- Marcel Tanner holds a PhD in medical biology from the University of Basel and a MPH from the University of London. He was Director of the Swiss Tropicaledit
The global prevalence of malaria has decreased over the past fifteen years, but similar gains have not been realized against Plasmodium vivax because this species is less responsive to conventional malaria control interventions aimed... more
The global prevalence of malaria has decreased over the past fifteen years, but similar gains have not been realized against Plasmodium vivax because this species is less responsive to conventional malaria control interventions aimed principally at P. falciparum. Approximately half of all malaria cases outside of Africa are caused by P. vivax. This species places dormant forms in human liver that cause repeated clinical attacks without involving another mosquito bite. The diagnosis of acute patent P. vivax malaria relies primarily on light microscopy. Specific rapid diagnostic tests exist but typically perform relatively poorly compared to those for P. falciparum. Better diagnostic tests are needed for P. vivax. To guide their development, FIND, in collaboration with P. vivax experts, identified the specific diagnostic needs associated with this species and defined a series of three distinct target product profiles, each aimed at a particular diagnostic application: (i) point-of-car...
Research Interests: Biology, Malaria, Medicine, Plasmodium, Biological Sciences, and 14 moreHumans, Blood, Plasmodium falciparum, Infectious disease control, Diagnostic Test, Parasitic Diseases, Species Specificity, Point of Care Testing, Plasmodium Vivax, Primaquine, Rapid diagnostic test, Malaria Falciparum, Medical and Health Sciences, and Malaria Vivax
Trypanosoma brucei (T b) gambiense is targeted to reach elimination as a public health problem by 2020 and full elimination by 2030. To achieve these goals, stakeholders need to consider strategies to accelerate elimination. Hence, we... more
Trypanosoma brucei (T b) gambiense is targeted to reach elimination as a public health problem by 2020 and full elimination by 2030. To achieve these goals, stakeholders need to consider strategies to accelerate elimination. Hence, we aimed to model several options related to current and emerging methods for case detection, treatment, and vector control across settings to assess cost-effectiveness and the probability of elimination. Five intervention strategies were modelled over 30 years for low, moderate, and high transmission settings. Model parameters related to costs, efficacy, and transmission were based on available evidence and parameter estimation. Outcomes included disability-adjusted life-years (DALYs), costs, and long-term prevalence. Sensitivity analyses were done to calculate the uncertainty of the results. To reach elimination targets for 2020 across all settings, approaches combining case detection, treatment, and vector control would be most effective. Elimination i...
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Bernard Pécoul and colleagues call for the establishment of a global biomedical R&D fund as a key priority of the G7 summit in June 2015.
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The survival time of Mycobacterium bovis in the natural habitat of infected free ranging wildlife was investigated. Seven different experimental sites near Skukuza in the Kruger National Park, South Africa, were selected to expose... more
The survival time of Mycobacterium bovis in the natural habitat of infected free ranging wildlife was investigated. Seven different experimental sites near Skukuza in the Kruger National Park, South Africa, were selected to expose macroscopically affected lung or lymph node tissue of African buffalo (Syncerus caffer) origin and spiked faecal specimens for various lengths of time over a 1-year period. Mycobacterium bovis could be isolated for a maximum period of 6 weeks from tissue specimens and 4 weeks from faeces. The longest survival of M. bovis in both specimen types was observed in winter and under moist conditions. Surprisingly, the survival time of M. bovis in buried specimens seemed greatly reduced to a maximum of 5 days.
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SummaryBackground Studies of factors affecting place of delivery have rarely considered the influence of gender roles and relations within the household. This study combines an understanding of gender issues relating to health and... more
SummaryBackground Studies of factors affecting place of delivery have rarely considered the influence of gender roles and relations within the household. This study combines an understanding of gender issues relating to health and help‐seeking behaviour with epidemiological knowledge concerning place of delivery.Methods In‐depth interviews, focus group discussions and participant observation were used to explore determinants of home delivery in southern Tanzania. Quantitative data were collected in a cross‐sectional survey of 21 600 randomly chosen households.Results Issues of risk and vulnerability, such as lack of money, lack of transport, sudden onset of labour, short labour, staff attitudes, lack of privacy, tradition and cultures and the pattern of decision‐making power within the household were perceived as key determinants of the place of delivery. More than 9000 women were interviewed about their most recent delivery in the quantitative survey. There were substantial vari...
