Efficacy and Safety of Mefloquine, Artesunate, Mefloquine-Artesunate, and Praziquantel against Schistosoma haematobium: Randomized, Exploratory Open-Label Trial

Background. Morbidity control of schistosomiasis relies on a single drug, praziquantel. The antimalarial drug mefloquine possesses interesting antischistosomal properties, yet no clinical studies have been performed. Methods. We conducted a randomized, exploratory open-label trial to assess the efficacy and safety of mefloquine (25 mg/kg), artesunate (3 doses of 4 mg/kg), mefloquine-artesunate (3 doses of 100 mg artesunate plus 250 mg mefloquine), and praziquantel (40 mg/kg) against Schistosoma haematobium. The effects on Schistosoma mansoni, malaria parasitemia, soil-transmitted helminths, and intestinal protozoa were also determined. Results. A total of 83 S. haematobium-infected schoolchildren were included in the study. Cure rates of mefloquine, artesunate, mefloquine-artesunate, and praziquantel against S. haematobium at day 26 after treatment were 21%, 25%, 61%, and 88%, respectively. Both mefloquine-artesunate and praziquantel resulted in egg reduction rates >95%. Significantly lower egg reduction rates were seen in the artesunate (85%) and mefloquine groups (74%). In children coinfected with S. mansoni, praziquantel and mefloquine-artesunate, but not mefloquine and artesunate alone, resulted in high cure rates and egg reduction rates. Mefloquine, artesunate, and mefloquine-artesunate completely cured infections due to Plasmodium falciparum. No effects were found against soil-transmitted helminths and intestinal protozoa. Abdominal pain was the most frequent adverse event, with a higher incidence among children treated with mefloquine (89%), mefloquine-artesunate (83%), and artesunate (60%) than among children treated with praziquantel (46%). Conclusions. The high efficacy of mefloquine-artesunate against S. haematobium warrants further investigation. Individuals coinfected with Plasmodium and Schistosoma who were treated with a mefloquine-artesunate combination against malaria might have a dual benefit: clearance of malaria parasitemia and reduction of schistosomiasisrelated morbidity. Clinical trials registration. Current Controlled Trials identifier: ISRCTN0649876

: The impact of war on the evolution of sleeping sickness in west-central Cote d'Ivoire

International audienceTo evaluate the situation of sleeping sickness in west-central Cote d'Ivoire from 2000 to 2003, in view of the war which broke out in September 2002. Active surveys by medical teams and passive case detection. Between 2000 and 2003, 250 patients were diagnosed with sleeping sickness. At first it appeared that sleeping sickness prevalence had fallen since the beginning of political troubles. But this apparent drop was due to poor population coverage. Participation in medical surveys differed according to ethnic group, reflecting land use conflicts between ethnic communities. Such conflicts are common in this area, but have been exacerbated by the war. In war, assessing the importance of sleeping sickness by medical surveys only is very difficult. But detection of sleeping sickness cases by passive surveillance increased.Evaluer la situation de la maladie du sommeil dans le centre-ouest de la Cote d'Ivoire de 2000 a 2003, en tenant compte des evenements survenus depuis en septembre 2002. Enquete active realisee par des equipes medicales et detection passive des cas. Entre 2000 et 2003, 250 patients ont ete diagnostiques pour la maladie du sommeil. De prime abord la prevalence de la maladie du sommeil semblait avoir baisse depuis le debut de la guerre. Mais cette baisse apparente etait due a une faible couverture de la population. La participation dans l'enquete medicale etait differente selon le groupe ethnique, refletant les conflits entre les differentes communautes pour les terres. De tels conflits sont courants dans la zone mais ont ete exacerbes par la guerre. L'evaluation de l'importance de la maladie du sommeil durant la guerre par enquete medicale seule est tres difficile. Mais la detection de la maladie du sommeil par surveillance passive a augmente

Empirical and theoretical investigation into the potential impacts of insecticide resistance on the effectiveness of insecticide-treated bed nets.

