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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with increased transmissibility, virulence and immune escape abilities have heavily altered the COVID-19 pandemic’s course. Deciphering local and global transmission patterns of those variants is thus key in building a profound understanding of the virus’ spread around the globe. In the present study, we investigate SARS-CoV-2 variant epidemiology in Côte d’Ivoire, Western sub-Saharan Africa. We therefore generated 234 full SARS-CoV-2 genomes stemming from Central and Northern Côte d’Ivoire. Covering the first and second pandemic wave the country had been facing, we identified 20 viral lineages and showed that in Côte d’Ivoire the second pandemic wave in 2021 was driven by the spread of the Alpha (B.1.1.7) and Eta (B.1.525) variant. Our analyses are consistent with a limited number of international introductions of Alpha and Eta into Côte d’Ivoire, and those introduction events mostly stemmed from within the West African subregion. This suggests that subregional travel to Côte d’Ivoire had more impact on local pandemic waves than direct intercontinental travel.

The human parasite Plasmodium malariae has relatives infecting African apes (Plasmodium rodhaini) and New World monkeys (Plasmodium brasilianum), but its origins remain unknown. Using a novel approach to characterise P. malariae-related sequences in wild and captive African apes, we found that this group comprises three distinct lineages, one of which represents a previously unknown, highly divergent species infecting chimpanzees, bonobos and gorillas across central Africa. A second ape-derived lineage is much more closely related to the third, human-infective lineage P. malariae, but exhibits little evidence of genetic exchange with it, and so likely represents a separate species. Moreover, the levels and nature of genetic polymorphisms in P. malariae indicate that it resulted from the zoonotic transmission of an African ape parasite, reminiscent of the origin of P. falciparum. In contrast, P. brasilianum falls within the radiation of human P. malariae, and thus reflects a recent anthroponosis.

SARS-CoV-2 variants of concern (VOC) and variants of interest (VOI) are heavily altering the COVID-19 pandemic’s course due to their increased transmissibility, virulence and immune escape abilities. Data on their spread in western sub-Saharan Africa is however still scarce. We therefore sequenced viral genomes from SARS-CoV-2 cases identified in central and northern Côte d’Ivoire between May 2020 and March 2021. We report the introduction of VOC B.1.1.7 as early as mid-January 2021, followed by detection of a single case of VOC B.1.351, as well as VOI B.1.525. Since early 2021 VOC/VOI are gradually dominating the SARS-CoV-2 virus pool in Côte d’Ivoire, as seen in other regions of the world. Intriguingly, we also find that another lineage, A.27, has also been on the rise over the same period. In sum, this study highlights again the extremely rapid local diffusion of VOC, VOI and possibly A.27, and the importance of further reinforcing capacities for genomic surveillance on the African continent.

Background Metabarcoding of vertebrate DNA found in invertebrates (iDNA) represents a potentially powerful tool for monitoring biodiversity. Preliminary evidence suggests fly iDNA biodiversity assessments compare favorably with established approaches such as camera trapping or line transects. Aims and Methods To assess whether fly-derived iDNA is consistently useful for biodiversity monitoring across a diversity of ecosystems, we compared metabarcoding of the mitochondrial 16S gene of fly pool-derived iDNA (range = 49–105 flies/site, N = 784 flies) with camera traps (range = 198–1,654 videos of mammals identified to the species level/site) at eight sites, representing different habitat types in five countries across tropical Africa. Results We detected a similar number of mammal species using fly-derived iDNA (range = 8–15 species/site) and camera traps (range = 8–27 species/site). However, the two approaches detected mostly different species (range = 6%–43% of species detected/site were detected with both methods), with fly-derived iDNA detecting on average smaller-bodied species than camera traps. Despite addressing different phylogenetic components of local mammalian communities, both methods resulted in similar beta-diversity estimates across sites and habitats. Conclusion These results support a growing body of evidence that fly-derived iDNA is a cost- and time-efficient tool that complements camera trapping in assessing mammalian biodiversity. Fly-derived iDNA may facilitate biomonitoring in terrestrial ecosystems at broad spatial and temporal scales, in much the same way as water eDNA has improved biomonitoring across aquatic ecosystems.

