Human and other faeces as breeding media of the trachoma vector Musca sorbens

A review of Musca sorbens (Diptera: Muscidae) and Musca domestica behavior and responses to chemical and visual cues

Musca flies (Diptera: Muscidae) have been found culpable in the mechanical transmission of several infectious agents, including viruses, bacteria, protozoans, and helminths, particularly in low-income settings in tropical regions. In large numbers, these flies can negatively impact the health of communities and their livestock through the transmission of pathogens. In some parts of the world, Musca sorbens is of particular importance because it has been linked with the transmission of trachoma, a leading cause of preventable and irreversible blindness or visual impairment caused by Chlamydia trachomatis, but the contribution these flies make to trachoma transmission has not been quantified and even less is known for other pathogens. Current tools for control and monitoring of house flies remain fairly rudimentary and have focused on the use of environmental management, insecticides, traps, and sticky papers. Given that the behaviors of flies are triggered by chemical cues from their environment, monitoring approaches may be improved by focusing on those activities that are associated with nuisance behaviors or with potential pathogen transmission, and there are opportunities to improve fly control by exploiting behaviors toward semiochemicals that act as attractants or repellents. We review current knowledge on the odor and visual cues that affect the behavior of M. sorbens and Musca domestica, with the aim of better understanding how these can be exploited to support disease monitoring and guide the development of more effective control strategies.

Progress Towards Elimination of Trachoma in Kenya 2017-2020

PURPOSE

Trachoma is endemic in Kenya. Since baseline trachoma surveys in 2004, a concerted programme has been undertaken to reduce the prevalence of disease. Here, we report on trachoma prevalence surveys carried out between 2017 and 2020 after interventions were implemented in some areas for trachoma elimination purposes.

METHODS

A total of 48 cross-sectional population-based trachoma prevalence surveys were conducted in 39 evaluation units (EUs; covering 45 subcounties) of Kenya between 2017 and 2020. Thirty EUs were surveyed once and nine EUs were surveyed twice over this period. Individuals ≥ 1 year old were assessed for trachomatous inflammation-follicular (TF), trachomatous inflammation-intense (TI) and trichiasis. Data were collected on household access to water, sanitation and hygiene (WASH).

RESULTS

A total of 147,573 people were examined. At the end of 2020, in the 39 EUs surveyed, the prevalence of TF in 1-9-year-olds was ≥5% in 11 EUs and the prevalence of trichiasis unknown to the health system in individuals aged ≥15 years was ≥0.2% in 25 EUs. A small minority of households (median <50% for all indicators) had access to improved WASH facilities.

CONCLUSION

Kenya has made excellent progress towards elimination of trachoma as a public health problem. However, there is more work to do. Between one and three rounds of antibiotic mass drug administration are required in 11 EUs. Sustained investment in surgical provision, continued TT case-finding, promotion of facial cleanliness and environmental improvement are required throughout the surveyed area.

Prevalence of Trachoma in Pre-validation Surveillance Surveys in 11 Evaluation Units (Covering 12 Districts) in Oromia Regional State, Ethiopia: Results from 2018-2020

PURPOSE

Interventions to reduce the prevalence of trachoma and transmission of ocular Chlamydia trachomatis have been implemented in Oromia Region, Ethiopia. Following an impact survey in which the trachomatous inflammation-follicular (TF) prevalence in 1-9-year-olds is <5%, a surveillance survey is recommended 2 years later, without additional antibiotic treatment. We report results of surveillance surveys in 11 evaluation units (EUs) covering 12 districts in Oromia Region, to plan whether future interventions are needed.

METHOD

We use a two-stage cluster-sampling cross-sectional survey design. In each EU, 26 clusters (villages) were systematically selected with probability proportional to size; from each cluster, 30 households were selected using compact segment sampling. Water, sanitation and hygiene (WASH) access was assessed in all selected households. All residents of selected households aged ≥1 year were examined for TF and trachomatous trichiasis (TT) by certified graders.

RESULT

Of 31,991 individuals enumerated, 29,230 (91% of) individuals were examined. Eight EUs had an age-adjusted TF prevalence in 1-9-year-olds of ≥5% and seven had a TT prevalence unknown to the health system among adults aged ≥15 years of ≥0.2%. About one-third of visited households had access to an improved water source for drinking, and 5% had access to an improved latrine.

CONCLUSION

Despite TF reductions to <5% at impact survey, prevalence recrudesced to ≥5% in all but three of the 11 EUs. Operational research is needed to understand transmission dynamics and epidemiology, in order to optimise elimination strategies in high-transmission settings like these.

The 100 most cited articles on trachoma: a bibliometric analysis

OBJECTIVE

Trachoma is the cause of blindness or visual impairment in 1.9 million people. Few bibliometric studies have been carried out, but none explore the characteristics of the 100 most cited articles on trachoma.

METHODS

A keyword-based search without time restriction was performed in September 2022 using the Scopus database. Search keywords include the following: "trachoma; trachome; tracoma; trachomatis." Two authors independently screened the literature and extracted data. The search result was obtained to classify the 100 articles according to their number of citations.

RESULTS

The Top 100 articles were published between 1957 and 2015 with a total of 11,102 citations (range 56-689). The country with the most significant contribution was the USA (n = 56). The Lancet was the most active journal (n = 15). Bailey RL was the author with the highest number of publications (n = 30). The Edna McConnell Clark Foundation (n = 26) was the most prominent funding entity. The type of original article was the most published (n = 83), in addition, the most frequent thematic area was prevention (n = 33). The most popular keywords were trachoma (n = 93), chlamydia trachomatis (n = 55), and azithromycin (n = 34).

CONCLUSIONS

The study provides new insight into trachoma research, information that may help healthcare providers, researchers, and stakeholders better understand trends and influential contributions. It highlights under-researched areas that could be the basis for future research.

Trachoma risk factors in Oromia Region, Ethiopia

BACKGROUND

Trachoma, the leading infectious cause of blindness, is caused by the bacterium Chlamydia trachomatis (Ct). Despite enormous disease control efforts and encouraging progress, trachoma remains a significant public health problem in 44 countries. Ethiopia has the greatest burden of trachoma worldwide, however, robust data exploring transmission risk factors and the association between socio-economic status is lacking from some regions. This is the first study to investigate these factors in this South-Eastern region of Oromia, Ethiopia.

METHODOLOGY/PRINCIPAL FINDINGS

A total of 1211 individuals were enrolled from 247 households in Shashemene Rural district in Oromia Region between 11th April and 25th June 2018, of whom 628 (51.9%) were female and 526 (43.4%) were children aged 1-9 years. Three standardised ophthalmic nurses examined each participant for the presence of active trachoma using the WHO simplified trachoma grading system. Conjunctival swab samples were collected from the upper tarsal conjunctiva of the left eye of each participant. Ct was detected using quantitative PCR. Risk factor data were collected through structured interviews and direct observations. Clinical signs of trachomatous inflammation-follicular among children aged 1-9 (TF1-9) were observed in at least one eye of 106/526 (20.2%) and trachomatous inflammation-intense among children aged 1-9 (TI1-9) were observed in at least one eye of 10/526 (1.9%). We detected Ct by PCR in 23 individuals, of whom 18 (78.3%) were in children aged 1-9 years. Among the 106 children aged 1-9 years with TF, 12 (11.3%) were Ct PCR positive and among 20 children aged 1-9 years with TI, 4 (20.0%) were Ct PCR positive. In a multivariable model, adjusting for household clustering, active trachoma was associated with younger age, the poorest households (aOR = 2.56, 95% CI 1.21-5.51), presence of flies on the face (aOR = 2.87, 95% CI 1.69-6.46), and ocular discharge (aOR = 1.89, 95% CI 1.03-3.24). Pre-school children face washing more than once a day had lower odds of having active trachoma (aOR = 0.59, 95% CI 0.19-0.84). The same was true for washing children's clothing at least once per week (aOR = 0.27, 95% CI 0.33-1.02).

CONCLUSION/SIGNIFICANCE

Younger age, personal hygiene in this age group (presence of ocular and nasal discharges, infrequent washing of faces and clothing) and fly-eye contacts are potential risk factors for trachoma in this setting, suggesting that hygiene interventions and environmental improvements are required to suppress transmission to ensure sustained reduction in disease burden Further studies are needed to evaluate these interventions for trachoma control and elimination. Trachoma remains a disease associated with lower socio-economic status, emphasising the need for continued implementation of control measures in addition to poverty reduction interventions in this region.

Potential mitigating role of ivermectin on the spread of Chlamydia trachomatis by Musca sorbens

Trachoma is the world's most frequent cause of blindness from an infectious agent. The disease caused by infection is associated with lack of access to sanitation and low hygiene standards. Trachoma is controlled through the Surgery, Antibiotics, Facial cleanliness, and Environmental improvement (SAFE) strategy, which delivers azithromycin (AZM) mass drug administration (MDA) in endemic areas. The putative vector Musca sorbens principally reproduce in human faecal matter left in the environment due to open defecation. Ivermectin (IVM) is on the WHO's essential medicines list and is administered as preventative chemotherapy against two neglected tropical diseases (NTDs)-onchocerciasis, as an annual or bi-annual treatment, and lymphatic filariasis, as an annual treatment in combination with albendazole. Ivermectin has a known inhibitive effect on insects that reproduce in dung. To assess if IVM could be a viable vector control tool against M. sorbens, this study evaluates existing data from trachoma, onchocerciasis and lymphatic filariasis mass drug administration (MDA) operations in Ethiopia. Persistent and recrudescent trachoma in evaluation units (EUs) were examined for whether AZM MDA in EUs was accompanied by IVM MDA, and whether co-administration was associated with greater likelihood of trachoma control. Results show an association suggesting that EUs that received both IVM and AZM MDA benefit from improved control of trachoma in persistent or recrudescent areas, when compared to EUs that received AZM MDA. This initial investigation supports the potential for ivermectin's use to support SAFE. Findings warrant further work to validate ivermectin's impact on M. sorbens reproduction through controlled lab and field-based studies.

