Enlightenment of blinding trachoma elimination in China

正Trachoma is a blinding eye disease caused by Chlamydia trachomatis infection.Trachoma was pandemic in the 19th century and rampant around the world,and was a widely prevalent infectious eye disease.Still prevalent in some countries and regions,it is an eye disease with the longest epidemic time.Trachoma is a blinding eye disease pandemic globally,having caused many people to lose their visions and     

The burden of trachoma in Ayod County of Southern Sudan

Background

Blindness due to trachoma is avoidable through Surgery, Antibiotics, Facial hygiene and Environmental improvements (SAFE). Recent surveys have shown trachoma to be a serious cause of blindness in Southern Sudan. We conducted this survey in Ayod County of Jonglei State to estimate the need for intervention activities to eliminate blinding trachoma.

Methodology and Findings

A cross-sectional two-stage cluster random survey was conducted in November 2006. All residents of selected households were clinically assessed for trachoma using the World Health Organization (WHO) simplified grading scheme. A total of 2,335 people from 392 households were examined, of whom 1,107 were over 14 years of age. Prevalence of signs of active trachoma in children 1–9 years of age was: trachomatous inflammation follicular (TF) = 80.1% (95% confidence interval [CI], 73.9–86.3); trachomatous inflammation intense (TI) = 60.7% (95% CI, 54.6–66.8); and TF and/or TI (active trachoma) = 88.3% (95% CI, 83.7–92.9). Prevalence of trachomatous trichiasis (TT) was 14.6% (95% CI, 10.9–18.3) in adults over 14 years of age; 2.9% (95% CI, 0.4–5.3) in children 1–14 years of age; and 8.4% (95% CI, 5.5–11.3) overall. The prevalence of corneal opacity in persons over 14 years of age with TT was 6.4% (95% CI, 4.5–8.3). No statistically significant difference was observed in the prevalence of trachoma signs between genders. Trachoma affected almost all households surveyed: 384/392 (98.0%) had at least one person with active trachoma and 130 (33.2%) had at least one person with trichiasis.

Conclusions

Trachoma is an unnecessary public health problem in Ayod. The high prevalence of active trachoma and trichiasis confirms the severe burden of blinding trachoma found in other post-conflict areas of Southern Sudan. Based on WHO recommended thresholds, all aspects of the SAFE strategy are indicated to eliminate blinding trachoma in Ayod.     

The cost of antibiotic mass drug administration for trachoma control in a remote area of South Sudan

Background

Mass drug administration (MDA) of antibiotics is a key component of the so-called “SAFE” strategy for trachoma control, while MDA of anthelminthics provides the cornerstone for control of a number of other neglected tropical diseases (NTDs). Simultaneous delivery of two or more of these drugs, renowned as “integrated NTD control,” is being promoted to reduce costs and expand intervention coverage. A cost analysis was conducted alongside an MDA campaign in a remote trachoma endemic area, to inform budgeting for NTD control in South Sudan.

Methods and Findings

A first round of antibiotic MDA was conducted in the highly trachoma endemic county of Mayom, Unity state, from June to August 2010. A core team of seven staff delivered the intervention, including recruitment and training of 44 supervisors and 542 community drug distributors. Using an ingredients approach, financial and economic costs were captured from the provider perspective in a detailed costing database. Overall, 123,760 individuals were treated for trachoma, resulting in an estimated treatment coverage of 94%. The economic cost per person treated was USD 1.53, excluding the cost of the antibiotic azithromycin. Ninety four per cent of the delivery costs were recurrent costs, with personnel and travel/transport costs taking up the largest share.

Conclusions

In a remote setting and for the initial round, MDA of antibiotics was considerably more expensive than USD 0.5 per person treated, an estimate frequently quoted to advocate for integrated NTD control. Drug delivery costs in South Sudan are unlikely to decrease substantially during subsequent MDA rounds, as the major cost drivers were recurrent costs. MDA campaigns for delivery of one or more drugs in South Sudan should thus be budgeted at around USD 1.5 per person treated, at least until further costing data for delivery of other NTD drugs, singly or in combination, are available.     