Yaws-like lesions are widely reported in wild African great apes, yet the causative agent has not been confirmed in affected animals. We describe yaws-like lesions in a wild chimpanzee in Guinea for which we demonstrate infection with Treponema pallidum subsp. pertenue. Assessing the conservation implications of this pathogen requires further research.

Wildlife detection in urban areas is very challenging. Conventional monitoring techniques such as direct observation are faced with the limitation that urban wildlife is extremely elusive. It was recently shown that invertebrate-derived DNA (iDNA) can be used to assess wildlife diversity in tropical rainforests. Flies, which are ubiquitous and very abundant in most cities, may also be used to detect wildlife in urban areas. In urban ecosystems, however, overwhelming quantities of domestic mammal DNA could completely mask the presence of wild mammal DNA. To test whether urban wild mammals can be detected using fly iDNA, we performed DNA metabarcoding of pools of flies captured in Berlin, Germany, using three combinations of blocking primers. Our results show that domestic animal sequences are, as expected, very dominant in urban environments. Nevertheless, wild mammal sequences can often be retrieved, although they usually only represent a minor fraction of the sequence reads. Fly iDNA metabarcoding is therefore a viable approach for quick scans of urban wildlife diversity. Interestingly, our study also shows that blocking primers can interact with each other in ways that affect the outcome of metabarcoding. We conclude that the use of complex combinations of blocking primers, although potentially powerful, should be carefully planned when designing experiments.

BackgroundCross-sectional surveys of chimpanzee (Pan troglodytes) communities across sub-Saharan Africa show large geographical variation in malaria parasite (Plasmodium spp.) prevalence. The drivers leading to this apparent spatial heterogeneity may also be temporally dynamic but data on prevalence variation over time are missing for wild great apes. This study aims to fill this fundamental gap.MethodsSome 681 faecal samples were collected from 48 individuals of a group of habituated chimpanzees (Taï National Park, Côte d’Ivoire) across four non-consecutive sampling periods between 2005 and 2015.ResultsOverall, 89 samples (13%) were PCR-positive for malaria parasite DNA. The proportion of positive samples ranged from 0 to 43% per month and 4 to 27% per sampling period. Generalized Linear Mixed Models detected significant seasonal and inter-annual variation, with seasonal increases during the wet seasons and apparently stochastic inter-annual variation. Younger individuals were also significantly more likely to test positive.ConclusionsThese results highlight strong temporal fluctuations of malaria parasite detection rates in wild chimpanzees. They suggest that the identification of other drivers of malaria parasite prevalence will require longitudinal approaches and caution against purely cross-sectional studies, which may oversimplify the dynamics of this host-parasite system.

Anthrax is a globally important animal disease and zoonosis. Despite this, our current knowledge of anthrax ecology is largely limited to arid ecosystems, where outbreaks are most commonly reported. Here we show that the dynamics of an anthrax-causing agent, Bacillus cereus biovar anthracis, in a tropical rainforest have severe consequences for local wildlife communities. Using data and samples collected over three decades, we show that rainforest anthrax is a persistent and widespread cause of death for a broad range of mammalian hosts. We predict that this pathogen will accelerate the decline and possibly result in the extirpation of local chimpanzee (Pan troglodytes verus) populations. We present the epidemiology of a cryptic pathogen and show that its presence has important implications for conservation.

