Jürg Utzinger

Publications (276)1201.75 Total impact

• Article: Statistical methodological issues in mapping historical schistosomiasis survey data.

  Frédérique Chammartin, Eveline Hürlimann, Giovanna Raso, Eliézer K N'goran, Jürg Utzinger, Penelope Vounatsou
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  ABSTRACT: For schistosomiasis and other neglected tropical diseases for which resources for control are still limited, model-based maps are needed for prioritizing spatial targeting of control interventions and surveillance of control programmes. Bayesian geostatistical modelling has been widely and effectively used to generate smooth empirical risk maps. In this paper, we review important issues related to the modelling of schistosomiasis risk, including Bayesian computation of large datasets, heterogeneity of historical data, stationary and isotropy assumptions and novel approaches for Bayesian geostatistical variable selection. We provide an example of advanced Bayesian geostatistical variable selection based on historical prevalence data of Schistosoma mansoni in Côte d'Ivoire. We include a "parameter expanded normal mixture of inverse-gamma" prior for the regression coefficients, which in turn allows selection of blocks of covariates, particularly categorical variables. The implemented Bayesian geostatistical variable selection provided a rigorous approach for the selection of predictors within a Bayesian geostatistical framework, identified the most important predictors of S. mansoni infection risk and led to a more parsimonious model compared to traditional selection approaches that ignore the spatial structure in the data. In conclusion, statistical advances in Bayesian geostatistical modelling offer unique opportunities to account for important inherent characteristics of the Schistosoma infection, and hence Bayesian geostatistical models can guide the spatial targeting of control interventions.
  Acta tropica 05/2013; · 2.22 Impact Factor
• Article: Effects of inflammation and Plasmodium falciparum infection on soluble transferrin receptor and plasma ferritin concentration in different age groups: a prospective longitudinal study in Cote d'Ivoire.

  Aurélie A Righetti, Rita Wegmüller, Dominik Glinz, Mamadou Ouattara, Lukas G Adiossan, Eliézer K N'goran, Jürg Utzinger, Richard F Hurrell
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  ABSTRACT: BACKGROUND: Iron deficiency (ID) is a major cause of anemia, along with other nutritional, parasitic, and genetic factors. Accurate biomarkers are needed to estimate the relative contribution of ID to anemia. Soluble transferrin receptor (sTfR) is thought to be unaffected by inflammation. OBJECTIVES: The objectives were to determine the difference in sTfR and plasma ferritin (PF) concentrations among infants (6-23 mo of age), school-age children (6-8 y of age), and women (15-25 y of age) with and without inflammation and with and without Plasmodium falciparum infection and to assess the effect of adjusting sTfR and PF for inflammation or for P. falciparum infection on the estimated prevalence of ID. DESIGN: The data were derived from a 14-mo prospective longitudinal survey on anemia, which was conducted in the Taabo area, south-central Côte d'Ivoire. RESULTS: At baseline, sTfR concentration was significantly higher in infants and school-age children with either inflammation or P. falciparum infection than in control individuals without inflammation or without P. falciparum infection. Individuals with inflammation had significantly higher PF concentrations than did subjects without inflammation. Adjustments in sTfR concentrations for inflammation or P. falciparum infection in infants and school-age children resulted in significantly lower ID prevalence. Adjustment of PF for inflammation and Plasmodium infection resulted in a higher ID prevalence in infants and women. CONCLUSIONS: In Ivorian infants and school-age children, ID prevalence was considerably lower after adjustment of sTfR for inflammation. However, as the prevalence estimates for ID differed widely if based on sTfR or PF, caution is still needed when estimating ID prevalence in areas with a high prevalence of inflammation or malaria. This trial was registered at controlled-trials.com as ISRCTN02181959.
  American Journal of Clinical Nutrition 04/2013; · 6.67 Impact Factor
• Article: Soil-transmitted helminth infection in South America: a systematic review and geostatistical meta-analysis.

