When her phone alarm buzzed in her pocket, she rose, stretched, and did a few light exercises.

She had been given the option of flying on the air ambulance instead of the Air Force transport. She would have been more comfortable there, but she’d wanted to remain with her team. To Peyton, it was a matter of principle. Besides, they had work to do. She had insisted that three of the older CDC employees take the seats on the air ambulance. They would be working in Nairobi, in support positions, and all three had thanked her for the more comfortable accommodations.

Elliott had chosen the Air Force transport as well. It had a large compartment for cargo and a separate area for passengers. The passenger section had twelve rows, each with five seats in the center, plus a single row of seats lining each of the right and left walls. At the head of the compartment were two narrow openings beside a wide wall that held a whiteboard.

Peyton imagined that the whiteboard was routinely used to brief military personnel and hammer out mission details. She was about to do the same. In fact, to an outside observer, the scene might have looked like a US Navy mission briefing.

Her audience included men and women dressed in tan service khakis identical to the uniforms worn by the US Navy, with similar rank insignias. Her troops, however, were not naval officers. They were officers in another uniformed service, one every bit as important.

Peyton was a CDC employee, but she was also a Commissioned Corps officer of the US Public Health Service. The Commissioned Corps was an elite team of highly skilled health professionals and one of the United States’ seven uniformed services (the other six being the Army, Navy, Air Force, Marines, Coast Guard, and National Oceanic and Atmospheric Administration Commissioned Corps). Over six thousand men and women served in the Public Health Service Commissioned Corps, and they wore uniforms similar to the US Navy’s: service dress blues, summer whites, and service khakis. Commissioned Corps officers held the same ranks as the Navy and Coast Guard: ensign to admiral.

Commissioned Corps officers served at the EPA, FDA, DOD, NIH, USDA, Coast Guard, CDC, and many other organizations. They were often the first responders during national disasters, and had deployed in response to hurricanes, earthquakes, and outbreaks. In 2001, over one thousand PHS officers deployed to New York City after the 9/11 attacks. In 2005, in the aftermath of three hurricanes—Katrina, Rita, and Wilma—more than two thousand PHS officers deployed to set up field hospitals and assist victims.

Over eight hundred Commissioned Corps officers worked full-time at the CDC. Visitors often mistook them for Navy officers.

Peyton held the rank of full commander in the Commissioned Corps. Elliott held the rank of rear admiral. Of the 160 EIS officers, 102 were Commissioned Corps officers.

The Corps was also well represented in the group sitting before Peyton: of the 63 men and women present, 51 were Commissioned Corps officers. Like Peyton, they dressed in service khakis, the PHSCC insignia on their left lapel, their rank insignia on their right.