This study was supported in part by the DFG Research Group “Sociality and Health in Primates” (FOR2136). JFG was supported by the Canadian Institutes of Health Research’s Strategic Training Initiative in Health Research’s Systems Biology Training Program, an NSERC Vanier Canada Graduate Scholarship (CGS), a long-term Research Grant from the German Academic Exchange Service (DAAD-91525837-57048249), and also by the DAAD with funds from the German Federal Ministry of Education and Research (BMBF) and the People Programme (Marie Curie Actions) of the European Union’s Seventh Framework Programme (FP7/2007-2013) under REA grant agreement n° 605728 (P.R.I.M.E. – Postdoctoral Researchers International Mobility Experience). Core-funding for the Taï Chimpanzee Project is provided 645 by the Max Planck Society. Living in groups provides benefits but also incurs costs such as attracting disease vectors. For example, synanthropic flies associate with human settlements, and higher fly densities increase pathogen transmission. We investigated whether such associations also exist in highly mobile nonhuman primate (NHP) Groups. We studied flies in a group of wild sooty mangabeys (Cercocebus atys atys) and three communities of wild chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d'Ivoire. We observed markedly higher fly densities within both mangabey and chimpanzee groups. Using a mark–recapture experiment, we showed that flies stayed with the sooty mangabey group for up to 12 days and for up to 1.3 km. We also tested mangabey-associated flies for pathogens infecting mangabeys in this ecosystem, Bacillus cereus biovar anthracis (Bcbva), causing sylvatic anthrax, and Treponema pallidum pertenue, causing yaws. Flies contained treponemal (6/103) and Bcbva (7/103) DNA. We cultured Bcbva from all PCR-positive flies, confirming bacterial viability and suggesting that this bacterium might be transmitted and disseminated by flies. Whole genome sequences of Bcbva isolates revealed a diversity of Bcbva, probably derived from several sources. We conclude that flies actively track mangabeys and carry infectious bacterial pathogens; these associations represent an understudied cost of sociality and potentially expose many social animals to a diversity of pathogens. Postprint

In 2015, favipiravir was administered on a compassionate-use basis to patients with Ebola virus disease in Guinea. This study reveals a trend toward improved survival in favipiravir-treated patients; however, the effect of treatment was not statistically significant, except for its influence on survival time., Background In 2015, the laboratory at the Ebola treatment center in Coyah, Guinea, confirmed Ebola virus disease (EVD) in 286 patients. The cycle threshold (Ct) of an Ebola virus–specific reverse transcription–polymerase chain reaction assay and 13 blood chemistry parameters were measured on admission and during hospitalization. Favipiravir treatment was offered to patients with EVD on a compassionate-use basis. Methods To reduce biases in the raw field data, we carefully selected 163 of 286 patients with EVD for a retrospective study to assess associations between potential risk factors, alterations in blood chemistry findings, favipiravir treatment, and outcome. Results The case-fatality rate in favipiravir-treated patients was lower than in untreated patients (42.5% [31 of 73] vs 57.8% [52 of 90]; P = .053 by univariate analysis). In multivariate regression analysis, a higher Ct and a younger age were associated with survival (P < .001), while favipiravir treatment showed no statistically significant effect (P = .11). However, Kaplan-Meier analysis indicated a longer survival time in the favipiravir-treated group (P = .015). The study also showed characteristic changes in blood chemistry findings in patients who died, compared with survivors. Conclusions Consistent with the JIKI trial, this retrospective study revealed a trend toward improved survival in favipiravir- treated patients; however, the effect of treatment was not statistically significant, except for its influence on survival time.

Significance Chimpanzees, bonobos, and gorillas harbor close relatives of human Plasmodium vivax, but current knowledge of these parasites is limited to a small number of gene fragments derived almost exclusively from mitochondrial DNA. We compared nearly full-length genomes of ape parasites with a global sample of human P. vivax and tested the function of human and ape P. vivax proteins believed to be important for erythrocyte binding. The results showed that ape parasites are 10-fold more diverse than human P. vivax and exhibit no evidence of species specificity, whereas human P. vivax represents a bottlenecked lineage that emerged from within this parasite group. Thus, African apes represent a large P. vivax reservoir whose impact on human malaria eradication requires careful monitoring., Wild-living African apes are endemically infected with parasites that are closely related to human Plasmodium vivax, a leading cause of malaria outside Africa. This finding suggests that the origin of P. vivax was in Africa, even though the parasite is now rare in humans there. To elucidate the emergence of human P. vivax and its relationship to the ape parasites, we analyzed genome sequence data of P. vivax strains infecting six chimpanzees and one gorilla from Cameroon, Gabon, and Côte d’Ivoire. We found that ape and human parasites share nearly identical core genomes, differing by only 2% of coding sequences. However, compared with the ape parasites, human strains of P. vivax exhibit about 10-fold less diversity and have a relative excess of nonsynonymous nucleotide polymorphisms, with site-frequency spectra suggesting they are subject to greatly relaxed purifying selection. These data suggest that human P. vivax has undergone an extreme bottleneck, followed by rapid population expansion. Investigating potential host-specificity determinants, we found that ape P. vivax parasites encode intact orthologs of three reticulocyte-binding protein genes (rbp2d, rbp2e, and rbp3), which are pseudogenes in all human P. vivax strains. However, binding studies of recombinant RBP2e and RBP3 proteins to human, chimpanzee, and gorilla erythrocytes revealed no evidence of host-specific barriers to red blood cell invasion. These data suggest that, from an ancient stock of P. vivax parasites capable of infecting both humans and apes, a severely bottlenecked lineage emerged out of Africa and underwent rapid population growth as it spread globally.