  Frédérique Chammartin, Ronaldo Gc Scholte, Luiz H Guimarães, Marcel Tanner, Jürg Utzinger, Penelope Vounatsou
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  ABSTRACT: BACKGROUND: The four common soil-transmitted helminth species-Ascaris lumbricoides, Trichuris trichiura, and the two hookworm species Ancylostoma duodenale and Necator americanus-are endemic in South America, but their distribution, infection prevalence, and regional burden are poorly understood. We aimed to estimate the risk and number of people infected with A lumbricoides, T trichiura, and hookworm across South America. METHODS: We did a systematic review of reports on the prevalence of soil-transmitted helminth infection in South America published up to May 14, 2012. We extracted and georeferenced relevant survey data and did a meta-analysis of the data to assess the geographical distribution of the infection risk with Bayesian geostatistical models. We used advanced Bayesian variable selection to identify environmental determinants that govern the distribution of soil-transmitted helminth infections. FINDINGS: We screened 4085 scientific papers and identified 174 articles containing relevant survey prevalence data. We georeferenced 6948 survey locations and entered the data into the open-access Global Neglected Tropical Diseases database. Survey data were sparse for the south of the continent and for the western coast, and we identified no relevant information for Uruguay and little data for smaller countries such as Suriname, Guyana, French Guiana, and Ecuador. Population-adjusted prevalence of infection with A lumbricoides was 15·6%, with T trichiura was 12·5%, and with hookworm was 11·9% from 2005 onwards. Risks of contracting soil-transmitted helminth infection have substantially reduced since 2005 (odds ratio 0·47 [95% Bayesian credible interval 0·46-0·47] for A lumbricoides, 0·54 [0·54-0·55] for T trichiura, and 0·58 [0·58-0·59] for hookworm infection). INTERPRETATION: Our findings offer important baseline support for spatial targeting of soil-transmitted helminthiasis control, and suggest that more information about the prevalence of soil-transmitted helminth infection is needed, especially in countries in which we estimate prevalence of infection to be high but for which current data are scarce. FUNDING: UBS Optimus Foundation and Brazilian Swiss Joint Research Programme (BSJRP 011008).
  The Lancet Infectious Diseases 04/2013; · 17.39 Impact Factor
• Article: Untapped potential of health impact assessment.

  Mirko S Winkler, Gary R Krieger, Mark J Divall, Guéladio Cissé, Mark Wielga, Burton H Singer, Marcel Tanner, Jürg Utzinger
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  ABSTRACT: The World Health Organization has promoted health impact assessment (HIA) for over 20 years. At the 2012 United Nations Conference on Sustainable Development (Rio+20), HIA was discussed as a critical method for linking health to "green economy" and "institutional framework" strategies for sustainable development. In countries having a high human development index (HDI), HIA has been added to the overall assessment suite that typically includes potential environmental and social impacts, but it is rarely required as part of the environmental and social impact assessment for large development projects. When they are performed, project-driven HIAs are governed by a combination of project proponent and multilateral lender performance standards rather than host country requirements. Not surprisingly, in low-HDI countries HIA is missing from the programme and policy arena in the absence of an external project driver. Major drivers of global change (e.g. population growth and urbanization, growing pressure on natural resources and climate change) inordinately affect low- and medium-HDI countries; however, in such countries HIA is conspicuously absent. If the cloak of HIA invisibility is to be removed, it must be shown that HIA is useful and beneficial and, hence, an essential component of the 21st century's sustainable development agenda. We analyse where and how HIA can become fully integrated into the impact assessment suite and argue that the impact of HIA must not remain obscure.
  Bulletin of the World Health Organisation 04/2013; 91(4):298-305. · 4.64 Impact Factor
• Article: Mobile Phone Microscopy for the Diagnosis of Soil-Transmitted Helminth Infections: A Proof-of-Concept Study.

  Isaac I Bogoch, Jason R Andrews, Benjamin Speich, Jürg Utzinger, Shaali M Ame, Said M Ali, Jennifer Keiser
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  ABSTRACT: We created a mobile phone microscope and assessed its accuracy for the diagnosis of soil-transmitted helminths compared with conventional microscopy. Mobile phone microscopy has a sensitivity of 69.4% for detecting any helminth egg and sensitivities of 81.0%, 54.4%, and 14.3% for the diagnosis of Ascaris lumbricoides, Trichuris trichiura, and hookworm, respectively.
  The American journal of tropical medicine and hygiene 03/2013; · 2.59 Impact Factor
• Article: Accuracy of Urine Circulating Cathodic Antigen Test for the Diagnosis of Schistosoma mansoni in Preschool-Aged Children before and after Treatment.