Modeling the "F" in "SAFE": The dynamic game of facial cleanliness in trachoma prevention

Trachoma, a neglected tropical disease (NTDs) caused by bacterium Chlamydia trachomatis, is a leading cause of infectious blindness. Efforts are underway to eliminate trachoma as a public health problem by using the "SAFE" strategy. While mathematical models are now standard tools used to support elimination efforts and there are a variety of models studying different aspects of trachoma transmission dynamics, the "F" component of the strategy corresponding to facial cleanliness has received very little attention so far. In this paper, we incorporate human behavior into a standard epidemiological model and develop a dynamical game during which individuals practice facial cleanliness based on their epidemiological status and perceived benefits and costs. We found that the number of infectious individuals generally increases with the difficulty to access a water source. However, this increase happens only during three transition periods and the prevalence stays constant otherwise. Consequently, improving access to water can help eliminate trachoma, but the improvement needs to be significant enough to cross at least one of the three transition thresholds; otherwise the improved access will have no noticeable effect.

Open defaecation by proxy: Tackling the increase of disposable diapers in waste piles in informal settlements

Disposable diapers are becoming increasingly popular and present an emerging challenge for global waste management, particularly within LMICs. They offer a cheap and convenient way for caregivers to manage child excreta; however, insufficient understanding of safe disposal methods, combined with limited access to waste management services results in hazardous disposal. Used diapers are being increasingly found dumped in the open environment, including in water bodies and in open fields, leading to faecal contamination of the environment and an enhanced risk of transmission of faecal-oral diseases such as cholera and typhoid. United Nations SDG 6 aims to end open defaecation globally by 2030; however, improper disposal of used diapers will hamper progress towards reaching this goal. In this review, we identify current trends in use and subsequent disposal of single use disposable diapers in LMICs, and critically discuss the environmental and public health impacts of current practices, and potential solutions to address these challenges. Contemporary methods for managing the disposal of single use diapers for communities in LMICs tend to be cost prohibitive with few alternative options other than dumping in the environment. Modern cloth diapers offer a low waste alternative to disposable diapers but often carry an unaffordable high upfront cost. Here, in addition to advocating improved efforts by governments to upgrade access and quality of waste management services, we recommend the design and implementation of intervention schemes aimed to increase awareness of safe and hygienic disposal practices for disposable diapers.

Exploring water, sanitation, and hygiene coverage targets for reaching and sustaining trachoma elimination: G-computation analysis

BACKGROUND

Trachoma is the leading infectious cause of blindness. To reduce transmission, water, sanitation, and hygiene (WaSH) improvements are promoted through a comprehensive public health strategy. Evidence supporting the role of WaSH in trachoma elimination is mixed and it remains unknown what WaSH coverages are needed to effectively reduce transmission.

METHODS/FINDINGS

We used g-computation to estimate the impact on the prevalence of trachomatous inflammation-follicular among children aged 1-9 years (TF1-9) when hypothetical WaSH interventions raised the minimum coverages from 5% to 100% for "nearby" face-washing water (<30 minutes roundtrip collection time) and adult latrine use in an evaluation unit (EU). For each scenario, we estimated the generalized prevalence difference as the TF1-9 prevalence under the intervention scenarios minus the observed prevalence. Data from 574 cross-sectional surveys conducted in 16 African and Eastern Mediterranean countries were included. Surveys were conducted from 2015-2019 with support from the Global Trachoma Mapping Project and Tropical Data. When modeling interventions among EUs that had not yet met the TF1-9 elimination target, increasing nearby face-washing water and latrine use coverages above 30% was generally associated with consistent decreases in TF1-9. For nearby face-washing water, we estimated a ≥25% decrease in TF1-9 at 65% coverage, with a plateau upon reaching 85% coverage. For latrine use, the estimated decrease in TF1-9 accelerated from 80% coverage upward, with a ≥25% decrease in TF1-9 by 85% coverage. Among EUs that had previously met the elimination target, results were inconclusive.

CONCLUSIONS

Our results support Sustainable Development Goal 6 and provide insight into potential WaSH-related coverage targets for trachoma elimination. Targets can be tested in future trials to improve evidence-based WaSH guidance for trachoma.

Prevalence of Trachoma in Benishangul Gumuz Region, Ethiopia, after Implementation of the SAFE Strategy: Results of Four Population-Based Surveys

PURPOSE

We aimed to estimate the prevalence of trachomatous inflammation-follicular (TF) in 1-9-year-olds and trachomatous trichiasis (TT) unknown to the health system in ≥15-year-olds in Benishangul Gumuz (BGZ) region, Ethiopia. This will help to assess progress towards the elimination of trachoma as a public health problem and determine the need for future interventions against trachoma in the region.

METHODS

Cross-sectional population-based trachoma prevalence surveys were conducted in four evaluation units (EUs) of BGZ using World Health Organization-recommended survey methodologies. Individuals were examined for clinical signs of trachoma. Household access to water, sanitation and hygiene facilities (WaSH) was assessed.

RESULTS

A total of 11,778 people aged ≥1 year were examined. The prevalence of TF in 1-9-year-olds was <5% in three EUs and ≥5% in one EU. The prevalence of TT unknown to the health system in people aged ≥15-years was ≥0.2% in all four EUs. The proportion of households with an improved drinking water source within a 30-minute round-trip ranged from 27-60%. The proportion of households with an improved latrine ranged from <1-6%.

CONCLUSIONS

Surgical interventions for TT are required in all EUs in BGZ. One annual round of mass drug administration (MDA) of azithromycin is required in one EU before resurvey to reassess progress in lowering TF prevalence below the WHO elimination threshold of 5% in 1-9-year-olds. MDA should be stopped in the other three EUs and trachoma surveillance surveys should be conducted at least 24 months after the surveys described here. Ongoing strengthening of WaSH infrastructure may help sustain the low prevalence of trachoma.

Community-level trachoma ecological associations and the use of geospatial analysis methods: A systematic review

Background

Trachoma is targeted for global elimination as a public health problem by 2030. Understanding individual, household, or community-associated factors that may lead to continued transmission or risk of recrudescence in areas where elimination has previously been achieved, is essential in reaching and maintaining trachoma elimination. We aimed to identify climatic, demographic, environmental, infrastructural, and socioeconomic factors associated in the literature with trachoma at community-level and assess the strength of their association with trachoma. Because of the potential power of geospatial analysis to delineate the variables most strongly associated with differences in trachoma prevalence, we then looked in detail at geospatial analysis methods used in previous trachoma studies.

Methods

We conducted a systematic literature review using five databases: Medline, Embase, Global Health, Dissertations & Theses Global, and Web of Science, including publications from January 1950 to January 2021. The review protocol was prospectively registered with PROSPERO (CRD42020191718).

Results

Of 35 eligible studies, 29 included 59 different trachoma-associated factors, with eight studies also including spatial analysis methods. Six studies included spatial analysis methods only. Higher trachomatous inflammation—follicular (TF) prevalence was associated with areas that: had lower mean annual precipitation, lower mean annual temperatures, and lower altitudes; were rural, were less accessible, had fewer medical services, had fewer schools; and had lower access to water and sanitation. Higher trachomatous trichiasis (TT) prevalence was associated with higher aridity index and increased distance to stable nightlights. Of the 14 studies that included spatial methods, 11 used exploratory spatial data analysis methods, three used interpolation methods, and seven used spatial modelling methods.

Conclusion

Researchers and decision-makers should consider the inclusion and potential influence of trachoma-associated factors as part of both research activities and programmatic priorities. The use of geospatial methods in trachoma studies remains limited but offers the potential to define disease hotspots and areas of potential recrudescence to inform local, national, and global programmatic needs.

The ambitious target to eliminate trachoma as a public health problem has led to impressive strides in reducing the disease burden worldwide, with the implementation of the World Health Organization (WHO)-endorsed surgery, antibiotics, facial cleanliness and environmental improvement (SAFE) strategy. However, some areas have struggled to reach the elimination threshold after the prescribed number of antibiotic mass drug administration rounds, and some areas have had evidence of trachoma recrudescence after previously having reached the elimination threshold. This systematic review assessed climatic, demographic, environmental, infrastructural, and socioeconomic factors associated with trachoma to reveal which covariates are associated with ongoing or renewed trachoma transmission. We also explored how geospatial analysis, which could help identify areas with ongoing trachoma transmission or heightened risk of recrudescence, has been used in previous trachoma studies. Thirty-five studies met the inclusion criteria for the review. Results indicated that researchers and decision-makers should consider the inclusion and potential influence of precipitation, temperature, and altitude along with variables related to ruralness, accessibility, access to medical services and schools, and community-level water and sanitation coverage, as part of both research activities and programmatic priorities for trachoma elimination.

Evaluation of facial cleanliness and environmental improvement activities: Lessons learned from Malawi, Tanzania, and Uganda

The World Health Organization promotes the SAFE (Surgery, Antibiotics, Facial cleanliness, and Environmental improvements) strategy for trachoma control and prevention. The F&E components of the strategy focus on promotion of healthy hygiene and sanitation behaviors. In order to monitor F&E activities implemented across villages and schools in Malawi, Tanzania, and Uganda, an F&E Monitoring and Evaluation (FEME) framework was developed to track quarterly program outputs and to provide the basis for a pre and post evaluation of the activities. Results showed an increase in knowledge at the school and household levels, and in some cases, an increase in presence of hand/face washing stations. However, this did not always result in a change in trachoma prevention behaviors such as facial cleanliness or keeping compounds free of human feces. The results highlight that the F&E programs were effective in increasing awareness of trachoma prevention but not able to translate that knowledge into changes in behavior during the time between pre and post-surveys. This study also indicates the potential to improve the data collection and survey design and notes that the period of intervention was not long enough to measure significant changes.

Trachoma control programs promote facial cleanliness, use of latrines, and emphasizes the importance of access to water as means to reduce trachoma transmission. To address these areas, various country ministries and supporting non-governmental organizations (NGOs) support the implementation of tailored behavior change programs. The process and results of evaluating these types of programs in Malawi, Tanzania, and Uganda are described here. The goal of this manuscript is to provide trachoma program managers and supporting NGOs with insights, recommendations, and data collection tools that could be used to support their efforts to conduct monitoring and evaluation of their current or future trachoma prevention activities.