The severe Ebola virus disease epidemic occurring in West Africa stems from a single zoonotic transmission event to a 2-year-old boy in Meliandou, Guinea. We investigated the zoonotic origins of the epidemic using wildlife surveys, interviews, and molecular analyses of bat and environmental samples. We found no evidence for a concurrent outbreak in larger wildlife. Exposure to fruit bats is common in the region, but the index case may have been infected by playing in a hollow tree housing a colony of insectivorous free-tailed bats (Mops condylurus). Bats in this family have previously been discussed as potential sources for Ebola virus outbreaks, and experimental data have shown that this species can survive experimental infection. These analyses expand the range of possible Ebola virus sources to include insectivorous bats and reiterate the importance of broader sampling efforts for understanding Ebola virus ecology.

A nanopore DNA sequencer is used for real-time genomic surveillance of the Ebola virus epidemic in the field in Guinea; the authors demonstrate that it is possible to pack a genomic surveillance laboratory in a suitcase and transport it to the field for on-site virus sequencing, generating results within 24 hours of sample collection. This paper reports the use of nanopore DNA sequencers (known as MinIONs) for real-time genomic surveillance of the Ebola virus epidemic, in the field in Guinea. The authors demonstrate that it is possible to pack a genomic surveillance laboratory in a suitcase and transport it to the field for on-site virus sequencing, generating results within 24 hours of sample collection. The Ebola virus disease epidemic in West Africa is the largest on record, responsible for over 28,599 cases and more than 11,299 deaths1. Genome sequencing in viral outbreaks is desirable to characterize the infectious agent and determine its evolutionary rate. Genome sequencing also allows the identification of signatures of host adaptation, identification and monitoring of diagnostic targets, and characterization of responses to vaccines and treatments. The Ebola virus (EBOV) genome substitution rate in the Makona strain has been estimated at between 0.87 × 10−3 and 1.42 × 10−3 mutations per site per year. This is equivalent to 16–27 mutations in each genome, meaning that sequences diverge rapidly enough to identify distinct sub-lineages during a prolonged epidemic2,3,4,5,6,7. Genome sequencing provides a high-resolution view of pathogen evolution and is increasingly sought after for outbreak surveillance. Sequence data may be used to guide control measures, but only if the results are generated quickly enough to inform interventions8. Genomic surveillance during the epidemic has been sporadic owing to a lack of local sequencing capacity coupled with practical difficulties transporting samples to remote sequencing facilities9. To address this problem, here we devise a genomic surveillance system that utilizes a novel nanopore DNA sequencing instrument. In April 2015 this system was transported in standard airline luggage to Guinea and used for real-time genomic surveillance of the ongoing epidemic. We present sequence data and analysis of 142 EBOV samples collected during the period March to October 2015. We were able to generate results less than 24 h after receiving an Ebola-positive sample, with the sequencing process taking as little as 15–60 min. We show that real-time genomic surveillance is possible in resource-limited settings and can be established rapidly to monitor outbreaks.

