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RESEARCH ARTICLE
Progress towards the elimination of trachoma as a public health
problem in four counties of Eastern Equatoria State, Republic of
South Sudan
Stephen Ohidor
1
| Nicholas A. Presley
2
| Angelia M. Sanders
2
| Andrew W. Nute
2
|
Tania A. Gonzalez
2
| Yak Yak Bol
3
| Albino W. Nyibong
4
| Paul Weiss
5
|
James Niquette
1
| E. Kelly Callahan
2
| Scott D. Nash
2
1
The Carter Center - South Sudan, The Carter
Center, Juba, Central Equatoria State, South Sudan
2
Trachoma Control Program, The Carter Center,
Atlanta, Georgia, USA
3
Department of PC-NTD, Ministry of Health,
Republic of South Sudan, Juba, Central Equatoria
State, South Sudan
4
Department of Eye Care, Ministry of Health,
Republic of South Sudan, Juba, Central Equatoria
State, South Sudan
5
Independent Contractor, Bogart, Georgia, USA
Correspondence
Nicholas A. Presley, The Carter Center, 453 John
Lewis Freedom Parkway NE, Atlanta, GA 30307,
USA.
Email: nicholas.presley@cartercenter.org
Abstract
Background: Trachoma is targeted by the World Health Organization (WHO) for
elimination as a public health problem by 2030. Trachoma impact surveys using stan-
dardised methodology are recommended to monitor progress towards elimination
and to determine eligibility for continued surgery, antibiotics, facial cleanliness, and
environmental improvement (SAFE) interventions. From 2007 to 2015, four counties
of Eastern Equatoria State, South Sudan, received three to five rounds of mass drug
administration with antibiotics. A trachoma impact survey in 2015 indicated all four
counties had trachomatous-inflammation follicular prevalence among children ages
1–9 years above the WHO elimination threshold (range 17.4%–47.6%). Based on these
results, the recommended number of years of SAFE interventions were implemented
and the counties were subsequently resurveyed.
Methods: Between 2021 and 2023, trachoma impact surveys were conducted in Budi,
Kapoeta East, Kapoeta North, and Kapoeta South counties using a two-stage cluster
sample design. Trained and certified graders examined participants for trachoma clini-
cal signs using the WHO simplified grading system to estimate county-level
prevalence.
Results: A total of 12,570 individuals from 3286 households in 116 survey clusters
were examined for trachoma. Prevalence of trachomatous-inflammation follicular
among children ages 1–9 years was 5.6% (95% confidence interval [CI]:3.7%–8.3%) in
Kapoeta South, 7.4% (CI:5.1%–10.7%) in Budi, 12.3% (CI:7.8%–18.9%) in Kapoeta
East, and 18.1% (CI:13.5%–24.0%) in Kapoeta North. Trachomatous inflammation-
intense prevalence among children ages 1–9 years ranged from 0.4% (CI:0.2%–1.0%)
in Kapoeta East to 2.1% (CI:1.4%–3.2%) in Kapoeta North, and trachomatous trichia-
sis in individuals ages ≥15 years ranged from 1.0% (CI:0.5%–2.1%) in Kapoeta North
to 1.9% (CI:1.3%–2.8%) in Budi.
Conclusions: As no county reached the WHO elimination thresholds of
trachomatous-inflammation follicular <5% or trachomatous trichiasis <0.2%, SAFE
interventions should continue. Furthermore, these districts are classified as having
persistent trachoma, based on trachomatous-inflammation follicular levels remaining
>5% after two impact surveys. Compared to results from 2015, the prevalence of
trachomatous-inflammation follicular, trachomatous inflammation-intense, and
Stephen Ohidor and Nicholas A. Presley contributed equally to this study.
Sustainable Development Goal: Good Health and Wellbeing
DOI: 10.1111/tmi.14078
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium,
provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
© 2025 The Authors Tropical Medicine & International Health published by John Wiley & Sons Ltd.
Trop Med Int Health. 2025;30:159–169. wileyonlinelibrary.com/journal/tmi 159
trachomatous trichiasis in all counties decreased, indicating that the Republic of South
Sudan Ministry of Health’s Trachoma Control Program is advancing towards its
elimination goal.
