Using reflective writing to enhance empathy among medical students.

Reflection is a skill which has the potential to enhance higher order thinking such as empathy and compassion. We aimed to study reflective writing as a means to nurture empathy among medical students. An interventional study was conducted among 73 final-year medical students using the Toronto Empathy Questionnaire. The questionnaire was administered anonymously before and after a clinical clerkship. Reflective writing generated strong emotional responses but did not improve Empathy Questionnaire scores. Reflective writing about patient care experiences may be useful in clinical clerkships to develop certain constructs of empathy such as perspective taking and compassion among medical students, but it may not raise empathy scores in the short term.

La réflexion est une compétence qui a le potentiel de développer la pensée de haut niveau telle que l'empathie et la compassion. Nous avons voulu étudier l'écriture réflexive comme moyen de développer l'empathie chez les étudiants en médecine. Une étude interventionnelle a été menée auprès de 73 étudiants en dernière année de médecine à l'aide du Toronto Empathy Questionnaire. Le questionnaire a été administré de manière anonyme avant et après un stage clinique. L'écriture réflexive a suscité de fortes réactions émotionnelles mais n'a pas amélioré les scores au questionnaire sur l'empathie. L'écriture réflexive sur les expériences de soins aux patients peut être utile dans les stages cliniques pour développer chez les étudiants en médecine certains concepts d'empathie tels que la compréhension du point de vue de l'autre et la compassion, sans pour autant augmenter les scores d'empathie à court terme.

Diversity and selection of SARS-CoV-2 minority variants in the early New York City outbreak

High error rates of viral RNA-dependent RNA polymerases lead to diverse intra-host viral populations during infection. Errors made during replication that are not strongly deleterious to the virus can lead to the generation of minority variants. However, accurate detection of minority variants in viral sequence data is complicated by errors introduced during sample preparation and data analysis. We used synthetic RNA controls and simulated data to test seven variant calling tools across a range of allele frequencies and simulated coverages. We show that choice of variant caller, and use of replicate sequencing have the most significant impact on single nucleotide variant (SNV) discovery and demonstrate how both allele frequency and coverage thresholds impact both false discovery and false negative rates. We use these parameters to find minority variants in sequencing data from SARS-CoV-2 clinical specimens and provide guidance for studies of intrahost viral diversity using either single replicate data or data from technical replicates. Our study provides a framework for rigorous assessment of technical factors that impact SNV identification in viral samples and establishes heuristics that will inform and improve future studies of intrahost variation, viral diversity, and viral evolution. IMPORTANCEWhen viruses replicate inside a host, the virus replication machinery makes mistakes. Over time, these mistakes create mutations that result in a diverse population of viruses inside the host. Mutations that are neither lethal to the virus, nor strongly beneficial, can lead to minority variants that are minor members of the virus population. However, preparing samples for sequencing can also introduce errors that resemble minority variants, resulting in inclusion of false positive data if not filtered correctly. In this study, we aimed to determine the best methods for identification and quantification of these minority variants by testing the performance of seven commonly used variant calling tools. We used simulated and synthetic data to test their performance against a true set of variants, and then used these studies to inform variant identification in data from clinical SARS-CoV-2 clinical specimens. Together, analyses of our data provide extensive guidance for future studies of viral diversity and evolution.

Effectiveness of Mass Drug Administration on Neglected Tropical Diseases in Schoolchildren in Zanzibar, Tanzania.

Soil-transmitted helminths and Schistosoma haematobium affect more than 3 billion people globally and mainly occur in sub-Saharan Africa. The present study assessed the overall infection status of a 1716-student cohort of school-children in Zanzibar and applied mass drug administration (MDA) to the cohort from 2007 to 2009. Schools in Pemba, Zanzibar, had a much higher prevalence of soil-transmitted helminth infections than those in Unguja, and the Chaani, Ghana, and Machui schools of Unguja exhibited high S. haematobium infection rates. The MDA program only partially controlled parasite infections, owing to high rates of re-infection. The infection rate of S. haematobium across all 10 schools, for example, was only reduced by 1.8%, and even this change not significant, even though the S. haematobiuminfection rates of the Chaani and Mzambarauni schools were significantly reduced from 64.4 and 23.4%, respectively, at the first screening, to 7.3 and 2.3% at the last screening. The overall infection rate of Ascaris lumbricoides was reduced from 36.0% at the first screening to 22.6% at the last screening. However, the infection rates for both Trichuris trichiuraand hookworm were generally unaffected by MDA. In the future, parasite control programs should involve strategically designed MDA schedules and holistic intervention (e.g., sanitation improvement, hygiene behavior changes, and control of intermediated hosts).