West Africa is currently witnessing the most extensive Ebola virus (EBOV) outbreak so far recorded. Until now, there have been 27,013 reported cases and 11,134 deaths. The origin of the virus is thought to have been a zoonotic transmission from a bat to a two-year-old boy in December 2013 (ref. 2). From this index case the virus was spread by human-to-human contact throughout Guinea, Sierra Leone and Liberia. However, the origin of the particular virus in each country and time of transmission is not known and currently relies on epidemiological analysis, which may be unreliable owing to the difficulties of obtaining patient information. Here we trace the genetic evolution of EBOV in the current outbreak that has resulted in multiple lineages. Deep sequencing of 179 patient samples processed by the European Mobile Laboratory, the first diagnostics unit to be deployed to the epicentre of the outbreak in Guinea, reveals an epidemiological and evolutionary history of the epidemic from March 2014 to January 2015. Analysis of EBOV genome evolution has also benefited from a similar sequencing effort of patient samples from Sierra Leone. Our results confirm that the EBOV from Guinea moved into Sierra Leone, most likely in April or early May. The viruses of the Guinea/Sierra Leone lineage mixed around June/July 2014. Viral sequences covering August, September and October 2014 indicate that this lineage evolved independently within Guinea. These data can be used in conjunction with epidemiological information to test retrospectively the effectiveness of control measures, and provides an unprecedented window into the evolution of an ongoing viral haemorrhagic fever outbreak. ispartof: Nature vol:524 issue:7563 pages:97-101 ispartof: location:England status: published

RATIONALE AND OBJECTIVES Contrast-carrying liposomes are potentially useful as computed tomography (CT) blood-pool agents. In the present study, preliminary safety, pharmacokinetics, and the CT imaging behavior of continuously extruded iopromide-carrying liposomes were studied. METHODS Iopromide liposomes were prepared by continuous high-pressure extrusion. Cell membrane-damaging characteristics were assessed in vitro in dog erythrocytes. Acute and subchronic toxicity and pharmacokinetics parameters were determined in rats. Computed tomography imaging efficiency was studied in rabbits. RESULTS The iopromide-carrying liposomes caused only minor morphological changes in dog erythrocytes. The median lethal dose in rats was approximately 4.5 g of total iodine per kilogram of body weight. In a subchronic tolerance study in rats that were administered six doses of 1 g iodine per kilogram twice a week, no adverse effects were observed. The pharmacokinetics in rats was dose dependent, and elimination of iopromide was almost complete within 7 days after intravenous administration. In rabbits, at a dose of 300 mg total iodine per kilogram, the iopromide-carrying liposomes displayed prolonged blood circulation, with mean CT density differences > 60 Hounsfield units (aorta) for up to 10 minutes. CONCLUSIONS The iopromide liposomes were well tolerated, almost completely excreted, and have potential as a CT blood-pool imaging agent.

Rationale and Objectives. The purpose of this study was to determine the feasibility of using iodinated liposomes as blood pool agents for computed tomography (CT) in nonhuman primates. Materials and Methods. Five normal adult baboons (15–21 kg) were anesthetized and intravenously injected with iopromide containing soy phosphatidyl glycerol liposomes with a diameter of 195 nm. Each animal received a dose of 300 mg total iodine per kilogram (46% encapsulation). Results. The animals tolerated the injections well, experiencing no measurable electrocardiographic changes, and recovered uneventfully from anesthesia. Sequential helical CT scans of the baboons from the base of the skull to the symphysis pubis acquired up to 40 minutes after injection showed persistent blood pool enhancement. Maximum mean enhancement of major vascular structures was 106 HU at 1 minute after contrast medium injection. Mean blood pool enhancement was 76, 72, and 67 HU at 10, 20, and 40 minutes after injection, respectively. Liver and spleen were enhanced by 40 and 41 HU, respectively, 40 minutes after injection. No significant enhancement was measured in the brain and pancreas. Conclusion. Soy phosphatidyl glycerol with iopromide liposomes produces prolonged vascular enhancement and has potential as a blood pool CT contrast agent in primates.

RATIONALE AND OBJECTIVES Surface-modified contrast-carrying liposomes potentially are useful as computed tomography (CT) blood-pool agents. The biodistribution and CT-imaging behavior of conventional as well as polyethylene glycol (PEG)-coated iopromide-carrying liposomes were tested. Two different types of PEG-ylated lipids were used to demonstrate possible differences. METHODS Iopromide-containing liposomes were prepared by a continuous high-pressure extrusion method and subsequently PEG-ylated by simple mixing with either DSPE-PEG2000 or CHHS-PEG2000. The resulting liposomes were investigated in rats (biodistribution) and rabbits (imaging). RESULTS Surface modification with CHHS-PEG consistently resulted in less effective stabilization of liposomes in the blood than with DSPE-PEG. In the biodistribution study, no significant differences in blood concentration could be found 1 hour after injection between the different formulations at a dose of 250 mg total iodine/kg body weight (approximately 500 mg lipid/kg). At this dose, the unmodified as well as the DSPE-PEG liposomes displayed prolonged blood circulation with CT density differences above 70 Hounsfield units (aorta) for up to 20 minutes (n = 1). CONCLUSIONS DSPE-PEG-coated and unmodified liposomes proved to be useful for CT blood-pool imaging displaying favorable imaging properties. Future studies will have to demonstrate whether PEG-ylation offers diagnostic or toxicologic advantages over conventional vesicles in this indication.