  Jean T Coulibaly, Yves K N'gbesso, Stefanie Knopp, Nicaise A N'guessan, Kigbafori D Silué, Govert J van Dam, Eliézer K N'goran, Jürg Utzinger
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  ABSTRACT: The Kato-Katz technique is widely used for the diagnosis of Schistosoma mansoni, but shows low sensitivity in light-intensity infections. We assessed the accuracy of a commercially available point-of-care circulating cathodic antigen (POC-CCA) cassette test for the diagnosis of S. mansoni in preschool-aged children before and after praziquantel administration. A 3-week longitudinal survey with a treatment intervention was conducted in Azaguié, south Côte d'Ivoire. Overall, 242 preschoolers (age range: 2 months to 5.5 years) submitted two stool and two urine samples before praziquantel administration, and 86 individuals were followed-up posttreatment. Stool samples were examined with duplicate Kato-Katz thick smears for S. mansoni. Urine samples were subjected to POC-CCA cassette test for S. mansoni, and a filtration method for S. haematobium diagnosis. Before treatment, the prevalence of S. mansoni, as determined by quadruplicate Kato-Katz, single CCA considering 'trace' as negative (t-), and single CCA with 'trace' as positive (t+), was 23.1%, 34.3% and 64.5%, respectively. Using the combined results (i.e., four Kato-Katz and duplicate CCA(t-)) as diagnostic 'gold' standard, the sensitivity of a single Kato-Katz, a single CCA(t-) or CCA(t+) was 28.3%, 69.7% and 89.1%, respectively. Three weeks posttreatment, the sensitivity of a single Kato-Katz, single CCA(t-) and CCA(t+) was 4.0%, 80.0% and 84.0%, respectively. The intensity of the POC-CCA test band reaction was correlated with S. mansoni egg burden (odds ratio = 1.2, p = 0.04). CONCLUSIONSSIGNIFICANCE: A single POC-CCA cassette test appears to be more sensitive than multiple Kato-Katz thick smears for the diagnosis of S. mansoni in preschool-aged children before and after praziquantel administration. The POC-CCA cassette test can be recommended for the rapid identification of S. mansoni infections before treatment. Additional studies are warranted to determine the usefulness of POC-CCA for assessing drug efficacy and monitoring the impact of control interventions.
  PLoS Neglected Tropical Diseases 03/2013; 7(3):e2109. · 4.69 Impact Factor
• Article: Dynamics of Anemia in Relation to Parasitic Infections, Micronutrient Status, and Growing Age in South-Central Cote d'Ivoire.

  Aurélie A Righetti, Lukas G Adiossan, Mamadou Ouattara, Dominik Glinz, Richard F Hurrell, Eliézer K N'goran, Rita Wegmüller, Jürg Utzinger
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  ABSTRACT: Background. Parasitic diseases (e.g., malaria and helminthiases) exert enormous burdens on public health and social wellbeing. Moreover, parasitic infections are important causes of anemia in tropical Africa, exacerbated by lack of diversified diet, inflammatory and genetic diseases. There is a paucity of longitudinal studies monitoring the dynamics of anemia in relation to the aforementioned parameters.Methods. We designed a 14-month prospective longitudinal study in three cohorts (i.e., infants aged 6-23 months, 6-8 year-old children, and women aged 15-25 years), in the Taabo health demographic surveillance system located in south-central Côte d'Ivoire. Parasitological, hematological, and micronutrient data were obtained at repeated cross-sectional surveys, utilizing standardized, quality-controlled methods.Results. We found that young age, Plasmodium and Schistosoma infections, cellular iron deficiency, and stunting were significantly negatively associated with hemoglobin concentration. Moreover, iron status biomarkers (i.e., ferritin and soluble transferrin receptor) were significantly associated with inflammatory parameters.Conclusions. Our results call for effective prevention and control measures targeting parasitic diseases and iron deficiency. These measures might include the distribution of long-lasting insecticidal nets, intermittent preventive treatment for malaria, regular anthelmintic drug administration, and improved intake of bioavailable iron, coupled with health and nutritional education, improved hygiene, water, and sanitation.
  The Journal of Infectious Diseases 02/2013; · 6.41 Impact Factor
• Article: A new rapid diagnostic test for detection of anti-Schistosoma mansoni and anti-Schistosoma haematobium antibodies.

  Jean T Coulibaly, Eliézer K N'goran, Jürg Utzinger, Michael J Doenhoff, Emily M Dawson
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  ABSTRACT: BACKGROUND: Parasitological methods are widely used for the diagnosis of schistosomiasis. However, they are insensitive, particularly in areas of low endemicity, and labour-intensive. Immunoassays based on detection of anti-schistosome antibodies have the merit of high sensitivity and recently a rapid diagnostic test (RDT), incorporating Schistosoma mansoni cercarial transformation fluid (SmCTF) for detection of anti-schistosome antibodies in blood has been developed. Here, we assessed the diagnostic performance of the SmCTF-RDT for S. mansoni and S. haematobium infections by comparing it with microscopy for egg detection. METHODS: A cross-sectional survey was carried out in Azaguie, south Cote d'Ivoire. 118 pre-school-aged children submitted two stool and two urine samples, which were subjected to the Kato-Katz and urine filtration methods for the detection of S. mansoni and S. haematobium eggs, respectively. Urine was also subjected to a commercially available cassette test for S. mansoni, which detects circulating cathodic antigen. A finger-prick blood sample was used for the SmCTF-RDT for detection of anti-S. mansoni and anti-S. haematobium antibodies. RESULTS: The prevalence of both anti-S. mansoni and anti-S. haematobium antibodies was more than three times higher than the prevalence of infection estimated by egg detection under a microscope. Using quadruplicate Kato-Katz as the reference standard for the diagnosis of S. mansoni infection, the sensitivity, negative predictive value (NPV), and positive predictive value (PPV) of the SmCTF-RDT was 75.0%, 84.2% and 22.5%, respectively. When two urine filtrations were considered as the reference standard for the diagnosis of S. haematobium infection, the sensitivity, NPV and PPV of SmCTF-RDT was 66.7%, 94.9% and 5.1%, respectively. The specificity of SmCTF-RDT, when using egg-detection as the reference standard, was estimated to be 34.4%. This low specificity may be a reflection of the relative insensitivity of the direct diagnostic approaches using microscopy. CONCLUSIONS: The SmCTF-RDT is at least as sensitive as duplicate Kato-Katz and a single urine filtration for detection of S. mansoni and S. haematobium, respectively. Further investigations into the specificity of the test for anti-schistosome antibodies are necessary, but our results suggest that it may be a useful tool for mapping the prevalence of anti-schistosome antibodies in a given population pending intervention.
  Parasites & Vectors 01/2013; 6(1):29. · 2.94 Impact Factor
• Article: Advances with the Chinese anthelminthic drug tribendimidine in clinical trials and laboratory investigations.

