Design and baseline data of a randomized trial to evaluate coverage and frequency of mass treatment with azithromycin: the Partnership for Rapid Elimination of Trachoma (PRET) in Tanzania and The Gambia

Accuracy, acceptability and feasibility of photography for use in trachoma surveys: a mixed methods study in Tanzania

BACKGROUND

Photography could be used to train individuals to diagnose trachomatous inflammation-follicular (TF) as trachoma prevalence decreases and to ensure accurate field TF grading in trachoma prevalence surveys. We compared photograph and field TF grading and determined the acceptability and feasibility of eyelid photography to community members and trachoma survey trainers.

METHODS

A total of 100 children ages 1-9 y were examined for TF in two Maasai villages in Tanzania. Two images of the right everted superior tarsal conjunctiva of each child were taken with a smartphone and a digital single-lens reflex (DSLR) camera. Two graders independently graded all photos. Focus group discussions (FGDs) were conducted with community members and Tropical Data trainers.

RESULTS

Of 391 photos, one-fifth were discarded as ungradable. Compared with field grading, photo grading consistently underdiagnosed TF. Compared with field grading, DSLR photo grading resulted in a higher prevalence and sensitivity than smartphone photo grading. FGDs indicated that communities and trainers found photography acceptable and preferred smartphones to DSLR in terms of practicalities, but image quality was of paramount importance for trainers.

CONCLUSIONS

Photography is acceptable and feasible, but further work is needed to ensure high-quality images that enable accurate and consistent grading before being routinely implemented in trachoma surveys.

Validation of a New Duplex Real-Time Polymerase Chain Reaction for Chlamydia trachomatis DNA Detection in Ocular Swab Samples

Trachoma is the world-leading infectious cause of preventable blindness and is caused by the bacteria Chlamydia trachomatis. 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 C. trachomatis cryptic plasmid and the human 18S rRNA gene, with an LOD95% for C. trachomatis 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 C. trachomatis 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.

Comparison of genovars and Chlamydia trachomatis infection loads in ocular samples from children in two distinct cohorts in Sudan and Morocco

Trachoma is a blinding disease caused by repeated conjunctival infection with different Chlamydia trachomatis (Ct) genovars. Ct B genovars have been associated with more severe trachoma symptoms. Here, we investigated associations between Ct genovars and bacterial loads in ocular samples from two distinct geographical locations in Africa, which are currently unclear. We tested ocular swabs from 77 Moroccan children (28 with trachomatous inflammation-follicular (TF) and 49 healthy controls), and 96 Sudanese children (54 with TF and 42 healthy controls) with a Ct-specific real-time polymerase chain reaction (PCR) assay. To estimate bacterial loads, Ct-positive samples were further processed by multiplex real-time qPCR to amplify the chromosomal outer membrane complex B and plasmid open reading frame 2 of Ct. Genotyping was performed by PCR-based amplification of the outer membrane protein A gene (~1120 base pairs) of Ct and Sanger sequencing. Ct-positivities among the Moroccan and Sudanese patient groups were 60·7% and 31·5%, respectively. Significantly more Sudanese patients than Moroccan patients were genovar A-positive. In contrast, B genovars were significantly more prevalent in Moroccan patients than in Sudanese patients. Significantly higher Ct loads were found in samples positive for B genovars (598596) than A genovar (51005). Geographical differences contributed to the distributions of different ocular Ct genovars. B genovars may induce a higher bacterial load than A genovars in trachoma patients. Our findings emphasize the importance of conducting broader studies to elucidate if the noted difference in multiplication abilities are genovar and/or endemicity level dependent.

We investigated the association between different Ct genovars, the approximate load of infection, and the distribution of Chlamydia genovars by comparing samples from one trachoma-endemic area (i.e., the city of El-Gadaref in Al Qadarif, Sudan) and one previously endemic area (i.e., the Zagora Province in Morocco), currently considered as non-endemic. This study is the first to reveal a significant difference between the genome copy numbers of Ct genovar A and B/Ba in children with TF. Evidence that Ct is still circulating in rural foci of countries like Morocco that are no longer considered endemic implies that the continuation of the trachoma surveillance must be warranted in future to avoid further spreading of Ct. The clinical significance of different infectious loads in the development of sequelae has to be determined as well as whether these differences are genovar specific or related to the given endemicity level.

Comparison of Smartphone Photography, Single-Lens Reflex Photography, and Field-Grading for Trachoma

Conjunctival examination for trachomatous inflammation-follicular (TF) guides public health decisions for trachoma. Smartphone cameras may allow remote conjunctival grading, but previous studies have found low sensitivity. A random sample of 412 children aged 1-9 years received an in-person conjunctival examination and then had conjunctival photographs taken with 1) a single-lens reflex (SLR) camera and 2) a smartphone coupled to a 3D-printed magnifying attachment. Three masked graders assessed the conjunctival photographs for TF. Latent class analysis was used to determine the sensitivity and specificity of each grading method for TF. Single-lens reflex photo-grading was 95.0% sensitive and 93.6% specific, and smartphone photo-grading was 84.1% sensitive and 97.6% specific. The sensitivity of the smartphone-CellScope device was considerably higher than that of a previous study using the native smartphone camera, without attachment. Magnification of smartphone images with a simple attachment improved the grading sensitivity while maintaining high specificity in a region with hyperendemic trachoma.

Mass drug administration with azithromycin for trachoma elimination and the population structure of Streptococcus pneumoniae in the nasopharynx

Objective

Mass drug administration (MDA) with azithromycin for trachoma elimination reduces nasopharyngeal carriage of Streptococcus pneumoniae in the short term. We evaluated S. pneumoniae carried in the nasopharynx before and after a round of azithromycin MDA to determine whether MDA was associated with changes in pneumococcal population structure and resistance.

Methods

We analysed 514 pneumococcal whole genomes randomly selected from nasopharyngeal samples collected in two Gambian villages that received three annual rounds of MDA for trachoma elimination. The 514 samples represented 293 participants, of which 75% were children aged 0–9 years, isolated during three cross-sectional surveys (CSSs) conducted before the third round of MDA (CSS-1) and at 1 (CSS-2) and 6 (CSS-3) months after MDA. Bayesian Analysis of Population Structure (BAPS) was used to cluster related isolates by capturing variation in the core genome. Serotype and multilocus sequence type were inferred from the genotype. Antimicrobial resistance determinants were identified from assemblies, including known macrolide resistance genes.

Results

Twenty-seven BAPS clusters were assigned. These consisted of 81 sequence types (STs). Two BAPS clusters not observed in CSS-1 (n = 109) or CSS-2 (n = 69), increased in frequency in CSS-3 (n = 126); BAPS20 (8.73%, p 0.016) and BAPS22 (7.14%, p 0.032) but were not associated with antimicrobial resistance. Macrolide resistance within BAPS17 increased after treatment (CSS-1 n = 0/6, CSS-2/3 n = 5/5, p 0.002) and was carried on a mobile transposable element that also conferred resistance to tetracycline.

Discussion

Limited changes in pneumococcal population structure were observed after the third round of MDA, suggesting treatment had little effect on the circulating lineages. An increase in macrolide resistance within one BAPS highlights the need for antimicrobial resistance surveillance in treated villages.

The Effect of Antibiotic Selection Pressure on the Nasopharyngeal Macrolide Resistome: A Cluster-randomized Trial

Background

Frequent use of antibiotics is thought to create selection pressure by clearing susceptible bacteria and allowing resistant bacteria to spread in a community. A cluster-randomized trial comparing 2 different frequencies of mass azithromycin distributions for trachoma provided a convenient experiment for determining the causal relationship between antibiotic consumption and antibiotic resistance.

Methods

Twenty-four communities were randomized to either annual or biannual mass azithromycin distributions for trachoma. Randomization was stratified on health catchment area and trachoma prevalence. Swabs were processed for the genetic macrolide resistance determinants ermB and mefA/E in a masked fashion from a random sample of 120 preschool children before treatment and another 120 children after 2 years of mass antibiotics.

Results

Macrolide resistance determinants were similar in the 12 annually and 12 biannually treated communities before treatment, with a median prevalence among preschool children of 20% (interquartile range [IQR], 10%-40%) in each group. By 24 months, macrolide resistance determinants were found more commonly in the biannually treated communities (median, 60% [IQR, 50%-80%]) than the annually treated communities (median, 40% [IQR, 20%-40%]; P < .001). Adjusting for baseline, the 24-month prevalence of macrolide resistance determinants in the biannual group was 29.4% higher than that of the annual group (95% confidence interval, 10.5%-56.7%).

Conclusions

This randomized trial used direct genetic methods to confirm the causal relationship of community antibiotic consumption and antibiotic resistance. Communities randomized to less frequent use of antibiotics had a significantly lower prevalence of genetic antibiotic resistance determinants.

Clinical Trials Registration

NCT00792922.

Comparison of anthropometric indicators to predict mortality in a population-based prospective study of children under 5 years in Niger

OBJECTIVE

In the present study, we aimed to compare anthropometric indicators as predictors of mortality in a community-based setting.

