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Diagnostics (Basel, Switzerland) Apr 2024Trachoma is the world-leading infectious cause of preventable blindness and is caused by the bacteria . In developing countries, diagnosis is usually based on clinical...
Trachoma is the world-leading infectious cause of preventable blindness and is caused by the bacteria . In developing countries, diagnosis is usually based on clinical evaluation. Serological-based tests are cheaper than molecular-based ones, but the latter are more sensitive and specific. The present study developed a new duplex qPCR which concomitantly detects the cryptic plasmid and the human 18S rRNA gene, with an LOD95% for DNA of 13.04 genome equivalents per reaction. The new qPCR was tested using 50 samples from an endemic area and 12 from a non-endemic area that were previously characterized using direct immunofluorescence assay (DFA) and clinical evaluation. Among the 50 endemic samples, 3 were found to be positive by clinical evaluation (6%), 18 were found to be positive by DFA (36%), and 48 were found to be positive by qPCR (96%). Next, the new duplex qPCR was validated using 50 samples previously characterized by qPCR. Validation was carried out on a benchtop instrument (ABI7500) or on a portable point-of-care instrument (Q3-Plus), showing 95% specificity and 100% sensitivity. The ubiquitous presence of DNA in samples from the endemic region confirms that constant monitoring is of paramount importance for the effective measurement of the elimination of trachoma. The newly developed duplex qPCR presented in this study, along with its validation in a portable qPCR system, constitutes important tools toward achieving this goal.
PubMed: 38732307
DOI: 10.3390/diagnostics14090892 -
Microbiology Resource Announcements May 2024The human pathogen has multiple serovariants that have distinct organotropisms. We recently revised genomic sequence data linked to ocular reference strain, B/HAR36....
The human pathogen has multiple serovariants that have distinct organotropisms. We recently revised genomic sequence data linked to ocular reference strain, B/HAR36. Now linked to its correct genomic data in the European Nucleotide Archive, we describe its genomic features.
PubMed: 38700340
DOI: 10.1128/mra.00029-24 -
PLoS Neglected Tropical Diseases Apr 2024Trachoma is the leading infectious cause of blindness worldwide and is now largely confined to around 40 low- and middle-income countries. It is caused by Chlamydia...
Trachoma is the leading infectious cause of blindness worldwide and is now largely confined to around 40 low- and middle-income countries. It is caused by Chlamydia trachomatis (Ct), a contagious intracellular bacterium. The World Health Organization recommends mass drug administration (MDA) with azithromycin for treatment and control of ocular Ct infections, alongside improving facial cleanliness and environmental conditions to reduce transmission. To understand the molecular epidemiology of trachoma, especially in the context of MDA and transmission dynamics, the identification of Ct genotypes could be useful. While many studies have used the Ct major outer membrane protein gene (ompA) for genotyping, it has limitations. Our study applies a typing system novel to trachoma, Multiple Loci Variable Number Tandem Repeat Analysis combined with ompA (MLVA-ompA). Ocular swabs were collected post-MDA from four trachoma-endemic zones in Ethiopia between 2011-2017. DNA from 300 children with high Ct polymerase chain reaction (PCR) loads was typed using MLVA-ompA, utilizing 3 variable number tandem repeat (VNTR) loci within the Ct genome. Results show that MLVA-ompA exhibited high discriminatory power (0.981) surpassing the recommended threshold for epidemiological studies. We identified 87 MLVA-ompA variants across 26 districts. No significant associations were found between variants and clinical signs or chlamydial load. Notably, overall Ct diversity significantly decreased after additional MDA rounds, with a higher proportion of serovar A post-MDA. Despite challenges in sequencing one VNTR locus (CT1299), MLVA-ompA demonstrated cost-effectiveness and efficiency relative to whole genome sequencing, providing valuable information for trachoma control programs on local epidemiology. The findings suggest the potential of MLVA-ompA as a reliable tool for typing ocular Ct and understanding transmission dynamics, aiding in the development of targeted interventions for trachoma control.
Topics: Chlamydia trachomatis; Trachoma; Humans; Ethiopia; Minisatellite Repeats; Bacterial Outer Membrane Proteins; Female; Male; Child, Preschool; Genotype; Molecular Typing; Azithromycin; Genetic Variation; Infant; Child; Anti-Bacterial Agents; DNA, Bacterial
PubMed: 38662795
DOI: 10.1371/journal.pntd.0012143 -
Clinical Infectious Diseases : An... Apr 2024Assessing the feasibility of 2030 as a target date for global elimination of trachoma, and identification of districts that may require enhanced treatment to meet World...