Iopromide-carrying liposomes prepared by the ethanol-evaporation method which encapsulated approximately 35% X-ray contrast agent at an average vesicle size of 300 nm were stabilized by lyophilization. Freezing behaviour of the suspension was studied by differential scanning calorimetry (DSC) and resistance/temperature measurement with respect to the maximum allowable temperature during primary drying. While melting of the suspension was observed at −21°C by DSC, conductivity changes down to −40°C could be detected by simultaneous resistance/temperature measurement. Furthermore, the influence of two different shelf-temperatures (−15°C and + 5°C) and three different chamber pressures (0.03 mbar, 0.08 mbar and 0.2 mbar) during primary drying on the quality of the lyophilized and rehydrated liposomes were investigated. A chamber pressure of 0.08 mbar and a shelf-temperature of −15°C during primary drying led to optimal product quality indicated by high contrast agent encapsulation. A chamber pressure of 0.08 mbar also proved to be optimal with respect to an economic lyophilization process. The residual water content of the freeze dried material proved to be very low (about 0.1%) independent of process parameters. Rehydration of the lyophilized liposomes with mannitol solution resulted in higher encapsulation efficiency of the rehydrated vesicles compared to rehydration with water or 20 mM tromethamine buffer (pH 7.5). The encapsulation efficiency could be further improved by increasing the concentration of the mannitol solution. Rehydration with iso-osmotic solutions of sucrose and KCl proved not to be as effective as mannitol solution in increasing the encapsulation efficiency of the rehydrated vesicles. Freeze-fracture images of lyophilized drug-free liposomes in contrast to iopromide-carrying liposomes revealed the lyoprotective effect of iopromide.

Surface-modified, contrast-carrying liposomes were generated by incorporation of amphipathic polymers into the membranes of continuously extruded vesicles. Besides the well described distearoylphosphatidylethanolamine monomethoxypolyethyleneglycol (DSPE-PEG), a new substance, cholesterylhemisuccinate monomethoxy-polyethyleneglycol (CholHS-PEG) was tested for the first time. Using the water-soluble radiographic contrast agent iopromide as well as the nuclear magnetic contrast agent Gd-DTPA, the impact of surface modification (SM) on liposome properties like vesicle size distribution, encapsulation efficiency, zeta potential and storage as well as plasma stability was investigated. In the course of the studies, the molar amount of amphipathic polymer employed as well as the time point of SM during the production process were varied. Incorporation of both, DSPE-PEG and CholHS-PEG into the lipid films formed before continuous extrusion resulted in a concentration-dependent decline of encapsulation efficiencies. When SM was carried out after vesicle formation, the observed effect diminished and even disappeared, as soon as PEG-coating was carried out after the last extrusion step. However, when using the latter procedure with DSPE-PEG, mean vesicle diameters showed a strong increase in the course of the pegylation process. The extent of bilayer modification was studied by zeta potential measurements of liposomes containing the negatively charged phospholipid SPG. In the presence of PEG-derivatives the high zeta potentials of unmodified vesicles were significantly reduced, irrespective of whether SM was carried out before, during or after extrusion. This result indicated a successful association of the PEG-derivatives with liposomal bilayers for all procedures. For CholHS-PEG complete incorporation into liposomes after extrusion could be demonstrated using gel filtration. Stability testing revealed an unchanged macroscopic appearance, encapsulation efficiency and vesicle size distribution of unmodified and CholHS-bearing liposomes after 4 months' storage at 2–8°C. In contrast to this, DSPE-PEG-containing vesicles displayed a pronounced size increase when SM was carried out during extrusion. Another important effect of DSPE-PEG incorporation was found during plasma stability experiments. Whereas CholHS-PEG-carrying and unmodified liposomes had similar leakage rates in human plasma, DSPE-PEG caused a concentration-dependent decrease in plasma stability, but only when SM had been carried out before extrusion. Altogether, from a merely technological point of view, Cho1HS-PEG revealed superior properties over DSPE-PEG for SM of continuously extruded contrast-carrying liposomes.