DESIGN

We conducted a population-based longitudinal study nested in a cluster-randomized trial. We assessed weight, height and mid-upper arm circumference (MUAC) on children 12 months after the trial began and used the trial's annual census and monitoring visits to assess mortality over 2 years.

SETTING

Niger.

PARTICIPANTS

Children aged 6-60 months during the study.

RESULTS

Of 1023 children included in the study at baseline, height-for-age Z-score, weight-for-age Z-score, weight-for-height Z-score and MUAC classified 777 (76·0 %), 630 (61·6 %), 131 (12·9 %) and eighty (7·8 %) children as moderately to severely malnourished, respectively. Over the 2-year study period, fifty-eight children (5·7 %) died. MUAC had the greatest AUC (0·68, 95 % CI 0·61, 0·75) and had the strongest association with mortality in this sample (hazard ratio = 2·21, 95 % CI 1·26, 3·89, P = 0·006).

CONCLUSIONS

MUAC appears to be a better predictor of mortality than other anthropometric indicators in this community-based, high-malnutrition setting in Niger.

Community-level Association between Clinical Trachoma and Ocular Chlamydia Infection after MASS Azithromycin Distribution in a Mesoendemic Region of Niger

Purpose: The clinical sign trachomatous inflammation - follicular (TF) is used to monitor indication for and response to mass azithromycin distribution in trachoma-endemic communities. Here, we assess the relationship between TF, trachomatous inflammation - intense (TI), and infection with ocular Chlamydia trachomatis over time during annual mass azithromycin distribution. Methods: We used data from a cluster-randomized trial of mass azithromycin distribution for trachoma control in a mesoendemic region of Niger. This study includes 24 communities that received 3 years of annual mass azithromycin distribution. TF, TI, and ocular chlamydia infection were monitored among children aged 0-5 years. We assessed the correlation between the prevalence of ocular chlamydia infection and 1) TF and 2) TI prevalence over time. Results: At baseline, ocular chlamydia prevalence was 21.2% (95% CI 14.3-28.1%), TF prevalence was 27.7% (95% CI 21.2-34.2%), and TI prevalence was 8.3% (95% CI 5.2-11.5%). The prevalence of all three measures decreased significantly over time (P < 0.001). At baseline, ocular chlamydia infection prevalence was strongly correlated with both TF (rho = 0.78, P < 0.0001) and TI (rho = 0.76, P < 0.0001). The correlation between ocular chlamydia infection and both TF and TI was weak at months 12 and 24. At 36 months, when TF prevalence had dropped below 10%, ocular chlamydia infection and TF were moderately correlated (rho = 0.70, P= 0.0002). Conclusions: Both TF and TI are good indicators of infection prevalence prior to mass azithromycin distribution. However, this relationship may be affected by repeated rounds of mass azithromycin distribution.

Childhood Mortality After Mass Distribution of Azithromycin: A Secondary Analysis of the PRET Cluster-randomized Trial in Niger

BACKGROUND

Mass distributions of azithromycin for trachoma have been associated with secondary benefits, including reductions in child mortality.

METHODS

In the Partnership for the Rapid Elimination of Trachoma cluster-randomized trial in Niger, 24 communities were randomized to annual treatment of everyone and 24 communities were randomized to biannual treatment of children under 12 for 3 years (clinicaltrials.gov, NCT00792922). Treatment was a single dose of directly observed oral azithromycin (20 mg/kg up to 1 g in adults). Vital status was assessed during annual census and monitoring visits. In this prespecified secondary analysis, we compared the mortality rate among children 6 months to less than 5 years of age by treatment arm using negative binomial regression.

RESULTS

Among children 6 months to less than 5 years of age, 404 deaths occurred during the study period. The mortality rate was 35.6 deaths per 1000 person-years (231 deaths, 95% CI: 30.9-40.9) in the annual arm and 29.0 deaths per 1000 person-years (173 deaths, 95% CI: 24.8-33.8) in the biannual arm. The mortality rate ratio comparing children in the biannual arm to the annual arm was 0.81 (95% CI: 0.66-1.00, P = 0.07; primary outcome). The mortality rate ratio comparing children who died from infectious causes in the biannual arm to the annual arm was 0.73 (95% CI: 0.57-0.94; P = 0.02). No adverse events were reported.

CONCLUSIONS

This secondary analysis of a cluster-randomized trial found a nonsignificant 19% decrease in mortality among children 6 months to less than 5 years of age who received biannual azithromycin compared with children who received annual azithromycin. This study was conducted in a high mortality, trachoma-endemic area; thus, results may be specific to this environment only. In addition, the trial was neither designed nor powered to detect a mortality effect, and we cannot rule out the possibility that mortality differences resulted from bias.

Anthropometry and Malaria among Children in Niger: A Cross-Sectional Study

The complex relationship between malnutrition and malaria affects morbidity and mortality in children younger than 5 years, particularly in parts of sub-Saharan Africa where these conditions occur together seasonally. Previous research on this relationship has been inconclusive. Here, we examine the association between anthropometric indicators and malaria infection in a population-based sample of children younger than 5 years in Niger. This cross-sectional study is a secondary analysis of a cluster-randomized trial comparing treatment strategies for trachoma in Niger. We included children aged 6-60 months residing in the 48 communities enrolled in the trial who completed anthropometric and malaria infection assessments at the final study visit. We evaluated the association between anthropometric indicators, including height-for-age z-score (HAZ) and weight-for-age z-score (WAZ) and indicators of malaria infection, including malaria parasitemia and clinical malaria. In May 2013, we collected data from 1,649 children. Of these, 780 (47.3%) were positive for malaria parasitemia and 401 (24.3%) had clinical malaria. In models of malaria parasitemia, the adjusted odds ratio (aOR) was 1.05 (95% confidence interval [CI]: 1.00-1.10) for HAZ and 1.07 (95% CI: 0.99, 1.15) for WAZ. In models of clinical malaria, the aOR was 1.07 (95% CI: 1.02-1.11) for HAZ and 1.09 (95% CI: 1.01-1.19) for WAZ. Overall, we did not find evidence of an association between most anthropometric indicators and malaria infection. Greater height may be associated with an increased risk of clinical malaria.

One round of azithromycin MDA adequate to interrupt transmission in districts with prevalence of trachomatous inflammation-follicular of 5.0-9.9%: Evidence from Malawi

Background

As highly trachoma-endemic countries approach elimination, some districts will have prevalences of trachomatous inflammation–follicular in 1–9-year-olds (TF_1-9) of 5.0–9.9%. The World Health Organization (WHO) previously recommended that in such districts, TF prevalence be assessed in each sub-district (groupings of at least three villages), with three rounds of azithromycin treatment offered to any sub-district in which TF≥10%. Given the large number of endemic districts worldwide and the human and financial resources required to conduct surveys, this recommendation may not be practical. In a group of 8 Malawi districts with baseline TF prevalences of 5.0–9.9%, the Malawi Ministry of Health administered one round of azithromycin mass treatment, to the whole of each district, achieving mean coverage of ~80%. Here, we report impact surveys conducted after that treatment.

Methods

We undertook population-based trachoma surveys in 18 evaluation units of the 8 treated districts, at least 6 months after the MDA. The standardized training package and survey methodologies of Tropical Data, which conform to WHO recommendations, were used.

Results

Each of the 18 evaluation units had a TF_1-9 prevalence <5.0%.

Conclusion

The study demonstrates that in Malawi districts with TF of 5.0–9.9%, one round of azithromycin MDA with ~80% coverage associates with a reduction in TF prevalence to <5%. Further evidence for this approach should be collected elsewhere.

Until now, in trachoma elimination programmes, the WHO recommendation for district-wide annual rounds of antibiotic mass drug administration was only applicable to districts with a trachomatous inflammation—follicular (TF_1-9) prevalence of 10% or more. Districts with a TF_1-9 prevalence of <5% were considered not to require intervention with antibiotics for trachoma. For districts with a prevalence of 5.0–9.9%, programmes were encouraged to determine the TF_1-9 prevalence at sub-district or “community” level. With the recent rapid scale-up in trachoma mapping, there are now a large number of districts known to have TF_1-9 prevalence of 5.0–9.9%, so this recommendation is likely to pose an implementation challenge to health ministries and their partners. In this study, we have demonstrated that in districts with TF_1-9 5.0–9.9%, a single round of mass drug administration with high coverage to the whole district can be followed by an impact survey TF_1-9 prevalences of <5%. This approach is likely to reduce the commodity need (one round of MDA to 100% of the population compared to 3 or more rounds to an average 50% of the population), reduce the number of surveys required, and ultimately accelerate the speed of progress to elimination. We recommend that this finding be further explored elsewhere to determine its generalizability, in order to justify consideration of global policy change.

Annual Versus Biannual Mass Azithromycin Distribution and Malaria Parasitemia During the Peak Transmission Season Among Children in Niger

BACKGROUND

Azithromycin has modest efficacy against malaria, and previous cluster randomized trials have suggested that mass azithromycin distribution for trachoma control may play a role in malaria control. We evaluated the effect of annual versus biannual mass azithromycin distribution over a 3-year period on malaria prevalence during the peak transmission season in a region with seasonal malaria transmission in Niger.