  Shu-Hua Xiao, Jürg Utzinger, Marcel Tanner, Jennifer Keiser, Jian Xue
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  ABSTRACT: The anthelminthic drug tribendimidine has been approved by Chinese authorities for human use in 2004, and a first comprehensive review was published in Acta Tropica in 2005. Here, we summarise further advances made through additional clinical trials and laboratory investigations. Two phase IV trials have been conducted in the People's Republic of China, the first one enrolling 1,292 adolescents and adults aged 15-70 years and the second one conducted with 899 children aged 4-14 years who were infected with one or multiple species of soil-transmitted helminths. Oral tribendimidine (single 400mg enteric-coated tablet given to adolescents/adults and 200mg to children) showed high cure rates against Ascaris lumbricoides (90.1-95.0%) and moderate-to-high cure rates against hookworm (82.0-88.4%). Another trial done in school-aged children using a rigorous diagnostic approach found a cure rate against hookworm of 76.5%. A single oral dose of tribendimidine showed only low cure rates against Trichuris trichiura (23.9-36.8%) confirming previous results. Tribendimidine administered to children infected with Enterobius vermicularis (two doses of 200mg each on consecutive days) resulted in a high cure rate (97.1%). Importantly, a series of randomised, exploratory trials revealed that tribendimidine shows interesting activity against the liver flukes Opisthorchis viverrini and Clonorchis sinensis, the tapeworm Taenia spp. and the threadworm Strongyloides stercoralis with respective cure rates of 70.0%, 40.0%, 53.3% and 36.4%. Pharmacokinetic studies in healthy Chinese volunteers indicated that after oral administration of tribendimidine, no parent drug was detected in plasma, but its primary metabolite, p-(1-dimethylamino ethylimino) aniline (aminoamidine, deacylated amidantel) (dADT), was found in plasma. dADT is then further metabolized to acetylated dADT (AdADT). dADT exhibits activity against several species of hookworm and C. sinensis in experimental studies, similar to that of tribendimidine. First studies elucidating the mechanism of action suggested that tribendimidine is an L-type nicotinic acetylcholine receptor agonist. Additional experimental studies revealed that the anti-parasite spectrum of tribendimidine is very broad. Indeed, to date, activity has been documented against 20 different nematode, trematode and cestode species. Taken together, tribendimidine warrants further scientific inquiry, including more comprehensive toxicity appraisals mechanism of action studies and clinical investigation as it holds promise as a broad spectrum anthelminthics.
  Acta tropica 01/2013; · 2.22 Impact Factor
• Article: Dynamics of people's socio-economic status in the face of schistosomiasis control interventions in Ukerewe district, Tanzania.