Assessing the feasibility of 2030 as a target date for global elimination of trachoma, and identification of districts that may require enhanced treatment to meet World Health Organization (WHO) elimination criteria by this date are key challenges in operational planning for trachoma programmes. Here we address these challenges by prospectively evaluating forecasting models of trachomatous inflammation-follicular (TF) prevalence, leveraging ensemble-based approaches. Seven candidate probabilistic models were developed to forecast district-wise TF prevalence in 11 760 districts, trained using district-level data on the population prevalence of TF in children aged 1-9 years from 2004 to 2022. Geographical location, history of mass drug administration treatment, and previously measured prevalence data were included in these models as key predictors. The best-performing models were included in an ensemble, using weights derived from their relative likelihood scores. To incorporate the inherent stochasticity of disease transmission and challenges of population-level surveillance, we forecasted probability distributions for the TF prevalence in each geographic district, rather than predicting a single value. Based on our probabilistic forecasts, 1.46% (95% confidence interval [CI]: 1.43-1.48%) of all districts in trachoma-endemic countries, equivalent to 172 districts, will exceed the 5% TF control threshold in 2030 with the current interventions. Global elimination of trachoma as a public health problem by 2030 may require enhanced intervention and/or surveillance of high-risk districts.
Topics: Trachoma; Humans; Child, Preschool; Infant; Child; Disease Eradication; Prevalence; Forecasting; Public Health; Models, Statistical; Mass Drug Administration; World Health Organization; Global Health; Male; Female
PubMed: 38662700
DOI: 10.1093/cid/ciae031 -
BMC Ophthalmology Apr 2024To analyze the clinicopathological characteristics and surgical outcomes of patients with Wolfring gland ductal cysts (WGDCs).
PURPOSE
To analyze the clinicopathological characteristics and surgical outcomes of patients with Wolfring gland ductal cysts (WGDCs).
METHODS
A retrospective, consecutive, interventional comparative case series was performed over a period of 7 years. Data on demographic and clinical characteristics, pathological findings and outcomes of surgically excised cysts were collected. A comparison between the transconjunctival and transcutaneous approaches was also assessed.
RESULTS
Forty-eight patients (48 eyelids) were included in the final analysis. The most common presenting symptom was painless eyelid swelling (81.3%). The median symptom duration was 11.5 months (IQR, 18.25). The upper eyelid was involved in 31 (64.6%) patients, 29/31 of whom had cysts in a medial or centromedial location. Forty-five (93.8%) cysts were bluish gray and transilluminable with clear contents on lid eversion and a median largest dimension of 22 mm (IQR, 8). A transverse conjunctival fibrotic band was observed along the proximal tarsal border in the cyst area in all patients. Signs of chronic trachoma were noted in 38 (79.2%) patients. Preoperative significant ptosis was present in 28/31 (90.3%) of the upper eyelid cysts. Thirty cysts (62.5%) were excised through the skin, and 18 cysts (37.5%) were excised transconjunctivally. Intraoperative cyst rupture, the need for conjunctival grafting and postoperative residual upper lid ptosis were significantly greater in the transconjunctival group (p = 0.009, p < 0.001, and p = 0.016, respectively).
CONCLUSION
The present study highlights the clinicopathological characteristics of a relatively large series of surgically excised WGDCs. Transcutaneous excision of WGDCs has proven to be an effective treatment with fewer adverse sequelae than the transconjunctival approach.
Topics: Humans; Retrospective Studies; Eyelids; Blepharoptosis; Treatment Outcome; Cysts
PubMed: 38622551
DOI: 10.1186/s12886-024-03420-x -
PLoS Neglected Tropical Diseases Apr 2024The Alliance for the Global Elimination of Trachoma (GET) endorses the full SAFE strategy to eliminate trachoma; Surgery (for trichiasis), Antibiotics (to reduce the... (Comparative Study)
Comparative Study
BACKGROUND
The Alliance for the Global Elimination of Trachoma (GET) endorses the full SAFE strategy to eliminate trachoma; Surgery (for trichiasis), Antibiotics (to reduce the community pool of infection, Facial cleanliness, and Environmental improvement (to decrease transmission). There is no accepted measure of facial cleanliness. This study compared two possible metrics for facial cleanliness.
METHOD/FINDINGS
Metric one: Clean face was defined as observed absence of ocular and nasal discharge on the face. Metric two: observing a grade of dirtiness (scale 10 = lightest to 0 = darkest) on a standard facial wipe. The reliability of grading a child's face or grading a facial wipe was determined in children in Kongwa Tanzania. We also observed both measurements in a cohort of 202 children ages 1 to <7years prior to face cleaning, immediately afterwards, and 4 hours afterwards. Fifty of the children did not have face cleaning and were controls. Intra-and interobserver reliability was similar for both measures, the latter = 0.53 for observing a clean face and 0.52 for grading a facial wipe. There was no correlation between the two. Both measures detected facial cleaning, compared to control children who were not cleaned, immediately after cleaning; control children with 53% clean faces and wipe score of 6.7 compared to cleaned children with 88% clean faces and wipe score of 8 (p = .0001, p = < .0001, respectively). Both measures also detected face washing 4 hours previously compared to controls.
CONCLUSIONS
The two metrics were equally reliable, and both measured the behavior of face washing. They measure different aspects of a clean face; one measures the amount of dirt on wiped area and the other measures ocular and nasal discharge. Both measurements appear to capture the behavior of facial cleaning, and the choice of metric would appear to rest on the measurement that captures the stated objective of the behavior, consideration of costs, training, logistics, and implementation.