Evaluation of integrated interventions layered on mass drug administration for urogenital schistosomiasis elimination: a cluster-randomised trial.

BACKGROUND: Elimination of schistosomiasis as a public health problem and interruption of transmission in selected areas are targets set by WHO for 2025. Our aim was to assess biannual mass drug administration (MDA) applied alone or with complementary snail control or behaviour change interventions for the reduction of Schistosoma haematobium prevalence and infection intensity in children from Zanzibar and to compare the effect between the clusters. METHODS: In a 5-year repeated cross-sectional cluster-randomised trial, 90 shehias (small administrative regions; clusters) in Zanzibar eligible owing to available natural open freshwater bodies and public primary schools were randomly allocated (ratio 1:1:1) to receive one of three interventions: biannual MDA with praziquantel alone (arm 1) or in combination with snail control (arm 2), or behaviour change activities (arm 3). Neither participants nor field or laboratory personnel were blinded to the intervention arms. From 2012 to 2017, annually, a single urine sample was collected from approximately 100 children aged 9-12 years in the main public primary school of each shehia. The primary outcome was S haematobium infection prevalence and intensity in 9-12-year-old children after 5 years of follow-up. This study is completed and was registered with the ISRCTN, number 48837681. FINDINGS: The trial was done from Nov 1, 2011, through to Dec 31, 2017 and recruitment took place from Nov 2, 2011, until May 17, 2017. At baseline we enrolled 8278 participants, of whom 2899 (35%) were randomly allocated to arm 1, 2741 (33%) to arm 2, and 2638 (32%) to arm 3. 120 (4·2%) of 2853 in arm 1, 209 (7·8%) of 2688 in arm 2, and 167 (6·4%) of 2613 in arm 3 had S haematobium infections at baseline. Heavy infections (≥50 eggs per 10 mL of urine) were found in 126 (1·6%) of 8073 children at baseline. At the 5-year endline survey, 46 (1·4%) of 3184 in arm 1, 56 (1·7%) of 3217 (odds ratio [OR] 1·2 [95% CI 0·6-2·7] vs arm 1) in arm 2, and 58 (1·9%) of 3080 (1·3 [0·6-2·9]) in arm 3 had S haematobium infections. Heavy infections were detected in 33 (0·3%) of 9462 children. INTERPRETATION: Biannual MDA substantially reduced the S haematobium prevalence and infection intensity but was insufficient to interrupt transmission. Although snail control or behaviour change activities did not significantly boost the effect of MDA in our study, they might enhance interruption of transmission when tailored to focal endemicity and applied for a longer period. It is now necessary to focus on reducing prevalence in remaining hotspot areas and to introduce new methods of surveillance and public health response so that the important gains can be maintained and advanced. FUNDING: University of Georgia Research Foundation Inc and Bill & Melinda Gates Foundation.

A 5-Year intervention study on elimination of urogenital schistosomiasis in Zanzibar: Parasitological results of annual cross-sectional surveys.