METHODS

Twenty-four communities in Matameye, Niger, were randomized to annual mass azithromycin distribution (3 distributions to the entire community during the peak transmission season) or biannual-targeted azithromycin distribution (6 distributions to children <12 years of age, including 3 in the peak transmission season and 3 in the low transmission season). Malaria indices were evaluated at 36 months during the high transmission season.

RESULTS

Parasitemia prevalence was 42.6% (95% confidence interval: 31.7%-53.6%) in the biannual distribution arm compared with 50.6% (95% confidence interval: 40.3%-60.8%) in the annual distribution arm (P = 0.29). There was no difference in parasite density or hemoglobin concentration in the 2 treatment arms.

CONCLUSIONS

Additional rounds of mass azithromycin distribution during low transmission may not have a significant impact on malaria parasitemia measured during the peak transmission season.

Spatial clustering of high load ocular Chlamydia trachomatis infection in trachoma: a cross-sectional population-based study

Chlamydia trachomatis (Ct) is the most common cause of bacterial sexually transmitted infection and infectious cause of blindness (trachoma) worldwide. Understanding the spatial distribution of Ct infection may enable us to identify populations at risk and improve our understanding of Ct transmission. In this study, we sought to investigate the spatial distribution of Ct infection and the clinical features associated with high Ct load in trachoma-endemic communities on the Bijagós Archipelago (Guinea Bissau). We collected 1507 conjunctival samples and corresponding detailed clinical data during a cross-sectional population-based geospatially representative trachoma survey. We used droplet digital PCR to estimate Ct load on conjunctival swabs. Geostatistical tools were used to investigate clustering of ocular Ct infections. Spatial clusters (independent of age and gender) of individuals with high Ct loads were identified using local indicators of spatial association. We did not detect clustering of individuals with low load infections. These data suggest that infections with high bacterial load may be important in Ct transmission. These geospatial tools may be useful in the study of ocular Ct transmission dynamics and as part of trachoma surveillance post-treatment, to identify clusters of infection and thresholds of Ct load that may be important foci of re-emergent infection in communities.

Risk factors for incidence of trachomatous scarring in a cohort of women in low endemic district

BACKGROUND/AIMS

To determine the incidence of scarring in women in a trachoma low endemic district of rural Tanzania and to determine the effects of lifetime cooking fire exposure and markers of lower socioeconomic status on incidence of scarring in these women.

METHODS

A prospective cohort study was conducted over a 3.5-year period from 2013 to 2016 in 48 villages in Kongwa, Tanzania where trachoma at baseline was 5.2% in children. A random sample of 2966 women aged 15 and older who were at risk for incident scarring were eligible for follow-up. Data on demographic factors, cooking fire exposure and trachomatous scarring were gathered at baseline and follow-up. An index of lifetime exposure to cooking fire exposure was created and bivariate analysis, age-adjusted logistic regression and multivariable logistic models were used to look for associations of demographic factors and cooking fire exposure with incident trachomatous scarring.

RESULTS

The cumulative incidence of scarring was 7.1% or 2.0% per year. Incidence of scarring increased with age and exposure to markers of lower socioeconomic status. A multivariable logistic regression model adjusting for confounding factors did not find an association between lifetime cooking fire exposure and incidence of scarring (OR=0.92; 95% CI 0.68 to 1.24, P=0.58).

CONCLUSIONS

There was still incident scarring in women in Tanzania despite low rates of active trachoma. There was no association between exposure to cooking fires and incident scarring. More research is needed to understand the factors that contribute to new scarring in these women.

Comparison of Mass Azithromycin Coverage Targets of Children in Niger: A Cluster-Randomized Trachoma Trial

Repeated oral azithromycin distribution targeted only to children has proven effective in reducing the ocular Chlamydia that causes trachoma. Here, we assess whether an enhanced coverage target of at least 90% of children is superior to the World Health Organization recommendation of at least 80%. Twenty-four trachoma-endemic communities in Matamèye, Niger, were randomized to a single day of azithromycin distribution aiming for at least 80% coverage or up to 4 days of treatment and > 90% coverage of children under age 12. All distributions were biannual. Children < 5 years of age and adults > 15 years were monitored for ocular Chlamydia infection by polymerase chain reaction every 6 months for 36 months in children and at baseline and 36 months in adults. Ocular Chlamydia prevalence in children decreased from 24.9% (95% confidence interval [CI] 15.9-33.8%) to 4.4% (95% CI 0.6-8.2%, P < 0.001) at 36 months in the standard coverage arm and from 15.6% (95% CI 10.0-21.2%) to 3.3% (95% CI 1.0-5.5%; P < 0.001) in the enhanced coverage arm. Enhanced coverage reduced ocular Chlamydia prevalence in children more quickly over time compared with standard (P = 0.04). There was no difference between arms at 36 months in children (2.4% lower with enhanced coverage, 95% CI 7.7-12.5%; P = 0.60). No infection was detected in adults at 36 months. Increasing antibiotic coverage among children from 80% to 90% may yield only short term improvements for trachoma control programs. Targeting treatment to children alone may be sufficient for trachoma control in this setting.

Trachomatous scarring among children in a formerly hyper-endemic district of Tanzania

Background

Associations between repeated ocular infections with Chlamydia trachomatis in childhood and conjunctival scarring in adulthood are well established. Trachomatous scarring (TS) in children has also been observed in hyper-endemic areas, but data are scant regarding childhood scarring in areas where trachoma has been reduced to hypo-endemic levels.

Methods/Principle findings

In this cross-sectional study, a random sample of children, ages 1–9 years, were selected from 38 communities in the formerly hyper-endemic district of Kongwa, Tanzania. Each participant received an ocular examination and eye-swab test for C. trachomatis infection. Conjunctival photographs were taken and analyzed at 5x magnification to determine scarring presence and severity. Community-level case clustering was assessed using intra-class correlation coefficients, and associations between TS presence and demographic/clinical factors were assessed using contingency table analyses. 1,496 children (78% of eligible) participated in this study. The mean age was 5.5 years and 51% were female. Scarring prevalence was 2.1% (95% CI: 1.5%– 3.0%). The prevalence of follicular trachoma and ocular C. trachomatis infection were 3.2% and 6.5%, respectively. Most TS cases (68.7%) fell into the mildest category, grade S1. 18.7% were grade S2; 12.6% were grade S3. No significant associations were seen between TS presence and age, sex, follicular trachoma, or active ocular C. trachomatis infection (p-values: 0.14, 0.48, 0.27, 0.15, respectively). Thirty communities (78.9%) had 0–1 TS cases, and the most seen in any single community was four cases. Three years ago, follicular trachoma prevalence averaged 4.9% in communities with 0–1 TS cases, but 7.6% in communities with 2–4 TS cases (p-value: 0.08).

Conclusions

In this formerly hyper-endemic district of Tanzania, TS was rare in 1–9 year-olds and usually mild when present. Communities with higher rates of follicular trachoma in the past were more likely to have ≥2 cases of scarring, but the association was not statistically significant.

Trachoma is a disease in which the conjunctiva of the eye is repeatedly infected by the intracellular organism Chlamydia trachomatis. This can cause scarring of the eyelid’s inner surface, which in turn can cause the eyelashes to turn inwards, scratching the eye and leading to blindness. This scarring process is associated with age and usually does not present until adulthood. However, in communities with very high trachoma rates, it has also been reported in children. There are scant data addressing the presence and nature of such scarring among children in areas where elimination efforts have reduced trachoma from high to low prevalence. In this study, we found that even though interventions in Kongwa, Tanzania, have successfully reduced trachoma levels in recent years, 1–9 year-olds can still be found with eyelid scarring. However, this scarring is rare and generally mild. Eyelid scarring from trachoma is known to increase with age, but interestingly, that was not seen in this cohort. This suggests that not only have interventions reduced eyelid scarring in children to low levels, but that this protective affect may be sustained into adolescence and adulthood.

Effectiveness of expanding annual mass azithromycin distribution treatment coverage for trachoma in Niger: a cluster randomised trial

BACKGROUND/AIMS

The WHO recommends 3-5 years of annual mass azithromycin distribution with at least 80% treatment coverage to districts with active trachoma prevalence over 10% among children. Here, we assess the efficacy of expanding the coverage target to at least 90% for trachoma control in a mesoendemic region of Niger.

METHODS

Twenty-four communities were randomised to a single day of azithromycin distribution with a coverage target of 80% of the community or up to 4 days of treatment, aiming for greater than 90% coverage. Distributions were annual and individuals above 6 months of age were treated. Children under 5 years of age were monitored for ocular chlamydia infection and active trachoma.

RESULTS

At baseline, ocular chlamydia prevalence was 20.5% (95% CI 9.8% to 31.2%) in the standard coverage arm and 21.9% (95% CI 11.3% to 32.5%) in the enhanced coverage arm, which reduced to 4.6% (95% CI 0% to 9.5%, p=0.008) and 7.1% (95% CI 2.7% to 11.4%, p<0.001) at 36 months, respectively. There was no significant difference in 36-month ocular chlamydia prevalence between the two arms (p=0.21). There was no difference in the rate of decline in ocular chlamydia between the two arms in a repeated measures model (p=0.80).