The burden of trachoma in South Sudan: assessing the health losses from a condition of graded severity

Introduction

Trachoma is a disease that can lead to visual impairment and ultimately blindness. Previous estimates of health losses from trachoma using the Global Burden of Disease methodology have not, however, included the stage prior to visual impairment. We estimated the burden of all stages of trachoma in South Sudan and assessed the uncertainty associated with the severity and duration of stages of trachoma prior to full blindness.

Methods

The prevalence of trachoma with normal vision, low vision and blindness in the Republic of South Sudan has been estimated previously. These estimates were used to model the incidence and duration of the different stages employing DISMOD II. Different assumptions about disability weights and duration were used to estimate the Years Lived with Disability (YLD).

Results

We have estimated the total burden of trachoma in South Sudan to be between 136,562 and 163,695 YLD and trichiasis with normal vision contributes between 5% and 21% of the total depending on the disability weight applied. Women experience more of this burden than men. The sensitivity of the results to different assumptions about the disability weights is partly dependent upon the assumed duration of the different disease states.

Interpretation

A better understanding of the natural history of trachoma is critical for a more accurate burden estimate.     

Serology,infection, and clinical trachoma as tools in prevalence surveys for re-emergence of trachoma in a formerly hyperendemic district

BackgroundTo eliminate trachoma as a public health problem, countries must achieve a district-level prevalence of trachomatous inflammation—follicular (TF) <5% in children ages 1–9 years. Re-emergence of TF could trigger additional rounds of mass drug/antibiotic administration (MDA), so accurate tools for use in surveys assessing trachoma prevalence are essential.Methodology & principal findingsWe surveyed 2401 children ages 1–9 years from 50 villages in Kongwa, Tanzania, 2 years post-MDA and 1.5 years after an impact survey found TF <5% in the same villages. Our survey included multiple tools: clinical determination of TF, Cepheid testing for Chlamydia trachomatis infection, and testing for anti-pgp3 antibodies via multiplex bead array. Photographs of the upper tarsal conjunctiva were taken in a subset of children to corroborate the field grades.Overall TF prevalence in 1–9 year olds was 7.1% (95% CI: 5.6%-8.9%), which decreased with age (p = <0.0001). TF prevalence by village was heterogeneous, with 19 villages having TF <5% and 16 villages having TF >10%. There was a strong correlation between field and photo grading of TF (kappa = 0.69; 95% CI: 0.60–0.78) and between TF and infection, with 21.5% of TF-positive children also testing positive for infection, as compared to only 1.6% of TF-negative children (p = 0.0010). Overall seroprevalence was 18.2% (95% CI: 14.8%-22.1%), which increased with age (p = <0.0001). Notably, 1–2 year olds, who were born after the cessation of MDA and theoretically should not have had exposure to C. trachomatis in the absence of transmission, had an average seroprevalence of 6.7%.Conclusions & significanceField TF prevalence, supported by photographic review and infection data, suggested re-emergence of trachoma in Kongwa. Moreover, seropositivity in the children born after cessation of MDA indicated exposure to C. trachomatis despite a previous survey finding of TF <5%. Examining seropositivity in specific age groups expected to have limited exposure to C. trachomatis can be used to detect re-emergence.     

A holocene pollen diagram from El Atrun,northern Sudan

Palynological investigations on a 3.36 m core from El Atrun, Nubia, show vegetation development and climatic change during a period from approximately 9800 to 7000 uncal B.P. From a dry period with a steppe-like vegetation at about 9800-9500 B.P. (zone A), a change to a period with a more favourable climate and a tree covered savanna-like vegetation can be observed in zone B (about 9500-8900 B.P.). In zone C (8900-8400 B.P.), a climatic setback is indicated, with spreading of steppe vegetation and an increase in swamp vegetation as a result of a low lake level. For zone D (about 8400-7000 B.P.), renewed spreading of wooded savanna is inferred.     

Patterns of morphological variation in the Acacia species (Mimosaceae) of northern Sudan

KORDOFANI, M. & INGROUILLE, M., 1991. Patterns of morphological variation in the Acacia species (Mimosaceae) of northern Sudan. A numerical taxonomic review has been carried out on the morphology of northern Sudanese Acacia species. Fifty-one characters were scored from 12 species sampled at 12 sites. There is evidence of large scale population variation. Within a single site species are distinct but a comparison of plants between different sites may obscure species differences. Each species has a peculiar local variant in each sampled site, even when sites are separated by only a few kilometres. The possible significance of this pattern of variation is discussed. Species complexes are delineated and useful species diagnostics described.     