Status of active trachoma infection among school children who live in villages of open field defecation: a comparative cross-sectional study

BACKGROUND

Although many efforts are made by different stakeholders, magnitude of active trachoma remains high among children in Ethiopia. Open field defecation was found to be the main source of active trachoma. However, comparative information on the effect of open field defecation and non-open field defecation on active trachoma is scarce in Ethiopia.

METHODS

Comparative community based cross-sectional study was conducted from June 1-30, 2019 in Boricha and Dale districts to assess prevalence of active trachoma among primary school children. We have selected four primary schools purposively from two districts in Sidama. Study participants were selected by using simpe random sampling method. Data were collected through face to face interview, direct observation and ophthalmic examination. Logistic regression analysis was conducted to assess factors associated with active trachoma infection among primary school children. Adjusted Odds Ratios with 95% confidence interval and p-value less than 0.05 were computed to determine the level of significance.

RESULT

From the total of 746 study participants, only 701 study participants gave full response for interview questions making a response rate of 94%. The overall prevalence of active trachoma infection was 17.5% (95% CI, 14.1-20.8) among primary school students. Specifically, prevalence of active trachoma infection was 67.5% among children who lived in open field defecation villages, but it was 88.5% among school children who live in Non-ODF Kebeles. Factors like: Living in open field defecation Kebeles (AOR = 2.52, 95% CI, 1.5-4.1), having ocular discharge (AOR = 5.715, 95% CI, 3.4-9.4), having nasal discharge (AOR = 1.9, 95% CI, 1.06-3.39), and fly on the face (AOR = 6.47, 95% CI, 3.36-12.44) of children were positively associated with active trachoma infection. However, finger cleanness (AOR = 0.43, 95% CI, 0.21-0.9) was protective factor against active trachoma infection in this study.

CONCLUSION

Significant variation in prevalence of active trachoma infection among school children between open filed and non-open field defecation Kebeles was observed. Surprisingly, the prevalence in open field defecation was significantly lower than non-open field defecation. Hence, this indicates active trachoma infection highly depends on the hand hygiene than environmental sanitation. Educational campaign of hand hygiene should be enhanced in the community for school students.

Persistence and Significance of Chlamydia trachomatis in the Housefly, Musca domestica L

Trachoma is the leading cause of infectious blindness worldwide. Ocular infection by the obligate intracellular pathogen, Chlamydia trachomatis, causes the eyelashes to turn in and scratch the cornea, leading to blindness if left untreated. The disease is most prevalent in poor, rural communities that lack the infrastructure for basic hygiene, clean water, and proper sanitation. Infection is often spread through infected clothes, contaminated hands, and face seeking flies. The goal of this research was to understand the biological role of Musca domestica flies in the transmission of C. trachomatis. PCR, tissue culture, and immunofluorescence microscopy were used to determine the presence, viability, and the anatomical location of C. trachomatis within the digestive tract of M. domestica. Flies were fed with C. trachomatis and then harvested at various time intervals after feeding. The data confirmed the presence of C. trachomatis DNA and viable elementary bodies (EBs) in fly crops, up to 24 h postfeeding. C. trachomatis DNA was also isolated from the upper portions of the alimentary tract of flies up to 48 h postfeeding. In addition, DNA was isolated from the regurgitation material from fly crops up to 12 h postfeeding. The viability of isolated C. trachomatis EBs was repeatedly confirmed between 12 and 48 h and up to 7 days in ex vivo crops stored at room temperature. Our data suggest that eye-seeking flies such as M. domestica can ingest C. trachomatis during regular feeding. Because M. sorbens does not occur in continental United States, we did not use it in any of our studies. These data also confirm, for the first time, that ingested chlamydia remains viable inside the flies for 24-48 h postfeeding. We further show that these flies can regurgitate and transmit the trachoma agent at their next feeding. We believe that these findings reveal an opportunity for efficient intervention strategies through fly vector control, especially as we near new target date for global elimination of trachoma.

Towards an odour-baited trap to control Musca sorbens, the putative vector of trachoma

Musca sorbens is a synanthropic filth fly that aggressively attacks people to feed from mucous membranes of the eyes, nose or mouth, from open sores, or from sweat. It has long been suspected that this fly contributes to the transmission of eye infections, particularly trachoma, and recent work has added to the evidence base that M. sorbens is a trachoma vector in Ethiopia. There are few options to control M. sorbens, largely due to a lack of evidence. Space spraying with insecticides is effective, but an environmentally sound and long-term sustainable solution would be better, for example, mass trapping. We tested commercially available and homemade trap types in a pilot (laboratory) study and three field studies. A homemade design, built from a bucket and two empty water bottles, baited with a commercially available lure, The Buzz, was found to be most effective. This trap caught 3848 M. sorbens over 26 trap 'events' (3- or 4-day periods); mean/median per 24 h 43.6 (standard deviation 137.10)/2.25 (IQR 0.25-12.67). The Buzz lure is cheap and effective for 4 weeks, and trap components cheap and locally available. Further studies are needed to understand the impact of this trap on local fly populations and the local transmission of trachoma.

Prevalence and associations of active trachoma among rural preschool children in Wadla district, northern Ethiopia

BACKGROUND

Trachoma is a neglected eye disease and an important cause of preventable corneal blindness. In endemic areas, initial infection can occur in early childhood and following a recurrent episodes, it progresses to scarring and visual impairment. Trachoma disappeared from high income countries through enhancements of hygiene and sanitation but the disease is still a challenge in developing countries. In Ethiopia, data indicate that Amhara is the region with the highest prevalence of active trachoma. The aim of this study was to assess the prevalence and associations of active trachoma among rural preschool children in Wadla district, Amhara region, Ethiopia.

METHODS

In this study, 596 children were screened for signs of active trachoma by using cluster-sampling technique. Following pre-testing of the survey instrument in a different district, questions about socio-demographic status were delivered for heads of households. Integrated eye care workers, previously trained to undertake trachoma screening for one month, performed eye examination. The logistic regression model was used to look for associations of active trachoma.

RESULTS

The prevalence of active trachoma among rural preschool children in Wadla district was 22%. Low economic status (adjusted odds ratio [AOR]3.8 (95%CI 1.3-11.4), being 37-48 months old (4.2;1.5-12.0), living in a house with thatched roof (4.4;1.4-13.6), presence of flies in a home (4.6;2.1-9.9), once-weekly face-washing frequency (8.6;2.5-29.3), having a face that had not been washed for longer than a week (10.6;2.9-37.7), and not using soap (4.5;1.8-11.3) had association to active trachoma.

CONCLUSION

The prevalence of active trachoma among rural pre-school children in Wadla district was high. This indicates that Trachoma is still a public health problem in the district. This high prevalence calls for further interventions to prevent future trachomatis blindness.

Eliminating Trachoma by 2020: Assessing Progress in Nigeria

Trachoma is a neglected tropical disease that causes an eye infection which can lead to blindness if left untreated. In 1998, the World Health Organisation (WHO) launched a new goal to eradicate trachoma by 2020. Over the years, in partnership with the WHO, an effective strategy plan was devised to help tackle and control the disease. This involved surgery for trichiasis, antibiotic treatment, facial cleanliness, and environmental improvement (SAFE). Consequently, the number of people affected by trachoma has significantly decreased in recent times. Despite this, trachoma remains a major public health concern in 44 countries worldwide, including Nigeria. Although improvements have been seen throughout Nigeria, the disjointed application of the SAFE strategy has delayed progress compared to other countries. Providing quality treatment to those with trachoma, in addition to improving preventative measures are challenges faced throughout the country. However, a multi-pronged approach emulating the methods of other countries is recommended to achieve trachoma elimination. This review aims to evaluate the progress and challenges faced in Nigeria with regards to eliminating trachoma.

Prevalence of trachoma and associated factors in the rural area of the department of Vaupés, Colombia

OBJECTIVES

The objectives of the study were to estimate the prevalence of different clinical signs of trachoma and identify possible factors associated with TF.

METHODOLOGY

Following the approval of the study protocol by the ethics committee, a cross-sectional study was conducted in Vaupés, a department of the Colombian Amazon, between the years 2012 and 2013 in two districts. Based on the records obtained from a standardized format for the clinical evaluation of the participants and the factors associated with follicular trachoma, an excel database was built and debugged, which was analyzed using IBM SPSS, Statistics Version 23 and Stata STATA (Version 14, 2015, StataCorp LLC, Texas, USA).

RESULTS

The records of 13,091 individuals was collected from 216 rural indigenous communities, of which 12,080 were examined (92.3%); 7,274 in the Western and 4,806 in the Eastern districts. A prevalence of trachomatous inflammation-follicular (TF) of 21.7% (n = 599; 95% CI 20.2-23.3) in the Western and 24.9% (n = 483; 95% CI 23.1-26.9) in the Eastern district was found in children aged 1 to 9 years. Regarding trachomatous trichiasis (TT), 77 cases were found, of which 14 belonged to the Western district (prevalence 0.3%, CI 95% 0.2-0.5) and 63 to the Eastern district (1.8%, CI 95% 1.4-2.4). Children aged between 1 to 9 years were significantly more likely to have TF when there was the presence of secretions on the face (OR: 3.2; 95% CI: 2.6-3.9).

CONCLUSIONS

Trachoma is a public health problem in Vaupés that requires the implementation of the SAFE strategy (S = Surgery, A = Antibiotics, F = Face Washing, E = Environment) in the Eastern and Western districts, for at least 3 consecutive years, in accordance with WHO recommendations.

