High levels of Schistosoma mansoni infections among schoolchildren in central Sudan one year after treatment with praziquantel

A longitudinal study was conducted to evaluate the impact of praziquantel (PZQ) for the treatment of Schistosoma mansoni infection among schoolchildren in Al Gunaid in Central Sudan. A cohort of schoolchildren (6-15 years of age) was investigated before and 1 year after treatment with a single dose of PZQ 40?mg/kg. Parasitological examinations for S. mansoni were performed before and after treatment, and prevalence and intensity of infection were analysed. Of 2741 schoolchildren recruited from six elementary schools at baseline, 2521 were successfully traced and re-examined at follow-up, with two complete sets of longitudinal parasitological data on S. mansoni. Boys showed significantly higher prevalence of S. mansoni infection than girls. A single dose of PZQ reduced the overall prevalence of S. mansoni infection by 36.7% (from 59.1 to 37.4%) and the intensity of infection by 41.1% (from 116.7 to 68.7 eggs per gram of stool) 1 year after treatment. The reduction in prevalence was significantly higher among the group of children with heavy infections (by 76.1%, from 6.7 to 1.6%) and among girls (by 54.1%, 42.3 to 19.4%) at 1 year after treatment. Thus, in spite of a significant reduction in the prevalence and intensity of S. mansoni infection 1 year after PZQ treatment, the prevalence of the disease was still high and further research is needed on this topic.     

The evaluation of control measures against Schistosoma mekongi in Cambodia by a mathematical model

We constructed a mathematical model for the transmission of Schistosoma mekongi in Cambodia. The simulation of the model will be instrumental in planning schistosomiasis control measures. The model includes two definitive hosts, humans and dogs, as animal reservoirs. Dogs are recognized to play an important role in schistosomiasis transmission in Cambodia. For the purpose of dealing with age-specific prevalence and intensity of infection, the human population was classified into eight age categories in the model. To describe the seasonal fluctuation of the intermediate host population of S. mekongi, the "Post-Spate Survival" hypothesis was adopted for the population dynamics of Neotricula aperta present in the Mekong River. We carried out simulations to evaluate the effect of universal treatment (UT) and targeted mass treatment (TT) with praziquantel on the reduction in prevalence of S. mekongi. The simulations indicated that biyearly UT for 8 years or yearly TT for 5 years after three courses of yearly UT could reduce the prevalence to below 5% when a UT or TT coverage of 85% of inhabitants was achieved. The simulation suggested that the suppression of S. mekongi in Cambodia would be possible by UT or TT with a high coverage rate.     

Intestinal parasites in Kampuchea, Takeo Province

Fresh stool samples obtained from 1407 adult patients who sought treatment in Takeo province hospital and 332 Takeo preschool and school-age children from 3 to 18 years of age were examined for the presence of intestinal parasites using the technique of native preparation and the flotation method of Faust with subsequent staining with Lugol solution to demonstrate cysts. In hospital patients, a total of 13 protozoan and 9 helminth species were diagnosed. The prevalence of Entamoeba histolytica (cysts and trophozoites) was highest in the age group 15-18 years (18.3%), the peak prevalence of Gairdia lamblia (27.6%) occurred in children of the age group 6-9 years. The highest frequency distribution of Pentatrichomonas hominis (20.1%) was recorded in 3 to 5 years old, that of Enteromonas hominis (12.8%) in 6 to 9 years old. The predominant helminth was Ancylostoma duodenale, with the peak prevalence (65.2%) in patients older than 18 years, followed by Ascaris lumbricoides and Strongyloides stercoralis. Almost half of children patients under 6 was infected with at least two species of parasites, patients over 6 were infected simultaneously with two or more intestinal parasites in an absolute majority of cases. In Takeo preschool and school children the spectrum of diagnosed protozoan and helminth species was somewhat narrower than seen in hospital patients, but their prevalence rates were higher, except for the flagellate Pentatrichomonas hominis. The highest prevalence rates recorded were for E. histolytica 29.5% (age category 10-14 years), for G. lamblia 34.8% (age category 6-9 years), for P. hominis 19.3% (age category 3-5 years), for E. hominis 10.5% (age category 3-5 years), for A. duodenale 85.9% (age category 15-18 years), for A. lumbricoides 26.1% (age category 6-9 years), and for S. stercoralis 18.8% (age category 6-9 years). As many as 70% of children at the age between 6 and 15 years were simultaneously infected with two or three species of intestinal parasites.     