  Joseph R Mwanga, Nicholas J S Lwambo, Susan F Rumisha, Penelope Vounatsou, Jürg Utzinger
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  ABSTRACT: There is a paucity of research on micro-level assessment of the dynamics of socio-economic status following health interventions. The use of household asset data to determine wealth indices is a common procedure for estimating socio-economic position in low-income countries. Indeed, in such settings information about income is usually lacking and the collection of individual consumption or expenditure data would require in-depth interviews and the risk of bias is considerable. In the study presented here, we determined the socio-economic status of 159 households in a village in north-western Tanzania before and 1 year after participatory hygiene and sanitation transformation (PHAST) intervention to control schistosomiasis. We constructed a household 'wealth index' based on durable assets ownership (e.g. bicycle and radio) and household characteristics dealing with ownership of land, house and house construction features (e.g. type of walls and roof). We employed principal components analysis and classified households into wealth quintiles. The study revealed that asset variables with positive factor scores were associated with higher socio-economic status, whereas asset variables with negative factor scores were associated with lower socio-economic status. Overall, households which were rated as the poorest and very poor were on the decrease, whereas those rated as poor, less poor and the least poor were on the increase after PHAST intervention. This decrease/increase was significant. The median shifted from -0.761 to -0.448, and the mean from -0.204 (standard deviation (SD) 1.924) to 0.193 (SD 2.079) between pre- and post-intervention phases. The difference in socio-economic status of the people comparing the pre- and post-intervention phase was highly statistically significant (p<0.001). This observation was confirmed by a multinomial model with a random effect on the households. We argue that significant changes in the socio-economic status observed in our study are attributable to the PHAST intervention, despite other sporadic interventions against schistosomiasis.
  Acta tropica 01/2013; · 2.22 Impact Factor
• Article: The relative contribution of co-infections to focal infection risk in children

  Joanne Lello, Stefanie Knopp, Khalfan A. Mohammed, I. Simba Khamis, Jürg Utzinger
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  ABSTRACT: 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.
  Proceedings of the Royal Society B: Biological Sciences 01/2013; 280(20122813). · 5.41 Impact Factor
• Article: Prevalence of intestinal protozoa infection among school-aged children on Pemba Island, Tanzania, and effect of single-dose albendazole, nitazoxanide and albendazole-nitazoxanide.

  Benjamin Speich, Hanspeter Marti, Shaali M Ame, Said M Ali, Isaac I Bogoch, Jürg Utzinger, Marco Albonico, Jennifer Keiser
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  ABSTRACT: BACKGROUND: Pathogenic intestinal protozoa infections are common in school-aged children in the developing world and they are frequently associated with malabsorption syndromes and gastrointestinal morbidity. Since diagnosis of these parasites is difficult, prevalence data on intestinal protozoa is scarce. METHODS: We collected two stool samples from school-aged children on Pemba Island, Tanzania, as part of a randomized controlled trial before and 3 weeks after treatment with (i) single-dose albendazole (400 mg); (ii) single-dose nitazoxanide (1,000 mg); (iii) nitazoxanide-albendazole combination (1,000 mg--400 mg), with each drug given separately on two consecutive days; and (iv) placebo. Formalin-fixed stool samples were examined for the presence of intestinal protozoa using an ether-concentration method to determine the prevalence and estimate cure rates (CRs). RESULTS: Almost half (48.7%) of the children were diagnosed with at least one of the (potentially) pathogenic protozoa Giardia intestinalis, Entamoeba histolytica/E. dispar and Blastocystis hominis. Observed CRs were high for all treatment arms, including placebo. Nitazoxanide showed a significant effect compared to placebo against the non-pathogenic protozoon Entamoeba coli. CONCLUSIONS: Intestinal protozoa infections might be of substantial health relevance even in settings where they are not considered as a health problem. Examination of a single stool sample with the ether-concentration method lacks sensitivity for the diagnosis of intestinal protozoa, and hence, care is indicated when interpreting prevalence estimates and treatment effects.
  Parasites & Vectors 01/2013; 6(1):3. · 2.94 Impact Factor
• Article: The relative contribution of co-infection to focal infection risk in children.

  Joanne Lello, Stefanie Knopp, Khalfan A Mohammed, I Simba Khamis, Jürg Utzinger, Mark E Viney
  [show abstract] [hide abstract]
  ABSTRACT: 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.
  Proceedings of the Royal Society B: Biological Sciences 01/2013; 280(1754):20122813. · 5.41 Impact Factor
• Article: Malaria surveillance-response strategies in different transmission zones of the People's Republic of China: preparing for climate change.

  Guo-Jing Yang, Marcel Tanner, Jürg Utzinger, John B Malone, Robert Bergquist, Emily Yy Chan, Qi Gao, Xiao-Nong Zhou
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  ABSTRACT: BACKGROUND: A sound understanding of malaria transmission patterns in the People's Republic of China (P.R. China) is crucial for designing effective surveillance-response strategies that can guide the national malaria elimination programme (NMEP). Using an established biology-driven model, it is expected to design and refine appropriate surveillance-response strategies for different transmission zones, and thus assist in optimizing the NMEP in the ongoing implementation (2010--2020) and, potentially, in the post-elimination stage (2020--2050). METHODS: Environmental data obtained from 676 locations across P.R. China, such as monthly temperature and yearly relative humidity (YRH), for the period 1961--2000 were prepared. Smoothed surface maps of the number of months suitable for parasite survival derived from monthly mean temperature and YRH were generated. For each decade, the final malaria prediction map was overlaid by two mask maps, in terms of number of months suitable for parasite survival and YRH map in excess of 60%. RESULTS: Considering multiple environmental factors simultaneously, the regions suitable for malaria transmission were found to have shifted northwards, which was especially pronounced in northern P.R. China. The unstable transmission regions (transmission period between five and six months) increased transmission intensity due to prolonged transmission periods, especially in the central part of the country. CONCLUSION: Adequate and effective surveillance-response strategies for NMEP must be designed to achieve the goal of malaria elimination in P.R. China by 2020, especially in the zones predicted to be most vulnerable to climate change.
  Malaria Journal 12/2012; 11(1):426. · 3.19 Impact Factor
• Article: Dynamics of Schistosoma haematobium egg output and associated infection parameters following treatment with praziquantel in school-aged children.