CONCLUSIONS

For annual mass azithromycin distribution programme to an entire community, there may be no additional benefit of increasing antibiotic coverage above the WHO's 80% target.

TRIAL REGISTRATION NUMBER

NCT00792922, post-results.

Mass Azithromycin and Malaria Parasitemia in Niger: Results from a Community-Randomized Trial

Studies designed to determine the effects of mass administration of azithromycin on trachoma have suggested that mass azithromycin distributions may also reduce the prevalence of malaria. These studies have typically examined the impact of a small number of treatments over short durations. In this prespecified substudy of a cluster-randomized trial for trachoma, we compared malaria parasitemia prevalence in 24 communities in Niger randomized to receive either annual or biannual mass azithromycin distributions over 3 years. The 12 communities randomized to annual azithromycin received three treatments during the high-transmission season, and the 12 communities randomized to biannual azithromycin received a total of six treatments: three during the high-transmission season and three during the low-transmission season. Blood samples were taken to assess malariometric indices among children in all study communities at a single time point during the high-transmission season after 3 years of the intervention. No significant differences were identified in malaria parasitemia, parasite density, or hemoglobin concentration between the annual and biannual treatment arms. When compared with annual mass azithromycin alone, additional mass azithromycin distributions given during the low-transmission season did not significantly reduce the subsequent prevalence of malaria parasitemia or parasite density after 3 years, as measured during the high-transmission season.

Treating village newcomers and travelers for trachoma: Results from ASANTE cluster randomized trial

TRIAL DESIGN

Trachoma is targeted for global elimination. Infection rates with Chlamydia trachomatis are higher in new arrivals to a community and in travelers who leave for extended periods, suggesting they are sources of re-infection. This community-randomized, clinical trial was designed to determine if a surveillance program that targeted newcomers and travelers, identified weekly, would result in more communities achieving levels of infection of ≤1%.

METHODS

52 communities were randomly allocated 1:1 to the control (annual MDA alone if warranted) or intervention arm (annual MDA if warranted, plus a surveillance program to identify and treat newcomers and travelers). In each community, surveys were completed every six months on a random sample of 100 children ages 1-9 years for trachoma and infection. The primary outcome was the proportion of communities in the intervention arm, compared to the control arm, which had a prevalence of infection at ≤1% by 24 months. Registered: clinicaltrials.gov(NCT01767506).

RESULTS

Intervention communities experienced an average of 110 surveillance events per month. At 24 months, 7 (27%) of 26 intervention communities achieved a prevalence of infection ≤1% compared to 4 (15%) of the 26 control communities (odds ratio = 2·6, 95%CI = 0·56-11·9). At 24 months, the average infection prevalence in the intervention communities was 4·8, compared to 6·9 in the control communities (p = ·06).

CONCLUSION

Despite surveillance programs for community newcomers and travelers, the proportion of intervention communities with a level of infection ≤1% was lower than expected and not significantly different from control communities.

Short-term increase in prevalence of nasopharyngeal carriage of macrolide-resistant Staphylococcus aureus following mass drug administration with azithromycin for trachoma control

Background

Mass drug administration (MDA) with azithromycin is a corner-stone of trachoma control however it may drive the emergence of antimicrobial resistance. In a cluster-randomized trial (Clinical trial gov NCT00792922), we compared the reduction in the prevalence of active trachoma in communities that received three annual rounds of MDA to that in communities that received a single treatment round. We used the framework of this trial to carry out an opportunistic study to investigate if the increased rounds of treatment resulted in increased prevalence of nasopharyngeal carriage of macrolide-resistant Staphylococcus aureus. Three cross-sectional surveys were conducted in two villages receiving three annual rounds of MDA (3 × treatment arm). Surveys were conducted immediately before the third round of MDA (CSS-1) and at one (CSS-2) and six (CSS-3) months after MDA. The final survey also included six villages that had received only one round of MDA 30 months previously (1 × treatment arm).

Results

In the 3 × treatment arm, a short-term increase in prevalence of S. aureus carriage was seen following MDA from 24.6% at CSS-1 to 38.6% at CSS-2 (p < 0.001). Prevalence fell to 8.8% at CSS-3 (p < 0.001). A transient increase was also seen in prevalence of carriage of azithromycin resistant (Azm^R) strains from 8.9% at CSS-1 to 34.1% (p < 0.001) in CSS-2 and down to 7.3% (p = 0.417) in CSS-3. A similar trend was observed for prevalence of carriage of macrolide-inducible-clindamycin resistant (iMLS_B) strains. In CSS-3, prevalence of carriage of resistant strains was higher in the 3 × treatment arm than in the 1 × treatment (Azm^R 7.3% vs. 1.6%, p = 0.010; iMLS_B 5.8% vs. 0.8%, p < 0.001). Macrolide resistance was attributed to the presence of msr and erm genes.

Conclusions

Three annual rounds of MDA with azithromycin were associated with a short-term increase in both the prevalence of nasopharyngeal carriage of S. aureus and prevalence of carriage of Azm^R and iMLS_BS. aureus.

Trial registration

This study was ancillary to the Partnership for the Rapid Elimination of Trachoma, ClinicalTrials.gov NCT00792922, registration date November 17, 2008.

Eyelash Epilation in the Absence of Trichiasis: Results of a Population-Based Prevalence Survey in the Western Division of Fiji

BACKGROUND

The WHO definition of trachomatous trichiasis (TT) is "at least one eyelash touching the globe, or evidence of recent epilation of in-turned eyelashes", reflecting the fact that epilation is used as a self-management tool for TT. In Fiji's Western Division, a high TT prevalence (8.7% in those aged ≥15 years) was reported in a 2012 survey, yet a 2013 survey found no TT and Fijian ophthalmologists rarely see TT cases. Local anecdote suggests that eyelash epilation is a common behaviour, even in the absence of trichiasis. Epilators may have been identified as TT cases in previous surveys.

METHODS

We used a preliminary focus group to design an interview questionnaire, and subsequently conducted a population-based prevalence survey to estimate the prevalence of epilation in the absence of trichiasis, and factors associated with this behaviour, in the Western Division of Fiji.

RESULTS

We sampled 695 individuals aged ≥15 years from a total of 457 households in 23 villages. 125 participants (18%) reported epilating their eyelashes at least once within the past year. Photographs were obtained of the eyes of 121/125 (97%) individuals who epilated, and subsequent analysis by an experienced trachoma grader found no cases of trachomatous conjunctival scarring or trichiasis. The age- and sex- adjusted prevalence of epilation in those aged ≥15 years was 8.6% (95% CI 5.7-11.3%). iTaukei ethnicity, female gender, and a higher frequency of drinking kava root were independently associated with epilation.

CONCLUSION

Epilation occurs in this population in the absence of trichiasis, with sufficient frequency to have markedly inflated previous estimates of local TT prevalence. Individuals with epilated eyelashes should be confirmed as having epilated in-turned eyelashes in an eye with scarring of the conjunctiva before being counted as cases of TT.

Surveillance and Azithromycin Treatment for Newcomers and Travelers Evaluation (ASANTE) Trial: Design and Baseline Characteristics

PURPOSE

Immigrants and travelers may be sources of re-emergent infection in trachoma-endemic communities close to trachoma elimination. The primary objective of the A Surveillance and Azithromycin Treatment for Newcomers and Travelers Evaluation (ASANTE) trial was to determine whether a newcomer and traveler surveillance and treatment program in addition to annual mass drug administration (MDA) would reduce Chlamydia trachomatis infection when compared to MDA alone.

METHODS

ASANTE was a randomized controlled trial in 52 communities in Kongwa, Tanzania. In 26 intervention communities, monitors treated everyone in new households, in-coming children and guardians in existing households, and all persons in households who had traveled between annual MDA events. A total of 26 usual practice communities received MDA only. Surveys of 100 1-9-year-olds from each community were conducted at baseline and every 6 months up to 2 years to assess clinical trachoma and C. trachomatis infection. Data on demographics and environmental factors were also collected.

RESULTS

Mean prevalences of trachomatous inflammation - follicular (TF) and C. trachomatis were equivalent between the two arms (5.2% and 3.7% in intervention, and 4.9% and 3.6% in usual practice communities, respectively). Of 318 children with TF, 36.5% tested positive for C. trachomatis. TF prevalence was higher among households without a bicycle (p = 0.03) and lower with increasing child's age (p < 0.001). Infection prevalence was higher among households >30 minutes from water (p = 0.015). TF and infection prevalence decreased with increasing years of education (p = 0.004 and p = 0.002, respectively).

CONCLUSION

The ASANTE trial will inform guidance on the surveillance and treatment of persons traveling or newly arriving to communities hypo-endemic for trachoma.

The Relationship between Active Trachoma and Ocular Chlamydia trachomatis Infection before and after Mass Antibiotic Treatment

Background

Trachoma is a blinding disease, initiated in early childhood by repeated conjunctival infection with the obligate intracellular bacterium Chlamydia trachomatis. The population prevalence of the clinical signs of active trachoma; ‘‘follicular conjunctivitis” (TF) and/or ‘‘intense papillary inflammation” (TI), guide programmatic decisions regarding the initiation and cessation of mass drug administration (MDA). However, the persistence of TF following resolution of infection at both the individual and population level raises concerns over the suitability of this clinical sign as a marker for C. trachomatis infection.