BACKGROUND: The Zanzibar Elimination of Schistosomiasis Transmission (ZEST) project aimed to eliminate urogenital schistosomiasis as a public health problem from Pemba and to interrupt Schistosoma haematobium transmission from Unguja in 5 years. METHODOLOGY: A repeated cross-sectional cluster-randomized trial was implemented from 2011/12 till 2017. On each island, 45 shehias were randomly assigned to receive one of three interventions: biannual mass drug administration (MDA) with praziquantel alone, or in combination with snail control or behavior change measures. In cross-sectional surveys, a single urine sample was collected from ~9,000 students aged 9- to 12-years and from ~4,500 adults aged 20- to 55-years annually, and from ~9,000 1st year students at baseline and the final survey. Each sample was examined for S. haematobium eggs by a single urine filtration. Prevalence and infection intensity were determined. Odds of infection were compared between the intervention arms. PRINCIPAL FINDINGS: Prevalence was reduced from 6.1% (95% confidence interval (CI): 4.5%-7.6%) to 1.7% (95% CI: 1.2%-2.2%) in 9- to 12-year old students, from 3.9% (95% CI: 2.8%-5.0%) to 1.5% (95% CI: 1.0%-2.0%) in adults, and from 8.8% (95% CI: 6.5%-11.2%) to 2.6% (95% CI: 1.7%-3.5%) in 1st year students from 2011/12 to 2017. In 2017, heavy infection intensities occurred in 0.4% of 9- to 12-year old students, 0.1% of adults, and 0.8% of 1st year students. Considering 1st year students in 2017, 13/45 schools in Pemba and 4/45 schools in Unguja had heavy infection intensities >1%. There was no significant difference in prevalence between the intervention arms in any study group and year. CONCLUSIONS/SIGNIFICANCE: Urogenital schistosomiasis was eliminated as public health problem from most sites in Pemba and Unguja. Prevalence was significantly reduced, but transmission was not interrupted. Continued interventions that are adaptive and tailored to the micro-epidemiology of S. haematobium in Zanzibar are needed to sustain and advance the gains made by ZEST.

Endonasal Endoscopic Complete Excision of Unilateral Nasal Hemangioma in a Child: Case Report and Technical Note.

Intranasal lobular hemangioma of the inferior turbinate is a rare occurrence in children. A 12-year-old girl presented with a two-month history of multiple epistaxis episodes. Contrast-enhanced computed tomography showed a large nasal mass in the right nasal cavity. Endonasal endoscopic excision of the hemangioma with cauterization of the feeding vessel was performed to remove the lesion completely. There was no recurrence at 11 months follow-up.

Whole genome amplification and exome sequencing of archived schistosome miracidia.

Adult schistosomes live in the blood vessels and cannot easily be sampled from humans, so archived miracidia larvae hatched from eggs expelled in feces or urine are commonly used for population genetic studies. Large collections of archived miracidia on FTA cards are now available through the Schistosomiasis Collection at the Natural History Museum (SCAN). Here we describe protocols for whole genome amplification of Schistosoma mansoni and Schistosome haematobium miracidia from these cards, as well as real time PCR quantification of amplified schistosome DNA. We used microgram quantities of DNA obtained for exome capture and sequencing of single miracidia, generating dense polymorphism data across the exome. These methods will facilitate the transition from population genetics, using limited numbers of markers to population genomics using genome-wide marker information, maximising the value of collections such as SCAN.

The usefulness and actual use of wearable devices among the elderly population.

BACKGROUND AND OBJECTIVE: Elderly populations are more prone to diseases and need continuous monitoring of parameters to ensure good health. Wearable devices (WDs) can be helpful in the early detection and management of medical conditions. However, less is known about the use of currently available WDs among elderly populations. The objectives of this study were to determine the usefulness and actual use of wearable devices among the elderly population. METHODS: Our methodology was based on a systematic review and a survey questionnaire. In the systematic review, search was conducted in four databases PubMed, MDPI, Sage, and Scopus with search terms "wearable device" and "elderly", "wearable sensor" and "elderly". The inclusion criteria were the studies which described health-related wearable devices, its use as the outcome, conducted on a minimum of ten participants and published in the last five years. The survey was conducted on the MOOCs (Massive Open Online Course) platform. The questionnaire was related to the use of technology, intention to use, security and privacy concerns, and willingness to pay. RESULTS: The review identified 4915 articles, of which, 31 studies eventually met the inclusion criteria. All studies reported positive impacts after assessing devices, despite certain drawbacks. The majority of the samples were males. The survey revealed responses from 233 individuals out of the 1100 participants of the course. The survey results were categorized into two age groups: 54.3% were elderly (>65 years) and 45.49% were non-elderly (≤65 years). Very few elderly people were currently using WD. More than 60% of elderly people were interested in the future use of wearable devices, and preferred future use to improve physical and mental activities. A majority of the respondents were female. CONCLUSIONS: This study suggests awareness should be created among elderly populations regarding the use of WDs for the early detection and prevention of complications and emergencies. Elderly populations are more prone to benefits from using WDs. The review concluded that devices should be tested on elderly groups as well, considering sex equality, and on both healthy and sick participants for better insights. The survey determined the elderly as frequent users of technology, but lack of knowledge of WD and demonstrated female interest in the use of WD. In future research on WDs, it is suggested that clinical studies be conducted for longer durations, and standard protocols such as age and sex equality should be considered. Requirements from both users and physicians should be acknowledged for better cognizance of WDs.