Optimal control of hepatitis C antiviral treatment programme delivery for prevention amongst a population of injecting drug users

In most developed countries, HCV is primarily transmitted by injecting drug users (IDUs). HCV antiviral treatment is effective, and deemed cost-effective for those with no re-infection risk. However, few active IDUs are currently treated. Previous modelling studies have shown antiviral treatment for active IDUs could reduce HCV prevalence, and there is emerging interest in developing targeted IDU treatment programmes. However, the optimal timing and scale-up of treatment is unknown, given the real-world constraints commonly existing for health programmes. We explore how the optimal programme is affected by a variety of policy objectives, budget constraints, and prevalence settings. We develop a model of HCV transmission and treatment amongst active IDUs, determine the optimal treatment programme strategy over 10 years for two baseline chronic HCV prevalence scenarios (30% and 45%), a range of maximum annual budgets (￡50,000-300,000 per 1,000 IDUs), and a variety of objectives: minimising health service costs and health utility losses; minimising prevalence at 10 years; minimising health service costs and health utility losses with a final time prevalence target; minimising health service costs with a final time prevalence target but neglecting health utility losses. The largest programme allowed for a given budget is the programme which minimises both prevalence at 10 years, and HCV health utility loss and heath service costs, with higher budgets resulting in greater cost-effectiveness (measured by cost per QALY gained compared to no treatment). However, if the objective is to achieve a 20% relative prevalence reduction at 10 years, while minimising both health service costs and losses in health utility, the optimal treatment strategy is an immediate expansion of coverage over 5-8 years, and is less cost-effective. By contrast, if the objective is only to minimise costs to the health service while attaining the 20% prevalence reduction, the programme is deferred until the final years of the decade, and is the least cost-effective of the scenarios.     

Evaluating spatially adaptive guidelines for the treatment of gonorrhea to reduce the incidence of gonococcal infection and increase the effective lifespan of antibiotics

In the absence of point-of-care gonorrhea diagnostics that report antibiotic susceptibility, gonorrhea treatment is empiric and determined by standardized guidelines. These guidelines are informed by estimates of resistance prevalence from national surveillance systems. We examined whether guidelines informed by local, rather than national, surveillance data could reduce the incidence of gonorrhea and increase the effective lifespan of antibiotics used in treatment guidelines. We used a transmission dynamic model of gonorrhea among men who have sex with men (MSM) in 16 U.S. metropolitan areas to determine whether spatially adaptive treatment guidelines based on local estimates of resistance prevalence can extend the effective lifespan of hypothetical antibiotics. The rate of gonorrhea cases in these metropolitan areas was 5,548 cases per 100,000 MSM in 2017. Under the current strategy of updating the treatment guideline when the prevalence of resistance exceeds 5%, we showed that spatially adaptive guidelines could reduce the annual rate of gonorrhea cases by 200 cases (95% uncertainty interval: 169, 232) per 100,000 MSM population while extending the use of a first-line antibiotic by 0.75 (0.55, 0.95) years. One potential strategy to reduce the incidence of gonorrhea while extending the effective lifespan of antibiotics is to inform treatment guidelines based on local, rather than national, resistance prevalence.     

Use of nasal mupirocin for Staphylococcus aureus: effect on nasal carriers and nosocomial infections

Staphylococcus aureus is the agent of community-acquired and nosocomial infections. Twenty to 35% of the population permanently carries it in the nose and oropharynx, and additional 50%, carries it intermittently. Topical calcium mupirocin is an antibacterial agent against Staphylococcus aureus recommended to eradicate nasal and hand colonization in patients and health care workers. The prevalence of nasal S. aureus was determined in patients undergoing cardiovascular surgery. In addition, the effect of mupirocine on the number of carriers and rate of nosocomial infections was evaluated. An experimental prospective study was undertaken with two groups of patients: one treated with mupirocin (n = 96), and the other without treatment (n = 95). Tests for presence of nasal S. aureus and nosocomial infections were conducted in all patients. A 34% prevalence of S. aureus carriers was found. A decrease of the prevalence was found in both treated (87%) and untreated patients (33%), but in significantly different proportions (p = 0.0002, RR = 0.22, 95%CI = 0.09-0.054). This result demonstrated the effectiveness of a mupirocin treatment program to decrease numbers of nasal carriers. With regard to nosocomial infection, S. aureus prevalence was 3.6%, occurring mostly in control patients (6 of 7). Total nosocomial infection prevalence was 17.3%, evenly distributed in treated and untreated patients. This suggested that mupirocin use did not decrease the number of nosocomial infections.     

