Infection with C. Trachomatis has decreased substantially in trachoma endemic areas following repeated annual mass drug administration (MDA) with azithromycin, although not as rapidly as anticipated. The investigators propose to conduct a clinical trial in 52 communities in Kongwa, Tanzania that on average have trachoma infection at 3.5%. The investigators plan that all communities would have annual rounds of MDA if infection is greater than 1% or follicular trachoma (TF) is 5% or more, but half would be randomized to a surveillance and treatment program to identify and treat new families and families who travel after mass treatment. Communities will have MDA stopped if infection is 1% or less, or TF is less than 5%. MDA will be reinstated if infection re-emerges to 6% or more. The proportion of communities that are able to stop mass treatment will be compared in the group of communities randomized to mass treatment plus the newcomer/traveler treatment program compared to the communities randomized to mass treatment alone after 24 months.

At the recommendation of the Data Safety and Monitoring Committee in March 2015, thirty eight (38) of the 52 communities identified as being at risk of trachoma re-emergence at 18 months will be surveyed at 30 months. At risk of trachoma re-infection communities have C. trachomatis infection rates less than or equal to 1% or TF < 5% at the time of the 18 month survey. Surveillance of communities for families that meet the newcomer or traveler status will extend 6 months beyond the 24 month survey to 30 months in the intervention communities only. A survey of sentinel children in the intervention and control communities at 30 months will be conducted to assess the level of trachoma and infection in all 38 communities at risk of trachoma re-emergence.

Inclusion Criteria:

Census and Mass Drug Administration (MDA): All persons residing in the 52 study communities will be eligible for both the census and the annual mass azithromycin administrations.

Intervention: In the 26 intervention communities, active surveillance for new families and returning travelers will be undertaken, and those meeting the criteria below will be eligible for family treatment with azithromycin if:

Families are "newcomers" and

• They have children under 10 years of age
• They have moved into a new house in the community or into an existing household
• They plan to reside for at least 1 month in the study community and
• They have moved from a community that has not had an MDA in the last year

Families are classified as having traveled and

• They have children under 10 years of age
• They participated in a previous census in the same community
• They left the community for at least 8 weeks (2 months) for an area that has not received MDA in the past year and at least one child has returned and
• They have returned to reside in the community for at least 2 months

Sentinel Children: In all 52 communities, samples of 135 children will be selected from the community census lists every six months for survey and examination.

These children:

• must be between 1 year and 9.9 years of age,
• must be a resident in the community and not a short-term (less than 2 months) visitor,
• must not have an ocular condition that would preclude grading trachoma or taking an ocular specimen,
• must be willing to have a swab taken as part of being a sentinel child (this is critical, as each swab result counts towards the criteria for stopping MDA), and
• must have an identifiable guardian capable of providing consent to participate.

Adult Women: In all 52 communities, samples of 100 women will be selected from the baseline community census list.

These women:

• must be aged 15 years and over
• must be a resident in the community and not a short term (less than 2 months) visitor
• must not have an ocular condition that precludes grading of scarring on upper conjunctiva
• must be able to provide informed consent.

Exclusion Criteria:

• none

We collected and analyzed data on community level. Age and sex were not part of final analysis.

Adverse event data were collected for 24 months. The Community Health Workers collected data on adverse events after each newcomer and traveler family was identified and treated.