KEYWORDS
Eastern Equatoria State, elimination as a public health problem, SAFE strategy, South Sudan, trachoma,
trachoma impact surveys
INTRODUCTION
Trachoma is a disease caused by ocular infection of the bacte-
rium Chlamydia trachomatis [1]. Active trachoma is clinically
diagnosed in two phases: trachomatous-inflammation follicu-
lar (TF), defined by the presence of at least five follicles
≥0.5 mm in diameter in the upper tarsal conjunctiva, and tra-
chomatous inflammation-intense (TI), defined by pro-
nounced inflammation of the tarsal conjunctiva that obscures
over half of the deep tarsal vessels [2]. Upon repeated infec-
tions and associated inflammatory responses, the disease can
progress to trachomatous trichiasis (TT), diagnosed by the
presence of at least one eyelash from the upper eyelid touch-
ing the eye and/or evidence of recent epilation. TT over time
can cause corneal opacity (CO) and irreversible blindness.
An estimated 40 countries and 115.7 million individuals
are known to require trachoma interventions [3]. To combat
the disease, the World Health Organization (WHO) recom-
mends the SAFE strategy, which includes Surgery for TT,
community-wide Antibiotic distribution with azithromycin
or tetracycline eye ointment to clear C. trachomatis infec-
tions, and Facial cleanliness and Environmental improve-
ments to limit C. trachomatis transmission [4]. Trachoma
impact surveys (TIS) using standardised methodology are
recommended to monitor progress towards elimination and
determine eligibility for continued SAFE interventions. In
agreement with WHO guidelines, countries are eligible for
validation as having eliminated trachoma as a public health
problem once all previously endemic districts demonstrate a
prevalence of TF <5% among children ages 1–9 years, as
well as a prevalence of TT unknown to the health system of
<0.2% among individuals ages ≥15 years [4, 5].
South Sudan is one of the nations with the highest burden
of neglected tropical diseases (NTDs) in the African
region [6], and previous studies have demonstrated that tra-
choma was hyperendemic (TF ≥30%) in many parts of the
country [7–9]. Since 2001, the Republic of South Sudan Min-
istry of Health (RSS-MoH) has implemented components of
the SAFE strategy within endemic parts of the country [10].
The aim of this study was to estimate the prevalence of tra-
choma in four counties (districts) of Eastern Equatoria State
(EES), a historically hyperendemic region of South Sudan
where trachoma interventions have occurred since 2007 [9].
METHODS
Ethics statement
Ethical clearance was received from the Ethical Committee of
the RSS-MoH (MOH/RERB/A33/2021, MOH/RERB/59/2022,
MOH/RERB/A22/2022) and the Emory University Institu-
tional Review Board (IRB00002467). Verbal informed con-
sent, recorded electronically, was obtained from all
participants due to high illiteracy. Parent or guardian verbal
consent was required for children <16 years of age, and par-
ticipants could withdraw consent at any time without
consequence.
FIGURE 1 Trachoma impact survey locations, Eastern Equatoria State, Republic of South Sudan, 2021–2023. South Sudan and surrounding areas (left)
and surveyed counties (right).
160 TROPICAL MEDICINE & INTERNATIONAL HEALTH
Survey settings
EES is divided into eight counties and experiences severe to
extreme malnutrition, insecurity, and other humanitarian
needs (Figure 1)[11]. In agreement with global standards, four
counties—Budi, Kapoeta East (KEC), Kapoeta North (KNC),
and Kapoeta South (KSC)—were selected based on their his-
tory of SAFE interventions and eligibility for TIS [12].
Between 2007 and 2015, these counties received multiple
rounds of mass drug administration (MDA) with antibiotics,
but TIS performed in 2015 indicated that none of the sur-
veyed counties had reached the elimination threshold for TF
or TT [9]. Furthermore, KEC, KNC, and KSC were hyperen-
demic for trachoma (programmatically defined as ≥30% TF
among children ages 1–9 years). SAFE interventions were
continued from 2015 to 2021, with each county receiving an
additional three to five annual rounds of annual MDA, TT-
targeted surgery camps, and health outreach activities
(Table 1). Between September 2021–February 2023, the
RSS-MoH conducted a second TIS in each county [13].
Survey methodology
To estimate TF prevalence among children ages 1–9 years at
a 95% confidence level, a TF prevalence in this age group of
4% ± 2.0% precision and a design effect of 2.7 was
assumed [14], with a 15% non-response rate and 1.3 children
in each household, consistent with previous survey results [9].
It was estimated that at least 1170 children ages 1–9 years in
each county would need to be surveyed to obtain prevalence
estimates with the desired precision. To achieve this sample
size, 30 clusters (villages) per county were targeted, with a
cluster consisting of 30 households from each selected village.