Topics: Humans; Trachoma; Child, Preschool; Face; Tanzania; Infant; Female; Male; Child; Hygiene; Reproducibility of Results
PubMed: 38598562
DOI: 10.1371/journal.pntd.0012090 -
The American Journal of Tropical... May 2024Millions of doses of azithromycin are distributed each year for trachoma, yet the treatment efficacy of a single dose of azithromycin for ocular Chlamydia infection has...
Millions of doses of azithromycin are distributed each year for trachoma, yet the treatment efficacy of a single dose of azithromycin for ocular Chlamydia infection has not been well characterized. In this study, four villages in Niger received a mass azithromycin distribution for trachoma. All 426 children aged 0-5 years residing in the study villages were offered conjunctival swabbing every 6 months to test for ocular Chlamydia trachomatis. Among the children infected with ocular Chlamydia before treatment, 6% (95% CI: 2-15%) tested positive for ocular Chlamydia infection 6 months later, and 15% (95% CI: 7-28%) tested positive 12 months later. The most important predictor of post-treatment ocular Chlamydia infection was pretreatment ocular Chlamydia infection (relative risk: 3.5, 95% CI: 1.3-9.4). Although the 6-monthly monitoring schedule was suboptimal for testing the treatment efficacy of an antibiotic, these findings are nonetheless consistent with high treatment efficacy of a single dose of azithromycin and suggest that additional interventions might be most effective if targeted to those children infected prior to treatment.
Topics: Azithromycin; Humans; Anti-Bacterial Agents; Child, Preschool; Infant; Female; Trachoma; Male; Longitudinal Studies; Chlamydia trachomatis; Treatment Outcome; Chlamydia Infections; Niger; Infant, Newborn
PubMed: 38507803
DOI: 10.4269/ajtmh.23-0540 -
Clinical Ophthalmology (Auckland, N.Z.) 2024Trachoma is a serious public health concern and cause of blindness globally. Despite its vulnerability to all ages, children are more vulnerable to its adverse outcomes...
BACKGROUND
Trachoma is a serious public health concern and cause of blindness globally. Despite its vulnerability to all ages, children are more vulnerable to its adverse outcomes and devastating complications. This study assessed the magnitude of trachoma among children in host and refugee communities in Gambella, Ethiopia.
METHODS
A community-based comparative survey was done among 743 participants. Multistage sampling technique was used to select participants. Selected children were examined for trachoma using a 2.5x binocular loupe and graded using the World Health Organization (WHO) simplified grading system. A standardized, structured, and pretested tool was used to collect the data. Data were collected through interviews and observation. Bivariable and multivariable logistic regression analyses were done to identify the associated factors. Variable with a p-value <0.05 was considered statistically significant.
RESULTS
The magnitude of active trachoma was 119 (16.5%; 95% CI: 13.5, 21.4) with 36 (14.5%; 95% CI: 11.9, 18.8) and 83 (17.5%; 95% CI: 14.3, 22.7) from refugees and host communities, respectively. Poor knowledge of caregiver about trachoma [AOR = 3.55, 95% CI: (1.48, 8.85)], presence of human feces near the house [AOR = 4.57, 95% CI: (1.84, 11.34)], presence of garbage near the house [AOR = 4.07, 95% CI: (1.34, 12.36)], and the presence of flies on the face of the child [AOR = 3.42, 95% CI: (1.32, 8.84)] were significantly associated factors with active trachoma.
CONCLUSION
Overall, one-sixth of children had experienced active trachoma. The magnitude of trachoma was higher in the host community compared to the refugees. Proper waste disposal and personal hygiene measures are important measures that should be addressed to tackle the problem.
PubMed: 38495676
DOI: 10.2147/OPTH.S448870 -
Revista Panamericana de Salud Publica =... 2024To estimate the prevalence of trachoma in indigenous and non-indigenous populations in selected areas of the state of Maranhão, in northeastern Brazil.
OBJECTIVE
To estimate the prevalence of trachoma in indigenous and non-indigenous populations in selected areas of the state of Maranhão, in northeastern Brazil.
METHODS
This was a population-based survey with probabilistic sampling. For the diagnosis of trachoma, external ocular examination was performed using head magnifying loupes, at 2.5X magnification. The prevalence of trachomatous inflammation - follicular (TF) in children aged 1-9 years and the prevalence of trachomatous trichiasis (TT) in the population aged ≥15 years were estimated. Relative frequencies of sociodemographic and environmental characteristics were obtained.
RESULTS
The study included 7 971 individuals, 3 429 from non-indigenous populations and 4 542 from indigenous populations. The prevalence of TF in non-indigenous and indigenous populations was 0.1% and 2.9%, respectively, and the prevalence of TT among indigenous populations was 0.1%.
CONCLUSIONS
The prevalence of TF and TT in the two evaluation units in the state of Maranhão were within the limits recommended for the elimination of trachoma as a public health problem. However, the prevalence of TF was higher in the indigenous evaluation unit, indicating a greater vulnerability of this population to the disease. The prevalence of TF of below 5.0% implies a reduction in transmission, which may have resulted from improved socioeconomic conditions and/or the implementation of the World Health Organization SAFE strategy.
PubMed: 38464869
DOI: 10.26633/RPSP.2024.19