Responses of the putative trachoma vector, Musca sorbens, to volatile semiochemicals from human faeces

The putative vector of trachoma, Musca sorbens, prefers to lay its eggs on human faeces on the ground. This study sought to determine whether M. sorbens females were attracted to volatile odours from human faeces in preference to odours from the faeces of other animals, and to determine whether specific volatile semiochemicals mediate selection of the faeces. Traps baited with the faeces of humans and local domestic animals were used to catch flies at two trachoma-endemic locations in The Gambia and one in Ethiopia. At all locations, traps baited with faeces caught more female M. sorbens than control traps baited with soil, and human faeces was the most successful bait compared with soil (mean rate ratios 44.40, 61.40, 10.50 [P<0.001]; 8.17 for child faeces [P = 0.004]). Odours from human faeces were sampled by air entrainment, then extracts of the volatiles were tested by coupled gas chromatography-electroantennography with laboratory-reared female M. sorbens. Twelve compounds were electrophysiologically active and tentatively identified by coupled mass spectrometry-gas chromatography, these included cresol, indole, 2-methylpropanoic acid, butanoic acid, pentanoic acid and hexanoic acid. It is possible that some of these volatiles govern the strong attraction of M. sorbens flies to human faeces. If so, a synthetic blend of these chemicals, at the correct ratios, may prove to be a highly attractive lure. This could be used in odour-baited traps for monitoring or control of this species in trachoma-endemic regions.

Unimproved water sources and open defecation are associated with active trachoma in children in internally displaced persons camps in the Darfur States of Sudan

Purpose

To estimate the proportion of children with trachomatous inflammation—follicular (TF) and adults with trachomatous trichiasis (TT) in internally displaced persons (IDP) camps in the Darfur States of Sudan and to evaluate associated risk factors.

Methods

IDP camps were identified from government census data. We conducted a subanalysis of data collected in these camps during 2014–2015 as part of surveys covering 37 districts of the Darfur States within the Global Trachoma Mapping Project. A random-effects hierarchical model was used to evaluate factors associated with TF in children or TT in adults.

Results

Thirty-six IDP camps were represented in the survey data, in which 1926 children aged 1–9 y were examined, of whom 38 (8%) had TF. Poor sanitation, younger age and living in a household that purchased water from a vendor were associated with TF in children aged 1–9 y. Of 2139 individuals examined aged ≥15 y, 16 (0.7%) had TT. TT was strongly independently associated with being older and living alone.

Conclusion

Trachoma is found at low levels in these camps, but still at levels where intervention is needed. Disease elimination in conflict-related settings presents a unique challenge for the trachoma community, and may require an innovative approach. Understanding how best to undertake trachoma elimination interventions in these areas should be prioritized.

Selecting behaviour change priorities for trachoma 'F' and 'E' interventions: A formative research study in Oromia, Ethiopia

Background

Trachoma is the leading infectious cause of blindness. However, little is known about the behavioural and environmental determinants of transmission of the causative organism, Chlamydia trachomatis. We conducted formative research in a trachoma hyper-endemic area of Ethiopia to explore the behaviours which are likely to contribute to trachoma transmission and map their determinants.

Methodology/Principal findings

Data on water use, hygiene, defecation, and sleeping arrangements were collected from five communities during the dry and rainy seasons in 2016. Data collection involved direct observation in households (n = 20), interviews with caregivers (n = 20) and focus group discussions (n = 11). Although several behaviours that likely contribute to trachoma transmission were identified, no single behaviour stood out as the dominant contributor. Hygiene practices reflected high levels of poverty and water scarcity. Face washing and soap use varied within and between households, and were associated with other factors such as school attendance. Children’s faces were rarely wiped to remove nasal or ocular discharge, which was not perceived to be socially undesirable. Bathing and laundry were performed infrequently due to the amount of time and water required. Open defecation was a normative practice, particularly for young children. Latrines, when present, were poorly constructed, maintained and used. Young children and parents slept closely together and shared bedding that was infrequently washed.

Conclusions/Significance

Existing norms and enabling factors in this context favour the development of interventions to improve facial cleanliness as more feasible than those that reduce unsafe faeces disposal. Interventions to increase the frequency of bathing and laundry may also be infeasible unless water availability within the home is improved.

Trachoma is the leading infectious cause of blindness globally. It is caused by Chlamydia trachomatis, which is believed to spread eye to eye through direct transmission on skin (e.g. after touching ocular and nasal secretions), indirect transmission on fomites (e.g. towels and bedsheets) and via eye-seeking flies (which breed in faeces). Interventions aiming to interrupt transmission of C. trachomatis can therefore be designed to promote behaviours ranging from face washing and handwashing to improving sanitation, waste disposal, laundry practices and sleeping practices. Changing behaviour is challenging and interventions are often ineffective if they fail to change important determinants of behaviour. We conducted formative research to understand trachoma-related behaviour and the determinants of these behaviours in order to inform future intervention design. We found that the hygiene practices we observed reflected high levels of poverty and water scarcity. In this context we found that it would be challenging to shift sub-optimal hygiene practices related to latrine use, bathing and laundry without a substantial and large-scale investment in water and sanitation infrastructure. Given this, it may be more feasible for the Government and supporting organisations to design trachoma prevention interventions which target facial cleanliness and hand hygiene.

Impact Survey Results after SAFE Strategy Implementation in 15 Local Government Areas of Kebbi, Sokoto and Zamfara States, Nigeria

Purpose: To determine prevalence of trachoma after interventions in 15 local government areas (LGAs) of Kebbi, Sokoto and Zamfara States, Nigeria.

Methods: A population-based impact survey was conducted in each LGA using Global Trachoma Mapping Project (GTMP) protocols. In each LGA, 25 villages were selected, except in Arewa LGA, where we selected 25 villages from each of four subunits to obtain finer-resolution prevalence information. Villages were selected with probability proportional to size. In each village, 25 households were enrolled and all consenting residents aged ≥1 year were examined by GTMP-certified graders for trachomatous inflammation—follicular (TF) and trachomatous trichiasis (TT). Information on sources of household water and types of sanitation facilities used was collected through questioning and direct observation.

Results: The number of households enrolled per LGA ranged from 623 (Kware and Tangaza) to 2488 (Arewa). There have been marked reductions in the prevalence of TF and TT since baseline surveys were conducted in all 15 LGAs. Eight of the 15 LGAs have attained TF prevalences <5% in children, while 10 LGAs have attained TT prevalences <0.2% in persons aged ≥15 years. Between 49% and 96% of households had access to water for hygiene purposes within 1 km of the household, while only 10–59% had access to improved sanitation facilities.

Conclusion: Progress towards elimination of trachoma has been made in these 15 LGAs. Collaboration with water and sanitation agencies and community-based trichiasis surgery are still needed in order to eliminate trachoma by the year 2020.

Prevalence of Trachoma and Access to Water and Sanitation in Benue State, Nigeria: Results of 23 Population-Based Prevalence Surveys

Purpose: We sought to determine the prevalence of trachoma in each local government area (LGA) of Benue State, Nigeria.

Methods: Two-stage cluster sampling was used to conduct a series of 23 population-based prevalence surveys. LGAs were the evaluation units surveyed. In each LGA, 25 households were selected in each of 25 clusters, and individuals aged 1 year and above resident in those households were invited to be examined for trachoma. Data on access to water and sanitation were also collected at household level.

Results: A total of 91,888 people were examined from among 93,636 registered residents across the 23 LGAs. The LGA-level prevalence of trachomatous inflammation—follicular (TF) in 1–9 year olds ranged from 0.3% to 5.3%. Two LGAs had TF prevalences of 5.0–9.9%. The LGA-level prevalence of trichiasis in ≥15-year-olds ranged from 0.0% to 0.35%. Access to improved drinking water sources ranged from 0% in Gwer West to 99% in Tarka, while access to improved sanitation ranged from 1% in Gwer West to 92% in Oturkpo.

Conclusion: There is a need for public health-level interventions against trachoma in three LGAs of Benue State.

Health and social impacts of open defecation on women: a systematic review

BACKGROUND

The significance of sanitation to safeguard human health is irrefutable and has important public health dimensions. Access to sanitation has been essential for human dignity, health and well-being. Despite 15 years of conjunctive efforts under the global action plans like Millennium Development Goals (MDGs), 2.3 billion people have no access to improved sanitation facilities (flush latrine or pit latrine) and nearly 892 million of the total world's population is still practicing open defecation.

METHODS

The study provides a systematic review of the published literature related to implications of open defecation that goes beyond the scope of addressing health outcomes by also investigating social outcomes associated with open defecation. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) was used to frame the review, empirical studies focusing upon open defecation in women aged 13-50 in low and middle income countries were included in the review. Research papers included in the review were assessed for quality using appropriate critical appraisal tools. In total 9 articles were included in the review; 5 of these related to health effects and 4 related to social effects of open defecation.

RESULTS

The review identified 4 overarching themes; Health Impacts of open defecation, Increased risk of sexual exploitation, Threat to women's privacy and dignity and Psychosocial stressors linked to open defecation, which clearly present a serious situation of poor sanitation in rural communities of Lower-Middle Income Countries (LMICs). The findings of the review identified that open defecation promotes poor health in women with long-term negative effects on their psychosocial well-being, however it is a poorly researched topic.

CONCLUSION

The health and social needs of women and girls remain largely unmet and often side-lined in circumstances where toilets in homes are not available. Further research is critically required to comprehend the generalizability of effects of open defecation on girls and women.

PROSPERO REGISTRATION

CRD42019119946 . Registered 9 January 2019 .

Pathogens transmitted in animal feces in low- and middle-income countries

Animals found in close proximity to humans in low-and middle-income countries (LMICs) harbor many pathogens capable of infecting humans, transmissible via their feces. Contact with animal feces poses a currently unquantified-though likely substantial-risk to human health. In LMIC settings, human exposure to animal feces may explain some of the limited success of recent water, sanitation, and hygiene interventions that have focused on limiting exposure to human excreta, with less attention to containing animal feces. We conducted a review to identify pathogens that may substantially contribute to the global burden of disease in humans through their spread in animal feces in the domestic environment in LMICs. Of the 65 potentially pathogenic organisms considered, 15 were deemed relevant, based on burden of disease and potential for zoonotic transmission. Of these, five were considered of highest concern based on a substantial burden of disease for which transmission in animal feces is potentially important: Campylobacter, non-typhoidal Salmonella (NTS), Lassa virus, Cryptosporidium, and Toxoplasma gondii. Most of these have a wide range of animal hosts, except Lassa virus, which is spread through the feces of rats indigenous to sub-Saharan Africa. Combined, these five pathogens cause close to one million deaths annually. More than half of these deaths are attributed to invasive NTS. We do not estimate an overall burden of disease from improperly managed animal feces in LMICs, because it is unknown what proportion of illnesses caused by these pathogens can be attributed to contact with animal feces. Typical water quantity, water quality, and handwashing interventions promoted in public health and development address transmission routes for both human and animal feces; however, sanitation interventions typically focus on containing human waste, often neglecting the residual burden of disease from pathogens transmitted via animal feces. This review compiles evidence on which pathogens may contribute to the burden of disease through transmission in animal feces; these data will help prioritize intervention types and regions that could most benefit from interventions aimed at reducing human contact with animal feces.