Significantly reduced intensity of infection but persistent prevalence of schistosomiasis in a highly endemic region in mali after repeated treatment

Background

Preventive chemotherapy against schistosomiasis has been implemented since 2005 in Mali, targeting school-age children and adults at high risk. A cross-sectional survey was conducted in 2010 to evaluate the impact of repeated treatment among school-age children in the highly-endemic region of Segou.

Methodology/Principal Findings

The survey was conducted in six sentinel schools in three highly-endemic districts, and 640 school children aged 7–14 years were examined. Infections with Schistosoma haematobium and S. mansoni were diagnosed with the urine filtration and the Kato-Katz method respectively. Overall prevalence of S. haematobium infection was 61.7%, a significant reduction of 30% from the baseline in 2004 (p<0.01), while overall prevalence of S. mansoni infection was 12.7% which was not significantly different from the baseline. Overall mean intensity of S. haematobium and S. mansoni infection was 180.4 eggs/10 ml of urine and 88.2 epg in 2004 respectively. These were reduced to 33.2 eggs/10 ml of urine and 43.2 epg in 2010 respectively, a significant reduction of 81.6% and 51% (p<0.001). The proportion of heavy S. haematobium infections was reduced from 48.8% in 2004 to 13.8% in 2010, and the proportion of moderate and heavy S. mansoni infection was reduced from 15.6% in 2004 to 9.4% in 2010, both significantly (p<0.01). Mathematical modelling suggests that the observed results were in line with the expected changes.

Conclusions/Significance

Significant reduction in intensity of infection on both infections and modest but significant reduction in S. haematobium prevalence were achieved in highly-endemic Segou region after repeated chemotherapy. However, persistent prevalence of both infections and relatively high level of intensity of S. mansoni infection suggest that more intensified control measures be implemented in order to achieve the goal of schistosomiasis elimination. In addition, closer monitoring and evaluation activities are needed in the programme to monitor the drug tolerance and to adjust treatment focus.     

Effects of Serratia marcescens on the F1 generation of laboratory-reared Heliothis virescens (Lepidoptera: Noctuidae)

The effects of the bacterium Serratia marcescens (Bizio) was investigated on the F1 generation of laboratory-reared Heliothis virescens (F.). There was no difference in adult male or female longevity (i.e., parental generation) for individuals inoculated with S. marcescens as larvae (Serratia treatment) and those that were free of the bacterium (control treatment). However, the number of eggs laid and the prevalence of eclosion of eggs from Serratia treatment adults were reduced relative to control treatment adults. A very low number of F1 Serratia treatment eggs exhibited signs of infection, but a higher prevalence of mortality was observed for F1 larvae (n = 2,888) for the Serratia (3.5-4.6%) than for the control (1.1-1.5%) treatment. No S. marcescens was isolated from dead control larvae; whereas, 48 -54% of dead F1 larvae for the Serratia treatment were positive for the bacterium. However, there was no significant difference in larval weights between treatments. There were also no differences in either mortality or weight of F1 male pupae between treatments, but F1 female pupae were significantly smaller and prevalence of mortality was higher for the Serratia treatment. Serratia marcescens was not isolated from any of the control F1 pupae, but 6% of pupal cadavers for the Serratia treatment were positive for the bacterium. No S. marcescens was recovered from the meconia of any of the F1 adults (n = 2,600) regardless of treatment, and there were no differences in adult weights between treatments. Although sublethal effects of S. marcescens were detected, the impact and prevalence of the bacterium were tremendously reduced over the F1 generation in the absence of all but the most basic management strategies.     