Methodology/Principle Findings

We systematically reviewed the literature for population-based studies and those including randomly selected individuals, which reported the prevalence of the clinical signs of active trachoma and ocular C. trachomatis infection by nucleic acid amplification test. We performed a meta-analysis to assess the relationship between active trachoma and C. trachomatis infection before and after MDA. TF and C. trachomatis infection were strongly correlated prior to MDA (r = 0.92, 95%CI 0.83 to 0.96, p<0.0001); the relationship was similar when the analysis was limited to children. A moderate correlation was found between TI and prevalence of infection. Following MDA, the relationship between TF and infection prevalence was weaker (r = 0.60, 95%CI 0.25 to 0.81, p = 0.003) and there was no correlation between TI and C. trachomatis infection.

Conclusions/Significance

Prior to MDA, TF is a good indicator of the community prevalence of C. trachomatis infection. Following MDA, the prevalence of TF tends to overestimate the underlying infection prevalence. In order to prevent unnecessary additional rounds of MDA and to accurately ascertain when elimination goals have been reached, a cost-effective test for C. trachomatis that can be administered in low-resource settings remains desirable.

Trachoma is the leading infectious cause of blindness worldwide, caused by the bacterium Chlamydia trachomatis. Repeated infection of the conjunctiva during childhood can initiate chronic conjunctival inflammation. This can lead to conjunctival scarring, in turning of the eyelashes, abrasion of the eyelashes on the cornea and eventually blindness later in adulthood. The World Health Organization recommends mass drug administration (MDA) for infection control when the prevalence of the clinical sign of Active Trachoma (TF) is ≥10% in 1–9 year olds. This systematic review of the literature examined the relationship between TF and C. trachomatis infection before and after MDA in order to evaluate the usefulness of TF for guiding trachoma control programmes. The population prevalence of TF and C. trachomatis infection were strongly correlated prior to MDA, however the relationship was weaker after MDA with a greater tendency for TF to overestimate the underlying infection prevalence. A cost effective test for C. trachomatis suitable for use in low resource settings could prevent unnecessary additional rounds of MDA in the population and could identify when trachoma elimination goals have been reached at an earlier time point.

Risk of Infection with Chlamydia trachomatis from Migrants to Communities Undergoing Mass Drug Administration for Trachoma Control

PURPOSE

To determine the risk of infection with Chlamydia trachomatis in children who are migrants to communities who are undergoing mass drug administration (MDA), and if their neighborhoods have higher rates of infection over time.

METHODS

In four communities in Kongwa, Tanzania, all children were enrolled in a longitudinal study of infection and trachoma. New children were identified at census updates as having not been in the community at the previous census. Within communities, neighborhoods were defined as spatially close groups of households, or "balozi". All children in the communities were invited to be examined for trachoma, and have ocular swabs taken for evidence of infection. Trachoma was graded using the World Health Organization simplified grading scheme, and swabs were processed using Amplicor.

RESULTS

Children who were migrants were more likely to be infected and to have trachoma than children who were resident in the community, which was significant by the time of the survey following the third year of MDA (odds ratio, OR, 2.49, 95% confidence interval, CI, 1.03-6.05). The neighborhoods where newcomers resided were more likely to have infection a year later than neighborhoods with no migrants, which was most pronounced following the third year of MDA (OR 2.86, 95% CI 1.07-7.65).

CONCLUSION

Migrants to communities may be an important source of re-emergent infection, especially as MDA lowers infection among residents. Highly migrant populations may need a special surveillance and treatment program to avoid slowing progress in communities under MDA.

Conjunctival fibrosis and the innate barriers to Chlamydia trachomatis intracellular infection: a genome wide association study

Chlamydia trachomatis causes both trachoma and sexually transmitted infections. These diseases have similar pathology and potentially similar genetic predisposing factors. We aimed to identify polymorphisms and pathways associated with pathological sequelae of ocular Chlamydia trachomatis infections in The Gambia. We report a discovery phase genome-wide association study (GWAS) of scarring trachoma (1090 cases, 1531 controls) that identified 27 SNPs with strong, but not genome-wide significant, association with disease (5 × 10⁻⁶ > P > 5 × 10⁻⁸). The most strongly associated SNP (rs111513399, P = 5.38 × 10⁻⁷) fell within a gene (PREX2) with homology to factors known to facilitate chlamydial entry to the host cell. Pathway analysis of GWAS data was significantly enriched for mitotic cell cycle processes (P = 0.001), the immune response (P = 0.00001) and for multiple cell surface receptor signalling pathways. New analyses of published transcriptome data sets from Gambia, Tanzania and Ethiopia also revealed that the same cell cycle and immune response pathways were enriched at the transcriptional level in various disease states. Although unconfirmed, the data suggest that genetic associations with chlamydial scarring disease may be focussed on processes relating to the immune response, the host cell cycle and cell surface receptor signalling.

Possible changes in the transmissibility of trachoma following MDA and transmission reduction: implications for the GET2020 goals

BACKGROUND

The role of mass drug administration (MDA) and the implementation of transmission reduction measures are essential to successfully control and eliminate a wide range of NTDs, including the ocular disease trachoma. Immunity to trachoma infection acts by reducing the duration of an individual's infectious period and by reducing their infectivity with each successive infection.

METHODS

In this study, we use a model of trachoma infection, which includes population immunity, to explore the impact of treatment and transmission reduction measures on trachoma prevalence. Specifically, we investigate the possibility of increasing transmissibility of trachoma arising as MDA and transmission reduction measures are scaled up in endemic settings.

RESULTS

We demonstrate this increase in transmissibility by calculating the effective reproduction number during several simulated control programmes and show that it is related to a decrease in the level of immunity in the population.

CONCLUSIONS

This effect should be studied in the field by measuring the rate of return of infection and disease in at least two separate age groups. If the decline of population immunity is operating, it should be accounted for when planning for the GET2020 goal of eliminating blinding trachoma by 2020.

Agreement between novice and experienced trachoma graders improves after a single day of didactic training

BACKGROUND/AIMS

Prevalence estimates and treatment decisions for trachoma are based entirely on ocular clinical examination. The aim of the current study is to demonstrate that ophthalmic assistants can be trained and certified to provide trachoma grading within a single day.

METHODS

Conjunctival photographs from an area with endemic trachoma were randomised into two sets of 60 cases. Photographs were graded for trachomatous inflammation-follicular (TF) and trachomatous inflammation-intense (TI) by three experienced graders. Inter-rater reliability of eight ophthalmic assistants and three experienced graders were compared before and after training.

RESULTS

The mean κ agreement between the ophthalmic assistants and the consensus grades of the experienced graders for TF was 0.38 (95% CI 0.18 to 0.58) before training, and increased to 0.60 (95% CI 0.42 to 0.78) after training (p=0.07). The mean κ agreement for TI was 0.16 (95% CI 0.02 to 0.30) before training, and increased to 0.39 (95% CI 0.20 to 0.58) after training (p=0.02).

CONCLUSION

A single day of training improves agreement between prospective and experienced trachoma graders, and provides the basis for certification of workers who are able to accurately grade trachoma and generate reliable prevalence estimates.

Costs of testing for ocular Chlamydia trachomatis infection compared to mass drug administration for trachoma in the Gambia: application of results from the PRET study

BACKGROUND

Mass drug administration (MDA) treatment of active trachoma with antibiotic is recommended to be initiated in any district where the prevalence of trachoma inflammation, follicular (TF) is ≥ 10% in children aged 1-9 years, and then to continue for at least three annual rounds before resurvey. In The Gambia the PRET study found that discontinuing MDA based on testing a sample of children for ocular Chlamydia trachomatis(Ct) infection after one MDA round had similar effects to continuing MDA for three rounds. Moreover, one round of MDA reduced disease below the 5% TF threshold. We compared the costs of examining a sample of children for TF, and of testing them for Ct, with those of MDA rounds.

METHODS

The implementation unit in PRET The Gambia was a census enumeration area (EA) of 600-800 people. Personnel, fuel, equipment, consumables, data entry and supervision costs were collected for census and treatment of a sample of EAs and for the examination, sampling and testing for Ct infection of 100 individuals within them. Programme costs and resource savings from testing and treatment strategies were inferred for the 102 EAs in the study area, and compared.

RESULTS

Census costs were $103.24 per EA plus initial costs of $108.79. MDA with donated azithromycin cost $227.23 per EA. The mean cost of examining and testing 100 children was $796.90 per EA, with Ct testing kits costing $4.80 per result. A strategy of testing each EA for infection is more expensive than two annual rounds of MDA unless the kit cost is less than $1.38 per result. However stopping or deciding not to initiate treatment in the study area based on testing a sample of EAs for Ct infection (or examining children in a sample of EAs) creates savings relative to further unnecessary treatments.

CONCLUSION

Resources may be saved by using tests for chlamydial infection or clinical examination to determine that initial or subsequent rounds of MDA for trachoma are unnecessary.