For all four surveyed counties, the same two-stage clus-
ter sampling design was employed. In the first stage, clusters
were selected randomly from a geographically ordered list
provided by the RSS-MoH’s Trachoma Control Program.
Villages with a population of <100 persons and towns with a
population of >5000 persons were excluded [15].
In the second stage, 30 households were selected from
each cluster using a compact segment sampling method [16].
Working with village leaders, survey teams developed sketch
maps of each cluster showing dwellings and/or generated a
list of all households by name. These households were divided
into segments of five households per segment and numbered.
These numbers were written on individual pieces of paper
and placed in a bowl for random selection by the village
leader. Six segments (30 households total) were chosen at ran-
dom from each cluster, and all selected households in the seg-
ment were included in the survey. Households with no one
home at the time of the survey visits were not replaced. All
residents of the selected households were enumerated, and
those present and providing consent were examined.
Surveys in KNC corresponded to a cluster randomised
control trial ‘Enhancing the A in Safe’(ETAS)
(ClinicalTrials.gov ID: NCT05634759) [17]. Survey sampling
for this trial differed slightly from that of the other three
counties. As part of this trial, in advance of the surveys, an
electronic census was performed within the 30 randomly
selected clusters whereby all residents and households were
enumerated. Census data were then used to randomly pre-
select 30 households from the census list (the second stage of
sampling). Survey teams used these lists to locate households
in KNC during the household survey visits; teams were made
up of individuals not involved in the census to reduce the
possibility of bias. Additional data related to this study are
currently being analysed and will be published separately.
Training
Survey teams were comprised of a trachoma grader, a data
recorder, a driver, and a field supervisor. Data recorders
were recruited from nearby communities to facilitate com-
munication with participants in their local dialects. Data
recorders underwent multi-day training on the study proto-
col and standardised procedures. Data recorders were
required to pass an examination to join the survey teams.
Consistent with previous surveys, graders were ophthal-
mic medical assistants/nurses and Ophthalmic Clinical Offi-
cers and were trained by an experienced Master Grader in
2018 [18]. The training included classroom-based sessions
and field practice using the WHO simplified grading system
[18, 19]. Each grader was required to pass both an in-class
slide test that included all five stages of trachoma, and a field
reliability exam with a ≥0.70 kappa score against the consen-
sus grade of the trainers, to join the survey teams. In August
2021, the same graders, who had been consistently working
on surveys throughout the country, returned for an addi-
tional refresher training before the surveys began.
Data collection
In each household, data recorders employed a structured
questionnaire. Preference was given for household
TABLE 1 Summary of SAFE interventions since most recent trachoma
impact surveys in four counties of Eastern Equatoria State, Republic of
South Sudan.
District
(county)
Previous TIS MDA rounds
since previous
TIS
TT
surgeries
providedDate TF
a
TT
b
Budi 2015 17.4 1.4 3 69
Kapoeta East 2015 47.6 1.9 5 820
Kapoeta North 2015 39.7 1.8 5 219
Kapoeta South 2015 30.1 1.3 5 197
Note: Health education was provided during MDA, at surgical camps, and during
other field-based activities.
Abbreviations: MDA, Mass drug administration; TF, trachomatous-inflammation
follicular; TT, trachomatous trichiasis.
a
Trachomatous-inflammation follicular in children ages 1–9 years.
b
Trachomatous trichiasis in individuals ≥15 years. Age-sex standardised through post-
stratification.
TROPICAL MEDICINE & INTERNATIONAL HEALTH 161
representatives that were female caregivers, as in this setting
they are the primary child caregivers and responsible for
household chores. Representatives were asked socioeco-
nomic, demographic, and water, sanitation, and hygiene
(WASH) questions. Improved sanitation was defined in line
with WHO/United Nations International Children’s Emer-
gency Fund guidelines and included private facilities of
piped septic systems, slab-covered pit latrines, ventilated
improved pit latrines, and composting toilets, and their
presence was visually verified by the survey team when pos-
sible [20]. An improved water source included public taps,
boreholes, piped water, rainwater, protected springs, and
protected dug wells [20]. Access to water was defined as
having a roundtrip travel time of ≤30 min to collect water.
All residents in selected households were enumerated
regardless of whether they were present or participated in
the survey. Present and consenting individuals 1 year of age
or older were examined by the graders for clinical signs of
trachoma, as defined by the WHO-simplified grading
scheme, using a 2.5loupe [19]. Graders observed the faces
of children ages 1–9 years to determine facial cleanliness, as
defined by the absence of ocular and/or nasal discharge [21].