Effect of Maternal Schistosoma mansoni Infection and Praziquantel Treatment During Pregnancy on Schistosoma mansoni Infection and Immune Responsiveness among Offspring at Age Five Years

Introduction

Offspring of Schistosoma mansoni-infected women in schistosomiasis-endemic areas may be sensitised in-utero. This may influence their immune responsiveness to schistosome infection and schistosomiasis-associated morbidity. Effects of praziquantel treatment of S. mansoni during pregnancy on risk of S. mansoni infection among offspring, and on their immune responsiveness when they become exposed to S. mansoni, are unknown. Here we examined effects of praziquantel treatment of S. mansoni during pregnancy on prevalence of S. mansoni and immune responsiveness among offspring at age five years.

Methods

In a trial in Uganda (ISRCTN32849447, http://www.controlled-trials.com/ISRCTN32849447/elliott), offspring of women treated with praziquantel or placebo during pregnancy were examined for S. mansoni infection and for cytokine and antibody responses to SWA and SEA, as well as for T cell expression of FoxP3, at age five years.

Results

Of the 1343 children examined, 32 (2.4%) had S. mansoni infection at age five years based on a single stool sample. Infection prevalence did not differ between children of treated or untreated mothers. Cytokine (IFNγ, IL-5, IL-10 and IL-13) and antibody (IgG1, Ig4 and IgE) responses to SWA and SEA, and FoxP3 expression, were higher among infected than uninfected children. Praziquantel treatment of S. mansoni during pregnancy had no effect on immune responses, with the exception of IL-10 responses to SWA, which was higher in offspring of women that received praziquantel during pregnancy than those who did not.

Conclusion

We found no evidence that maternal S. mansoni infection and its treatment during pregnancy influence prevalence and intensity of S. mansoni infection or effector immune response to S. mansoni infection among offspring at age five years, but the observed effects on IL-10 responses to SWA suggest that maternal S. mansoni and its treatment during pregnancy may affect immunoregulatory responsiveness in childhood schistosomiasis. This might have implications for pathogenesis of the disease.     

Obesity reduction within a generation: the dual roles of prevention and treatment

In 2010, the White House Task Force on Childhood Obesity provided benchmark goals for reducing childhood obesity. We evaluated the balance of prevention and treatment required for achieving Task Force goals in benchmark years 2015, 2020, and 2030. We created a simulation of US birth cohorts (2-19 years) born 2008-2030. For each year, we assumed "old" birth cohorts (part of previous benchmark obesity estimates) would benefit from obesity treatment strategies, and "new" birth cohorts would benefit from obesity prevention strategies. We assessed obesity prevalence that must be achieved through prevention strategies, under varying assumptions of treatment effectiveness. When we assumed a 1% absolute reduction in prevalence through treatment, we found that prevention strategies would need to achieve an obesity prevalence of 12% by 2015, 8% by 2020, and 0.3% by 2030. Because of higher obesity prevalence among minority children, prevention strategies would need to achieve a negative prevalence by 2030, which is implausible. Under more generous assumptions of treatment effectiveness, estimates became positive but remained low. Task Force goals are more difficult to achieve with each benchmark year. Policies must focus on obesity treatment interventions, particularly targeted to racial/ethnic minority children, to make progress in stemming the epidemic.     

A Bayesian approach to estimate the age-specific prevalence of Schistosoma mansoni and implications for schistosomiasis control

Models that accurately estimate the age-specific infection prevalence of Schistosoma mansoni can be useful for schistosomiasis control programmes, particularly with regard to whether mass drug administration or selected treatment should be employed. We developed a Bayesian formulation of an immigration-death model that has been previously proposed, which used maximum likelihood inference for estimating the age-specific S. mansoni prevalence in a dataset from Egypt. For comparative purposes, we first applied the Bayesian formulation of the immigration-death model to the dataset from Egypt. We further analysed data obtained from a cross-sectional parasitological survey that determined the infection prevalence of S. mansoni among 447 individuals in a village in C?te d'Ivoire. Three consecutive stool samples were collected from each participant and analysed by the Kato-Katz technique. In the C?te d'Ivoire study, the observed S. mansoni infection prevalence was 41.6% and varied with age. The immigration-death model was able to correctly predict 50% of the observed age group-specific point prevalences. The model presented here can be utilized to estimate S. mansoni community infection prevalences, which in turn helps in the strategic planning of schistosomiasis control.     