In spite of widespread insecticide resistance in vector mosquitoes throughout Africa, there is limited evidence that long-lasting insecticidal bed nets (LLINs) are failing to protect against malaria. Here, we showed that LLIN contact in the course of host-seeking resulted in higher mortality of resistant Anopheles spp. mosquitoes than predicted from standard laboratory exposures with the same net. We also found that sublethal contact with an LLIN caused a reduction in blood feeding and subsequent host-seeking success in multiple lines of resistant mosquitoes from the laboratory and the field. Using a transmission model, we showed that when these LLIN-related lethal and sublethal effects were accrued over mosquito lifetimes, they greatly reduced the impact of resistance on malaria transmission potential under conditions of high net coverage. If coverage falls, the epidemiological impact is far more pronounced. Similarly, if the intensity of resistance intensifies, the loss of malaria control increases nonlinearly. Our findings help explain why insecticide resistance has not yet led to wide-scale failure of LLINs, but reinforce the call for alternative control tools and informed resistance management strategies

Mise en évidence de nouveaux virus à ARN chez Pteroteinon laufella Hewitson (Lepidoptera Hesperidae), défoliateur du palmier à huile en Côte d'Ivoire = Discovery of new RNA viruses in Pteroteinon laufella Hewitson (Lepidoptera Hesperidae), an oil palm leaf eater in the Ivory Coast

Parmi les principaux défoliateurs du palmier à huile en Côte d'Ivoire, une espèce, #Pteroteinon laufella$ pullule fréquemment et il est alors nécessaire d'intervenir à l'aide d'insecticides chimiques. Pendant les pullulations de cette espèce, des cas de mortalité naturelle dus à des microorganismes, notamment des virus, se manifestent dans les populations à forte densité. Deux nouveaux virus icosaédriques et non enveloppés à ARN, l'un de 40 nm de diamètre et l'autre de 30 nm de diamètre, ont été isolés. La capside du virus de 40 nm est constituée de 3 types de protéines, dont une majeure d'un poids moléculaire de 53.000 daltons et de 2 mineures d'un poids moléculaire de 65.000 et 34.000 daltons. Leurs propriétés biophysiques, biochimiques et immunologiques ne permettent pas actuellement de les rapprocher véritablement d'une autre famille de virus à ARN. (Résumé d'auteur

Trypanosoma brucei gambiense group 1 is distinguished by a unique amino acid substitution in the HpHb receptor implicated in human serum resistance

Trypanosoma brucei rhodesiense (Tbr) and T. b. gambiense (Tbg), causative agents of Human African Trypanosomiasis (sleeping sickness) in Africa, have evolved alternative mechanisms of resisting the activity of trypanosome lytic factors (TLFs), components of innate immunity in human serum that protect against infection by other African trypanosomes. In Tbr, lytic activity is suppressed by the Tbr-specific serum-resistance associated (SRA) protein. The mechanism in Tbg is less well understood but has been hypothesized to involve altered activity and expression of haptoglobin haemoglobin receptor (HpHbR). HpHbR has been shown to facilitate internalization of TLF-1 in T.b. brucei (Tbb), a member of the T. brucei species complex that is susceptible to human serum. By evaluating the genetic variability of HpHbR in a comprehensive geographical and taxonomic context, we show that a single substitution that replaces leucine with serine at position 210 is conserved in the most widespread form of Tbg (Tbg group 1) and not found in related taxa, which are either human serum susceptible (Tbb) or known to resist lysis via an alternative mechanism (Tbr and Tbg group 2). We hypothesize that this single substitution contributes to reduced uptake of TLF and thus may play a key role in conferring serum resistance to Tbg group 1. In contrast, similarity in HpHbR sequence among isolates of Tbg group 2 and Tbb/Tbr provides further evidence that human serum resistance in Tbg group 2 is likely independent of HpHbR functio

