The outbreak of the Zika Virus (ZIKV) and its association with fetal abnormalities have raised worldwide concern. However, the cellular tropism and the mechanisms of ZIKV transmission to the fetus ...during early pregnancy are still largely unknown. Therefore, we ex vivo modeled the ZIKV transmission at the maternal-fetal interface using organ culture from first trimester pregnancy samples. Here, we provide evidence that ZIKV strain circulating in Brazil infects and damages tissue architecture of the maternal decidua basalis, the fetal placenta and umbilical cord. We also show that ZIKV replicates differentially in a wide range of maternal and fetal cells, including decidual fibroblasts and macrophages, trophoblasts, Hofbauer cells as well as umbilical cord mesenchymal stem cells. The striking cellular tropism of ZIKV and its cytopathic-induced tissue injury during the first trimester of pregnancy could provide an explanation for the irreversible congenital damages.
Microbiota of Anopheles midgut can modulate vector immunity and block Plasmodium development. Investigation on the bacterial biodiversity in Anopheles, and specifically on the identification of ...bacteria that might be used in malaria transmission blocking approaches, has been mainly conducted on malaria vectors of Africa. Vietnam is an endemic country for both malaria and Bancroftian filariasis whose parasitic agents can be transmitted by the same Anopheles species. No information on the microbiota of Anopheles mosquitoes in Vietnam was available previous to this study.
The culture dependent approach, using different mediums, and culture independent (16S rRNA PCR - TTGE) method were used to investigate the bacterial biodiversity in the abdomen of 5 Anopheles species collected from Dak Nong Province, central-south Vietnam. Molecular methods, sequencing and phylogenetic analysis were used to characterize the microbiota.
The microbiota in wild-caught Anopheles was diverse with the presence of 47 bacterial OTUs belonging to 30 genera, including bacterial genera impacting Plasmodium development. The bacteria were affiliated with 4 phyla, Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria, the latter being the dominant phylum. Four bacterial genera are newly described in Anopheles mosquitoes including Coxiella, Yersinia, Xanthomonas, and Knoellia. The bacterial diversity per specimen was low ranging from 1 to 4. The results show the importance of pairing culture and fingerprint methods to better screen the bacterial community in Anopheles mosquitoes.
Sampled Anopheles species from central-south Vietnam contained a diverse bacterial microbiota that needs to be investigated further in order to develop new malaria control approaches. The combination of both culture and DNA fingerprint methods allowed a thorough and complementary screening of the bacterial community in Anopheles mosquitoes.
The probability of being seropositive for at least two antigens after 36 months was 53·6% (95% CI 51·6–55·6) in participants who received ansuvimab (m114 mAb), 73·5% (71·5–75·5) in participants who ...received REGN-EB3 (a mix of three mAbs), 78·5% (76·5–80·5) in participants who received ZMapp, and 76·8% (74·8–78·8) in participants who received remdesivir. ...the authors concluded that these results raise questions about the potential negative effect of treatment with monoclonal antibodies in survivors who might be at risk for Ebola virus disease reactivation or reinfection. At this stage, the interpretation of analysed data on the effect of mAbs on the reduction of antibodies in survivors of Ebola virus disease are associated with measured correlations, but have not yet been experimentally proven. ...to move from speculation to a conclusion, it would be important to increase the sample size of studies including survivors, but also to do comparative in-vivo studies testing viral reduction in survivors treated with ansuvimab, REGN-B3 (WHO recommended treatment for Ebola virus disease), and remdesivir, and studies of antigen presentation, antibody production, and associated cell signalling pathways. Passive immunotherapy using horse polyclonal antibodies is the oldest historical tool to mitigate pathologies associated with viral infections such as rabies.4 Horse polyclonal anti-Ebola virus-Zaire F(ab’)2 product has been successfully assayed in vivo.5 The polyclonal approach would have numerous advantages, including large spectrum of neutralising efficacy as demonstrated against avian flu viruses,6 and the absence of both induction of antibody-dependent infection enhancement, and antigenic drift. Since the objective of Ebola virus disease mitigation is to maximise the number of survivors along with their quality of life, and the security and wellbeing of the community, we need to improve antiviral strategies and improve drugs to markedly reduce the deleterious inflammatory consequences of Ebola virus disease.
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•Norovirus is considered to be the second leading cause of morbidity and mortality among children under five with severe diarrheal infection in Africa.•Norovirus infection was ...detected only in Congolese children under 24 months.•Higher prevalence of norovirus infection in dry season.•GII genogroup was the most prevalent in Congolese samples.
Acute diarrhea is a leading cause of morbidity and mortality among children under five worldwide. As no published data is available on the occurrence of this infection in the Republic of Congo, this study aimed at (1) determining the prevalence and (2) characterizing genotypes of norovirus strains in Brazzaville.
From June 2012 to June 2013, stool samples were collected from hospitalized young children with acute gastroenteritis. A total of 545 samples were tested for GI and GII norovirus infections using nested duplex reverse-transcription–polymerase chain reaction and sequencing.
The GI and GII norovirus infection were detected in 148 samples. Males (28%) were not significantly more infected than females (25%). Norovirus infection was found exclusively in children aged under 24 months with a higher prevalence (P=0,048) in the age group of 7–12 months, and throughout the year with a peak in August and September. Genetic diversity of norovirus strains revealed that GII was the most prevalent (87%). No risk factor was significantly associated with norovirus infection.
This study showed that noroviruses are important agents responsible for acute diarrhea in Congolese children and highlights the importance of continued surveillance.