Biodistribution and computed tomography (CT) imaging characteristics of iopromide-carrying liposomes were investigated in healthy or tumor-bearing rats. The mean diameter of the liposomes obtained by the ethanol evaporation method was approximately 0.5 urn and the encapsulation amounted to 32 %. In the biodistribution study a significant accumulation of the liposomal contrast medium was observed at both examined doses (250 and 1000 mg total iodine/kg b.w.) in liver and spleen. A dose-dependent enrichment in these organs could be demonstrated. Increasing the iodine and thus lipid dose resulted in a marked increase in blood iodine concentration for prolonged time periods due to saturation of liver uptake. Increasing the injection rate 20-fold at a dose of 250 mg iodine/kg b.w. did not significantly (p > 0.05) change the biodistribution behaviour. In the CT study in healthy rats doses in the range from 100 to 2000 mg iodine/kg were investigated/There was an increase in density in liver and spleen in ...

Rationale and Objectives:The use of contrast-carrying liposomes in diagnostic applications (1) or of haemoglobin liposomes in blood replacement therapy (2) requires infusion of large lipid doses. Saturated lipids like HSPC are often used in these formulations to render the liposomes more stable (3). Previous studies have indicated that intravenous injection of such liposome preparations can result in significant haemodynamic changes in rats (14). The purpose of this study was to systematically evaluate cardio- and haemodynamic effects of liposomes prepared from saturated and unsaturated phosphatidylcholine alone or in combination with other lipid components.Methods;Liposomes made from SPC, HSPC, DSPC, DSPC/CH, DSPC/DSPG, DSPC/CH/DSPG were infused in anaesthetized rats (total lipid dose: 300 mg lipid/kg BW) and cardio-heamodynamic parameters were measured.Results:DSPC-liposomes significantly reduced blood pressure (BP) and total peripheral resistance (TPR) by -53.7 % and -45.7 % of prevalue, respec...

Purpose. The dose-proportionality of pharmacokinetics of an iodinated contrast medium, iopromide, encapsulated into liposomes was investigated.

Iopromide-carrying liposomes were prepared by the ethanol evaporation method and pharmacokinetic parameters and CT imaging efficiency were determined in rats and rabbits. The mean diameter of the liposomes was 0.5±0.1 urn and the encapsulation efficiency was between 30 and 40%. The liposomes were stable in human, bovine, dog, pig, rat and rabbit plasma for more than 6 h. The pharmacokinetics in rats and rabbits were dose-dependent. Increasing the dose resulted in lower total clearance, and longer terminal half-life. Elimination of iodine was complete and the main route of excretion was via the kidneys. A clinically relevant CT enhancement of the liver was reached after 200 mg iodine/kg in rat and 150 mg iodine/kg in rabbit.

RATIONALE AND OBJECTIVES Iopromide-carrying liposomes were prepared and were characterized pharmaceutically and biologically. METHODS The liposomes were prepared by the ethanol evaporation method and were characterized by quasi-elastic light scattering (size) and equilibrium dialysis (encapsulation efficiency and stability). Acute and subchronic toxicity was tested in mice and/or rats and cardiovascular tolerance in rabbits. Pharmacokinetic parameters were determined in rats. Computed tomography (CT) imaging efficiency was obtained from rat and rabbit studies. RESULTS The mean diameter was 0.5 +/- 0.1 micron and the encapsulation efficiency ranged between 30% and 40%. The liposomes were stable in human and rabbit plasma for approximately 24 hours. The LD50 in mouse and rat was approximately 3 g iodine/kg. In a subchronic toxicity study in rats with six doses of 1 g iodine/kg given every three days, no adverse effects were observed. The pharmacokinetics in rats were dose-dependent. Increasing the dose resulted in lower total clearance, and longer terminal half-life. Elimination of iodine was complete and the main route of excretion was via the kidneys. A clinically relevant computed tomography enhancement of the liver was reached after approximately 200 mg iodine/kg in rats and 150 mg iodine/kg in rabbits. CONCLUSIONS The iopromide-carrying liposomes were well tolerated in animal studies and seemed to be suitable for the imaging of the liver.