Climate Change and the Neglected Tropical Diseases

Climate change is expected to impact across every domain of society, including health. The majority of the world's population is susceptible to pathological, infectious disease whose life cycles are sensitive to environmental factors across different physical phases including air, water and soil. Nearly all so-called neglected tropical diseases (NTDs) fall into this category, meaning that future geographic patterns of transmission of dozens of infections are likely to be affected by climate change over the short (seasonal), medium (annual) and long (decadal) term. This review offers an introduction into the terms and processes deployed in modelling climate change and reviews the state of the art in terms of research into how climate change may affect future transmission of NTDs. The 34 infections included in this chapter are drawn from the WHO NTD list and the WHO blueprint list of priority diseases. For the majority of infections, some evidence is available of which environmental factors contribute to the population biology of parasites, vectors and zoonotic hosts. There is a general paucity of published research on the potential effects of decadal climate change, with some exceptions, mainly in vector-borne diseases.

The burden of and risk factors for active trachoma in the North and South Wollo Zones of Amhara Region, Ethiopia: a cross-sectional study

BACKGROUND

Trachoma is a disease of the eye, caused by the bacteria Chlamydia trachomatis, which can lead to blindness if left untreated. Ethiopia is one of the most trachoma-affected countries in the world. The objective of this study was to determine the prevalence of and associated risk factors for active trachoma among children in selected woredas of North and South Wollo Zones in Amhara Region, Ethiopia.

METHODS

This study was a community-based, cross-sectional study, which was conducted from October to December 2014 among children aged 1-8. A four-stage random cluster sampling technique was employed to select the study areas and participants. From each selected household, one child was clinically assessed for active trachoma. A structured questionnaire was used to collect sociodemographic, behavioral, and clinical data. Multivariate logistic regression analysis was used to analyze the association between predictor variables and active trachoma.

RESULTS

The overall prevalence of active trachoma among 1358 children was found to be 21.6% (95% CI: 19.4-23.8%). When analyzed by the presence or absence of individual WHO simplified system signs of active trachoma, trachomatous inflammation-follicular cases constituted18% (95% CI: 15.9-20.2%), while 4.7% (95% CI: 3.6-5.8%) were trachomatous inflammation-intense cases. Ocular discharge (aOR = 5.2; 95% CI: 3.3-8.2), nasal discharge (aOR = 1.8; 95% CI: 1.2-2.7), time taken to fetch water (aOR = 0.02; 95% CI: 0.01-0.05), frequency of hand and face washing (aOR = 4.4; 95% CI: 1.1-17.8), and access to a latrine (aOR = 0.006; 95% CI: 0.001-0.030) were found to be independently associated with the presence of active trachoma.

CONCLUSIONS

There is a high burden of active trachoma among children in the study areas. Lack of personal hygiene and limited access to a safe water supply and latrines were associated with increased prevalence of active trachoma. In order to reduce the burden of active trachoma, facial cleanliness and environmental improvement components of the SAFE strategy should be upgraded in the study areas.

Active trachoma and community use of sanitation, Ethiopia

Objective

To investigate, in Amhara, Ethiopia, the association between prevalence of active trachoma among children aged 1–9 years and community sanitation usage.

Methods

Between 2011 and 2014, prevalence of trachoma and household pit latrine usage were measured in five population-based cross-sectional surveys. Data on observed indicators of latrine use were aggregated into a measure of community sanitation usage calculated as the proportion of households with a latrine in use. All household members were examined for clinical signs, i.e. trachomatous inflammation, follicular and/or intense, indicative of active trachoma. Multilevel logistic regression was used to estimate prevalence odds ratios (OR) and 95% confidence intervals (CI), adjusting for community, household and individual factors, and to evaluate modification by household latrine use and water access.

Findings

In surveyed areas, prevalence of active trachoma among children was estimated to be 29% (95% CI: 28–30) and mean community sanitation usage was 47% (95% CI: 45–48). Despite significant modification (p < 0.0001), no pattern in stratified ORs was detected. Summarizing across strata, community sanitation usage values of 60 to < 80% and ≥ 80% were associated with lower prevalence odds of active trachoma, compared with community sanitation usage of < 20% (OR: 0.76; 95% CI: 0.57–1.03 and OR: 0.67; 95% CI: 0.48–0.95, respectively).

Conclusion

In Amhara, Ethiopia, a negative correlation was observed between community sanitation usage and prevalence of active trachoma among children, highlighting the need for continued efforts to encourage higher levels of sanitation usage and to support sustained use throughout the community, not simply at the household level.

Prevalence of Trachoma in Car-Nicobar Island, India after Three Annual Rounds of Mass Drug Administration with Azithromycin

Background

A high proportion of active trachoma infection in children of Car-Nicobar Island was reported through the Trachoma Rapid Assessment survey conducted in year 2010 by the same researchers. Annual mass drug treatment with azithromycin was administered from years 2010–12 to all individuals residing in this island for reducing the burden of active trachoma infection. A cross-sectional prevalence survey was conducted in the year 2013 to assess the post-treatment burden of trachoma in this population.

Methods

In the 15 randomly selected compact segments from each village of the island, children aged 1–9 years were examined for evidence of active trachoma infection and participants aged ten years and above were examined for trachomatous trichiasis and corneal opacity.

Results

A total of 809 children (1–9 years) and 2735 adults were examined. Coverage with azithromycin for all the three rounds was more than 80%. The prevalence of active trachoma infection in children aged 1–9 years old was 6.8% (95% CI 5.1, 8.5) and Trachomatous Trichiasis (TT) was 3.9% (95% CI 3.2, 4.6). The risk factors associated with active trachoma infection were older age and unclean faces. The risk factors associated with TT were older age and lower literacy level.

Conclusion

Trachoma has not been eliminated from Car-Nicobar Island in accordance to ‘Global Elimination of Trachoma, 2020’ guidelines. Sustained efforts and continuous surveillance admixed with adequate programmatic response is imperative for elimination of trachoma in the island.

Molecular detection and antimicrobial resistance of Klebsiella pneumoniae from house flies (Musca domestica) in kitchens, farms, hospitals and slaughterhouses

Identifying disease vectors and pathogens is one of the key steps in controlling vector-borne diseases. This study investigated the possible role of house flies (Musca domestica) as vectors in the transmission of Klebsiella pneumoniae in Chaharmahal VA Bakhtiari and Isfahan provinces of Iran. House flies were captured from household kitchens, cattle farms, chicken farms, animal hospitals, human hospitals and slaughterhouses. Isolation of K. pneumoniae from external surfaces and guts of the flies was performed using MacConkey agar (MA) and thioglycollate broth (TGB). Identification of the isolates was performed with phenotypic techniques and polymerase chain reaction (PCR). A total of 600 house flies were sampled during the study period from different locations in four different seasons. Overall, 11.3% of the captured house flies were positive for K. pneumoniae. In Chaharmahal VA Bakhtiari province, the prevalence was 12.7%, while in Isfahan province, 10.0% of the sampled house flies were infected with K. pneumoniae. Season-wise, the highest prevalence of infections among the house flies was in summer. The organisms were highly resistant to ampicillin, amoxicillin, cefotaxime and piperacillin. A lowest level of resistance was observed for imipenem/cilastatin. The findings of this study demonstrated that house flies are potential vectors of antibiotic-resistant K. pneumoniae in Isfahan and Chaharmahal provinces, Iran. Control efforts for infections caused by this particular bacterium should take M. domestica into account.

The Global Trachoma Mapping Project: Methodology of a 34-Country Population-Based Study

Purpose: To complete the baseline trachoma map worldwide by conducting population-based surveys in an estimated 1238 suspected endemic districts of 34 countries.

Methods: A series of national and sub-national projects owned, managed and staffed by ministries of health, conduct house-to-house cluster random sample surveys in evaluation units, which generally correspond to “health district” size: populations of 100,000–250,000 people. In each evaluation unit, we invite all residents aged 1 year and older from h households in each of c clusters to be examined for clinical signs of trachoma, where h is the number of households that can be seen by 1 team in 1 day, and the product h × c is calculated to facilitate recruitment of 1019 children aged 1–9 years. In addition to individual-level demographic and clinical data, household-level water, sanitation and hygiene data are entered into the purpose-built LINKS application on Android smartphones, transmitted to the Cloud, and cleaned, analyzed and ministry-of-health-approved via a secure web-based portal. The main outcome measures are the evaluation unit-level prevalence of follicular trachoma in children aged 1–9 years, prevalence of trachomatous trichiasis in adults aged 15 + years, percentage of households using safe methods for disposal of human feces, and percentage of households with proximate access to water for personal hygiene purposes.

Results: In the first year of fieldwork, 347 field teams commenced work in 21 projects in 7 countries.

Conclusion: With an approach that is innovative in design and scale, we aim to complete baseline mapping of trachoma throughout the world in 2015.

The impact of climate on the abundance of Musca sorbens, the vector of trachoma

BACKGROUND

To assess the extent to which climate may affect the abundance of Musca sorbens, a putative vector of trachoma.

DATA SOURCES

Studies were identified by systematically searching online databases including CAB abstracts, Embase, Global Health, Medline, Web of Science and BIOS Online, references from key articles, and the websites of relevant international agencies.