Urogenital schistosomiasis transmission on Unguja Island, Zanzibar: characterisation of persistent hot-spots.

BACKGROUND: Elimination of urogenital schistosomiasis transmission is a priority for the Zanzibar Ministry of Health. Preventative chemotherapy together with additional control interventions have successfully alleviated much of the disease burden. However, a persistently high Schistosoma haematobium prevalence is found in certain areas. Our aim was to characterise and evaluate these persistent "hot-spots" of transmission and reinfection in comparison with low-prevalence areas, to support the intervention planning for schistosomiasis elimination in Zanzibar. METHODS: Prevalences of S. haematobium were annually determined by a single urine filtration in schoolchildren from 45 administrative areas (shehias) in Unguja in 2012, 2013 and 2014. Coverage data for biannual treatment with praziquantel were available from ministerial databases and internal surveys. Among the 45 shehias, five hot-spot (≥ 15 % prevalence) and two low-prevalence (≤ 5 %) shehias were identified and surveyed in mid-2014. Human-water contact sites (HWCSs) and the presence of S. haematobium-infected and uninfected Bulinus globosus, as well as safe water sources (SWSs) and their reliability in terms of water availability were determined and mapped. RESULTS: We found no major difference in the treatment coverage between persistent hot-spot and low-prevalence shehias. On average, there were considerably more HWCSs containing B. globosus in hot-spot than in low-prevalence shehias (n = 8 vs n = 2) and also more HWCSs containing infected B. globosus (n = 2 vs n = 0). There was no striking difference in the average abundance of SWSs in hot-spot and low-prevalence shehias (n = 45 vs n = 38) and also no difference when considering SWSs with a constant water supply (average: 62 % vs 62 %). The average number of taps with a constant water supply, however, was lower in hot-spot shehias (n = 7 vs n = 14). Average distances from schools to the nearest HWCS were considerably shorter in hot-spot shehias (n = 229 m vs n = 722 m). CONCLUSION: The number of HWCSs, their infestation with B. globosus and their distance to schools seem to play a major role for a persistently high S. haematobium prevalence in children. In addition to treatment, increasing access to reliably working taps, targeted snail control at HWCSs near schools and enhanced behaviour change measures are needed to reduce prevalences in hot-spot areas and to finally reach elimination. TRIAL REGISTRATION: ISRCTN48837681 .

Increasing the reach: Involving local Muslim religious teachers in a behavioral intervention to eliminate urogenital schistosomiasis in Zanzibar.

In Zanzibar, United Republic of Tanzania, Madrassa schools are influential institutions, where children and adults can learn about the interpretation of the Koran. We aimed to explore the involvement of Madrassa teachers for behavior change interventions in a randomized operational research trial designed to investigate the impact of multiple approaches to eliminate urogenital schistosomiasis transmission from Zanzibar. Madrassa teachers performing in the 30 communities of the behavior change study arm were trained in new interactive and participatory teaching methods by the local behavioral team and provided with schistosomiasis-teaching tools for teaching about transmission and prevention in their Madrassa. In July 2014, in a qualitative research study, we conducted 25 semi-structured interviews with Madrassa teachers to find out how they perceived their involvement in interventions against schistosomiasis. In 2014, 5926 among the 8497 registered Madrassa students in 30 communities on Unguja and Pemba islands received health education and participated in interactive behavior change exercises about schistosomiasis. Madrassa teachers reported that they valued their inclusion in the study and the opportunity to educate their students about schistosomiasis transmission, prevention, and treatment. They also perceived personal and community benefits as a result of their training and strongly supported the inclusion of additional Madrassa teachers in future intervention activities. Madrassa teachers are influential in the Zanzibari society, and hence are important change agents within our community-level behavioral intervention. They might constitute an untapped resource that can help to expand and increase acceptance of and participation in schistosomiasis and other neglected tropical disease control activities in African Muslim communities.

Community Knowledge, Perceptions, and Practices Associated with Urogenital Schistosomiasis among School-Aged Children in Zanzibar, United Republic of Tanzania.

