Effect of Intensive Fly Control on Trachoma and Ocular Chlamydia Infection in Tanzania
Information source: Johns Hopkins University
Information obtained from ClinicalTrials.gov on June 20, 2008
Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Trachoma
Intervention: 10% permethrin in water applied as low volume spray (Procedure)
Phase: Phase 4
Status: Active, not recruiting
Sponsored by: Johns Hopkins University Official(s) and/or principal investigator(s):
Sheila West, Principal Investigator, Affiliation: Johns Hopkins University
Summary
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.
Clinical Details
Official title: Strategies for the Control of Blinding Trachoma: Effect of Fly Spray
Study design: Prevention, Randomized, Single Blind, Active Control, Parallel Assignment, Efficacy Study
Primary outcome: clinical trachoma
Secondary outcome: ocular C. trachomatis infection
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
Eligibility
Minimum age: 12 Months.
Maximum age: 8 Years.
Gender(s): Both.
Criteria:
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
Locations and Contacts
Johns Hopkins University/ Kongwa Trachoma Project, Baltimore, Maryland 21205, United States
Additional Information
Starting date: June 2000
Ending date: October 2002
Last updated: November 28, 2006
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