  Katarina Stete, Stefanie J Krauth, Jean T Coulibaly, Stefanie Knopp, Jan Hattendorf, Ivan Müller, Laurent K Lohourignon, Winfried V Kern, Eliézer K N'goran, Jürg Utzinger
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  ABSTRACT: BACKGROUND: Praziquantel is the drug of choice in preventive chemotherapy targeting schistosomiasis. Increasing large-scale administration of praziquantel requires monitoring of drug efficacy to detect early signs of development of resistance. Standard protocols for drug efficacy monitoring are necessary. Here, we determined the optimal time point for praziquantel efficacy assessment against Schistosoma haematobium and studied the dynamics of infection parameters following treatment. METHODS: Ninety school-aged children from south Cote d'Ivoire with a parasitologically confirmed S. haematobium infection were treated with a single oral dose of praziquantel (40 mg/kg) and followed up for 62 days post-treatment. Urine samples were collected on 23 schooldays during this period and were subjected to visual examination (macrohaematuria), urine filtration and microscopy (S. haematobium eggs) and reagent strip testing (microhaematuria, proteinuria and leukocyturia). RESULTS: Observed cure and egg reduction rates were highly dependent on the time point post-treatment. Egg reduction rates were high (>97%) in weeks 3--9 post-treatment. Cure rates were highest in weeks 6 (92.9%) and 9 (95.0%) post-treatment. The prevalence of infection-associated parameters decreased after treatment, reaching a minimum of 2.4% in weeks 5 (proteinuria) and 7 (leukocyturia) post-treatment, and 16.3% at the end of week 8 (microhaematuria). Macrohaematuria disappeared between weeks 3 and 6 post-treatment. CONCLUSIONS: For monitoring praziquantel efficacy against S. haematobium, we recommend that the cure rate is assessed at week 6 post-treatment. The egg reduction rate can be evaluated earlier, from day 14 post-treatment onwards. Reagent strips are a useful additional tool for evaluating treatment outcomes in areas with high endemicity, preferably at weeks 5 and 6 post-treatment. The delayed decrease of microhaematuria confirms that lesions in the urinary tract persist longer than egg excretion post-treatment.
  Parasites & Vectors 12/2012; 5(1):298. · 2.94 Impact Factor
• Article: Willingness to use a rapid diagnostic test for malaria in a rural area of central Cote d'Ivoire.

  Colombe Coffie Comoé, Allassane F Ouattara, Giovanna Raso, Marcel Tanner, Jürg Utzinger, Benjamin G Koudou
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  ABSTRACT: BACKGROUND: Malaria mortality is mainly a direct consequence of inadequate and/or delayed diagnosis and case management. Some important control interventions (e.g. long-lasting insecticidal nests) have contributed to reduce malaria morbidity and mortality in different parts of the world. Moreover, the development and effective use of rapid diagnostic tests (RDTs) hold promise to further enhance the control and elimination of malaria, particularly in areas where health services are deficient. The aim of this study was to determine knowledge, attitudes, practices and beliefs in relation to RDTs for malaria in rural Cote d'Ivoire. METHODS: One hundred individuals from Bozi and Yoho who sought care at the health centre in Bozi and were offered an RDT for malaria were interviewed in April 2010 using a pre-tested questionnaire on practice and perceptions in relation to RDTs for malaria. The relationships between acceptance of RDTs and factors related to opinions were identified, using generalized linear mixed models. Qualitative data from open-ended questions complemented the quantitative analysis. RESULTS: Only 34 out of 100 patients who were offered an RDT for malaria were willing to undergo the test. People who perceived blood as a sacred body fluid were less likely to comply with an RDT. The concurrent availability and use of RDTs for HIV and malaria was associated with an unwilling attitude towards RDTs for malaria (Fisher's exact test, p <0.001). The initial willingness of patients to accept malaria testing with RDTs was significantly related to general fear and wanting to know malaria infection status. For further and regular use of RDTs, a strong relationship was observed between acceptance and the idea that an RDT is a pretext used by health worker to know HIV status (odds ratio (OR) = 16.61, 95% confidence interval (CI) = 1.03-268.5). Those thinking that blood samples were useful for medical diagnoses were 8.31-times (95% CI = 2.22-31.1) more likely to undergo an RDT compared to those rejecting blood sampling as a diagnostic strategy. CONCLUSION: Socio-cultural factors might be barriers for accepting RDTs in general health services. There are social representations of malaria and HIV/AIDS, symbolic for blood or experiences in relation to blood taking and blood-related diseases in relation to the introduction and routine use of RDTs. Special attention should be given to these barriers as otherwise the promotion of RDTs for prompt and effective diagnosis and subsequent management of malaria is hampered.
  BMC Public Health 12/2012; 12(1):1089. · 2.00 Impact Factor
• Article: Safety and efficacy of praziquantel syrup (Epiquantel(®)) against Schistosoma haematobium and S. mansoni in preschool-aged children in Niger.

