Effect of Intensive Fly Control on Trachoma and Ocular Chlamydia Infection in Tanzania

April 12, 2013 updated by: Johns Hopkins University

Strategies for the Control of Blinding Trachoma: Effect of Fly Spray

The purpose of this community-based randomized trial was to determine, in trachoma hyper-endemic communities of Tanzania, the added value of intensive spraying to control flies on the fly population and on trachoma and ocular chlamydia infection at 6 months and one year after mass antibiotic treatment.

Study Overview

Status

Completed

Conditions

Detailed Description

Trachoma is the leading infectious cause of blindness in the world. The World Health Organization (WHO), recognizing the important public health impact of trachoma, has adopted a resolution to eliminate blinding trachoma by the year 2020 (3). In order to accomplish this ambitious goal, WHO recommends the use of "SAFE" strategy for countries implementing trachoma control programs. This multi-faceted approach includes Surgery for trichiasis cases, Antibiotics to treat the community pool of infection, Face washing to reduce transmission, and Environmental change.

The environmental change component currently rests largely on efforts to reduce the fly populations in these communities. A pilot study and clinical trial using intense insecticide spraying reduced both flies and trachoma in a trachoma hypo-endemic area of The Gambia. In The Gambia setting, flies appear to be an important vector for trachoma, but it is not clear that flies are equally important in areas with hyper-endemic trachoma, nor is it known if fly control adds value to the provision of mass antibiotic treatment for active trachoma as part of the SAFE strategy.

The purpose of this community-based randomized trial was to determine, in trachoma hyper-endemic communities of Tanzania, the added value of intensive spraying to control flies on the fly population and on trachoma and ocular C. trachomatis infection at 6 months and one year after mass antibiotic treatment. Neighborhoods with intensive spraying (Intervention) and neighborhoods with no spraying (control) all received mass antibiotic treatment with azithromycin immediately prior to the start of the study, enabling us to evaluate the additional impact of fly control on trachoma.

Kongwa district in central Tanzania has been shown to have a high prevalence of active trachoma, and was chosen as the site of this study. We randomized sixteen balozi to receive either mass treatment with azithromycin alone (control), or mass treatment plus an intensive fly spraying program (intervention). Pre-school aged children are the reservoirs of infection and disease within these communities. Therefore, within each balozi, all children aged less than eight served as sentinel markers for the status of trachoma at baseline, 6 months, and one year after baseline. In the eight intervention balozi, 119 children from 87 families were enrolled at baseline, and in the eight control balozi, 183 children from 145 families were enrolled.

The balozis were surveyed and an area surrounding the intervention balozis was targeted for insecticide spray. A solution of 10% permethrin in water was used with a Hudson and MicronAir sprayer machines, At the outset, spraying was carried out every two days for two weeks (attack phase) then once per week (maintenance phase) for the rest of the study.

Two sticky traps, fly paper strips were placed in each balozi to capture flies. The traps were changed every week, and the number of flies captured were counted. If the average number in the intervention balozis exceeded 25% of that in the control balozis, an attack phase, as described above, was reinstituted to keep the fly population low in the intervention group.

The primary outcome was the prevalence of trachoma in the pre-school aged children at 6 months and one year post mass antibiotic treatment.Outcomes are reported based on masked photographic gradings. Secondary outcome was ocular C. trachomatis infection, based on use of Amplicor C. trachomatis qualitative PCR assay.

comparison: Balozi randomized to receive intensive fly spray intervention,compared to Balozi with no fly spray intervention

Study Type

Interventional

Enrollment

350

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • Maryland
      • Baltimore, Maryland, United States, 21205
        • Johns Hopkins University/ Kongwa Trachoma Project

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

1 year to 8 years (Child)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Balozi in Chiwe area
  • Sentinel children: age less than 8 years

Exclusion Criteria:

  • Balozi in Chiwe without geographic borders
  • Sentinel children:age more than 8 years

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
No Intervention: control
no active fly spray intervention
Active Comparator: intervention
aerial spray of permethrin daily for two weeks and weekly as needed by assessment of fly density

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
clinical trachoma
Time Frame: 1 year
clinical grading of conjunctival photographs for follicular trachoma
1 year

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
ocular C. trachomatis infection
Time Frame: 6 months
laboratory assessment of chlamydial DNA on ocular swab; measured as present or absent
6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Collaborators

Investigators

  • Principal Investigator: Sheila West, Johns Hopkins University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

June 1, 2000

Primary Completion (Actual)

September 1, 2002

Study Completion (Actual)

October 1, 2002

Study Registration Dates

First Submitted

June 29, 2006

First Submitted That Met QC Criteria

July 3, 2006

First Posted (Estimate)

July 4, 2006

Study Record Updates

Last Update Posted (Estimate)

April 15, 2013

Last Update Submitted That Met QC Criteria

April 12, 2013

Last Verified

May 1, 2004

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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