Background Youth are using social media regularly and represent a group facing substantial risk for sexually transmitted infection (STI). Although there is evidence that the Internet can be used effectively in supporting healthy sexual behavior, this hasn't yet extended to social networking sites. Purpose To determine whether STI prevention messages delivered via Facebook are efficacious in preventing increases in sexual risk behavior at 2 and 6 months. Design Cluster RCT, October 2010–May 2011. Setting/participants Individuals (seeds) recruited in multiple settings (online, via newspaper ads and face-to-face) were asked to recruit three friends, who in turn recruited additional friends, extending three waves from the seed. Seeds and waves of friends were considered networks and exposed to either the intervention or control condition. Intervention Exposure to Just/Us, a Facebook page developed with youth input, or to control content on 18–24 News, a Facebook page with current events for 2 months. Main outcome measures Condom use at last sex and proportion of sex acts protected by condoms. Repeated measures of nested data were used to model main effects of exposure to Just/Us and time by treatment interaction. Results 1578 participants enrolled, with 14% Latino and 35% African-American; 75% of participants completed at least one study follow-up. Time by treatment effects were observed at 2 months for condom use (intervention 68% vs control 56%, p=0.04) and proportion of sex acts protected by condoms (intervention 63% vs control 57%, p=0.03) where intervention participation reduced the tendency for condom use to decrease over time. No effects were seen at 6 months. Conclusions Social networking sites may be venues for efficacious health education interventions. More work is needed to understand what elements of social media are compelling, how network membership influences effects, and whether linking social media to clinical and social services can be beneficial. Trial registration This study is registered at www.clinicaltrials.gov NCT00725959.

Eighteen months after licensure, the vast majority of pediatricians and family physicians reported offering HPV vaccine. Fewer physicians strongly recommended the vaccine for younger adolescents than for older adolescents, and physicians reported financial obstacles to vaccination.

A minimum of 11 genera of parasites, including 7 known or suspected to cause zoonoses, were detected in dogs in 2 northern Canadian communities. Dogs in remote settlements receive minimal veterinary care and may serve as sources and sentinels for parasites in persons and wildlife, and as parasite bridges between wildlife and humans.

Online social networks are growing in popularity. Conducting research on social media sites requires deliberate attention to consent, confidentiality, and security.

We explored the feasibility of engaging young black men in a 12-week text messaging programme about HIV prevention. There were two non-randomized groups of 30 young men each. The participants were aged 16-20 years, self-identifying as black or African-American, sexually active, who owned a mobile phone and lived in Philadelphia. They received three text messages per week for 12 weeks. People in the intervention group received text messages about HIV prevention, while those in the control group received text messages about nutrition. The intervention participants showed trends in increased monogamy at follow-up compared to controls. Awareness of sexual health was significantly higher in the intervention group. Condom norms were significantly higher for the control group. There were no differences in the proportion of protected sex acts. The participants embraced the project, and were enrolled and retained in numbers that suggest such an intervention is worth examining for efficacy.