Research Interests: Reproduction, Developing Countries, Population Dynamics, Health, Public Health, and 15 moreMedicine, Gender Identity, Interviews, Pregnancy, Population, Humans, Female, Male, Focus Group, Data Collection, Infant Mortality, Educational Status, Cross Sectional Analysis, Health Facility, and Quality of health care
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An observational time-motion study investigated logistic, programmatic and safety-related advantages and limits in the delivery of a fully liquid DTP-HepB-Hib combination vaccine versus a lyophilized combination vaccine requiring... more
An observational time-motion study investigated logistic, programmatic and safety-related advantages and limits in the delivery of a fully liquid DTP-HepB-Hib combination vaccine versus a lyophilized combination vaccine requiring reconstitution. The study was conducted in 2006, observing 312 child vaccinations in a tertiary hospital setting in Kolkata, India. The time for vaccination was on average 46s (35.12%) lower with the fully liquid vaccine (p<0.05). In addition, the fully liquid combination was easier and potentially safer to handle and as well tolerated as the lyophilized formulation. Fully liquid combination vaccines have the potential to simplify immunization schedules, contribute to better resource management and improve efficiency of immunization programs.
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It has been recently documented that the antimalarial drug mefloquine shows in vivo activity against schistosomes. In the present study, we assessed the effect of mefloquine on the morphology of adult Schistosoma japonicum worms. Mice... more
It has been recently documented that the antimalarial drug mefloquine shows in vivo activity against schistosomes. In the present study, we assessed the effect of mefloquine on the morphology of adult Schistosoma japonicum worms. Mice were infected with S. japonicum cercariae for 35 days and then treated with a single 400-mg/kg oral dose of mefloquine. Groups of mice were killed between 24 h and 14 days post-treatment and worms were recovered from the liver and mesenteric veins, fixed in 70% alcohol, stained with acid carmine, and examined under a light microscope. Worms obtained from nontreated mice served as controls. S. japonicum recovered from mice 24 h post-treatment had severely dilated guts and the entire worm body was swollen. Meanwhile, reproductive glands, including the testis, ovary, and vitelline gland, showed signs of degeneration. Damage further progressed, particularly among vitelline glands, which resulted in disturbance of ova formation and cessation of oviposition 3 days post-treatment. Three to 7 days after mefloquine administration, adherence of host leukocytes on the damaged tegument was observed. Our results confirm that mefloquine possesses antischistosomal properties, exhibiting a rapid onset of action and causing extensive morphologic damage to adult S. japonicum.
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New research has shown that mefloquine, an arylaminoalcohol used against malaria, is active against Schistosoma japonicum and Schistosoma mansoni in vivo. To enhance our understanding of the potential mechanism of action of mefloquine... more
New research has shown that mefloquine, an arylaminoalcohol used against malaria, is active against Schistosoma japonicum and Schistosoma mansoni in vivo. To enhance our understanding of the potential mechanism of action of mefloquine against schistosomiasis, we examined the dynamics of histopathological changes in adult S. japonicum. Mice infected with S. japonicum for 35 days were treated intragastrically with a single dose of mefloquine (400 mg/kg). One to 35 days after mefloquine administration, drug-induced histopathological alterations were studied. Twenty-four hours after treatment, S. japonicum showed signs of degeneration, including focal roughing and swelling of the tegument and/or muscles, dilatation of the gut, focal desquamation of gut epithelial cells, and a decrease in pigment particles. There was extensive degeneration of vitelline cells and appearance of pigment particles visible in the cytoplasm in female worms. The extent and severity of histopathological changes increased over time; 48 h posttreatment, two thirds of female worms and a quarter of male worms were classified as dead. Three to 14 days posttreatment, typical histological changes observed in surviving male worms were vesiculation, swelling of parenchymal tissues, and dilatation of gut. In females, there was disintegration and infiltration of inflammatory cells, forming dead worm abscesses and early stage of dead worm granuloma. Finally, 35 days posttreatment, only dead male and female worm granuloma were found. Our results provide further evidence of in vivo activity of mefloquine against adult schistosomes.
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... although there was no vegetation present in the in-vestigated irrigation channel. It is well agreed that Biomphalaria and Bulinus species do not occur in water bodies where the water velocity is above 30 cm/s for longer periods... more
... although there was no vegetation present in the in-vestigated irrigation channel. It is well agreed that Biomphalaria and Bulinus species do not occur in water bodies where the water velocity is above 30 cm/s for longer periods (Apple-ton, 1975). ... Bull. Wld. Hlth. Org. ...