METHODS

A systematic literature review was conducted of field and laboratory studies that reported the impact of climate factors (e.g., temperature, humidity) on the synanthropic fly Musca sorbens. Data were systematically extracted and studies assessed for quality by two readers. Study results were reported narratively.

RESULTS

A total of 16 studies met the inclusion criteria but only three evaluated associations between climatic/abiotic factors and M. sorbens. Limited evidence indicates that M. sorbens abundance has an optimal temperature and humidity range. Thirteen studies reported seasonal patterns but no consistent pattern was found between season and the abundance of M. sorbens.

CONCLUSIONS

The evidence base regarding the effect of climatic factors on M. sorbens is limited, so it is difficult to construct a biological model driven by climate for this species. A multivariate statistical approach based on the climate of sites where M. sorbens is found may better capture its complex relationship with climatic factors as well as aid in mapping the global range of M. sorbens.

Multilevel Analysis of Trachomatous Trichiasis and Corneal Opacity in Nigeria: The Role of Environmental and Climatic Risk Factors on the Distribution of Disease

The distribution of trachoma in Nigeria is spatially heterogeneous, with large-scale trends observed across the country and more local variation within areas. Relative contributions of individual and cluster-level risk factors to the geographic distribution of disease remain largely unknown. The primary aim of this analysis is to assess the relationship between climatic factors and trachomatous trichiasis (TT) and/or corneal opacity (CO) due to trachoma in Nigeria, while accounting for the effects of individual risk factors and spatial correlation. In addition, we explore the relative importance of variation in the risk of trichiasis and/or corneal opacity (TT/CO) at different levels. Data from the 2007 National Blindness and Visual Impairment Survey were used for this analysis, which included a nationally representative sample of adults aged 40 years and above. Complete data were available from 304 clusters selected using a multi-stage stratified cluster-random sampling strategy. All participants (13,543 individuals) were interviewed and examined by an ophthalmologist for the presence or absence of TT and CO. In addition to field-collected data, remotely sensed climatic data were extracted for each cluster and used to fit Bayesian hierarchical logistic models to disease outcome. The risk of TT/CO was associated with factors at both the individual and cluster levels, with approximately 14% of the total variation attributed to the cluster level. Beyond established individual risk factors (age, gender and occupation), there was strong evidence that environmental/climatic factors at the cluster-level (lower precipitation, higher land surface temperature, higher mean annual temperature and rural classification) were also associated with a greater risk of TT/CO. This study establishes the importance of large-scale risk factors in the geographical distribution of TT/CO in Nigeria, supporting anecdotal evidence that environmental conditions are associated with increased risk in this context and highlighting their potential use in improving estimates of disease burden at large scales.

Trichiasis (TT) and corneal opacity (CO) are chronic stages of trachoma, which remains an important cause of blindness. This study used multilevel spatial models to investigate risk factors for TT/CO in Nigeria, including data for more than 13,500 adults aged 40 years and above collected in the 2007 National Blindness and Visual Impairment survey. Individual-level risk factors were consistent with those identified in other studies, including a higher risk in females, older individuals and those with lower socioeconomic status. After controlling for these factors, there was evidence that a number of environmental and climatic factors are associated with the distribution of TT/CO in Nigeria. These findings establish for the Nigerian context the importance of risk factors at different scales for the later stages of trachoma, supporting anecdotal evidence that hotter, drier environmental conditions are associated with increased risk.

Prevalence of Active Trachoma and Its Associated Factors among Rural and Urban Children in Dera Woreda, Northwest Ethiopia: A Comparative Cross-Sectional Study

Background. Trachoma is the most common infectious cause of blindness worldwide. Once an epidemic in most parts of the world, it has largely now disappeared from developed countries. However, it continues to be endemic in many developing countries like Ethiopia. Even if several studies were conducted in different parts of Ethiopia, most of them did not show the independent predictors for rural and urban children separately. Therefore, this study aimed at assessing the prevalence and associated factors of active trachoma in urban and rural children. Methods. Community based comparative cross-sectional study was conducted in Dera woreda. Multistage sampling technique was used to select 671 children of one up to nine years of age. Data were collected by face to face interview and observation using a structured and pretested questionnaire. Binary Logistic Regression Model was fitted to consider adding independent predictors of outcome. Results. Out of 671 children, 20 (9.3%) of urban and 85 (18.6%) of rural children were positive for active trachoma. Having discharge on eye (AOR = 6.9, 95% CI: 1.79–27.89), presence of liquid waste around the main house (AOR = 5.6, 95% CI: 1.94–16.18), and living in households without latrine (AOR = 4.39, 95% CI: 1.39–13.89) were significantly associated with active trachoma of urban children. Rural children who had discharge on their eye (AOR = 5.86, 95% CI: 2.78–12.33), those who had unclean face (AOR = 4.68, 95% CI: 2.24–9.81), and those living in households with feces around their main houses (AOR = 1.94, 95% CI: 1.04–3.62) were significantly associated with active trachoma. Conclusion. The result showed that the prevalence of active trachoma in urban areas of the district was below WHO threshold of 10% to determine trachoma as public health problem. However, in rural areas of the district it is far from elimination of trachoma as a public health problem. Thus, in order to improve awareness of the community there is a need of health education programs regarding facial cleanliness, utilization of latrine, and proper solid waste and liquid waste disposal using multidisciplinary approach.

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.

Phenotypic variation of the housefly, Musca domestica: amounts and patterns of wing shape asymmetry in wild populations and laboratory colonies

Musca domestica L. (Diptera: Muscidae) is a vector of a range variety of pathogens infecting humans and animals. During a year, housefly experiences serial population bottlenecks resulted in reduction of genetic diversity. Population structure has also been subjected to different selection regimes created by insect control programs and pest management. Both environmental and genetic disturbances can affect developmental stability, which is often reflected in morphological traits as asymmetry. Since developmental stability is of great adaptive importance, the aim of this study was to examine fluctuating asymmetry (FA), as a measure of developmental instability, in both wild populations and laboratory colonies of M. domestica. The amount and pattern of wing shape FA was compared among samples within each of two groups (laboratory and wild) and between groups. Firstly, the amount of FA does not differ significantly among samples within the group and neither does it differ between groups. Regarding the mean shape of FA, contrary to non-significant difference within the wild population group and among some colonies, the significant difference between groups was found. These results suggest that the laboratory colonies and wild samples differ in buffering mechanisms to perturbations during development. Hence, inbreeding and stochastic processes, mechanisms dominating in the laboratory-bred samples contributed to significant changes in FA of wing shape. Secondly, general patterns of left-right displacements of landmarks across both studied sample groups are consistent. Observed consistent direction of FA implies high degrees of wing integration. Thus, our findings shed light on developmental buffering processes important for population persistence in the environmental change and genetic stress influence on M. domestica.

The impact of climatic risk factors on the prevalence, distribution, and severity of acute and chronic trachoma

BACKGROUND AND OBJECTIVES

Trachoma is the most common cause of infectious blindness. Hot, dry climates, dust and water scarcity are thought to be associated with the distribution of trachoma but the evidence is unclear. The aim of this study was to evaluate the epidemiological evidence regarding the extent to which climatic factors explain the current prevalence, distribution, and severity of acute and chronic trachoma. Understanding the present relationship between climate and trachoma could help inform current and future disease elimination.

METHODS

A systematic review of peer-reviewed literature was conducted to identify observational studies which quantified an association between climate factors and acute or chronic trachoma and which met the inclusion and exclusion criteria. Studies that assessed the association between climate types and trachoma prevalence were also reviewed.

RESULTS

Only eight of the 1751 papers retrieved met the inclusion criteria, all undertaken in Africa. Several papers reported an association between trachoma prevalence and altitude in highly endemic areas, providing some evidence of a role for temperature in the transmission of acute disease. A robust mapping study found strong evidence of an association between low rainfall and active trachoma. There is also consistent but weak evidence that the prevalence of trachoma is higher in savannah-type ecological zones. There were no studies on the effect of climate in low endemic areas, nor on the effect of dust on trachoma.

CONCLUSION

Current evidence on the potential role of climate on trachoma distribution is limited, despite a wealth of anecdotal evidence. Temperature and rainfall appear to play a role in the transmission of acute trachoma, possibly mediated through reduced activity of flies at lower temperatures. Further research is needed on climate and other environmental and behavioural factors, particularly in arid and savannah areas. Many studies did not adequately control for socioeconomic or environmental confounders.

Evaluation of household latrine coverage in Kewot woreda, Ethiopia, 3 years after implementing interventions to control blinding trachoma

The SAFE strategy for trachoma control includes Surgery, Antibiotic distribution, Facial cleanliness and Environmental improvements, including promotion of latrine construction. In this study, household latrine coverage was estimated in order to evaluate SAFE implementation in a district of Ethiopia where reported coverage in rural areas was 97%. Characteristics of latrine adopters and non-adopters were explored. Interviews were conducted in 442 households selected at random in a multistage cluster sample. Overall, estimated household latrine coverage was 56.2% (95% CI 37.5-74.8%) and in rural areas coverage was 67.7% (95% CI 59.6-75.7%). Previously owning a latrine was reported by 12.7% (95% CI 8.9-16.5%) of respondents, of which 32.0% (95% CI 15.9-48.2%) had built a replacement. Latrine adopters were more likely to be male (P < 0.0001), to report their primary occupation as agriculture (P < 0.0001), have more than five residents in their household (P = 0.004) and live in a rural area (P < 0.0001). Respondents who were advised by a health extension worker (P < 0.0001) or development agent (P < 0.0001) were more likely to have built a latrine. Household latrine coverage has increased from the 2007 zonal estimate (8.9%), but was lower than that reported. Latrine promotion should include emphasis on rebuilding latrines. More support may be needed by small households as well as those with a female head if universal latrine access is to be achieved in Kewot.