An Analysis of the Proportion of the U.S. Population that Ingests Soil or Other Non-Food Substances

Reliable quantitative data are lacking that document the prevalence of ingestion of soil and other “non-food” substances among U.S. children and adults. This article explores the proportion of the U.S. population that ingests substances such as soil, clay, starch, paint, or plaster. We compiled data from the National Health and Nutrition Examination Survey (NHANES) collected from years 1971–1975 (NHANES I) and 1976–1980 (NHANES II) because these particular surveys asked participants specific questions about non-food ingestion practices. We examined the prevalence of the behavior across multiple demographic variables, such as age, gender, education, and income level. Approximately 1% (NHANES II) to 2.5% (NHANES I) of the U.S. population ingests some type of non-food substance. The most notable variation across the demographic subgroups studied was the difference in estimated prevalence among young children (1 to <3 years) compared to older children and adults. Estimated prevalence was also higher among blacks compared to whites and within lower compared to higher socioeconomic groups. This analysis helps fill data gaps on the relative pattern of non-food ingestion practices on a national scale. This information provides perspective for risk assessors when evaluating exposure variables and for risk managers when weighing risk management alternatives.     

Schistosoma haematobium infections in preschool children from two rural communities in Ijebu East, south-western Nigeria

There is an urgent need for information on schistosomiasis in preschool children, who are often excluded in mass treatment programmes. The prevalence and intensity of Schistosoma haematobium infection were determined in preschool children aged ≤ 6 years in two rural communities in Ijebu East, south-western Nigeria. Two urine samples each were collected from 83 preschool children from the two communities, tested for microhaematuria using reagent strips and then processed and examined with a microscope for S. haematobium eggs. Focus group discussions on perceptions of the disease and water contact practices were held in the communities with their guardians, caregivers and preschool children, using an interview guide. The prevalence of S. haematobium in the two communities was 14 (16.9%), with no significant differences (P = 0.661) in infection rate between boys (18.4%) and girls (14.7%). Both prevalence and intensity of infection did not increase significantly with age in both Korede and Obada community. However, there were significant differences in prevalence of infection between the two communities (P = 0.035). There was no association (P = 0.750) between intensity in boys (0.176 eggs/10 ml urine) and girls (0.110 eggs/10 ml urine). Focal group discussions with guardians and caregivers revealed that preschool children acquired infection early in their lives through exposure to infected stream water by their mothers, while the older children visit the stream for playing, bathing and swimming. It has therefore become imperative for preschool children to be included in the planning of schistosomiasis intervention programmes as a means of reducing transmission.     

Prevalence of Intestinal Parasitic Infections among Children under Five Years of Age with Emphasis on Schistosoma mansoni in Wonji Shoa Sugar Estate,Ethiopia

Intestinal parasite infections are major public health problems of children in developing countries causing undernutrition, anemia, intestinal obstruction and mental and physical growth retardation. This study was conducted to assess the prevalence of intestinal helminthic infections among children under five years of age with emphasis on Schistosoma mansoni in Wonji Shoa Sugar Estate, Ethiopia. A cross-sectional parasitological survey was conducted in under-five children living in Wonji Shoa Sugar Estate Ethiopia, April, 2013. Stool samples were collected and examined for intestinal parasites using single Kato-Katz and single Sodium acetate-acetic acid-formalin (SAF) solution concentration methods. Out of 374 children examined using single Kato-Katz and single SAF-concentration methods, 24.3% were infected with at least one intestinal parasite species. About 10.4%, 8.8%, 4.6%, 2.9%, 1.6% and 0.8% of the children were infected with Hymenolepis nana, Schistosoma mansoni, Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis and hookworm, respectively. Prevalence of double, triple and quadruple intestinal helminthic infection was 6.4%, 0.54% and 1.1%, respectively. A significant increase in prevalence of S. mansoni (8.3% versus 3.2%) and T. trichiura (2.7% versus 0.5%) infection was observed when determined via the single Kato-Katz method compared to the prevalence of the parasites determined via the single SAF-concentration method. On the other hand, the single SAF-concentration method (9.1%) revealed a significantly higher prevalence of H. nana infection than the single Kato-Katz (1.6%) does. In conclusion, intestinal helminths infections particularly S. mansoni and H. nana were prevalent in under-five children of Wonji Shoa Sugar Estate. Including praziquantel treatment in the deworming program as per the World Health Organization guidelines would be vital to reduce the burden of these diseases in areas where S. mansoni and H. nana infections are prevalent among under-fives. Kato-Katz can be used in estimating the prevalence of S. mansoni and other helminth infections.     