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Research Interests: Family Medicine, Medical Ethics, Developing Countries, Medicine, Breastfeeding, and 15 morePregnancy, Population, Humans, Female, Placebos, Lancet, Scopus, Newborn Infant, Internationality, Pregnant Women, Regimen, Clinical Trials as Topic, Randomized Controlled Trials as Topic, Medical and Health Sciences, and HIV infections
Malaria continues to be one of mankind's most devastating diseases despite the many and varied efforts to combat it. Indispensable for malaria elimination and eventual eradication is the development of effective vaccines. Controlled... more
Malaria continues to be one of mankind's most devastating diseases despite the many and varied efforts to combat it. Indispensable for malaria elimination and eventual eradication is the development of effective vaccines. Controlled human malaria infection (CHMI) is an invaluable tool for vaccine efficacy assessment and investigation of early immunological and molecular responses against Plasmodium falciparum infection. Here, we investigated gene expression changes following CHMI using RNA-Seq. Peripheral blood samples were collected in Bagamoyo, Tanzania, from ten adults who were injected intradermally (ID) with 2.5x104 aseptic, purified, cryopreserved P. falciparum sporozoites (Sanaria® PfSPZ Challenge). A total of 2,758 genes were identified as differentially expressed following CHMI. Transcriptional changes were most pronounced on day 5 after inoculation, during the clinically silent liver phase. A secondary analysis, grouping the volunteers according to their prepatent peri...
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A comprehensive 60-year review of antischistosomal drug discovery and development research in the People's Republic of China (P.R. China) is presented. In the 1950s, three antimonials were developed, which, compared to potassium... more
A comprehensive 60-year review of antischistosomal drug discovery and development research in the People's Republic of China (P.R. China) is presented. In the 1950s, three antimonials were developed, which, compared to potassium antimony tartrate-the treatment of choice against schistosomiasis at the time-showed equal efficacy but lower toxicity when administered orally or intramuscularly. Activity of furapromidum against Schistosoma japonicum was reported in the early 1960s, and this drug became the first non-antimonial used in clinical treatment of schistosomiasis japonica. Subsequently, two additional nitrofuran derivatives (furadiamine and fuvinazole) were investigated in the laboratory and clinically. In the late 1960s, niridazole and amoscanate were developed by western scientists, which encouraged Chinese researchers to synthesise and further modify the chemical structures of these compounds. However, the modified compounds were less efficacious but similarly toxic, which...
Research Interests: Pharmacology, Microbiology, Parasitology, Political Science, Medical Microbiology, and 15 moreDrug Discovery, China, Medicine, Drug, Humans, Animals, Research and Development, Potassium, Chine, Control Strategy, Chinese traditional medicine, Mechanism of action, Anthelmintics, Praziquantel, and Chemical Structure
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Research Interests: Business, Marketing, Program Evaluation, Social Marketing, Poverty, and 15 moreMalaria, Public Health, Tanzania, Medicine, Social Class, Equity, Insecticides, Rural Health, Humans, Animals, Socioeconomic Status, Mosquito Control, Public health systems and services research, Public Assistance, and Insect Vectors
SummaryObjective To assess malaria prevalence rates and seasonal patterns among clinically diagnosed malaria cases at the level of primary care facilities in an urban Sahelian setting.Method Screening all patients consulting two private... more
SummaryObjective To assess malaria prevalence rates and seasonal patterns among clinically diagnosed malaria cases at the level of primary care facilities in an urban Sahelian setting.Method Screening all patients consulting two private and two governmental providers on a randomly selected weekday over a period of 9 months. Patients with presumptive malaria underwent a blood test.Results Of 1658 patients included in the survey, 47% were clinically diagnosed and treated as malaria cases. Malaria was more often diagnosed by private providers. There were no clear seasonal patterns in presumptive malaria. A 30% of clinically diagnosed cases were positive for Plasmodium (all falciparum) by thick film examination. Thus, false positive cases constituted more than 70% of the clinically diagnosed malaria cases. The highest positive prevalence rates were found at the end and shortly after the rainy season (44%–47%) and the lowest during the dry season (2%).Conclusions Clinical diagnosis of ma...