Community mass treatment with azithromycin for trachoma: Factors associated with change in participation of children from the first to the second round

BACKGROUND

Mass drug administration (MDA) with azithromycin is an important part of trachoma control programs. Maintaining high participation among children is challenging.

AIM

We assessed factors identifying households with a child who changed participation from the first MDA to the second MDA compared to households where all children participated at both MDAs.

METHODS

Two case-control comparisons were conducted in 11 Tanzanian communities, which underwent MDA in 2008 and 2009. The first case group (n=165) was a random sample of households with a child who changed from a 2008 non-participant to a 2009 participant (delayed participant). The second case group (n=165) was a random sample of households with a child who went from a 2008 participant to a 2009 non-participant (change to non-participant). Controls (n=330) were a random sample of households where all children participated in both rounds. Risk factors were assessed using questionnaires asked of children's guardians. Logistic models with a random-intercept were used to estimate odds ratios and 95% confidence intervals.

RESULTS

Households with delayed participation were more likely to be in communities with fewer treatment days (OR=2.98, 95% CI=1.80-4.92) and assigned to Community Treatment Assistants (CTA) with a wide area to cover (OR=1.88, 95% CI=1.09-3.23). Households with change to non-participation were more likely to live further from the distribution site (OR=3.17, 95% CI=1.19-8.46), have the guardian born outside the village with short-term residency (OR=2.64, 95% CI=1.32-5.31), and be assigned to a male CTA (OR=1.75, 95% CI=1.08-2.83).

CONCLUSIONS

Factors related to program accessibility were associated with delayed participation and maintaining participation.

Mass drug administration for trachoma: how long is not long enough?

Background

Blinding trachoma is targeted for elimination by 2020 using the SAFE strategy (Surgery, Antibiotics, Facial cleanliness, and Environmental improvements). Annual mass drug administration (MDA) with azithromycin is a cornerstone of this strategy. If baseline prevalence of clinical signs of trachomatous inflammation – follicular among 1-9 year-olds (TF1-9) is ≥10% but <30%, the World Health Organization guidelines are for at least 3 annual MDAs; if ≥30%, 5. We assessed the likelihood of achieving the global elimination target of TF1-9 <5% at 3 and 5 year evaluations using program reports.

Methodology/Principal Findings

We used the International Trachoma Initiative’s prevalence and treatment database. Of 283 cross-sectional survey pairs with baseline and follow-up data, MDA was conducted in 170 districts. Linear and logistic regression modeling was applied to these to investigate the effect of MDA on baseline prevalence. Reduction to <5% was less likely, though not impossible, at higher baseline TF1-9 prevalences. Increased number of annual MDAs, as well as no skipped MDAs, were significant predictors of reduced TF1-9 at follow-up. The probability of achieving the <5% target was <50% for areas with ≥30% TF1-9 prevalence at baseline, even with 7 or more continuous annual MDAs.

Conclusions

Number of annual MDAs alone appears insufficient to predict program progress; more information on the effects of baseline prevalence, coverage, and underlying environmental and hygienic conditions is needed. Programs should not skip MDAs, and at prevalences >30%, 7 or more annual MDAs may be required to achieve the target. There are five years left before the 2020 deadline to eliminate blinding trachoma. Low endemic settings are poised to succeed in their elimination goals. However, newly-identified high prevalence districts warrant immediate inclusion in the global program. Intensified application of the SAFE strategy is needed in order to guarantee blinding trachoma elimination by 2020.

Trachoma, the world’s leading infectious cause of blindness, is scheduled for elimination by 2020. Reaching this elimination target depends on successful implementation of the SAFE strategy (Surgery, Antibiotics, Facial cleanliness, and Environmental improvements). Annual mass antibiotic distributions are key to breaking the cycle of transmission in a community. However, it is not clear how many annual mass treatments need to be carried out in order to achieve elimination. Our study analyzes the effect of mass antibiotic distribution on different baseline prevalence levels of trachoma, in order to assess factors that affect the success of reaching elimination goals. We find that the prevailing belief, which suggests that 3 annual mass treatments can achieve local elimination of trachoma at prevalences between 10–30%, and 5 annual mass treatments for districts above this benchmark, is probably incorrect. In fact, much longer intervals may be required with “business as usual” programmatic strategies, which often include skipped years of treatment. Districts with high prevalence levels may require more intense treatment strategies to eliminate trachoma. Intensified recommendations must be implemented without delay in order to reach the 2020 elimination deadline.

Anthropometric indices of Gambian children after one or three annual rounds of mass drug administration with azithromycin for trachoma control

Background

Mass drug administration (MDA) with azithromycin, carried out for the control of blinding trachoma, has been linked to reduced mortality in children. While the mechanism behind this reduction is unclear, it may be due, in part, to improved nutritional status via a potential reduction in the community burden of infectious disease. To determine whether MDA with azithromycin improves anthropometric indices at the community level, we measured the heights and weights of children aged 1 to 4 years in communities where one (single MDA arm) or three annual rounds (annual MDA arm) of azithromycin had been distributed.

Methods

Data collection took place three years after treatment in the single MDA arm and one year after the final round of treatment in the annual MDA arm. Mean height-for-age, weight-for-age and weight-for-height z scores were compared between treatment arms.

Results

No significant differences in mean height-for-age, weight-for-age or weight-for-height z scores were found between the annual MDA and single MDA arms, nor was there a significant reduction in prevalence of stunting, wasting or underweight between arms.

Conclusions

Our data do not provide evidence that community MDA with azithromycin improved anthropometric outcomes of children in The Gambia. This may suggest reductions in mortality associated with azithromycin MDA are due to a mechanism other than improved nutritional status.

Optimal seasonal timing of oral azithromycin for malaria

Mass administration of azithromycin for trachoma has been shown to reduce malarial parasitemia. However, the optimal seasonal timing of such distributions for antimalarial benefit has not been established. We performed numerical analyses on a seasonally forced epidemic model (of Ross-Macdonald type) with periodic impulsive annual mass treatment to address this question. We conclude that when azithromycin-based trachoma elimination programs occur in regions of seasonal malaria transmission, such as Niger, the optimal seasonal timing of mass drug administration (MDA) may not occur during the season of maximum transmission.

Does mass azithromycin distribution impact child growth and nutrition in Niger? A cluster-randomized trial

Background

Antibiotic use on animals demonstrates improved growth regardless of whether or not there is clinical evidence of infectious disease. Antibiotics used for trachoma control may play an unintended benefit of improving child growth.

Methodology

In this sub-study of a larger randomized controlled trial, we assess anthropometry of pre-school children in a community-randomized trial of mass oral azithromycin distributions for trachoma in Niger. We measured height, weight, and mid-upper arm circumference (MUAC) in 12 communities randomized to receive annual mass azithromycin treatment of everyone versus 12 communities randomized to receive biannual mass azithromycin treatments for children, 3 years after the initial mass treatment. We collected measurements in 1,034 children aged 6–60 months of age.

Principal Findings

We found no difference in the prevalence of wasting among children in the 12 annually treated communities that received three mass azithromycin distributions compared to the 12 biannually treated communities that received six mass azithromycin distributions (odds ratio = 0.88, 95% confidence interval = 0.53 to 1.49).

Conclusions/Significance

We were unable to demonstrate a statistically significant difference in stunting, underweight, and low MUAC of pre-school children in communities randomized to annual mass azithromycin treatment or biannual mass azithromycin treatment. The role of antibiotics on child growth and nutrition remains unclear, but larger studies and longitudinal trials may help determine any association.

Recent studies suggest that antibiotic use could have an effect on growth in humans. Azithromycin is an antibiotic used for trachoma control, and hence, may have an unintended benefit of improving child growth. Niger is a trachoma-endemic country where mass antibiotic distributions for trachoma take place and where malnutrition is widespread among children. In addition, azithromycin may have an effect on common childhood diseases associated with malnutrition, such as diarrhea, pneumonia, and malaria. In a community-randomized trachoma trial in Matameye, Niger, we assessed child growth by measuring height, weight, and mid-upper arm circumference of pre-school children who have received 3 years of annual or biannual mass azithromycin treatment. While these measures were better in the biannually treated communities, the difference was not statistically significant. Thus, further research will help determine the impact of antibiotics on child growth and nutrition.

Non-participation during azithromycin mass treatment for trachoma in The Gambia: heterogeneity and risk factors

BACKGROUND

There is concern that untreated individuals in mass drug administration (MDA) programs for neglected tropical diseases can reduce the impact of elimination efforts by maintaining a source of transmission and re-infection.

METHODOLOGY/PRINCIPAL FINDINGS

Treatment receipt was recorded against the community census during three MDAs with azithromycin for trachoma in The Gambia, a hypo-endemic setting. Predictors of non-participation were investigated in 1-9 year olds using random effects logistic regression of cross-sectional data for each MDA. Two types of non-participators were identified: present during MDA but not treated (PNT) and eligible for treatment but absent during MDA (EBA). PNT and EBA children were compared to treated children separately. Multivariable models were developed using baseline data and validated using year one and two data, with a priori adjustment for previous treatment status. Analyses included approximately 10000 children at baseline and 5000 children subsequently. There was strong evidence of spatial heterogeneity, and persistent non-participation within households and individuals. By year two, non-participation increased significantly to 10.4% overall from 6.2% at baseline, with more, smaller geographical clusters of non-participating households. Multivariable models suggested household level predictors of non-participation (increased time to water and household head non-participation for both PNT and EBA; increased household size for PNT status only; non-inclusion in a previous trachoma examination survey and younger age for EBA only). Enhanced coverage efforts did not decrease non-participation. Few infected children were detected at year three and only one infected child was EBA previously. Infected children were in communities close to untreated endemic areas with higher rates of EBA non-participation during MDA.