BACKGROUND: On the Zanzibar islands, United Republic of Tanzania, elimination of urogenital schistosomiasis is strived for in the coming years. This qualitative study aimed to better understand community knowledge, perceptions, and practices associated with schistosomiasis among school-aged children on Unguja and Pemba islands, in order to inform the development of behavior change interventions contributing to eliminate urogenital schistosomiasis. METHODOLOGY: In 2011, we conducted 35 children's discussion groups, 41 in-depth interviews with parents and teachers, and 5 focus group discussions with community members in Zanzibar. Using a modified-grounded theory approach, we transcribed and coded the narrative data followed by thematic analysis of the emergent themes. PRINCIPAL FINDINGS: Urogenital schistosomiasis is a common experience among children in Zanzibar and typically considered a boys' disease. Children engage in multiple high-risk behaviors for acquiring schistosomiasis because of poor knowledge on disease transmission, lack of understanding on severity of disease-associated consequences, and lack of alternative options for water related activities of daily living and recreational play. Local primary school teachers had little to no training about the disease and no teaching tools or materials for students. CONCLUSIONS/SIGNIFICANCE: Conducting activities in open natural freshwater contaminated by S. haematobium larvae compromises the health of school-aged children in Zanzibar. The perception of urogenital schistosomiasis as a minor illness rather than a serious threat to a child's well-being contributes to the spread of disease. Understanding community perceptions of disease along with the barriers and facilitators to risk reduction behaviors among children can inform health promotion activities, campaigns, and programs for the prevention, control, and elimination of urogenital schistosomiasis in Zanzibar.

Praziquantel coverage in schools and communities targeted for the elimination of urogenital schistosomiasis in Zanzibar: a cross-sectional survey.

BACKGROUND: Biannual mass drug administration (MDA) with praziquantel and additional interventions to eliminate urogenital schistosomiasis has been implemented on the Zanzibar islands, United Republic of Tanzania, since 2012. We aimed to assess the coverage of school-based treatment (SBT) and community-wide treatment (CWT), to validate the coverage reported by the Zanzibar Ministry of Health (MoH) and to identify reasons for non-compliance. METHODS: We conducted a post-MDA cross-sectional survey in 93 schools and 92 communities on Pemba and Unguja islands in early 2014, 3-5 months after the last MDA round. Pupils and adults were asked whether they had received and taken the praziquantel treatment provided in the last SBT or CWT, respectively, and the observed and reported coverage were compared. Reasons for non-compliance were recorded in a pretested questionnaire and assessed in qualitative interviews. Urine samples of participants were examined for Schistosoma haematobium eggs with a single urine filtration. RESULTS: Around 8000 pupils and 4000 adults were included in the analysis. Our survey revealed a SBT coverage of 85.2% in Pemba and of 86.9% in Unguja, which was in line with MoH reports from Pemba (84.3%) and higher than reports from Unguja (63.9%). However, 15 among the 48 schools surveyed in Unguja had not received SBT. Among the interviewed adults, 53.6% in Pemba and 64.9% in Unguja had received praziquantel during CWT, which was less than the 59.0% and 67.7%, respectively, indicated by MoH reports. Moreover, only 43.8% and 54.0% of adults in Pemba and Unguja, respectively, had taken all the tablets as recommended. The main reasons for not receiving or taking praziquantel were absence during CWT, no drug distributor coming, being busy, fear of adverse events, pregnancy, breastfeeding or feeling healthy. CONCLUSION: To increase coverage and compliance in Zanzibar, SBT should target all schools and mobilization, sensitization and implementation of the CWT need to be improved. To reach elimination of urogenital schistosomiasis transmission in Zanzibar and elsewhere, a very high treatment coverage and compliance at national and local level is key and additional control measures such as snail control and behaviour change interventions will need to be implemented area wide. TRIAL REGISTRATION: ISRCTN48837681.

Sensitivity and Specificity of a Urine Circulating Anodic Antigen Test for the Diagnosis of Schistosoma haematobium in Low Endemic Settings.

