Background: Text or voice messages containing health behavior change content may be an inexpensive, discreet, sustainable and scalable way to reach populations at high risk for HIV. In Cambodia, one of the important high-risk populations is female entertainment workers (FEWs). This ethnographic study aims to explore typical phone use, examining patterns and behaviors that may influence the design of future mHealth interventions.
Methods:The study consisted of one 8-hour non-participant observation session for 15 randomly sampled Results: In this ethnographic study, all 15 participants made calls, checked the time and received researchrelated texts. More than half (n=8) of the participants engaged in texting to a non-research recipient. About half (n=7) went on Facebook (FB) and some (n=5) listened to music and looked at their FB newsfeed. Fewer played a mobile game, posted a photo to FB, went on YouTube, used FB chat/messenger, watched a video on FB, played a game on FB, used FB call/voice chat, looked at their phone's background or used the LINE app. Fewer still shared their phones, left them unattended, added airtime or changed their SIM cards.When participants received a research text message, most did not share the text message with anyone, did not ask for help deciphering the message and did not receive help composing a response. Notable themes from observer notes, HIV outreach workers and researchers include reasons why phone calls were the most frequent mode of communication, examples of how cell phone company text messages are used as a form of behavior change, literacy as a persistent barrier for some FEWs, and FEWs' high interest in receiving health-related messages and less concern about privacy and phone-sharing issues than expected.Conclusions: This study suggests texting is a part of normal phone use although not as frequently used as voice calls or Facebook. Despite the less frequent use, FEWs were able to send and receive messages, were interested in health messages and were not overly concerned about privacy issues. Texting and voice messaging may be useful tools for health behavior change within the FEW population in Cambodia.