive by each of polymerase chain reaction alone, culture alone or culture and polymerase chain reaction together.