The use of liposomal contrast agents for computed tomography (CT) imaging applications is considered. The properties of the various liposome types as well as methods for their preparation are discussed. Specific challenges for the preparation and use of CT contrast-carrying liposomes are outlined. Available experience on the use of CT liposomes for liver and spleen imaging in preclinical animal models and humans is reviewed. The use of surface-modified and conventional liposomes for CT blood-pool imaging is discussed in light of the published animal data. Finally, new trends in the use of CT liposomes are considered based on the limited data available to date.

Liposomes were prepared by stepwise extrusion through 5, 1, 0.4, 0.2, 0.1 and 0.05 microm pore sizes using two different filter-extruders, the continuous high pressure device Dispex Maximator (CE) or alternatively the discontinuous Avestin LiposoFast (DE). The liposome dispersions obtained were compared in terms of particle size, lamellarity and encapsulation efficiency of calcein. The liposomes were smaller with CE than DE at all stages due to higher flow rates and pressure drops, except for final filter pore size (0.05 microm) where both preparations had similar sizes. The particle size analysis technique itself had a strong influence on the liposome sizes measured. For bigger liposomes (extruded through 0.4 microm filters) the Nicomp 370 revealed bigger volume-based mean particle sizes along with more stringent differences between volume-based and number-based diameters than the Malvern Zetasizer. In contrast, for small liposomes extruded through 0.05 microm filters, similar liposome sizes were found no matter which of the two PCS techniques or cryo-transmission electron microscopy was used. In congruence to the liposome sizes measured, encapsulation efficiencies were smaller for CE than DE at all filter stages except the final (0.05 microm). No lipid loss occurred and lyso-phosphatidylcholine formation was negligible irrespective of which extrusion technique was used.

Background. A unit of the European Mobile Laboratory (EMLab) consortium was deployed to the Ebola virus disease (EVD) treatment unit in Guéckédou, Guinea, from March 2014 through March 2015. Methods. The unit diagnosed EVD and malaria, using the RealStar Filovirus Screen reverse transcriptionpolymerase chain reaction (RT-PCR) kit and a malaria rapid diagnostic test, respectively. Results. The cleaned EMLab database comprised 4719 samples from 2741 cases of suspected EVD from Guinea. EVD was diagnosed in 1231 of 2178 hospitalized patients (57%) and in 281 of 563 who died in the community (50%). Children aged 74 years (90%) and low in patients aged 1019 years (40%). On admission, RT-PCR analysis of blood specimens from patients who died in the hospital yielded a lower median cycle threshold (Ct) than analysis of blood specimens from survivors (18.1 vs 23.2). Individuals who died in the community had a median Ct of 21.5 for throat swabs. Multivariate logistic regression on 1047 data sets revealed that low Ct values, ages of

Despite the magnitude of the Ebola virus disease (EVD) outbreak in West Africa, there is still a fundamental lack of knowledge about the pathophysiology of EVD 1 . In particular, very little is known about human immune responses to Ebola virus (EBOV) 2,3 . Here, we have for the first time evaluated the physiology of the human T cell immune response in EVD patients at the time of admission at the Ebola Treatment Center (ETC) in Guinea, and longitudinally until discharge or death. Through the use of multiparametric flow cytometry established by the European Mobile Laboratory in the field, we have identified an immune signature that is unique in EVD fatalities. Fatal EVD was characterized by high percentage of CD4 and CD8 T cells expressing the inhibitory molecules cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death-1 (PD-1), which was correlated with elevated inflammatory markers and high virus load. Conversely, surviving individuals showed significantly lower expression of CTLA-4 and PD-1 as well as lower inflammation despite comparable overall T cell activation. Concommittant with virus clearance, survivors mounted a robust EBOV-specific T cell response. Our findings suggest that dysregulation of the T cell response is a key component of EVD pathophysiology.