CONCLUSIONS/SIGNIFICANCE

In hypo-endemic settings, with good coverage and no association between non-participation and infection, efforts to improve participation during MDA may not be required. Further research could investigate spatial hotspots of infection and non-participation in other low and medium prevalence settings before allocating resources to increase participation.

Gender and performance of community treatment assistants in Tanzania

OBJECTIVE

To examine the effects of gender and demographics of community treatment assistants (CTAs) on their performance of assigned tasks and quantity of speech during mass drug administration of azithromycin for trachoma in rural Tanzania.

DESIGN

Surveys of CTAs and audio recordings of interactions between CTAs and villagers during drug distribution.

SETTING

Mass drug administration program in rural Kongwa district.

PARTICIPANTS

Fifty-seven randomly selected CTAs, and 3122 residents of villages receiving azithromycin as part of the Kongwa Trachoma Project.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Speech quantity graded by Roter interaction analysis system, presence of culturally appropriate greeting and education on facial hygiene for trachoma prevention from coded analysis of audio-recorded interactions.

RESULTS

At sites with all female CTAs, each CTA spent more time and spoke more in each interaction in comparison with CTAs at sites with only male CTAs and CTAs at 'mixed gender' sites (sites with both male and female CTAs). At 'mixed gender' sites, males spoke significantly more than females. Female CTAs mentioned trachoma prevention with facial cleanliness more than twice as often as male CTAs; however, both genders mentioned hygiene in <10% of interactions. Both genders had culturally appropriate greetings in <25% of interactions.

CONCLUSIONS

Gender dynamics affect the amount of time that CTAs spend with villagers during drug distribution, and the relative amount of speech when both genders work together. Both genders are not meeting expectations for trachoma prevention education and greeting villagers, and novel training methods are necessary.

Importance of including borderline cases in trachoma grader certification

We assessed trachoma grading agreement among field graders using photographs that included the complete spectrum of disease and compared it with cases where there was consensus among experienced graders. Trained photographers took photographs of children's conjunctiva during a clinical trial in Ethiopia. We calculated κ-agreement statistics using a complete set of 60 cases and then recalculated the κ using a consensus set where cases were limited to those cases with agreement among experienced graders. When the complete set of 60 cases was used, agreement was moderate (κ = 0.61, 95% confidence interval [95% CI] = 0.56-0.67). When the consensus set was used, agreement improved significantly (κ = 0.75, 95% CI = 0.68-0.80). The κ of the consensus set was higher than the complete set by 0.14 (95% CI = 0.12-0.16) (P < 0.001). If testing sets remove difficult-to-grade cases, agreement in trachoma grading may be higher than actually seen in population-based trachoma surveys.

Risk factors for active trachoma and ocular Chlamydia trachomatis infection in treatment-naïve trachoma-hyperendemic communities of the Bijagós Archipelago, Guinea Bissau

BACKGROUND

Trachoma, caused by ocular infection with Chlamydia trachomatis, is hyperendemic on the Bijagós Archipelago of Guinea Bissau. An understanding of the risk factors associated with active trachoma and infection on these remote and isolated islands, which are atypical of trachoma-endemic environments described elsewhere, is crucial to the implementation of trachoma elimination strategies.

METHODOLOGY/PRINCIPAL FINDINGS

A cross-sectional population-based trachoma prevalence survey was conducted on four islands. We conducted a questionnaire-based risk factor survey, examined participants for trachoma using the World Health Organization (WHO) simplified grading system and collected conjunctival swab samples for 1507 participants from 293 randomly selected households. DNA extracted from conjunctival swabs was tested using the Roche Amplicor CT/NG PCR assay. The prevalence of active (follicular and/or inflammatory) trachoma was 11% (167/1508) overall and 22% (136/618) in 1-9 year olds. The prevalence of C. trachomatis infection was 18% overall and 25% in 1-9 year olds. There were strong independent associations of active trachoma with ocular and nasal discharge, C. trachomatis infection, young age, male gender and type of household water source. C. trachomatis infection was independently associated with young age, ocular discharge, type of household water source and the presence of flies around a latrine.

CONCLUSIONS/SIGNIFICANCE

In this remote island environment, household-level risk factors relating to fly populations, hygiene behaviours and water usage are likely to be important in the transmission of ocular C. trachomatis infection and the prevalence of active trachoma. This may be important in the implementation of environmental measures in trachoma control.

Reliability of trachoma clinical grading--assessing grading of marginal cases

BACKGROUND

Clinical examination of trachoma is used to justify intervention in trachoma-endemic regions. Currently, field graders are certified by determining their concordance with experienced graders using the kappa statistic. Unfortunately, trachoma grading can be highly variable and there are cases where even expert graders disagree (borderline/marginal cases). Prior work has shown that inclusion of borderline cases tends to reduce apparent agreement, as measured by kappa. Here, we confirm those results and assess performance of trainees on these borderline cases by calculating their reliability error, a measure derived from the decomposition of the Brier score.

METHODS AND FINDINGS

We trained 18 field graders using 200 conjunctival photographs from a community-randomized trial in Niger and assessed inter-grader agreement using kappa as well as reliability error. Three experienced graders scored each case for the presence or absence of trachomatous inflammation-follicular (TF) and trachomatous inflammation-intense (TI). A consensus grade for each case was defined as the one given by a majority of experienced graders. We classified cases into a unanimous subset if all 3 experienced graders gave the same grade. For both TF and TI grades, the mean kappa for trainees was higher on the unanimous subset; inclusion of borderline cases reduced apparent agreement by 15.7% for TF and 12.4% for TI. When we assessed the breakdown of the reliability error, we found that our trainees tended to over-call TF grades and under-call TI grades, especially in borderline cases.

CONCLUSIONS

The kappa statistic is widely used for certifying trachoma field graders. Exclusion of borderline cases, which even experienced graders disagree on, increases apparent agreement with the kappa statistic. Graders may agree less when exposed to the full spectrum of disease. Reliability error allows for the assessment of these borderline cases and can be used to refine an individual trainee's grading.

Impact of mass azithromycin distribution on malaria parasitemia during the low-transmission season in Niger: a cluster-randomized trial

We assessed the effect of mass azithromycin treatment on malaria parasitemia in a trachoma trial in Niger. Twenty-four study communities received treatment during the wet, high-transmission season. Twelve of the 24 communities were randomized to receive an additional treatment during the dry, low-transmission season. Outcome measurements were conducted at the community-level in children < 1-72 months of age in May-June 2011. Parasitemia was higher in the 12 once-treated communities (29.8%, 95% confidence interval [CI] = 21.5-40.0%) than in the 12 twice-treated communities (19.5%, 95% CI = 13.0-26.5%, P = 0.03). Parasite density was higher in once-treated communities (354 parasites/μL, 95% CI = 117-528 parasites/μL) than in twice-treated communities (74 parasites/μL, 95% CI = 41-202 parasites/μL, P = 0.03). Mass distribution of azithromycin reduced malaria parasitemia 4-5 months after the intervention. The results suggest that drugs with antimalaria activity can have long-lasting impacts on malaria during periods of low transmission.

Mass administration of azithromycin and Streptococcus pneumoniae carriage: cross-sectional surveys in the Gambia

OBJECTIVE

To evaluate the effect of repeated mass drug administration (MDA) of azithromycin in the Gambia on the nasopharyngeal carriage of Streptococcus pneumoniae and on the emergence of antibiotic-resistant strains.

METHODS

This study involved villages that participated in a cluster randomized trial comparing the effect of one versus three azithromycin MDA rounds on the prevalence of trachoma. Only villages in which most children received 7-valent pneumococcal conjugate vaccine were included. Three cross-sectional surveys were performed in two villages that received three annual MDA rounds: the first immediately before the third MDA round and the second and third, 1 and 6 months, respectively, after the third MDA round. The third survey also covered six villages that had received one MDA round 30 months previously. Pneumococcal carriage was assessed using nasopharyngeal swabs and azithromycin resistance was detected using the Etest.

FINDINGS

The prevalence of pneumococcal carriage decreased from 43.4% to 19.2% between the first and second surveys (P < 0.001) but rebounded by the third survey (45.8%; P = 0.591). Being a carrier at the first survey was a risk factor for being a carrier at the second (odds ratio: 3.71; P <  0.001). At the third survey, the prevalence of carriage was similar after one and three MDA rounds (50.3% versus 45.8%, respectively; P = 0.170), as was the prevalence of azithromycin resistance (0.3% versus 0.9%, respectively; P = 0.340).

