Nodding syndrome and epilepsy in onchocerciasis endemic regions: comparing preliminary observations from South Sudan and the Democratic Republic of the Congo with data from Uganda.

BACKGROUND: Nodding syndrome (NS) is an epilepsy disorder occurring in children in South Sudan, northern Uganda and Tanzania. The etiology of NS is unknown, but epidemiological studies demonstrate an association between NS and onchocerciasis. METHODS: Between November 2013 and July 2015 we visited onchocerciasis endemic regions in South Sudan, Uganda, and the Democratic Republic of the Congo (DRC) to assess the epilepsy situation. In South Sudan we interviewed patients and affected families, health officials, colleagues and healthcare workers, and performed a small household survey to estimate the epilepsy prevalence in the village of Mvolo, Western Equatoria State. Most information from Uganda was collected through discussions with colleagues and a review of published literature and reports. In the Bas-Uélé district of the DRC, we visited the villages of Liguga, Titule and Dingila, interviewed patients with epilepsy and family members and conducted a preliminary entomological assessment. RESULTS: In South Sudan there is an ongoing NS and epilepsy epidemic in the Western Equatoria state that started around 1990. A survey of 22 households in Mvolo revealed that 28 out of 168 (16.7%) children suffered from NS or another form of epilepsy. Thirteen (59%) households had at least one child, and nine (41%) households at least two children with NS or another form of epilepsy. In northern Uganda, an NS and epilepsy epidemic started around 2000. The occurrence of new NS cases has been in decline since 2008 and no new NS cases were officially reported in 2013. The decline in NS cases coincided with the bi-annual distribution of ivermectin and the treatment of blackfly-breeding rivers with larvicides. In Bas-Uélé district in the DRC, epilepsy appears to be endemic with cases clustered in villages close to blackfly-infested, rapid-flowing rivers. The majority of epilepsy cases in Liguga, Dingila and Titule presented with generalized (tonic-clonic) seizures without nodding, but with mental retardation. In Titule, an epilepsy prevalence of 2.3% was documented. The only anthropophilic species of blackfly collected in the region belonged to the Simulium damnosum complex. CONCLUSION: Blackflies may play a key role in the transmission of an etiological agent that either directly or indirectly cause, not only NS, but also other forms of epilepsy in onchocerciasis endemic regions.

Prevalence of trachoma in unity state, South Sudan: results from a large-scale population-based survey and potential implications for further surveys.

BACKGROUND: Large parts of South Sudan are thought to be trachoma-endemic but baseline data are limited. This study aimed to estimate prevalence for planning trachoma interventions in Unity State, to identify risk factors and to investigate the effect of different sampling approaches on study conclusions. METHODS AND FINDINGS: The survey area was defined as one domain of eight counties in Unity State. Across the area, 40 clusters (villages) were randomly selected proportional to the county population size in a population-based prevalence survey. The simplified grading scheme was used to classify clinical signs of trachoma. The unadjusted prevalence of trachoma inflammation-follicular (TF) in children aged 1-9 years was 70.5% (95% CI: 68.6-72.3). After adjusting for age, sex, county and clustering of cases at household and village level the prevalence was 71.0% (95% CI: 69.9-72.1). The prevalence of trachomatous trichiasis (TT) in adults was 15.1% (95% CI: 13.4-17.0) and 13.5% (95% CI: 12.0-15.1) before and after adjustment, respectively. We estimate that 700,000 people (the entire population of Unity State) require antibiotic treatment and approximately 54,178 people require TT surgery. Risk factor analyses confirmed child-level associations with TF and highlighted that older adults living in poverty are at higher risk of TT. Conditional simulations, testing the alternatives of sampling 20 or 60 villages over the same area, indicated that sampling of only 20 villages would have provided an acceptable level of precision for state-level prevalence estimation to inform intervention decisions in this hyperendemic setting. CONCLUSION: Trachoma poses an enormous burden on the population of Unity State. Comprehensive control is urgently required to avoid preventable blindness and should be initiated across the state now. In other parts of South Sudan suspected to be highly trachoma endemic, counties should be combined into larger survey areas to generate the baseline data required to initiate interventions.

Trachoma rapid assessments in Unity and Northern Bahr-el-Ghazal States, Southern Sudan.