  Amadou Garba, Mariama S Lamine, Ali Djibo, Tahirou Almoustapha, Mahamadou Aboubacar Aouami, Aichatou Alfari, Anna E Phillips, Alan Fenwick, Jürg Utzinger
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  ABSTRACT: Given the characteristic age-prevalence curve of Schistosoma infection, preventive chemotherapy with praziquantel is primarily targeted at school-aged children, whilst, in highly endemic areas, other high-risk groups might be included for regular treatment. Nevertheless, schistosomiasis can affect children well before they reach school-age, but this population group is usually excluded from preventive chemotherapy. We assessed the safety and efficacy of praziquantel syrup (Epiquantel(®)) in preschool-aged children in three villages of Niger. Children aged ≤72 months provided multiple urine and stool samples that were microscopically examined using standard protocols. Schistosoma-positive children were treated with praziquantel syrup at a dose of 40mg/kg after a meal of millet porridge. Children remained under medical supervision for four hours and adverse events were recorded. Additionally, a questionnaire was administrated to the mothers/guardians 24hours post-treatment for further probing of adverse events. Treatment efficacy was evaluated three and six weeks post-treatment using multiple stool and urine samples. A third of the 243 treated children reported adverse events within four hours, whilst a further 6.2% reported adverse events upon probing 24hours post-treatment. Abdominal pain, bloody diarrhoea and sleepiness were the most common adverse events, but these were transient and self-limiting. Praziquantel syrup showed moderate-to-high efficacy against S. haematobium with egg reduction rates of 69.4% and 71.2% three and six weeks post-treatment and cure rates of 85.7% (95% confidence interval (CI) 79.7-90.5%) and 94.9% (95% CI 90.5-97.6%), respectively. Considerably lower cure and egg reduction rates were observed against S. mansoni (e.g. cure rate at 6-week post-treatment follow-up was only 50.6% (95% CI 39.9-61.2%). Concluding, praziquantel syrup is well tolerated in preschool-aged children with moderate-to-high efficacy against S. haematobium, but considerably lower efficacy against S. mansoni in Niger. A larger study is warranted to investigate the observed differences in species-specific susceptibilities and to assess operational issues and community-effectiveness.
  Acta tropica 12/2012; · 2.22 Impact Factor
• Article: Efficacy and Safety of Tribendimidine against Clonorchis sinensis.

  Men-Bao Qian, Peiling Yap, Yi-Chao Yang, Hai Liang, Zhi-Hua Jiang, Wei Li, Yu-Guang Tan, Hui Zhou, Jürg Utzinger, Xiao-Nong Zhou, Jennifer Keiser
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  ABSTRACT: Background. Clonorchiasis is of considerable public health importance, particularly in the People's Republic of China (P.R. China), where most of the 15 million individuals infected with Clonorchis sinensis are currently concentrated. Praziquantel is the drug of choice, but tribendimidine might be an alternative.Methods. We performed a randomized open-label trial in Guangxi, P.R. China to assess the efficacy and safety of 400 mg tribendimidine once, 400 mg tribendimidine daily for three days, and 75 mg/kg praziquantel in one day divided in three doses against parasitological confirmed C. sinensis infections. Cure and egg reduction rates were determined 3 weeks post-treatment using available case analysis. Clinical symptoms were documented at baseline, and adverse events were recorded and graded 3 and 24 h after each dose.Results. A total of 74 patients were included in the final analysis. Single-dose tribendimidine achieved a cure rate of 44%, while cure rates of 58% and 56% were obtained for tribendimidine administered for 3 days and praziquantel, respectively. High egg reduction rates (97.6-98.8%) were observed for all treatment regimens. Single-dose tribendimidine was the best-tolerated treatment scheme. Patients treated with praziquantel experienced significantly more adverse events than tribendimidine recipients (P <0.05).Conclusions. Tribendimidine has an efficacy comparable to praziquantel in the treatment of C. sinensis infection and resulted in fewer adverse events compared to praziquantel. Larger clinical trials are warranted among C. sinensis-infected patients to determine the potential of tribendimidine against clonorchiasis and other helminthiases.Trial registration. Controlled-Trials.com, identifier: ISRCTN80829842.
  Clinical Infectious Diseases 12/2012; · 9.15 Impact Factor
• Article: Efficacy and Safety of Praziquantel in Preschool-Aged Children in an Area Co-Endemic for Schistosoma mansoni and S. haematobium.