Discovery of mating in the major African livestock pathogen Trypanosoma congolense

The protozoan parasite, Trypanosoma congolense, is one of the most economically important pathogens of livestock in Africa and, through its impact on cattle health and productivity, has a significant effect on human health and well being. Despite the importance of this parasite our knowledge of some of the fundamental biological processes is limited. For example, it is unknown whether mating takes place. In this paper we have taken a population genetics based approach to address this question. The availability of genome sequence of the parasite allowed us to identify polymorphic microsatellite markers, which were used to genotype T. congolense isolates from livestock in a discrete geographical area of The Gambia. The data showed a high level of diversity with a large number of distinct genotypes, but a deficit in heterozygotes. Further analysis identified cryptic genetic subdivision into four sub-populations. In one of these, parasite genotypic diversity could only be explained by the occurrence of frequent mating in T. congolense. These data are completely inconsistent with previous suggestions that the parasite expands asexually in the absence of mating. The discovery of mating in this species of trypanosome has significant consequences for the spread of critical traits, such as drug resistance, as well as for fundamental aspects of the biology and epidemiology of this neglected but economically important pathogen

Burden of disease and circulating serotypes of rotavirus infection in sub-Saharan Africa: systematic review and meta-analysis.

Two new rotavirus vaccines have recently been licensed in many countries. However, their efficacy has only been shown against certain serotypes commonly circulating in Europe, North America, and Latin America, but thought to be globally important. To assess the potential impact of these vaccines in sub-Saharan Africa, where rotavirus mortality is high, knowledge of prevalent types is essential because an effective rotavirus vaccine is needed to protect against prevailing serotypes in the community. We did two systematic reviews and two meta-analyses of the most recent published data on the burden of rotavirus disease in children aged under 5 years and rotavirus serotypes circulating in countries in sub-Saharan Africa. Eligible studies were selected from PubMed/Medline, Cochrane Library, EmBase, LILACS, Academic Search Premier, Biological Abstracts, ISI Web of Science, and the African Index Medicus. Depending on the heterogeneity, DerSimonian-Laird random-effects or fixed-effects models were used for meta-analyses. Geographical variability in rotavirus burden within countries in sub-Saharan Africa is substantial, and most countries lack information on rotavirus epidemiology. We estimated that annual mortality for this region was 243.3 (95% CI 187.6-301.7) deaths per 100,000 under 5 years (ie, a total of 300,000 children die of rotavirus infection in this region each year). The most common G type detected was G1 (34.9%), followed by G2 (9.1%), and G3 (8.6%). The most common P types detected were P[8] (35.5%) and P[6] (27.5%). Accurate information should be collected from surveillance based on standardised methods in these countries to obtain comparable data on the burden of disease and the circulating strains to assess the potential impact of vaccine introduction

Mechanical properties and drop-weight impact performance of injection-molded HDPE/birch fiber composites

Natural-fiber-reinforced composites offer various advantages over synthetic composites, including low density, useful mechanical properties and environmental friendliness. In spite of the progress achieved in the field, the mechanical performance of these composite materials has yet to be fully characterized, particularly in terms of impact resistance. In this study, we measured the drop weight impact, Izod impact strength, hardness, tensile strength and elastic modulus of birch-fiber-reinforced HDPE obtained by injection molding. Drop weight impact energy absorbed was constant and independent of fiber content whereas impact strength was inversely proportional to fiber content. Material toughness decreased slightly at 40% fiber. The Shore D hardness of virgin HDPE increased from 50.6 at 0% fiber to 74.6 at 30% fiber. The improvement of the elastic modulus of a composite containing 40% fiber was 27.2% superior to that reported for similar material made by compression molding. The corresponding improvement in tensile strength was superior by 19.7%. Birch-fiber-reinforced HDPE could be an adequate alternative to technical polymers widely used in several industrial sectors. © 2020 The Author