Individuals with signs of active trachoma (TF and/or TI)
were offered treatment with 1% tetracycline eye ointment.
Those identified with TT were checked for signs of epilation,
asked about their surgical history, registered, and advised to
undergo TT surgery during the next surgical campaign in
the county.
Analysis
Survey data were collected electronically on Android phones
loaded with custom-built NEMO survey software [22].
While in the field, supervisors reviewed the survey data for
accuracy and completeness. Statistical analysis was con-
ducted using the R Statistical Software v4.3.0 [23]. Sampling
weights were calculated as the inverse of the probability of
selection at both stages of sampling. Confidence intervals
(CI) were calculated at the 95% level using Taylor series lin-
earization through the survey package in R, accounting for
the multi-level structure of the sampling [24]. Unpaired
t-tests were used to evaluate if there were statistically signifi-
cant differences between the sexes for TF and TT. Maps
were produced in ArcGIS Pro [25], with graphs created
using the ggplot2 package in R [26].
To estimate the prevalence of TT and TT unknown to
the health system, post-stratification weighting using five-
year age-sex bands from the survey census population was
used within the entire population and among individuals
ages ≥15 years. This age-sex adjustment accounted for the
systematic over-representativeness of older women in sur-
veyed populations, deemed important as women bear a
higher burden of TT [27]. TT unknown to the health system
was defined as anyone who had not been offered or recieved
surgery, nor had refused surgery for at least one eye present-
ing the clinical signs of TT.
RESULTS
Between 2021 and 2023, 3477 households in 116 clusters
were surveyed in the four counties of EES (Table 2). Of the
120 targeted clusters, four were not surveyed due to insecu-
rity (n=3) or no longer existed (n=1). Representatives
from 3286 households (95%) were present at the time of the
survey, of which 15 households did not consent to partici-
pate. Within consenting households, a total of 15,143 indi-
viduals were enumerated. Among these, 12,570 (83%)
individuals were present and consented to examination and
were included in the analyses. Among enumerated children
ages 1–9 years, 5848 (91%) were present and examined.
Study participants had a mean age of 18.6 years, which
was slightly younger than non-participants (19.5 years).
Among examined individuals, 5848 (46.5%) were children
ages 1–9 years, 5092 (40.5%) were individuals ages
≥15 years, and 7433 (59.1%) were female.
The prevalence of an improved primary water source
ranged from 26.0% (CI:18.4%–35.3%) in Budi to 61.8%
(CI:49.4%–72.8%) in KNC (S2). KSC had the highest pro-
portion of households with access to water within 30 min
(60.2%, CI:45.1%–73.5%), which was lowest in KNC (38.9%,
CI:26.3%–53.2%). Improved sanitation prevalence was low,
with <10% of households in three counties (Budi, KEC,
KNC) having improved sanitation. Household representa-
tives reported washing their children’s faces at least one time
a day in 93.4% of surveyed households, and 72.7% of exam-
ined children ages 1–9 years had a clean face (S3). House-
hold adult education levels were low across the four
counties, and electricity, generators, and radios were rare.
The prevalence of TF among children ages 1–9 years
was 5.6% (CI:3.7%–8.3%) in KSC, 7.4% (CI:5.1%–10.7%) in
Budi, 12.3% (CI:7.8%–18.9%) in KEC, and 18.1%
(CI:13.5%–24.0%) in KNC (Table 3, Figure 2a). The preva-
lence of TI among children ages 1–9 years ranged from
0.4% (CI:0.2%–1.0%) in KEC to 2.1% (CI:1.4%–3.2%) in
KNC. Among children in this age range, there was not a sta-
tistically significant difference between boys and girls for TF
prevalence (12.2% vs. 11.6%, p=0.5) or TI prevalence
(1.0% vs. 0.9%, p=0.7). Both TF and TI tended to be higher
in younger children (ages <6 years) and lower in children
ages 6–9 years (Figure 3). Both TF and TI were uncommon
in individuals ages ≥15 years (TF: 0.8% [CI:0.5–1.4%]; TI:
0.1% [CI:0.1–0.3%]).