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Research Interests: Health Promotion, Environmental Health, Malaria, Public Health, Adolescent, and 15 moreMedicine, Humans, Female, Male, Psychological Intervention, Mosquito Control, Middle Aged, Adult, Local Knowledge, Health Care System, Marketing of Health Services, Large Scale, Marital Status, attitude to health, and Insecticide treated net
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Research Interests: Microbiology, Immunology, Polymorphism, Medical Microbiology, Biology, and 15 moreMalaria, Medicine, Placebo, Blood sampling, Polymerase Chain Reaction, Iron, Randomised Controlled Trial, Iron supplementation, Genotype, Public health systems and services research, Odds ratio, Plasmodium falciparum, Multiple Infection, Genotypes, and Relative Risk
Research Interests: Cultural Studies, Demography, Public Health, Adolescent, Medicine, and 15 moreHumans, Older people, Health related Quality of Life, Female, Male, Health Status, Aged, Middle Aged, Adult, Morbidity, Public health systems and services research, Health surveys, Quality Life, Health Survey, and Population surveillance
Schistosomiasis, a chronic and debilitating parasitic disease, affects ≈200 million people in the developing world and imposes a substantial public health and economic impact. Accurately diagnosing at the individual level, monitoring... more
Schistosomiasis, a chronic and debilitating parasitic disease, affects ≈200 million people in the developing world and imposes a substantial public health and economic impact. Accurately diagnosing at the individual level, monitoring disease progression, and assessing the impact of pharmacological interventions at the population level are of prime importance for controlling schistosomiasis. Using a Schistosoma mansoni -mouse model, we present a characterization of a parasitic infection by metabolic profiling, employing 1 H NMR spectroscopy and multivariate pattern recognition techniques. We infected 10 mice with 80 S. mansoni cercariae each and collected urine samples 49 and 56 days postinfection. Urine samples were also obtained from 10 uninfected control mice at the same time. The metabolic signature of an S. mansoni infection consists of reduced levels of the tricarboxylic acid cycle intermediates, including citrate, succinate, and 2-oxoglutarate, and increased levels of pyruvate...
Research Interests: Pattern Recognition, Biology, Metabolomics, NMR Spectroscopy, Medicine, and 15 moreMultidisciplinary, Multivariate Analysis, Humans, Mice, Animals, Developing World, Economic Impact, Mouse Model, Biological markers, Disease Progression, Disease Surveillance and Epidemiology, Diagnostic Test, High Sensitivity, Amino Acid Metabolism, and Disease Surveillance
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Research Interests: Pediatrics, Africa, Malaria, Medicine, Population, and 15 moreHumans, Female, Male, Infant, Incidence, Meningitis, Plasmodium falciparum, Age Factors, Malaria Vaccine, Seizures, New England Journalof Medicine, Malaria Vaccines, Malaria Falciparum, Medical and Health Sciences, and Intention to treat analysis
Research Interests: Pediatrics, Africa, Malaria, Medicine, Population, and 15 moreHumans, Female, Male, Infant, Incidence, Plasmodium falciparum, Malaria Vaccine, New England Journalof Medicine, Proportional Hazards Models, Malaria Vaccines, Adverse effect, Malaria Falciparum, Immunization Schedule, Medical and Health Sciences, and Intention to treat analysis
Research Interests: Genetics, Africa, Biology, East Africa, Medicine, and 15 moreMiddle East, Biological Sciences, Molecular, Humans, Animals, Drug Resistance, Antimalarials, Drug treatment, Dihydrofolate Reductase, DNA mutational analysis, alleles, Malaria Falciparum, dihydropteroate synthase, Medical and Health Sciences, and Drug combinations
Research Interests: Child health, Focus Groups, Behavior, Culture, Malaria, and 15 moreDeveloping Countries, Economic Development, Health, Beliefs, Attendance, Humans, Female, Attitudes, Infant, Data Collection, Local Knowledge, Antimalarials, Focus Group Discussion, Intermittent Preventive Treatment, and Interviews as topic
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Hepatitis B and C markers were tested in 980 pregnant women, in the infants born to infected mothers, and in a random sample of 42 and 50, respectively, children born to uninfected mothers in Tanzania. Sixty-two women (6.3%) were positive... more
Hepatitis B and C markers were tested in 980 pregnant women, in the infants born to infected mothers, and in a random sample of 42 and 50, respectively, children born to uninfected mothers in Tanzania. Sixty-two women (6.3%) were positive for HBsAg and 15 (24%) were HBeAg-seropositive. Anti-HCV was detected in 49 women (5%), 15 (31%) of whom had detectable viremia. HCV RNA serum levels were low and only genotype 4 was identified. Sixty-six women (6.7%) were positive for anti-HIV, six of whom were coinfected with HBV and one with HCV. Anti-HEV was negative in the 180 women tested. At 8 months of age, HBsAg was detected in 8% and 2% of children born to HBV-infected and noninfected mothers, respectively (P = 0.2). Corresponding figures at 18 months of age were 31% and 21% (P = 0.3). When tested at 2 months of age, HCV RNA was not detected in any of the 43 children born to anti-HCV-positive mothers nor in any of 50 children born to anti-HCV-negative mothers. At 18 months, only one child, born to an anti-HCV-positive mother, had detectable HCV RNA. None of the infants born to women with HIV coinfection were infected with hepatitis viruses. This study suggests that exposure to HEV does not occur in southern Tanzania. The prevalence of current HBV infection in pregnant women from rural Tanzania is lower than in other sub-Saharan areas. In early childhood, HBV infection appears to occur by horizontal rather than maternofilial mechanisms of transmission. The prevalence of HCV infection is similar to that in other African countries. The results of this study show for the first time in Africa that mother-to-infant transmission does not play a significant role in the acquisition of HCV infection.