Evaluation of community intervention with pit latrines for trachoma control in Ghana, Mali, Niger and Nigeria

Trachoma is the leading cause of preventable blindness worldwide and is controlled with an integrated strategy of treatment and prevention which includes latrine provision and promotion. We aimed to evaluate the latrine uptake, construction, and usage in villages participating in latrine promotion programmes supported by The Carter Center in Ghana, Mali, Niger and Nigeria where 113 457 new latrines have been reported from 2002 to 2008. In each country a two stage cluster random sampling design was used to select villages and households for evaluation. Household heads were interviewed using a standardised structured questionnaire and latrines were inspected. The sample included 1154 households (Ghana: 326; Mali: 293; Niger: 300; and Nigeria: 235). Overall, 813 (70.5%, 95% confidence interval [CI] 65.7-74.8) had pit latrines, ranging from 30.3% of households in Niger to over 92.0% of households in Ghana and Mali. Of those with latrines 762 (93.7%) were found to be usable and 659 (86.5%) were in use. Overall 659/1154 (57.1%) of households in the targeted communities were using latrines at least 12 months after latrine promotion was initiated. Latrine promotion had been successful increasing access to sanitation in different country contexts and demonstrates the target population are willing to construct, use and maintain household latrines.

Efficacy of latrine promotion on emergence of infection with ocular Chlamydia trachomatis after mass antibiotic treatment: a cluster-randomized trial

The World Health Organization (WHO) recommends environmental improvements such as latrine construction in the integrated trachoma control strategy, SAFE. We report a cluster-randomized trial assessing the effect of intensive latrine promotion on emergence of infection with ocular Chlamydia trachomatis after mass treatment with antibiotics.Twenty-four communities in Goncha Seso Enesie woreda, Amhara Regional State, Ethiopia, were enumerated, and a random selection of 60 children aged 0- 9 years in each was monitored for clinical signs of trachoma and ocular chlamydial infection at baseline, 12 and 24 months. All community members were offered treatment with a single dose of oral azithromycin or topical tetracycline. After treatment, 12 subkebeles were randomized to receive intensive latrine promotion. Mean cluster ocular infection in the latrine and the non-latrine arms were reduced from 45.5% (95% CI 34.1-56.8%) and 43.0% (95% CI 31.1-54.8%) respectively at baseline to 14.6% (95% CI 7.4-21.8%) and 14.8% (95% CI 8.9-20.8%) respectively at 24 months (P=0.93). Clinical signs fell from 72.0% (95% CI 58.2-85.5%) and 61.3% (95% CI 44.0-78.5%) at baseline to 45.8% (36.0-55.6%) and 48.5% (34.0-62.9%) respectively at 24 months (P=0.69). At 24 months, estimated household latrine coverage and use were 80.8% and 61.7% respectively where there had been intensive latrine promotion and 30.0% and 25.0% respectively in the single treatment only arm. We were unable to detect a difference in the prevalence of ocular chlamydial infection in children due to latrine construction.

Impact of Indian Total Sanitation Campaign on latrine coverage and use: a cross-sectional study in Orissa three years following programme implementation

BACKGROUND

Faced with a massive shortfall in meeting sanitation targets, some governments have implemented campaigns that use subsidies focused on latrine construction to overcome income constraints and rapidly expand coverage. In settings like rural India where open defecation is common, this may result in sub-optimal compliance (use), thereby continuing to leave the population exposed to human excreta.

METHODS

We conducted a cross-sectional study to investigate latrine coverage and use among 20 villages (447 households, 1933 individuals) in Orissa, India where the Government of India's Total Sanitation Campaign had been implemented at least three years previously. We defined coverage as the proportion of households that had a latrine; for use we identified the proportion of households with at least one reported user and among those, the extent of reported use by each member of the household.

RESULTS

Mean latrine coverage among the villages was 72% (compared to <10% in comparable villages in the same district where the Total Sanitation Campaign had not yet been implemented), though three of the villages had less than 50% coverage. Among these households with latrines, more than a third (39%) were not being used by any member of the household. Well over a third (37%) of the members of households with latrines reported never defecating in their latrines. Less than half (47%) of the members of such households reported using their latrines at all times for defecation. Combined with the 28% of households that did not have latrines, it appears that most defecation events in these communities are still practiced in the open.

CONCLUSION

A large-scale campaign to implement sanitation has achieved substantial gains in latrine coverage in this population. Nevertheless, gaps in coverage and widespread continuation of open defecation will result in continued exposure to human excreta, reducing the potential for health gains.

Rapid assessment of trachoma in underserved population of Car-Nicobar Island, India

PURPOSE

To determine the burden of trachoma and its related risk factors amongst the native population of Car-Nicobar Island in India.

METHODS

Rapid assessment for trachoma was conducted in ten villages of Car-Nicobar Island according to standard WHO guidelines. An average of 50 children aged 1-9 years were assessed clinically for signs of active trachoma and facial cleanliness in each village. Additionally, all adults above 15 years of age in these households were examined for evidence of trachomatous trichiasis and corneal opacity. Environmental risk factors contributing to trachoma like limited access to potable water & functional latrine, presence of animal pen and garbage within the Nicobari hut were also noted in all villages.

RESULTS

Out of a total of fifteen villages in Car-Nicobar Island, ten villages were selected for trachoma survey depending on evidence of socio-developmental indicators like poverty and decreased access to water, sanitation and healthcare facilities. The total population of the selected clusters was 7277 in the ten villages. Overall, 251 of 516 children (48.6%;CI: 46.5-55.1) had evidence of follicular stage of trachoma and 11 children (2.1%;CI:1.0-3.4) had evidence of inflammatory stage of trachoma. Nearly 15%(CI:12.1-18.3) children were noted to have unclean faces in the ten villages. Trachomatous trichiasis was noted in 73 adults (1.0%;CI:0.8-1.2). The environmental sanitation was not found to be satisfactory in the surveyed villages mainly due to the co-habitance of Nicobari people with domestic animals like pigs, hens, goats, dogs, cats etc in most (96.4%) of the households.

CONCLUSION

Active trachoma and trachomatous trichiasis was observed in all the ten villages surveyed, wherein trachoma control measures are needed.

Intestinal parasite prevalence in an area of ethiopia after implementing the SAFE strategy, enhanced outreach services, and health extension program

Background

The SAFE strategy aims to reduce transmission of Chlamydia trachomatis through antibiotics, improved hygiene, and sanitation. We integrated assessment of intestinal parasites into large-scale trachoma impact surveys to determine whether documented environmental improvements promoted by a trachoma program had collateral impact on intestinal parasites.

Methodology

We surveyed 99 communities for both trachoma and intestinal parasites (soil-transmitted helminths, Schistosoma mansoni, and intestinal protozoa) in South Gondar, Ethiopia. One child aged 2–15 years per household was randomly selected to provide a stool sample of which about 1 g was fixed in sodium acetate-acetic acid-formalin, concentrated with ether, and examined under a microscope by experienced laboratory technicians.

Principal Findings

A total of 2,338 stool specimens were provided, processed, and linked to survey data from 2,657 randomly selected children (88% response). The zonal-level prevalence of Ascaris lumbricoides, hookworm, and Trichuris trichiura was 9.9% (95% confidence interval (CI) 7.2–12.7%), 9.7% (5.9–13.4%), and 2.6% (1.6–3.7%), respectively. The prevalence of S. mansoni was 2.9% (95% CI 0.2–5.5%) but infection was highly focal (range by community from 0–52.4%). The prevalence of any of these helminth infections was 24.2% (95% CI 17.6–30.9%) compared to 48.5% as found in a previous study in 1995 using the Kato-Katz technique. The pathogenic intestinal protozoa Giardia intestinalis and Entamoeba histolytica/E. dispar were found in 23.0% (95% CI 20.3–25.6%) and 11.1% (95% CI 8.9–13.2%) of the surveyed children, respectively. We found statistically significant increases in household latrine ownership, use of an improved water source, access to water, and face washing behavior over the past 7 years.

Conclusions

Improvements in hygiene and sanitation promoted both by the SAFE strategy for trachoma and health extension program combined with preventive chemotherapy during enhanced outreach services are plausible explanations for the changing patterns of intestinal parasite prevalence. The extent of intestinal protozoa infections suggests poor water quality or unsanitary water collection and storage practices and warrants targeted intervention.

Part of the SAFE strategy (surgery, antibiotics, facial cleanliness, and environmental improvement) to eliminate blinding trachoma involves improving access to, and use of, water and sanitation. We combined the assessment of parasitic worm and intestinal protozoa infections with surveys of trachoma in an area of Ethiopia where the SAFE strategy, together with enhanced outreach services and the health extension program, had been implemented for more than 5 years. We compared our findings with results from a survey conducted in the mid-1990s. We documented significant increases in household access and use of latrines and clean water: the F and E components of the SAFE strategy as promoted by the health extension program. We found considerably lower levels of parasitic worm infections than those reported previously. Moreover, we documented, for the first time in this zone, pathogenic intestinal protozoa infections, which indicate poor water quality and unhygienic water collection and storage practices in the communities surveyed. A plausible hypothesis for the decline in parasitic worm infections might be the combined impact of ongoing simultaneous health programs: SAFE strategy for trachoma control alongside the health extension program and regular deworming of preschool-aged children.

Human intestinal parasites in non-biting synanthropic flies in Ogun State, Nigeria

Filth-feeding and breeding, non-biting synanthropic flies have been incriminated in the dissemination of human enteropathogens in the environment. This study determined the species of non-biting synanthropic flies associated with four filthy sites in Ilishan, Ogun State, southwest Nigeria, and assessed their potentials for mechanical transmission of human intestinal parasites. 7190 flies identified as Musca domestica (33.94%), Chrysomya megacephala (26.01%), Musca sorbens (23.23%), Lucilia cuprina (8.76%), Calliphora vicina (4.59%), Sarcophaga sp. (2.78%) and Fannia scalaris (0.70%) were examined for human intestinal parasites by the formol-ether concentration and modified Ziehl-Neelsen techniques. Eggs of the following parasites: Ascaris lumbricoides (34.08%), Trichuris trichiura (25.87%), hookworms (20.45%), Taenia sp. (2.36%), Hymenolepis nana (1.11%), Enterobius vermicularis (0.56%), Strongyloides stercoralis (larvae; 3.89%) and cysts of Entamoeba histolytica/dispar (27.26%), Entamoeba coli (22.67%), Giardia lamblia (3.34%) and Cryptosporidium sp. (1.81%) were isolated from the body surfaces and or gut contents of 75.24% of 719 pooled fly batches. The helminths A. lumbricoides and T. trichiura and the protozoans, E. histolytica/dispar and E. coli were the dominant parasites detected, both on body surfaces and in the gut contents of flies. C. megacephala was the highest carrier of parasites (diversity and number). More parasites were isolated from the gut than from body surfaces (P < 0.05). Flies from soiled ground often carried more parasites than those from abattoir, garbage or open-air market. Synanthropic fly species identified in this study can be of potential epidemiological importance as mechanical transmitters of human intestinal parasites acquired naturally from filth and carried on their body surfaces and or in the gut, because of their vagility and feeding mechanisms.