BACKGROUND: Elimination of schistosomiasis as a public health problem and interruption of transmission in selected areas are key goals of the World Health Organization for 2025. Conventional parasitological methods are insensitive for the detection of light-intensity infections. Techniques with high sensitivity and specificity are required for an accurate diagnosis in low-transmission settings and verification of elimination. We determined the accuracy of a urine-based up-converting phosphor-lateral flow circulating anodic antigen (UCP-LF CAA) assay for Schistosoma haematobium diagnosis in low-prevalence settings in Zanzibar, Tanzania. METHODOLOGY: A total of 1,740 urine samples were collected in 2013 from children on Pemba Island, from schools where the S. haematobium prevalence was <2%, 2-5%, and 5-10%, based on a single urine filtration. On the day of collection, all samples were tested for microhematuria with reagent strips and for the presence of S. haematobium eggs with microscopy. Eight months later, 1.5 ml of urine from each of 1,200 samples stored at -20°C were analyzed by UCP-LF CAA assay, while urine filtration slides were subjected to quality control (QCUF). In the absence of a true 'gold' standard, the diagnostic performance was calculated using latent class analyses (LCA). PRINCIPAL FINDINGS: The 'empirical' S. haematobium prevalence revealed by UCP-LF CAA, QCUF, and reagent strips was 14%, 5%, and 4%, respectively. LCA revealed a sensitivity of the UCP-LF CAA, QCUF, and reagent strips of 97% (95% confidence interval (CI): 91-100%), 86% (95% CI: 72-99%), and 67% (95% CI: 52-81%), respectively. Test specificities were consistently above 90%. CONCLUSIONS/SIGNIFICANCE: The UCP-LF CAA assay shows high sensitivity for the diagnosis of S. haematobium in low-endemicity settings. Empirically, it detects a considerably higher number of infections than microscopy. Hence, the UCP-LF CAA employed in combination with QCUF, is a promising tool for monitoring and surveillance of urogenital schistosomiasis in low-transmission settings targeted for elimination.

Cessation of mass drug administration for lymphatic filariasis in Zanzibar in 2006: was transmission interrupted?

BACKGROUND: Lymphatic filariasis (LF) is targeted for elimination through annual mass drug administration (MDA) for 4-6 years. In 2006, Zanzibar stopped MDA against LF after five rounds of MDA revealed no microfilaraemic individuals during surveys at selected sentinel sites. We asked the question if LF transmission was truly interrupted in 2006 when MDA was stopped. METHODOLOGY/PRINCIPAL FINDINGS: In line with ongoing efforts to shrink the LF map, we performed the WHO recommended transmission assessment surveys (TAS) in January 2012 to verify the absence of LF transmission on the main Zanzibar islands of Unguja and Pemba. Altogether, 3275 children were tested on both islands and 89 were found to be CFA positive; 70 in Pemba and 19 in Unguja. The distribution of schools with positive children was heterogeneous with pronounced spatial variation on both islands. Based on the calculated TAS cut-offs of 18 and 20 CFA positive children for Pemba and Unguja respectively, we demonstrated that transmission was still ongoing in Pemba where the cut-off was exceeded. CONCLUSIONS: Our findings indicated ongoing transmission of LF on Pemba in 2012. Moreover, we presented evidence from previous studies that LF transmission was also active on Unguja shortly after stopping MDA in 2006. Based on these observations the government of Zanzibar decided to resume MDA against LF on both islands in 2013.

Elimination of schistosomiasis transmission in Zanzibar: baseline findings before the onset of a randomized intervention trial.