BACKGROUND: Trachoma is thought to be endemic over large parts of Southern Sudan, but empirical evidence is limited. While some areas east of the Nile have been identified as highly endemic, few trachoma surveys have been conducted in the remainder of the country. This study aimed to determine whether trachoma constitutes a problem to public health in Northern Bahr-el-Ghazal and Unity State, both located west of the Nile. METHODS AND PRINCIPAL FINDINGS: Trachoma rapid assessments (TRA) were conducted between July and September 2009. Seven villages in Northern Bahr-el-Ghazal State and 13 villages in Unity State were surveyed; an average of 50 children (age 1-9 years) and 44 women (age 15 years and above) were examined per village. Samples for analysis using the APTIMA Combo-2 nucleic acid amplification test (NAAT) were collected from participants with active trachoma in eight villages in Unity State. In Northern Bahr-el-Ghazal State, only three children with active trachoma (trachomatous inflammation follicular (TF) and/or trachomatous inflammation intense (TI)) and two women with trichiasis (TT) were found, in two of the seven villages surveyed. In Unity State, trachoma was endemic in all thirteen villages surveyed; the proportion of children with active trachoma ranged from 33% to 75% between villages, while TF in children ranged from 16% to 44%. Between 4% to 51% of examined women showed signs of TT. Samples from active trachoma cases tested using the NAAT were positive for Chlamydia trachomatis infection for 46.6% of children and 19.0% of women. CONCLUSIONS: Trachoma presents a major problem to public health Unity State, while the disease is of low priority in Northern-Bahr-el-Ghazal State. Implementation of a population-based prevalence survey is now required in Unity State to generate baseline prevalence data so that trachoma interventions can be initiated and monitored over time.

Targeting trachoma control through risk mapping: the example of Southern Sudan.

BACKGROUND: Trachoma is a major cause of blindness in Southern Sudan. Its distribution has only been partially established and many communities in need of intervention have therefore not been identified or targeted. The present study aimed to develop a tool to improve targeting of survey and control activities. METHODS/PRINCIPAL FINDINGS: A national trachoma risk map was developed using Bayesian geostatistics models, incorporating trachoma prevalence data from 112 geo-referenced communities surveyed between 2001 and 2009. Logistic regression models were developed using active trachoma (trachomatous inflammation follicular and/or trachomatous inflammation intense) in 6345 children aged 1-9 years as the outcome, and incorporating fixed effects for age, long-term average rainfall (interpolated from weather station data) and land cover (i.e. vegetation type, derived from satellite remote sensing), as well as geostatistical random effects describing spatial clustering of trachoma. The model predicted the west of the country to be at no or low trachoma risk. Trachoma clusters in the central, northern and eastern areas had a radius of 8 km after accounting for the fixed effects. CONCLUSION: In Southern Sudan, large-scale spatial variation in the risk of active trachoma infection is associated with aridity. Spatial prediction has identified likely high-risk areas to be prioritized for more data collection, potentially to be followed by intervention.

Trachoma in Western Equatoria State, Southern Sudan: implications for national control.

BACKGROUND: Trachoma is thought to be common over large parts of Southern Sudan. However, many areas of the country, particularly west of the Nile, have not yet been surveyed. The aim of this study was to confirm whether trachoma extends into Western Equatoria State from neighboring Central Equatoria, where trachoma is highly prevalent, and whether intervention with the SAFE strategy is required. METHODS AND FINDINGS: Population-based cross-sectional surveys were conducted using a two-stage cluster random sampling method to select the study population. Subjects were examined for trachoma by experienced graders using the World Health Organization (WHO) simplified grading scheme. Two counties thought to be most likely to have trachoma were surveyed, Maridi and Mundri. In Maridi, prevalence of one of the signs of active trachoma (trachomatous inflammation-follicular (TF)) in children aged 1-9 years was 0.4% (95% confidence interval (CI), 0.0%-0.8%), while no children showing the other possible sign, trachomatous inflammation-intense (TI), were identified. No trachomatous trichiasis (TT) was found in those aged under 15, and prevalence was 0.1% (95% CI, 0.0%-0.4%) in those aged 15 years and above. In Mundri, active trachoma was also limited to signs of TF, with a prevalence of 4.1% (95% CI, 1.4%-6.9%) in children aged 1-9 years. Again, no TT was found in those aged under 15, and prevalence in those aged 15 years and above was 0.3% (95% CI, 0.0%-0.8%). CONCLUSION: Trachoma prevalence in the east of Western Equatoria State is below the WHO recommended intervention threshold for mass drug administration of antibiotic treatment in all villages. However, the prevalence of TF and TT in some villages, particularly in Mundri County, is sufficiently high to warrant targeted interventions at the community level. These results demonstrate that trachoma is not a major public health problem throughout Southern Sudan. Further studies will be required to determine trachoma prevalence in other areas, particularly west of the Nile, but there are presently no resources to survey each county. Studies should thus be targeted to areas where collection of new data would be most informative.