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.     

The impact of access to water supply and sanitation on the prevalence of active trachoma in Ethiopia: A systematic review and meta-analysis

BackgroundTrachoma is a worldwide infectious disease causing blindness. Trachoma continued as a public health problem in Ethiopia due to a lack of sanitation and inadequate prevention strategies. This study aimed to identify the impact of water supply and sanitation intervention on preventing active trachoma among children.MethodsSystematic literature searches were performed from 4 international databases. The search involved articles published from January 1995 up to March 2019. The Cochran Q and I² statistical tests were used to check heterogeneity among the studies. A random-effect meta-analysis was employed to determine the pooled estimates with a 95% confidence interval (CI). Data analysis was performed using the CMA V.3 and RevMan 5 software program, and the result of the systematic review was reported using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.FindingsOut of 211 studies screened for the analysis, only 29 studies were finally included in this systematic review and meta-analysis. The result revealed factors that are significantly associated with increased odds of active trachoma. Accordingly, households with no access to toilet facilities (odds ratio [OR]: 2.04, 95% CI: 1.75–2.38), no access to improved water (OR: 1.58, 95% CI: 1.27–1.96), and do not practice regular face washing for children (OR: 4.19, 95% CI: 3.02–5.81) have shown increased odds of active trachoma. Besides, the results show a higher prevalence of active trachoma among children who did not wash their faces with soap and frequently.ConclusionsThe study found strong evidence that lack of access to water, sanitation, and hygiene (WASH) was associated with increased prevalence of active trachoma among children. Therefore, a comprehensive and partnership-oriented program is needed to tackle the problem, but further study will be required to strengthen its implementation.     

Water quality and public health in northern Sudan: a study of rural and peri-urban communities

Access to adequate supplies of good quality drinking water continues to be limited among many rural and peri-urban communities in Africa, despite several decades of water improvement programmes. The present study investigated water quality at the source and point of consumption among rural and peri-urban communities in northern Sudan. Faecal coliform counts were determined by the membrane filtration technique and geometric mean counts compared in different seasons and among the different communities. Among nomadic pastoralists and riverine villages, both water sources and water stored for consumption had faecal coliform counts grossly in excess of WHO standards, with higher counts at the end of the rainy season. In the peri-urban community on the outskirts of Omdurman, while water quality from the distribution system had faecal coliform counts generally below 10 dl - 1, after storage, water was of considerably lower quality, with faecal coliform counts up to 1000 d1 - 1. The highest counts again occurred in the rainy season. Rates of diarrhoeal disease for Khartoum province were also greatest towards the end of the rainy season. The study has shown that poor quality water continues to be a major risk factor for public health in these communities.     

Long-term testicular responses to blinding in rats

Gonadal responses to the blinding of one month old rats have been studied at 1,2,3,5,7,9, and 12 month intervals post-surgically. Testosterone in both testicular vein and peripheral venous plasma was measured by radioimmunoassay and spermatogenesis was evaluated by means of differential germ cell counting. The weights of endocrines and accessory sex glands were routinely recorded.Blinding was without effect upon gametogenic function of the testis, at all intervals of study. Testicular venous levels of testosterone in intact rats showed a ‘post-pubertal spurt’ followed by a more pronounced ‘seasonal peak’ and the latter was paralleled by a similar peak in peripheral testosterone. Blinding led to suppression of the post-puberal surge in testicular secretion but testicular vein levels of the hormones were not significantly altered from control values for the remainder of the investigation. In contrast, testosterone concentrations in peripheral plasma of blinded rats were more consistently lower than in control animals until 12 months post-surgery. Atrophic responses of the accessory sex glands to blinding occurred during the initial periods of the study but these had totally disappeared by 9 months. Taken together, the results illustrate a somewhat small degree of gonadal dependency upon photic input in the male rat, particularly when compared with responses reported for the hamster subjected to similar experimental conditions.