Number of teeth and risk of root caries

Objective: This study aimed to investigate the association between number of natural teeth and prevalence of root caries. Design: A cross‐sectional design was adopted. A stratified multi‐stage purposive sampling method was used to select a wide range of elderly people from all social classes, educational levels and sexes. Data was collected through interviews and clinical examinations. Setting: Urban area in Chiang Mai‐Thailand. Participants: 549 elderly dentate aged 60‐74 years. Main Outcome Measures: Teeth with decay and filled roots (DF‐T). Results: The prevalence of root caries was 18.2% with a mean DF‐T of 0.58 (S.D. 2.02). Results of multiple logistic regression showed that number of teeth, DMF‐S scores, sex, and socio economic factors were statistically significantly associated with root caries (P<0.05). Adjusted odds ratios demonstrated a 14% increase in the chance of having root caries when the number of teeth increased one unit. Similarly, a 3% increase was observed for each unit increase in the DMF‐S scores (p<0.001). Being male, having more than four years of education and earning more than 1500 baht/month increased the chances of root caries by 76%, 139% and 85% respectively (p<0.001). Recession and age were not statistically significantly associated with root caries. Conclusions: Having more teeth, higher DMF‐S scores, earning more than 1500 baht/month, having more than 4 years of education and being male increased the likelihood of having root caries.     

Schistosomiasis mansoni in three localities of western lowland of the state of Maranháo before and after mass treatments.

A cross-sectional study for schistosomiasis was carried out in the localities of Alian?a, Alegre and Coroatá (districts of Cururupu, S?o Bento and S?o Jo?o Batista, respectively) in the lowland of the state of Maranh?o, after respectively 13, 11 and 4 mass treatments with oxamniquine in the period of ten years (1977-1987). The study included clinical and quantitative fecal examination, skin test for Schistosoma mansoni infection, evaluation of man-water contact of the total population (829 persons) in the three localities and other epidemiological investigations such as infection rate and dynamics of the snail population. After 13 mass treatments in Alian?a, the prevalence of S. mansoni infection was reduced from 57.9% to 7.4%. In Coroatá with 11 mass treatments the prevalence fell from 69.2% to 12.8% and in Alegre, with only 4 mass treatments there was practically no reduction in prevalence: 22.9% to 21%. After mass treatments the type II hepatointestinal clinical form was 10.8% in Alian?a, 17.9% in Alegre and 18% in Coroatá. The hepatosplenic (type III) form was not seen in Alian?a and Coroatá but unexplanably it was 7.6% in Alegre. There was no correlation between the egg load elimination and the clinical forms.     

Infection intensity-dependent accuracy of reagent strip for the diagnosis of Schistosoma haematobium and estimation of treatment prevalence thresholds

BackgroundReagent strip to detect microhematuria as a proxy for Schistosoma haematobium infections has been considered an alternative to urine filtration for individual diagnosis and community-based estimates of treatment needs for preventive chemotherapy. However, the diagnostic accuracy of reagent strip needs further investigation, particularly at low infection intensity levels.MethodsWe used existing data from a study conducted in Tanzania that employed urine filtration and reagent strip testing for S. haematobium in two villages, including a baseline and six follow-up surveys after praziquantel treatment representing a wide range of infection prevalence. We developed a Bayesian model linking individual S. haematobium egg count data based on urine filtration to reagent strip binary test results available on multiple days and estimated the relation between infection intensity and sensitivity of reagent strip. Furthermore, we simulated data from 3,000 hypothetical populations with varying mean infection intensity to infer on the relation between prevalence observed by urine filtration and the interpretation of reagent strip readings.Principal findingsReagent strip showed excellent sensitivity even for single measurement reaching 100% at around 15 eggs of S. haematobium per 10 ml of urine when traces on reagent strip were considered positive. The corresponding specificity was 97%. When traces were considered negative, the diagnostic accuracy of the reagent strip was equivalent to urine filtration data obtained on a single day. A 10% and 50% urine filtration prevalence based on a single day sampling corresponds to 11.2% and 48.6% prevalence by reagent strip, respectively, when traces were considered negative, and 17.6% and 57.7%, respectively, when traces were considered positive.Conclusions/SignificanceTrace results should be included in reagent strip readings when high sensitivity is required, but excluded when high specificity is needed. The observed prevalence of reagent strip results, when traces are considered negative, is a good proxy for prevalence estimates of S. haematobium infection by urine filtration on a single day.     