Risk factors for trachomatous trichiasis in children: cross-sectional household surveys in Southern Sudan.

We have previously documented blinding trachoma to be a serious public health problem in Southern Sudan, with an unusually high prevalence of trachomatous trichiasis (TT) among children. We aimed to investigate risk factors for TT in children in Southern Sudan. Cross-sectional surveys were undertaken in 11 districts between 2001 and 2006, and eligible participants were examined for trachoma signs. Risk factors were assessed through interviews and observations. Using logistic regression, associations between TT in children and potential risk factors were investigated. In total, 11155 children aged 1-14 years from 3950 households were included in the analysis. Overall prevalence of TT was 1.5% (95% CI 1.1-2.1). Factors independently associated with increased odds of TT in children aged 1-14 years were: increasing age (P(trend)<0.001); female gender (odds ratio=1.5; 95% CI 1.1-2.1); increasing proportion of children in the household with trachomatous inflammation-intense (TI) (P(trend)=0.002); and increasing number of adults in the household with TT (P(trend)<0.001). Our study revealed risk factors for TT in children consistent with those previously reported for TT in adults. While the associations of TT in children with TI in siblings and TT in adult relatives merit further investigation, there is an urgent need for trachoma prevention interventions and trichiasis surgery services that are tailored to cater for young children in Southern Sudan.

Examining Media Habits: implications for health promotion programs among the Toposa in Southern Sudan.

Dissemination of appropriate health education messages is essential to any health promotion campaign. This cross-sectional study examined media ownership, access and media preferences by target groups in Kapoeta South County, Southern Sudan. The target groups were segmented into household heads (n = 368); women with children under five years (n = 580); and youth 11-16 years old (n = 349). Interviewees were selected at random from 49 villages. Overall, a small portion owned radios (6.8%) and television sets (0.2%); more had access to radio (27.1%), listened to cassettes (50.8%), and had access to television and movies (21.4%). The majority were interested in programs developed in the vernacular (89.0%). A very low literacy rate (1.3%) and difficulty in understanding signage (29.7%) posed potential obstacles for use of print media as a primary source of health communication. Heads of household were more likely to own radios (P < 0.001), watch TV outside of the home (P = 0.034), and see posters (P = 0.038) than other groups. Traditional entertainment was attended by 94.4% of respondents. Information from chiefs (61.5%) and elders (51.5%) was considered trustworthy by the majority of respondents. This research highlights the utility in understanding media access, habits and preferences of community members when designing a health promotion campaign.

Estimation of population coverage for antibiotic distribution for trachoma control: a comparison of methods.

Trachoma control includes mass drug administration (MDA) with antibiotics targeting coverage of at least 80%. Coverage is traditionally calculated by dividing doses distributed by population estimate, which is unreliable. We compared a verifiable coverage assessment method against self-reported participation and the traditional calculation, and examined factors associated with MDA participation in Akobo County, Southern Sudan. During MDA, recipients were marked with indelible ink and followed-up using a two-stage household survey: 25 clusters from three districts, and 10 households per cluster. All household members were enumerated; asked about self-reported participation and observed for indelible marks. Household heads were interviewed to assess factors associated with MDA. Overall 11 419 treatments were given and 1358 residents from 247 households surveyed. By traditional methods MDA coverage was 20.9% (95% CI: 20.6-21.3); 61.5% (95 % CI: 49.4-73.6) by self-reporting; and 37.5% (95% CI: 25.1%-49.9%) from observed ink marks. Controlling for other factors, presence of a health worker (OR 2.3, 95% CI: 1.5-3.6); head of household knowledge of azithromycin (OR 1.6, 95% CI: 1.5-3.1); and head of household advance notice of MDA (OR 34.9, 18.1-66.3) were independent predictors of participation. Cluster randomised surveys can estimate MDA coverage better than the traditional method and implementation of indelible marking merits investigation.