  Jean T Coulibaly, Yve K N'gbesso, Stefanie Knopp, Jennifer Keiser, Eliézer K N'goran, Jürg Utzinger
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  ABSTRACT: In sub-Saharan Africa the recommended strategy to control schistosomiasis is preventive chemotherapy. Emphasis is placed on school-aged children, but in high endemicity areas, preschool-aged children are also at risk, and hence might need treatment with praziquantel. Since a pediatric formulation (e.g., syrup) is not available outside of Egypt, crushed praziquantel tablets are used, but the efficacy and safety of this treatment regimen is insufficiently studied. We assessed the efficacy and safety of crushed praziquantel tablets among preschool-aged children (<6 years) in the Azaguié district, south Côte d'Ivoire, where Schistosoma mansoni and S. haematobium coexist. Using a cross-sectional design, children provided two stool and two urine samples before and 3 weeks after treatment. Crushed praziquantel tablets, mixed with water, were administered at a dose of 40 mg/kg. Adverse events were assessed and graded 4 and 24 hours posttreatment by interviewing mothers/guardians. Overall, 160 preschool-aged children had at least one stool and one urine sample examined with duplicate Kato-Katz thick smears and a point-of-care circulating cathodic antigen (POC-CCA) cassette for S. mansoni, and urine filtration for S. haematobium diagnosis before and 3 weeks after praziquantel administration. According to the Kato-Katz and urine filtration results, we found high efficacy against S. mansoni (cure rate (CR), 88.6%; egg reduction rate (ERR), 96.7%) and S. haematobium (CR, 88.9%; ERR, 98.0%). POC-CCA revealed considerably lower efficacy against S. mansoni (CR, 53.8%). Treatment was generally well tolerated, but moderately severe adverse events (i.e., body and face inflammation), were observed in four Schistosoma egg-negative children. Crushed praziquantel administered to preschool-aged children at a dose of 40 mg/kg is efficacious against S. mansoni and S. haematobium in a co-endemic setting of Côte d'Ivoire. Further research is required with highly sensitive diagnostic tools and safety must be investigated in more depth. Controlled-Trials.com ISRCTN53172722.
  PLoS Neglected Tropical Diseases 12/2012; 6(12):e1917. · 4.69 Impact Factor
• Article: An In-Depth Analysis of a Piece of Shit: Distribution of Schistosoma mansoni and Hookworm Eggs in Human Stool.

  Stefanie J Krauth, Jean T Coulibaly, Stefanie Knopp, Mahamadou Traoré, Eliézer K N'goran, Jürg Utzinger
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  ABSTRACT: An accurate diagnosis of helminth infection is important to improve patient management. However, there is considerable intra- and inter-specimen variation of helminth egg counts in human feces. Homogenization of stool samples has been suggested to improve diagnostic accuracy, but there are no detailed investigations. Rapid disintegration of hookworm eggs constitutes another problem in epidemiological surveys. We studied the spatial distribution of Schistosoma mansoni and hookworm eggs in stool samples, the effect of homogenization, and determined egg counts over time in stool samples stored under different conditions. Whole-stool samples were collected from 222 individuals in a rural part of south Côte d'Ivoire. Samples were cut into four pieces and helminth egg locations from the front to the back and from the center to the surface were analyzed. Some samples were homogenized and fecal egg counts (FECs) compared before and after homogenization. The effect of stool storing methods on FECs was investigated over time, comparing stool storage on ice, covering stool samples with a water-soaked tissue, or keeping stool samples in the shade. We found no clear spatial pattern of S. mansoni and hookworm eggs in fecal samples. Homogenization decreased S. mansoni FECs (p = 0.026), while no effect was observed for hookworm and other soil-transmitted helminths. Hookworm FECs decreased over time. Storing stool samples on ice or covered with a moist tissue slowed down hookworm egg decay (p<0.005). Our findings have important implications for helminth diagnosis at the individual patient level and for epidemiological surveys, anthelmintic drug efficacy studies and monitoring of control programs. Specifically, homogenization of fecal samples is recommended for an accurate detection of S. mansoni eggs, while keeping collected stool samples cool and moist delayed the disintegration of hookworm eggs.
  PLoS Neglected Tropical Diseases 12/2012; 6(12):e1969. · 4.69 Impact Factor