BACKGROUND: Gaining and sustaining control of schistosomiasis and, whenever feasible, achieving local elimination are the year 2020 targets set by the World Health Organization. In Zanzibar, various institutions and stakeholders have joined forces to eliminate urogenital schistosomiasis within 5 years. We report baseline findings before the onset of a randomized intervention trial designed to assess the differential impact of community-based praziquantel administration, snail control, and behavior change interventions. METHODOLOGY: In early 2012, a baseline parasitological survey was conducted in ~20,000 people from 90 communities in Unguja and Pemba. Risk factors for schistosomiasis were assessed by administering a questionnaire to adults. In selected communities, local knowledge about schistosomiasis transmission and prevention was determined in focus group discussions and in-depths interviews. Intermediate host snails were collected and examined for shedding of cercariae. PRINCIPAL FINDINGS: The baseline Schistosoma haematobium prevalence in school children and adults was 4.3% (range: 0-19.7%) and 2.7% (range: 0-26.5%) in Unguja, and 8.9% (range: 0-31.8%) and 5.5% (range: 0-23.4%) in Pemba, respectively. Heavy infections were detected in 15.1% and 35.6% of the positive school children in Unguja and Pemba, respectively. Males were at higher risk than females (odds ratio (OR): 1.45; 95% confidence interval (CI): 1.03-2.03). Decreasing adult age (OR: 1.04; CI: 1.02-1.06), being born in Pemba (OR: 1.48; CI: 1.02-2.13) or Tanzania (OR: 2.36; CI: 1.16-4.78), and use of freshwater (OR: 2.15; CI: 1.53-3.03) showed higher odds of infection. Community knowledge about schistosomiasis was low. Only few infected Bulinus snails were found. CONCLUSIONS/SIGNIFICANCE: The relatively low S. haematobium prevalence in Zanzibar is a promising starting point for elimination. However, there is a need to improve community knowledge about disease transmission and prevention. Control measures tailored to the local context, placing particular attention to hot-spot areas, high-risk groups, and individuals, will be necessary if elimination is to be achieved.

The relative contribution of co-infection to focal infection risk in children.

Co-infection is ubiquitous in people in the developing world but little is known regarding the potential for one parasite to act as a risk factor for another. Using generalized linear mixed modelling approaches applied to data from school-aged children from Zanzibar, Tanzania, we determined the strength of association between four focal infections (i.e. Ascaris lumbricoides, Trichuris trichiura, hookworm and self-reported fever, the latter used as a proxy for viral, bacterial or protozoal infections) and the prevalence or intensity of each of the helminth infections. We compared these potential co-infections with additional risk factors, specifically, host sex and age, socioeconomic status and physical environment, and determined what the relative contribution of each risk factor was. We found that the risk of infection with all four focal infections was strongly associated with at least one other infection, and that this was frequently dependent on the intensity of that other infection. In comparison, no other incorporated risk factor was associated with all focal infections. Successful control of infectious diseases requires identification of infection risk factors. This study demonstrates that co-infection is likely to be one of these principal risk factors and should therefore be given greater consideration when designing disease-control strategies. Future work should also incorporate other potential risk factors, including host genetics which were not available in this study and, ideally, assess the risks via experimental manipulation.

Use of sentinel snails for the detection of Schistosoma haematobium transmission on Zanzibar and observations on transmission patterns.

Urogenital schistosomiasis is an important public health issue in Zanzibar. Transmission of the parasite to the human population is related to the distribution of the intermediate snail host, Bulinus globosus. We measured B. globosus abundance and Schistosoma haematobium prevalence within snails in a series of naturally occurring populations and compared prevalence detected by observing cercarial shedding for patent infections, and by PCR using DraI repeat. A total of 2146 B. globosus were collected throughout the study period from 2003 to 2007; of these 85 (3.96%) were shedding cercariae. The levels of infection detected by PCR were consistently higher (40-100 percent). Levels of exposure to miracidia in the field were measured using sentinel snails. B. globosus (a susceptible host) and B. nasutus (a non-susceptible host) were placed in cages at transmission sites for 72h to observe rates of penetration by miracidia. Both B. globosus and B. nasutus tested positive for S. haematobium by PCR (up to 24% infected) indicating frequent contamination of the waterbodies with S. haematobium miracidia. The use of sentinel snails coupled with PCR diagnostics could be a sensitive tool for mapping and monitoring transmission of schistosomiasis in areas of low prevalence.

Time to set the agenda for schistosomiasis elimination.