The two volumes of Acute Phase Proteins book consist of chapters that give a large panel of fundamental and applied knowledge on one of the major elements of the inflammatory process during the acute ...phase response, i.e., the acute phase proteins expression and functions that regulate homeostasis. We have organized this book in two volumes - the first volume, mainly containing chapters on structure, biology and functions of APP, the second volume discussing different uses of APP as diagnostic tools in human and veterinary medicine.
Dengue virus (DV) is an important re‐emerging arthropod‐borne virus of global significance. The defining characteristic of DV infection‐associated pathology is haemorrhagic fever, which often leads ...to a fatal shock‐like syndrome (DHF/DSS) owing to an increase in vascular endothelial permeability. Here, we show, in a viral dose‐dependent manner, that DV‐infected immature dendritic cells overproduce soluble gelatinolytic matrix metalloproteinase (MMP)‐9—and to a lesser extent MMP‐2—which enhances endothelial permeability, but which are reduced by specific inhibitors and a neutralizing anti‐MMP‐9 antibody. This permeability was associated with a loss of expression of the platelet endothelial adhesion molecule 1 (PECAM‐1) and vascular endothelium (VE)‐cadherin cell adhesion molecules and redistribution of F‐actin fibres. These in vitro observations were confirmed in an in vivo vascular‐leakage mouse model. These results provide a molecular basis for DHF/DSS that could be a basis for a general model of haemorrhagic fever‐inducing viruses, and identify a new therapeutic approach for the treatment of viral‐induced vascular leakage by specifically targeting gelatinolytic metalloproteases.
The Hepatitis C virus (HCV) infection exhibits a high global prevalence frequently associated with hepatocellular carcinoma, taking years to develop. Despite the standardization of highly sensitive ...HCV quantitative RT-PCR (qRT-PCR) detection methods, false-negative diagnoses may be generated with current methods, mainly due to the presence of PCR inhibitors and/or low viral loads in the patient's sample. These false-negative diagnoses impact both public health systems, in developing countries, and an in lesser extent, in developed countries, including both the risk of virus transmission during organ transplantation and/or blood transfusion and the quality of the antiviral treatment monitoring. To adopt an appropriate therapeutic strategy to improve the patient's prognosis, it is urgent to increase the HCV detection sensitivity. Based upon previous studies on HBV, we worked on the capacity of the scavenger acute phase protein, Apolipoprotein H (ApoH) to interact with HCV. Using different approaches, including immunoassays, antibody-inhibition, oxidation, ultracentrifugation, electron microscopy and RT-PCR analyses, we demonstrated specific interactions between HCV particles and ApoH. Moreover, when using a two-step HCV detection process, including capture of HCV by ApoH-coated nanomagnetic beads and a home-made real-time HCV-RT-PCR, we confirmed the presence of HCV for all samples from a clinical collection of HCV-seropositive patients exhibiting an RT-PCR COBAS® TaqMan® HCV Test, v2.0 (COBAS)-positive result. In contrast, for HCV-seropositive patients with either low HCV-load as determined with COBAS or exhibiting HCV-negative COBAS results, the addition of the two-step ApoH-HCV-capture and HCV-detection process was able to increase the sensitivity of HCV detection or more interestingly, detect in a genotype sequence-independent manner, a high-proportion (44%) of HCV/RNA-positive among the COBAS HCV-negative patients. Thus, the immune interaction between ApoH and HCV could be used as a sample preparation tool to enrich and/or cleanse HCV patient's samples to enhance the detection sensitivity of HCV and therefore significantly reduce the numbers of false-negative HCV diagnosis results.
Prior to the first recorded outbreak of Rift Valley fever (RVF) in Uganda, in March 2016, earlier studies done until the 1970's indicated the presence of the RVF virus (RVFV) in the country, without ...any recorded outbreaks in either man or animals. While severe outbreaks of RVF occurred in the neighboring countries, none were reported in Uganda despite forecasts that placed some parts of Uganda at similar risk. The Ministry of Agriculture, Animal Industry and Fisheries (MAAIF) undertook studies to determine the RVF sero-prevalence in risk prone areas. Three datasets from cattle sheep and goats were obtained; one from retrospective samples collected in 2010-2011 from the northern region; the second from the western region in 2013 while the third was from a cross-sectional survey done in 2016 in the south-western region. Laboratory analysis involved the use of the Enzyme Linked Immunosorbent Assays (ELISA). Data were subjected to descriptive statistical analyses, including non-parametric chi-square tests for comparisons between districts and species in the regions.
During the Yellow Fever outbreak investigation of 2010-2011 in the northern region, a total sero-prevalence of 6.7% was obtained for anti RVFV reacting antibodies (IgG and IgM) among the domestic ruminant population. The 2013 sero-survey in the western region showed a prevalence of 18.6% in cattle and 2.3% in small ruminants. The 2016 sero-survey in the districts of Kabale, Kanungu, Kasese, Kisoro and Rubirizi, in the south-western region, had the respective district RVF sero-prevalence of 16.0, 2.1, 0.8, 15.1and 2.7% among the domestic ruminants combined for this region; bovines exhibited the highest cumulative sero-prevalence of 15.2%, compared to 5.3 and 4.0% respectively for sheep and goats per species for the region.
The absence of apparent outbreaks in Uganda, despite neighboring enzootic areas, having minimal restrictions to the exchange of livestock and their products across borders, suggest an unexpected RVF activity in the study areas that needs to be unraveled. Therefore, more in-depth studies are planned to mitigate the risk of an overt RVF outbreak in humans and animals as has occurred in neighboring countries.
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