A total of 105 cases of TT were observed by the survey
teams. The prevalence of TT in individuals ages ≥15 years
ranged from 1.0% (CI:0.5%–2.1%) in KNC to 1.9%
(CI:1.3%–2.8%) in Budi (Table 3, Figure 2b). TT prevalence
was higher among females than males (2.7% vs. 0.6%,
p< 0.001) in this age group. The median age of TT cases
across the surveyed population was 56.5 years, and two indi-
viduals <15 years were observed as having TT. A total of
127 cases of CO were observed (Budi =43, KEC =24,
KNC =17, KSC =43) in the survey population.
Among individuals ages ≥15 years with TT, 14 (13.6%)
reported having had surgery and 39 (37.5%) had observed
162 TROPICAL MEDICINE & INTERNATIONAL HEALTH
signs of epilation on at least one eye. For those who did not
report having surgery, 87/89 (97.8%) said it was due to
not being offered, and no one responded as having refused
surgery. The prevalence of TT unknown to the health sys-
tem closely matched the TT prevalence across the four
counties, with KNC reporting identical estimates. Both TT
and TT unknown to the health system increased with age
(Figure 3).
TF, TI, and TT prevalence estimates were lower in all
four counties during this survey compared to the 2015
TIS [9] (Figure 4). TF prevalence decreases ranged from an
81.4% decrease in KSC to a 54.4% decrease in KNC.
Reductions in TI prevalence were observed and ranged from
97.4% in KEC to 74.1% in KNC. In addition, the age-specific
prevalence of TF and TI among children ages 1–9 years was
lower for each year of age when compared to children sur-
veyed in 2015 (Figure 5).
DISCUSSION
These population-based prevalence surveys demonstrated
that the RSS-MoH is progressing towards eliminating tra-
choma as a public health problem in four counties of EES.
TABLE 2 Survey population and response rate by county, Eastern Equatoria State, South Sudan, 2021–2023.
Enumerated Examined
County
Year of
survey Clusters Households
All
ages
Children
1–9 years
Households
(%)
a
All
ages (%)
a
Children
1–9 years (%)
a
Budi 2023 28 827 4230 1795 807 (98%) 3451 (82%) 1693 (94%)
Kapoeta East 2021 29 867 3600 1623 839 (97%) 3356 (93%) 1576 (97%)
Kapoeta North 2022 30 910 3944 1671 824 (91%) 2830 (72%) 1389 (83%)
Kapoeta South 2021 29 873 3369 1317 816 (93%) 2933 (87%) 1190 (90%)
Total 116 3477 15,143 6406 3286 (95%) 12,570 (83%) 5848 (91%)
a
Percents shown correspond to each row’s categories and are calculated as the number examined/number enumerated.
TABLE 3 Prevalence of clinical signs of trachoma by county in Eastern Equatoria State, South Sudan, 2021–2023.
Clinical sign Budi: % (95% CI) KEC: % (95% CI) KNC: % (95% CI) KSC: % (95% CI)
TF, ages 1–9 years 7.4 (5.1–10.7) 12.3 (7.8–18.9) 18.1 (13.5–24.0) 5.6 (3.7–8.3)
TI, ages 1–9 years 0.5 (0.2–1.1) 0.4 (0.2–1.0) 2.1 (1.4–3.2) 0.5 (0.2–1.1)
TT, ages ≥15 years 2.4 (1.6–3.4) 1.2 (0.6–2.2) 1.3 (0.6–2.6) 1.8 (1.0–2.9)
TT, ages ≥15 years
a
1.9 (1.3–2.8) 1.1 (0.6–2.2) 1.0 (0.5–2.1) 1.6 (1.0–2.7)
TT unknown to the health system, ages ≥15 years 2.0 (1.4–3.0) 1.0 (0.5–1.9) 1.3 (0.6–2.6) 1.2 (0.7–2.1)
TT unknown to the health system, ages ≥15 years
a
1.7 (1.1–2.6) 1.0 (0.5–1.9) 1.0 (0.5–2.1) 1.1 (0.6–2.0)
CO, ages ≥15 years
a
2.5 (1.6–3.8) 1.5 (0.7–3.1) 1.3 (0.8–2.3) 3.3 (2.4–4.6)
Abbreviations: CI, confidence interval; CO, corneal opacity; KNC, Kapoeta North County; KEC, Kapoeta East County; KSC, Kapoeta South County;TF, trachomatous
inflammation-follicular; TI, trachomatous inflammation-intense; TT, trachomatous trichiasis; %, percent.
a
Age-sex standardised through post-stratification.