Active trachoma and associated risk factors among children in Baso Liben District of East Gojjam, Ethiopia

Background

Trachoma is the leading cause of preventable blindness worldwide. It is common in areas where the people are socio-economically deprived. The aim of this study was to assess active trachoma and associated risk factors among children 1–9 years in East Gojjam.

Methods

Community-based cross-sectional study was conducted in Baso Liben District from February to April 2012. A two-stage random cluster-sampling technique was employed and all children 1–9 years old from each household were clinically assessed for trachoma based on simplified WHO 1983 classification. Data were collected by using semi-structured interview, pre-tested questionnaire and observation. The data were entered and analyzed using SPSS version 16 statistical package.

Results

From a total of 792 children screened for trachoma (of which 50.6% were girls), the overall prevalence of active trachoma was 24.1% consisting of only 17.2% [95% CI: 14.8, 20.1] TF and 6.8% TI. There were variations among children living in low land (29.3%) and in medium land (21.4%). In multivariate analysis, low monthly income (AOR = adjusted odds ratio) 2.98; 95% CI (confidence interval): 1.85-7.85), illiterate family (AOR = 5.18; 95% CI: 2.92-9.17); unclean face (AOR = 18.68; 95% CI: 1.98-175.55); access to water source (AOR = 2.01; 95% CI: 1.27-3.15); less than 20 liters of water use (AOR = 4.88; 95% CI: 1.51-15.78); not using soap for face washing (AOR = 5.84; 95% CI: 1.98-17.19); not using latrine frequently (AOR = 1.75; 95% CI: 0.01-0.42); density of flies (AOR = 3.77; 95% CI: 2.26-6.29); less knowledgeable family (AOR = 3.91; 95% CI: 2.40-6.38) and average monthly income (AOR = 2.98; 95% CI: 1.85-7.85) were found independently associated with trachoma.

Conclusion

Active trachoma is a major public problem among 1–9 years children and significantly associated with a number of risky factors. Improvement in awareness of facial hygiene, environmental conditions, mass antibiotic distribution and health education on trachoma transmission and prevention should be strengthened in the District.

Prevalence of and risk factors for trachoma in Kano state, Nigeria

Background

In northern Nigeria, trachoma is an important public health problem, but there are currently few population-based data on prevalence of disease and no formal trachoma control programs.

Methodology / Principal Findings

In Kano state, Nigeria, we conducted a population-based cross-sectional survey using multistage cluster random sampling, combining examination for clinical signs of trachoma and application of questionnaires assessing potential household-level risk factors. A total of 4491 people were examined in 40 clusters, of whom 1572 were aged 1–9 years, and 2407 (53.6%) were female. In 1–9 year-olds, the prevalence of trachomatous inflammation–follicular (TF) was 17.5% (95% CI: 15.7–19.5%). In a multivariate model, independent risk factors for active trachoma were the presence of flies on the face (OR 1.98, 95% CI 1.30–3.02); a dirty face (OR 2.45, 95% CI 1.85–3.25) and presence of animal dung within the compound of residence (OR 3.46, 95% CI 1.62–7.41). The prevalence of trachomatous trichiasis in persons aged ≥15years was 10.9% (95% CI: 9.7–12.2%). Trichiasis was significantly more common in adult females than in adult males.

Conclusion/Significance

There is an urgent need for a trachoma control program in Kano state, with emphasis given to provision of good quality trichiasis surgery. Particular effort will need to be made to identify women with trichiasis and engage them with appropriate services while also taking steps to secure azithromycin for mass treatment and ensuring personal and environmental hygiene.

Contributions to the Improvement of Living Conditions among Neglected Populations with Trachoma

Objective: Trachoma (Chlamydia-triggered blinding infection) provoked irreversible visual impairment in about 8 million people in 2011, and the prevalence among children with dirty faces is more than three fold that among children with clean faces. In 250 villages with a high prevalence of trachoma (Kolofata district, Far North Region, Cameroon), the lack of water for facial cleanliness was reported during trachoma awareness campaigns. The objective of this study was to determine if the lack of water was linked with the absence of means to dig wells.

Methods: Wells, waterholes, motorcycles, irrigation pumps, electricity, goats and oxen, cell phones and distance from waterholes were recorded in January 2011 in 50 randomized villages of Kolofata’s district.

Results: The number of villages with <25 goats and <5 oxen was 0 and the number of adults owning <1 goat was 0. The cost of a pail of water was 0.01 USD. Motorcycles, cell phones and televisions have been reported in more than 66% of villages. The cost for the construction of lined shaft wells ranged between 15–35 goats and 0.5–3 oxen; the cost for drinking water wells ranged between 50–200 goats and 3–30 oxen.

Discussion: No link between the means for digging wells at the village level and access to water was found. Social solidarity, which refers to a social debt owed by each person to his/her group, should be added to training guides to gauge its ability to release people from the dead end of having to wait for external assistance to gain access to water.

Integrated monitoring and evaluation and environmental risk factors for urogenital schistosomiasis and active trachoma in Burkina Faso before preventative chemotherapy using sentinel sites

Background

Over 1 billion of the world's poorest inhabitants are afflicted by neglected tropical diseases (NTDs). Integrated control programmes aimed at tackling these debilitating NTDs have been recently initiated, mainly using preventative chemotherapy. Monitoring and evaluation (M&E) of these integrated programs presents particular challenges over and above those required for single disease vertical programmes. We used baseline data from the National NTD Control Programme in Burkina Faso in order to assess the feasibility of an integrated survey design, as well as to elucidate the contribution of environmental variables to the risk of either Schistosoma haematobium, trachoma, or both among school-aged children.

Methods

S. haematobium infection was diagnosed by detecting eggs in urine. A trachoma case was defined by the presence of Trachomatous inflammation-Follicular (TF) and/or Trachomatous inflammation-Intense (TI) in either eye. Baseline data collected from 3,324 children aged 7-11 years in 21 sentinel sites across 11 regions of Burkina Faso were analyzed using simple and multivariable hierarchical binomial logistic regression models fitted by Markov Chain Monte Carlo estimation methods. Probabilities of the risk of belonging to each infection/disease category were estimated as a function of age, gender (individual level), and environmental variables (at sentinel site level, interpolated from national meteorological stations).

Results

Overall prevalence at the sentinel sites was 11.79% (95% CI: 10.70-12.89) for S. haematobium; 13.30% (12.14-14.45) for trachoma and 0.84% (0.53-1.15) for co-infections. The only significant predictor of S. haematobium infection was altitude. There were significant negative associations between the prevalence of active trachoma signs and minimum temperature, and air pressure. Conditional upon these predictors, these data are consistent with the two pathogens being independent.

Conclusions

Urogenital schistosomiasis and trachoma constitute public health problems in Burkina Faso. Sentinel site (at school level) surveys for these two NTDs can be implemented simultaneously. However, to support MDA treatment decisions in Burkina Faso, the protocol used in this study would only be applicable to hypoendemic trachoma areas. More research is needed to confirm if these findings can be generalized to West Africa and beyond.

Molecular Approach by PCR is the Best Method to Detect the Presence of Chlamydia Trachomatis and to Define the True Agent of Ocular Bacterial Inflammation

Chlamydia trachomatis (Ct) is an atypical agent for acute, subclinical and chronic conjunctivitis in developed countries, as stated by the International League against Trachoma. In order to evaluate the presence of Ct, from a total of 3,520 patients visiting the consulting room of the Eye Clinic of G. d'Annunzio University of Chieti, Italy from 2006–2008, we enrolled 171 patients affected by occasional mild, moderate or severe conjunctivitis in a three-arm prospective open study, using traditional analysis such as Immune Fluorescent Assay and Enzyme–Linked Fluorescent Assay (IFA and ELFA) and molecular analysis with Polymerase Chain Reaction (PCR) procedure for Ct DNA research (Ct DNA). At the same time, microbiological culture was carried out for common germs and mycetes. These patients were analyzed at different subsequent times. In the first arm (Group A) of 82 patients with IFA and ELFA only 10 people (12.2%) resulted positive to Ct infection with both methods. The presence of Ct was never alone, but always overlapped with contaminants, like corynebacteria, staphylococci, streptococci and colonbacteria, randomly distributed, while no growth of mycetes was observed. Of these positive patients, only one 47-year-old female, suffering from a moderate form of ocular chlamydial infection, showed serological conversion against this infection; furthermore, this female had also been suffering from reactive arthritis for sometime. In the second arm (Group B) of 89 patients, we carried out PCR for Ct detection: 82 (94.25%) were found positive to Ct – DNA research, with common germ growth randomly associated, without sex or age prevalence, as in group A; no mycetes were found. The third arm (Group C) included 37 negative patients from Group A with severe or moderate chronic conjunctivitis, randomly recruited between relapsing cases, with the addition of the single previously positive seroconversion case, for a total of 38 patients, who were re-evaluated by PCR Ct-DNA analysis. All these patients, negative to IFA and ELFA, were positive to Ct-DNA analysis. These data indicate a higher rate of Ct infection in patients with severe or moderate chronic conjunctivitis, resistant to usual therapies even after eradication of common germs, thus showing the advantage of introducing this molecular technique of analysis in mild to severe chronic or recurrent conjunctivitis.