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Research Interests: Microbiology, Medical Microbiology, Biology, Scanning Electron Microscopy, Drug development, and 15 moreMedicine, Trematoda, Mice, Female, Animals, Fasciola hepatica, Antimicrobial chemotherapy, In Vivo, Mouse Model, Rats, In Vitro Studies, Adamantane, Fascioliasis, Bile ducts, and Pharmacology and pharmaceutical sciences
The drug, artemether, has been shown to be active against the juvenile stages of Schistosoma japonicum and Schistosoma mansoni in experimentally infected animals, while it is less effective on adult worms. These findings have been... more
The drug, artemether, has been shown to be active against the juvenile stages of Schistosoma japonicum and Schistosoma mansoni in experimentally infected animals, while it is less effective on adult worms. These findings have been confirmed in randomised controlled trials in humans. Consequently, it could be expected that artemether is also active against Schistosoma haematobium. We present here the first results from experiments assessing the effect of artemether on S. haematobium. Hamsters with a single infection received intra-gastrically an initial dose of 300 mg/kg artemether on day 14, 21 or 28, followed by further doses at varying treatment regimens. In all the treatment groups, the total and female worm reduction rates were highly significant, and ranged from 78 to 100% in hamsters harbouring juvenile schistosomes. Hamsters infected three times with S. haematobium, on days 0, 4 and 9, and repeatedly treated with artemether at the same dose as above, showed highly significant total and female worm reduction rates of between 94 and 99%. Artemether was also active against 77-day-old adult S. haematobium, since its administration on two consecutive days resulted in highly significant total and female worm reduction rates of 76-89%. Our findings confirm that artemether is also active against S. haematobium, especially the schistosomules. These results provide a basis for clinical trials in humans, for further assessment of the potential of artemether for schistosomiasis control.
Research Interests: Microbiology, Parasitology, Clinical Trial, Biology, Medicine, and 15 moreLiver, Schistosomiasis, Female, Animals, Male, Randomised Controlled Trial, Experimental Infection, Sesquiterpenes, For, Schistosoma Mansoni, Schistosoma japonicum, Cote D Ivoire, artemether, Cricetinae, and Schistosoma Haematobium
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Research Interests: Geography, Irrigation, Biology, Agriculture, Biological Control, and 15 moreMedicine, Biological Sciences, Humans, Animals, Natural Product, Environmental Control, Japanese encephalitis, Culex, Mosquito Control, Geographic distribution, Environment, Mortality rate, Culex tritaeniorhynchus, Insect Vectors, and Medical and Health Sciences
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Research Interests: Demography, Biology, China, Medicine, Biological Sciences, and 15 moreHumans, Habitat, Animals, Land Use, Landsat TM, Disease mapping, Geographic Information, Environment, Geographic Information System, Geographic Information Systems, Normalized Difference Vegetation Index, Dry Season, High risk, Medical and Health Sciences, and buffer zone
The 'One Medicine' concept by Calvin Schwabe has seen an unprecedented revival in the last decade and has evolved towards 'One Health' conceptual thinking, emphasising epidemiology and public health. Pathologists rightly... more
The 'One Medicine' concept by Calvin Schwabe has seen an unprecedented revival in the last decade and has evolved towards 'One Health' conceptual thinking, emphasising epidemiology and public health. Pathologists rightly recall the contribution of their discipline by close genomic relationship of animals and humans e.g. in cancer genetics. We need to change our 'us versus them' perspective towards a perspective of 'shared risk' between humans and animals. Professional organisations have declared their adhesion, governments have created joint public and animal health working groups and numerous research and surveillance programmes have been incepted as demonstrated on the 'One Health Initiative' website. Above all these beneficial developments, we should not forget however, that there remains a huge divide between human and veterinary medicine borne from unprecedented (over) specialisation of disciplines and increasingly reductionist approaches...