FIGURE 2 Prevalence of trachomatous-inflammation follicular (TF) among children ages 1–9 years (a) and trachomatous trichiasis (TT) prevalence in
individuals ≥15 years (b) in Eastern Equatoria State (EES), South Sudan, 2021–2023.
TROPICAL MEDICINE & INTERNATIONAL HEALTH 163
The prevalence of TF among children ages 1–9yearsranged
from 5.6% to 18.1%, while the prevalence of TT in individuals
ages ≥15 years ranged from 1.0% to 1.9%. Although none of
the surveyed counties reached the established elimination
thresholds for TF or TT, both indicators were considerably
closer to the threshold in these surveys when compared to the
2015 TIS. With sustained high-quality SAFE interventions,
these counties are on track for their elimination goal.
The RSS-MoH has a long history of providing trachoma
interventions and monitoring in EES. Baseline surveys con-
ducted at the sub-county administrative level (payams) in
2004 found a TF prevalence of 40% and a TT prevalence of
17% in the Kimotong payam of Budi, and a TF prevalence of
35.4% and a TT prevalence of 6.3% in the Narus payam of
KEC [7]. However, as these baseline surveys were designed for
different evaluation units, they cannot be directly compared to
the 2015 and 2021–2023 county-level estimates. When com-
paring the 2021–2023 results with those from the 2015 sur-
veys, reductions in TF, TI, and TT were observed across the
four counties and age-specific prevalences of TF and TI
among children ages 1–9 years decreased across the whole age
range. TI estimates at the current surveys were ≤0.5% in three
counties (Budi, KEC, and KSC) suggesting that the prevalence
of ocular C. trachomatis infection was low [28].
25 Elimination
Threshold (5%)
20
15
10
TF Prevalence (%)
TT Prevalence (%)
5
0
20
15
10
5
0
15-24 25-34 35-44 45-54 55-64 65-74 75+
Age in Years
123 45 678 9
25
20
15
10
TI Prevalence (%)
5
0
Age in Years
A
g
e in Years
Elimination Threshold (0.2%) TT unknown to the health system TT (overall)
123 45 678 9
FIGURE 3 Age-specific prevalence of TF and TI among children ages 1–9 years (top), and age-specific prevalence of TT and TT unknown to the health
system for individuals 15 years and older (bottom), in four counties in Eastern Equatoria State, South Sudan, 2021–2023. TF, trachomatous inflammation-
follicular; TI, trachomatous inflammation-intense; TT, trachomatous trichiasis; TT unknown to the health system is defined as cases of TT not previously
detected by the health system; TT overall is defined as all cases of TT, including those previously registered by the health system.
164 TROPICAL MEDICINE & INTERNATIONAL HEALTH
These findings support an overall downward trend in
trachoma in this region. The trend is likely attributable
to the history of SAFE interventions in the region, which
started in 2007. The impact of sustaining investments in
the SAFE strategy—particularly in the face of civil unrest
and local insecurity—serves as valuable proof of concept
for the RSS-MoH and is relevant for other hyperendemic
states such as Jonglei, Upper Nile, and Unity [7,
8, 29, 30]. These three states include counties with some
of the highest prevalences of trachoma in the country
and are a source of internally displaced populations
stemming from a combination of conflict, instability, and
environmental crises [11]. They are also the source of
South Sudanese refugees living in Sudan, a population
where trachoma was observed during surveys performed
in refugee camps [31]. Maintaining interventions in these
three states and EES will require sustained support from
the RSS-MoH’s Trachoma Control Program and partner
organisations and will be particularly important given the
migratory and pastoral populations between South Sudan
and the neighbouring trachoma-endemic countries of
Kenya and Ethiopia [30, 32, 33].
2015
0
10
20
20
25
15
10
5
0
30
40
50
60
2021-2023
TF 1y - 9y (%)
BUDI KEC
2015 2021-2023
KNC
2015 2021-2023
KSC
2015 2021-2023
TIS Year
2015
2021-2023
TIS Year
2015
2021-2023
TIS Year
2015
2021-2023
Elimination
Threshold (5%)
Elimination
Threshold (0.2%)
2015 2021-2023
BUDI
TI 1y - 9y (%)
TT ≥ 15y (%)
KEC
2015 2021-2023
KNC
2015 2021-2023
KSC
2015 2021-2023
2015 2021-2023
BUDI
0
2
4
6
KEC
2015 2021-2023
KNC
County
2015 2021-2023
KSC
2015 2021-2023
FIGURE 4 County prevalence of TF and TI among children ages 1–9 years and TT for individuals ≥15 years between the first (2015) and second
(2021–2023) trachoma impact surveys of four counties in Eastern Equatoria State, South Sudan. KEC, Kapoeta East County; KNC, Kapoeta North County;
KSC, Kapoeta South County; TF, trachomatous inflammation-follicular; TI, trachomatous inflammation-intense; TT, trachomatous trichiasis; TIS, trachoma
impact survey; TT defined as all cases of TT, including those previously registered by the health system; Y, year. TT estimates calculated through age-
standardised post-stratification.