It is time to raise global awareness to the possibility of schistosomiasis elimination and to support endemic countries in their quest to determine the most appropriate approaches to eliminate this persistent and debilitating disease. The main interventions for schistosomiasis control are reviewed, including preventive chemotherapy using praziquantel, snail control, sanitation, safe water supplies, and behaviour change strategies supported by information, education and communication (IEC) materials. Differences in the biology and transmission of the three main Schistosoma species (i.e. Schistosoma haematobium, S. mansoni and S. japonicum), which impact on control interventions, are considered. Sensitive diagnostic procedures to ensure adequate surveillance in areas attaining low endemicity are required. The importance of capacity building is highlighted. To achieve elimination, an intersectoral approach is necessary, with advocacy and action from local communities and the health community to foster cooperative ventures with engineers, the private sector, governments and non-governmental organizations specialized in water supply and sanitation. Examples of successful schistosomiasis control programmes are reviewed to highlight what has been learnt in terms of strategy for control and elimination. These include St. Lucia and other Caribbean islands, Brazil and Venezuela for S. mansoni; Saudi Arabia and Egypt for both S. mansoni and S. haematobium; Morocco, Tunisia, Algeria, Mauritius and the Islamic Republic of Iran for S. haematobium; Japan and the People's Republic of China for S. japonicum. Additional targets for elimination or even eradication could be the two minor human schistosome species S. guineenisis and S. intercalatum, which have a restricted distribution in West and Central Africa. The examples show that elimination of schistosomiasis is an achievable and desirable goal requiring full integration of preventive chemotherapy with the tools of transmission control. An agenda for the elimination of schistosomiasis would aim to identify the gaps in knowledge, and define the tools, strategies and guidelines that will help national control programmes move towards elimination, including an internationally accepted mechanism that allows verification/confirmation of elimination.

DNA barcoding of Schistosoma haematobium on Zanzibar reveals substantial genetic diversity and two major phylogenetic groups.

To shed light on the genetic diversity of Schistosoma haematobium on Zanzibar a DNA barcoding study was performed on parasite material isolated from different time-points 4 years apart. Substantive sequence variation was found within the mitochondrial cytochrome oxidase subunit I (cox1) and the NADH-dehydrogenase subunit 1 (nad1) with 27 and 22 unique haplotypes identified respectively and 38 when both gene regions were considered. Upon phylogenetic analysis and comparison with other S. haematobium isolates, haplotypes or barcode types partitioned into two discrete major groups, designated Group 1 and Group 2. Whilst Group 1 isolates were recovered from both Zanzibar and the African mainland, Group 2 isolates were exclusive to Zanzibar. A mixture of Group 1 and 2 parasites were recovered from individual children with no child shedding parasites of a single group haplotype alone. Whilst changes in general levels of genetic diversity between the two parasite isolation time-points were observed, no obvious change in genetic diversity was detected, despite large-scale drug distribution of praziquantel during the intervening period and there was no biased of Group 1 or 2 parasites persisting at the different time-points. To assist in future genetic screening of schistosome larval stages e.g. eggs, miracidia or cercariae, two new DNA-typing assays based on group-specific PCR primers and SNaPshot™ probes have been developed to distinguish Group 1 and 2 haplotypes.

From morbidity control to transmission control: time to change tactics against helminths on Unguja Island, Zanzibar.

In Zanzibar, the prevalence and intensity of helminth infections have markedly declined over the past 25 years, which is generally attributed to morbidity control programmes emphasising 'preventive chemotherapy'. Here we provide an update of the current situation of soil-transmitted helminthiasis and urinary schistosomiasis on Unguja Island, and highlight socioeconomic development, improvement in sanitation and health education as additional drivers against helminthiases. Our data were obtained from cross-sectional surveys carried out between 2006 and 2009 with stool and urine samples from 2858 and 879 individuals, respectively, examined for helminth eggs and larvae. Additionally, several hundred people were interviewed on sanitation and hygienic behaviour. Data on Unguja's economic growth and improvements in access to clean water and household latrines in the recent past were derived from the extant literature. Pooled prevalences of Trichuris trichiura, Schistosoma haematobium, Ascaris lumbricoides, hookworm and Strongyloides stercoralis were 35%, 29%, 12%, 10% and 6%, respectively. However, there were considerable differences in prevalences between different age-groups and at village and district level. Moreover, some hotspots for A. lumbricoides, T. trichiura and S. haematobium were identified with prevalences above 60% among school-aged children. Availability of a latrine and washing hands before eating did not significantly lower the risk of helminth infections in our study population. Nevertheless, a considerable increase in access to household latrines (from 49% to 72%) and piped water (from 45% to 71%) between 1991 and 2005 is likely to have contributed to reducing the force of transmission of helminthiases in Zanzibar. The next logical step in Unguja is to change the tactics from morbidity control to interruption of helminth transmission and ultimately local elimination. Hence, 'preventive chemotherapy' needs to be further consolidated, placing particular emphasis on health education and improved access to clean water and sanitation.