CONCLUSION

Three azithromycin MDA rounds did not increase the prevalence of nasopharyngeal carriage of azithromycin-resistant S. pneumoniae strains compared with one round.

The effect of multiple rounds of mass drug administration on the association between ocular Chlamydia trachomatis infection and follicular trachoma in preschool-aged children

Purpose

To examine the relationship between ocular Chlamydia trachomatis infection and follicular trachoma (TF) in children prior to and following multiple rounds of annual mass drug administration (MDA) with azithromycin.

Methodology/principal findings

Thirty-two communities with endemic trachoma in Kongwa District, Tanzania, were offered annual MDA as part of a district-wide trachoma control program. Presence of ocular C. trachomatis infection and TF were assessed in 3,200 randomly sampled children aged five years and younger, who were examined prior to each MDA. Infection was detected using the Amplicor CT/NG assay and TF was identified by clinical examination using the World Health Organization (WHO) simplified grading system. The association between chlamydial infection and TF in children was evaluated at baseline prior to any treatment, and 12 months after each of three annual rounds of mass treatment. Factors associated with infection were examined using generalized estimating equation models.

At baseline, the overall prevalence of chlamydial infection and TF was 22% and 31%, respectively. Among children with clinical signs of TF, the proportion of those with infection was 49% prior to treatment and declined to 30% after three MDAs. The odds of infection positivity among children with clinical signs of TF decreased by 26% (OR 0.74, 95% CI 0.65 to 0.84, p = <0.01) with each MDA, after adjusting for age. For children aged under one year, who did not receive treatment, the relationship was unchanged.

Conclusions/significance

The association between ocular C. trachomatis infection and TF weakened in children with each MDA, as both infection and clinical disease prevalence declined. However, there was still a significant proportion of TF cases with infection after three rounds of MDA. New strategies are needed to assess this residual infection for optimal treatment distribution.

Trachoma, which is caused by infection by the bacterium Chlamydia trachomatis, is the leading preventable cause of blindness worldwide. Annual mass drug administration with azithromycin is recommended for trachoma control; however, monitoring the impact of azithromycin, which targets C. trachomatis, relies on the clinical assessment of follicular trachoma. If the relationship between chlamydial infection and the presence or absence of follicular trachoma were to remain unchanged with each round of treatment, we would be able to predict the level of residual infection, and the need for additional treatment, from the prevalence of follicular trachoma. In this study, we examined the association between infection and presence or absence of follicular trachoma in children prior to and following multiple rounds of treatment. Findings suggest that with increasing rounds of treatment, the prevalence of infection declines in children both with and without signs of follicular trachoma. Newer strategies, including tests that can rapidly detect infection under field conditions, may be needed to assess residual infection in treated communities.

Increased carriage of macrolide-resistant fecal E. coli following mass distribution of azithromycin for trachoma control

BACKGROUND

Mass drug treatment with azithromycin (MDA) is part of the WHO-endorsed 'SAFE' strategy for trachoma control in endemic communities. MDA has been associated with reduced trachoma prevalence and short-term reductions in other bacterial infections, but can also lead to increased circulation of macrolide-resistant bacteria.

METHODS

We prospectively monitored macrolide resistance in fecal E. coli collected from young children participating in the PRET+ Study in rural Tanzania. MDA was administered in four villages with >10% trachoma prevalence. Four nearby communities with lower trachoma prevalence served as controls. Rectal swabs were collected during cross-sectional surveys performed at baseline, 1, 3 and 6 months after MDA. Fecal E. coli isolates were screened for macrolide susceptibility using disc diffusion and minimum inhibitory concentration methods. Cross-sectional and longitudinal differences in resistance prevalence by MDA exposure were compared using t-tests and logistic regression.

RESULTS

There was no difference in the proportion of individuals carrying azithromycin-resistant E. coli at baseline (0.21 vs. 0.16, P > 0.05). Azithromycin resistance carriage prevalence remained stable over follow-up in non-MDA villages but increased sharply in MDA villages (0.61 at 1 month, 0.42 at 3 months and 0.31 at 6 months). MDA exposure was highly associated with azithromycin resistance carriage at 1 month post-MDA (OR 15.27, P < 0.001) and subsequent surveys. Younger age and recent diarrhoea were also associated with increased odds of resistance (P < 0.01).

CONCLUSIONS

MDA resulted in significantly increased prevalence of macrolide resistance in E. coli. Although MDA is effective for trachoma elimination, it has costs; it is essential to monitor antimicrobial resistance following MDA.

Conjunctival scarring in trachoma is associated with the HLA-C ligand of KIR and is exacerbated by heterozygosity at KIR2DL2/KIR2DL3

BACKGROUND

Chlamydia trachomatis is globally the predominant infectious cause of blindness and one of the most common bacterial causes of sexually transmitted infection. Infections of the conjunctiva cause the blinding disease trachoma, an immuno-pathological disease that is characterised by chronic conjunctival inflammation and fibrosis. The polymorphic Killer-cell Immunoglobulin-like Receptors (KIR) are found on Natural Killer cells and have co-evolved with the Human Leucocyte Antigen (HLA) class I system. Certain genetic constellations of KIR and HLA class I polymorphisms are associated with a number of diseases in which modulation of the innate responses to viral and intracellular bacterial pathogens is central.

METHODOLOGY

A sample of 134 Gambian pedigrees selected to contain at least one individual with conjunctival scarring in the F1 generation was used. Individuals (n = 830) were genotyped for HLA class I and KIR gene families. Family Based Association Tests and Case Pseudo-control tests were used to extend tests for transmission disequilibrium to take full advantage of the family design, genetic model and phenotype.

PRINCIPLE FINDINGS

We found that the odds of trachomatous scarring increased with the number of genome copies of HLA-C2 (C1/C2 OR = 2.29 BHP-value = 0.006; C2/C2 OR = 3.97 BHP-value = 0.0004) and further increased when both KIR2DL2 and KIR2DL3 (C2/C2 OR = 5.95 BHP-value = 0.006) were present.

CONCLUSIONS

To explain the observations in the context of chlamydial infection and trachoma we propose a two-stage model of response and disease that balances the cytolytic response of KIR expressing NK cells with the ability to secrete interferon gamma, a combination that may cause pathology. The data presented indicate that HLA-C genotypes are important determinants of conjunctival scarring in trachoma and that KIR2DL2/KIR2DL3 heterozygosity further increases risk of conjunctival scarring in individuals carrying HLA-C2.

Effect of azithromycin mass drug administration for trachoma on spleen rates in Gambian children

OBJECTIVE

To assess the effect of azithromycin mass drug administration regimens on spleen rates in children aged 0-5 years.

METHODS

Clinical assessment of spleen size was carried out during a cluster-randomised trial of azithromycin mass treatment for trachoma elimination in The Gambia. Twenty-four communities received three annual mass treatments with azithromycin, and 24 communities received treatment at baseline only.

RESULTS

At the 30-month follow-up, 3646 children aged 0-5 years had spleen examination and measurement. Palpable splenomegaly was significantly lower in annually treated vs. baseline-only treatment communities and in treated vs. untreated children at 24 months in the annual treatment arm.

CONCLUSION

The results suggest an effect of azithromycin on spleen rates at the individual level and are most plausibly due to the antimalarial effects of azithromycin.

The efficacy of oral azithromycin in clearing ocular chlamydia: mathematical modeling from a community-randomized trachoma trial

Mass oral azithromycin distributions have dramatically reduced the prevalence of the ocular strains of chlamydia that cause trachoma. Assessing efficacy of the antibiotic in an individual is important in planning trachoma elimination. However, the efficacy is difficult to estimate, because post-treatment laboratory testing may be complicated by nonviable organisms or reinfection. Here, we monitored ocular chlamydial infection twice a year in pre-school children in 32 communities as part of a cluster-randomized clinical trial in Tanzania (prevalence in children was lowered from 22.0% to 4.7% after 3-year of annual treatment). We used a mathematical transmission model to estimate the prevalence of infection immediately after treatment, and found the effective field efficacy of antibiotic in an individual to be 67.6% (95% CI: 56.5–75.1%) in this setting. Sensitivity analyses suggested that these results were not dependent on specific assumptions about the duration of infection. We found no evidence of decreased efficacy during the course of the trial. We estimated an 89% chance of elimination after 10 years of annual treatment with 95% coverage.

Plasmid copy number and disease severity in naturally occurring ocular Chlamydia trachomatis infection

The Chlamydia trachomatis plasmid is a virulence factor. Plasmid copy number, C. trachomatis load and disease severity were assessed in a treatment-naive population where trachoma is hyperendemic. By using droplet digital PCR, plasmid copy number was found to be stable (median, 5.34 [range, 1 to 18]) and there were no associations with C. trachomatis load or disease severity.

Pooling ocular swab specimens from Tanzania for testing by Roche Amplicor and Aptima Combo 2 assays for the detection of Chlamydia trachomatis: accuracy and cost-savings

Ocular swabs collected in Tanzania were evaluated by Amplicor CT PCR and Aptima Combo2 assays for the detection of Chlamydia trachomatis to determine if pooling could be used to reduce the cost of detection. Pooling would be an accurate method and has thus far resulted in a cost-savings of 62.2%.