TROPICAL MEDICINE & INTERNATIONAL HEALTH 165
In agreement with WHO recommendations, all four
counties will require continued MDA. In KEC and KNC,
where TF prevalence estimates for children ages 1–9 years
were within the 10%–29.9% range, three additional MDA
rounds should be performed [13]. Evidence has demon-
strated that one round of MDA can reduce TF prevalence to
<5% in settings where TF prevalence was between 5% and
9.9%, and thus for Budi and KSC only one additional round
of MDA is recommended [34]. Each MDA campaign should
seek to attain a coverage of ≥80% and a standardised TIS
should be performed ≥6 months after the last planned
MDA [35].
While consideration should be made to the high baseline
levels of trachoma recorded in these counties, all four con-
tinue to have TF levels >5% after two impact surveys and
thus can be designated as having persistent trachoma [36].
Persistent trachoma poses a significant endgame challenge
in both South Sudan and for the global trachoma pro-
gramme [36]. In December 2021, 8% of districts ever
endemic for trachoma could be classified as persistent. To
address this, modified ‘more frequent than annual’(MFTA)
strategies for MDA have been proposed, with modelling
studies supporting the role that MFTA could have to accel-
erate trachoma reductions [37]. Following this survey, one
district, KNC, was enrolled in an MFTA trial to explore the
cost, feasibility, and acceptability of two MFTA treatment
schemes for wider use in South Sudan, with results forth-
coming [17]. Given the high TF prevalence in other parts of
South Sudan such as Jonglei and Upper Nile, MFTA MDA
approaches will likely be important for timely elimination of
trachoma in South Sudan.
This study found that all four surveyed counties had low
WASH infrastructure. Further investments into WASH
could accelerate reductions in C. trachomatis infections and
help sustain reductions after MDA ceases, though these
interventions are expensive, complicated to monitor, and
challenging to implement in the South Sudanese con-
text [11]. However, given the role that access to water and
Age in Years
TIS Year: 2015 2021-2023
TIS Year: 2015 2021-2023
TF 1Y - 9y (%)
TI 1Y - 9y (%)
Elimination Threshold (5%)
A
g
e in Years
1
0
10
20
0
10
15
20
5
30
40
50
23456789
12345678 9
FIGURE 5 TF and TI prevalence in children ages 1–9 years between the first (2015) and second (2021–2023) trachoma impact surveys of four counties
in Eastern Equatoria State, South Sudan. KEC, Kapoeta East County; KNC, Kapoeta North County; KSC, Kapoeta South County; TF, trachomatous-
inflammation follicular; TI, trachomatous inflammation-intense; TIS: trachoma impact survey; Y, year.
166 TROPICAL MEDICINE & INTERNATIONAL HEALTH
sanitation has in managing other NTDs and in improving
health outcomes [38], a multisectoral approach could ensure
that funding and governance of WASH infrastructure
improvements are sustainable. Furthermore, as a key com-
ponent of future F and E activities will be related to educa-
tion campaigns, how to reach a population with limited
infrastructure and limited access to electricity, cell phones,
and radios should be considered.
TT unknown to the health system and overall TT preva-
lence in individuals ages ≥15 years closely aligned in all
counties and was above the WHO elimination threshold.