Parasite diversity as an indicator of environmental change? An example from tropical grouper (Epinephelus fuscoguttatus) mariculture in Indonesia

Fish parasites are used to monitor long-term change in finfish grouper mariculture in Indonesia. A total of 210 Epinephelus fuscoguttatus were sampled in six consecutive years between 2003/04 and 2008/09 and examined for parasites. The fish were obtained from floating net cages of a commercially run mariculture facility that opened in 2001. The fauna was species rich, consisting of ten ecto- and 18 endoparasite species. The ectoparasite diversity and composition was relatively stable, with the monogeneans Pseudorhabdosynochus spp. (83-100% prevalence, Berger-Parker Index of 0·82-0·97) being the predominant taxon. Tetraphyllidean larvae Scolex pleuronectis and the nematodes Terranova sp. and Raphidascaris sp. 1 were highly abundant in 2003/04-2005/06 (max. prevalence S. pleuronectis 40%, Terranova sp. 57%, Raphidascaris sp. 1 100%), and drastically reduced until 2008/09. These parasites together with the prevalence of Trichodina spp., ecto-/endoparasite ratio and endoparasite diversity illustrate a significant change in holding conditions over the years. This can be either referred to a definite change in management methods such as feed use and fish treatment, or a possible transition of a relatively undisturbed marine environment into a more affected habitat. By visualizing all parameters within a single diagram, we demonstrate that fish parasites are useful bioindicators to monitor long-term change in Indonesian grouper mariculture. This also indicates that groupers can be used to monitor environmental change in the wild. Further taxonomic and systematic efforts in less sampled regions significantly contributes to this new application, supporting fish culture and environmental impact monitoring also in other tropical marine habitats.     

Current status of sensitivity to praziquantel in a focus of potential drug resistance in Egypt

A decade ago, a study revealed that praziquantel (PZQ) failed to cure 1.6% of those with intestinal schistomiasis in five villages of the Nile delta region. The recommended dosage of PZQ is a single 40 mg/kg oral dose, and each of these patients continued to pass viable Schistosoma mansoni eggs despite three successive doses at or above this level. The eggs passed by these uncured villagers produced adult worms that were, in most cases, significantly less responsive to PZQ in vitro. This report investigates the current sensitivity of S. mansoni infections to PZQ after 10 years of therapeutic pressure in the same villages, testing the hypothesis that the number of drug failures would have increased as continued drug pressure selected for worms with diminished sensitivity to PZQ. The data show that these villages have experienced a significant decrease in the prevalence and intensity of S. mansoni infections, with present infection rate of 10.9%, compared with 25.1% in 1994. The first treatment resulted in normal range of cure rates, between 73.8 and 92.3% in each of the five villages in the study. After three successive doses (40, 40, and 60 mg/kg, the same treatment protocol applied a decade ago) there were no uncured patients remaining in the study. This shows that there has not been an increase of drug failure, despite 10 years of therapeutic pressure in these villages where there had been resistant infections and worms with decreased response to PZQ.     

pime: A package for discovery of novel differences among microbial communities

The data used for profiling microbial communities is usually sparse with some microbes having high abundance in a few samples and being nearly absent in others. However, current bioinformatics tools able to deal with this sparsity are lacking. pime (Prevalence Interval for Microbiome Evaluation) was designed to remove those taxa that may be high in relative abundance in just a few samples but have a low prevalence overall. The reliability and robustness of pime were compared against existing methods and tested using 16S rRNA independent data sets. pime filters microbial taxa not shared in a per treatment prevalence interval started at 5% prevalence with increasing increments of 5% at each filtering step. For each prevalence interval, hundreds of decision trees were calculated to predict the likelihood of detecting differences in treatments. The best prevalence‐filtered data set was user‐selected by choosing the prevalence interval that kept a large portion of the 16S rRNA sequences in the data set while also showing the lowest error rate. To obtain the likelihood of introducing type I error while building prevalence‐filtered data sets, an error detection step based was also included. A pime reanalysis of published data sets uncovered other expected microbial associations than previously reported, which may be masked when only relative abundance was considered.