Interestingly, although 97.8% of TT cases reported having
never been offered surgery, no TT case reported
having refused surgery, implying that current limitations to
surgical uptake are related to its provision and not accep-
tance. House-to-house TT case detection coupled with com-
munity awareness campaigns may be an effective outreach
strategy to ensure TT patients are identified and offered sur-
gery, as has been seen in neighbouring countries such as
Kenya [39] and Sudan [40]. However, the lack of trained
surgeons at regional and county levels is one of the main
limitations for scaling up surgery camps in EES. A study
from 2011 found <1 ophthalmologist per one million indi-
viduals in South Sudan [41], and data from 2014 estimated
South Sudan ranked 187th out of 191 countries for ophthal-
mologists per million [42, 43]. Community-based screening
through TT case detection could be attractive to health pro-
viders, as it reduces the time surgeons need to spend with
each patient. In addition, the timing and location of future
surgery camps should align with the population’s migratory
activities—such as cattle herding and crop harvesting—to
ensure patients can access them. Although refusal does not
seem to be a driver of the high level of TT unknown to the
health system, as more individuals are identified and offered
surgery this may change. Targeted surgery camps will
increase not only the coverage of the intervention but will
have the added benefit of limiting potential barriers to its
uptake, as direct and indirect costs of surgery have been seen
to be barriers to uptake [44]. Integrating surgical camps with
other services, such as cataract surgeries, could be effective
at sustaining the provision of TT surgery as TT levels
decrease. These camps could also further confirm the con-
siderable levels of CO detected in this population and help
address underlying, non-trachoma causes. Since these sur-
veys were performed in 2021–2023, integrated camps such
as these have been piloted in counties across South Sudan,
including in Budi [45]. Finally, given that 37.5% of TT cases
showed signs of epilation, promoting quality epilation prac-
tices could be a strategy to prevent the progression of TT
cases to irreversible blindness within the surveyed popula-
tion while surgical services are scaled up [46].
Although the target number of clusters was not reached
in three counties (Budi, KEC, and KSC), all four surveys
exceeded the targeted number of children ages 1–9 years for
TF estimates. The survey in KNC was conducted as part of
the ETAS study and had a slightly different study design,
though as mentioned previously the overall selection process
was largely unchanged when compared to the other three
counties [17]. Finally, these surveys were designed to esti-
mate TF prevalence among children and were not designed
to precisely estimate the prevalence of TT in adults [47].
However, the results of this study clearly demonstrated that
TT levels are still above the WHO threshold of 0.2%, so fur-
ther interventions by the RSS-MoH will be needed to reduce
the burden of TT in these counties.
CONCLUSION
The RSS-MoH’s Trachoma Control Program has conducted
years of SAFE interventions in EES and is advancing
towards its goal of eliminating trachoma as a public health
problem by 2030. Compared to the most recent TIS from
2015, the prevalence of TF, TI, and TT in the counties of
Budi, KEC, KNC, and KSC decreased, though WASH infra-
structure was low across all four countries. As no county
reached the WHO-established elimination thresholds of TF
<5% in children ages 1–9 years old or TT <0.2% in individ-
uals ≥15 years, SAFE interventions should be continued
across the state.
ACKNOWLEDGEMENTS
We would like to thank the local health workers, field coor-
dinators, graders, recorders, and logistical support staff who
made these surveys possible and participants who gave their
time to participate in them. We also thank the Eastern
Equatoria State Ministry of Health and officials for their
continued collaboration and guidance. Finally, we would like
to thank the Bill and Melinda Gates Foundation for funding
these surveys.
FUNDING INFORMATION
This is a routine monitoring activity of the Trachoma Con-
trol Program technically and financially assisted by The Car-
ter Center in collaboration with the Republic of South
Sudan Ministry of Health (RSS-MoH) and carried out by
Program personnel. External funding was provided by the
Bill and Melinda Gates Foundation.
CONFLICT OF INTEREST STATEMENT
The authors declare no conflicts of interest.
DATA AVAILABILITY STATEMENT
The data used for this study are not owned by The Carter
Center but by the Republic of South Sudan Ministry of
Health. Data and rights of use were granted to The Carter
Center by the Republic of South Sudan Ministry of Health.
Requests to use the data for study purposes should be
directed to the South Sudan Ministry of Health.
ORCID
Nicholas A. Presley https://orcid.org/0009-0000-6593-
9244
Scott D. Nash https://orcid.org/0000-0001-5741-8537
TROPICAL MEDICINE & INTERNATIONAL HEALTH 167
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SUPPORTING INFORMATION
Additional supporting information can be found online in
the Supporting Information section at the end of this article.
How to cite this article: Ohidor S, Presley NA,
Sanders AM, Nute AW, Gonzalez TA, Bol YY, et al.
Progress towards the elimination of trachoma as a
public health problem in four counties of Eastern
Equatoria State, Republic of South Sudan. Trop Med
Int Health. 2025;30(3):159–69. https://doi.org/10.
1111/tmi.14078
TROPICAL MEDICINE & INTERNATIONAL HEALTH 169
