scholarly journals What is stirring in the reservoir? Modelling mechanisms of henipavirus circulation in fruit bat hosts

2019 ◽  
Vol 374 (1782) ◽  
pp. 20190021 ◽  
Author(s):  
Emma E. Glennon ◽  
Daniel J. Becker ◽  
Alison J. Peel ◽  
Romain Garnier ◽  
Richard D. Suu-Ire ◽  
...  
Keyword(s):  
Direct Evidence ◽  
Latent Infection ◽  
Full Range ◽  
Reservoir Host ◽  
Infectious Period ◽  
High Morbidity ◽  
Fruit Bat ◽  
Novel Approach ◽  
Reservoir Hosts ◽  
Eidolon Helvum

Pathogen circulation among reservoir hosts is a precondition for zoonotic spillover. Unlike the acute, high morbidity infections typical in spillover hosts, infected reservoir hosts often exhibit low morbidity and mortality. Although it has been proposed that reservoir host infections may be persistent with recurrent episodes of shedding, direct evidence is often lacking. We construct a generalized SEIR (susceptible, exposed, infectious, recovered) framework encompassing 46 sub-models representing the full range of possible transitions among those four states of infection and immunity. We then use likelihood-based methods to fit these models to nine years of longitudinal data on henipavirus serology from a captive colony of Eidolon helvum bats in Ghana. We find that reinfection is necessary to explain observed dynamics; that acute infectious periods may be very short (hours to days); that immunity, if present, lasts about 1–2 years; and that recurring latent infection is likely. Although quantitative inference is sensitive to assumptions about serology, qualitative predictions are robust. Our novel approach helps clarify mechanisms of viral persistence and circulation in wild bats, including estimated ranges for key parameters such as the basic reproduction number and the duration of the infectious period. Our results inform how future field-based and experimental work could differentiate the processes of viral recurrence and reinfection in reservoir hosts. This article is part of the theme issue ‘Dynamic and integrative approaches to understanding pathogen spillover’.

scholarly journals The discovery of biological subphenotypes in ARDS: a novel approach to targeted medicine?

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Karin Wildi ◽  
Samantha Livingstone ◽  
Chiara Palmieri ◽  
Gianluigi LiBassi ◽  
Jacky Suen ◽  
...  
Keyword(s):  
Age Groups ◽  
Geographical Location ◽  
High Morbidity ◽  
Shock State ◽  
Pharmacological Agents ◽  
New Approach ◽  
Novel Approach ◽  
Active Research ◽  
Targeted Medicine ◽  
Core Features

AbstractThe acute respiratory distress syndrome (ARDS) is a severe lung disorder with a high morbidity and mortality which affects all age groups. Despite active research with intense, ongoing attempts in developing pharmacological agents to treat ARDS, its mortality rate remains unaltered high and treatment is still only supportive. Over the years, there have been many attempts to identify meaningful subgroups likely to react differently to treatment among the heterogenous ARDS population, most of them unsuccessful. Only recently, analysis of large ARDS cohorts from randomized controlled trials have identified the presence of distinct biological subphenotypes among ARDS patients: a hypoinflammatory (or uninflamed; named P1) and a hyperinflammatory (or reactive; named P2) subphenotype have been proposed and corroborated with existing retrospective data. The hyperinflammatory subphenotyope was clearly associated with shock state, metabolic acidosis, and worse clinical outcomes. Core features of the respective subphenotypes were identified consistently in all assessed cohorts, independently of the studied population, the geographical location, the study design, or the analysis method. Additionally and clinically even more relevant treatment efficacies, as assessed retrospectively, appeared to be highly dependent on the respective subphenotype. This discovery launches a promising new approach to targeted medicine in ARDS. Even though it is now widely accepted that each ARDS subphenotype has distinct functional, biological, and mechanistic differences, there are crucial gaps in our knowledge, hindering the translation to bedside application. First of all, the underlying driving biological factors are still largely unknown, and secondly, there is currently no option for fast and easy identification of ARDS subphenotypes. This narrative review aims to summarize the evidence in biological subphenotyping in ARDS and tries to point out the current issues that will need addressing before translation of biological subohenotypes into clinical practice will be possible.

scholarly journals Updated and Validated Pan-Coronavirus PCR Assay to Detect All Coronavirus Genera

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 599
Author(s):  
Myndi G. Holbrook ◽  
Simon J. Anthony ◽  
Isamara Navarrete-Macias ◽  
Theo Bestebroer ◽  
Vincent J. Munster ◽  
...  
Keyword(s):  
Host Species ◽  
High Sensitivity ◽  
Respiratory Illness ◽  
Reservoir Host ◽  
Pcr Assay ◽  
Wildlife Reservoirs ◽  
Viral Surveillance ◽  
Reservoir Hosts

Coronavirus (CoV) spillover events from wildlife reservoirs can result in mild to severe human respiratory illness. These spillover events underlie the importance of detecting known and novel CoVs circulating in reservoir host species and determining CoV prevalence and distribution, allowing improved prediction of spillover events or where a human–reservoir interface should be closely monitored. To increase the likelihood of detecting all circulating genera and strains, we have modified primers published by Watanabe et al. in 2010 to generate a semi-nested pan-CoV PCR assay. Representatives from the four coronavirus genera (α-CoVs, β-CoVs, γ-CoVs and δ-CoVs) were tested and all of the in-house CoVs were detected using this assay. After comparing both assays, we found that the updated assay reliably detected viruses in all genera of CoVs with high sensitivity, whereas the sensitivity of the original assay was lower. Our updated PCR assay is an important tool to detect, monitor and track CoVs to enhance viral surveillance in reservoir hosts.

scholarly journals Ecological Factors Characterizing the Prevalence of Bacterial Tick-Borne Pathogens in Ixodes ricinus Ticks in Pastures and Woodlands

2010 ◽  
Vol 76 (13) ◽  
pp. 4413-4420 ◽  
Author(s):  
Lénaïg Halos ◽  
Séverine Bord ◽  
Violaine Cotté ◽  
Patrick Gasqui ◽  
David Abrial ◽  
...  
Keyword(s):  
Forest Fragmentation ◽  
Ixodes Ricinus ◽  
Spotted Fever ◽  
Ecological Factors ◽  
Adult Tick ◽  
Reservoir Host ◽  
Host Community ◽  
Infection Prevalence ◽  
Spotted Fever Group ◽  
Reservoir Hosts

ABSTRACT Ecological changes are recognized as an important driver behind the emergence of infectious diseases. The prevalence of infection in ticks depends upon ecological factors that are rarely taken into account simultaneously. Our objective was to investigate the influences of forest fragmentation, vegetation, adult tick hosts, and habitat on the infection prevalence of three tick-borne bacteria, Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, and Rickettsia sp. of the spotted fever group, in questing Ixodes ricinus ticks, taking into account tick characteristics. Samples of questing nymphs and adults were taken from 61 pastures and neighboring woodlands in central France. The ticks were tested by PCR of pools of nymphs and individual adults. The individual infection prevalence was modeled using multivariate regression. The highest infection prevalences were found in adult females collected in woodland sites for B. burgdorferi sensu lato and A. phagocytophilum (16.1% and 10.7%, respectively) and in pasture sites for Rickettsia sp. (8.7%). The infection prevalence in nymphs was lower than 6%. B. burgdorferi sensu lato was more prevalent in woodlands than in pastures. Forest fragmentation favored B. burgdorferi sensu lato and A. phagocytophilum prevalence in woodlands, and in pastures, the B. burgdorferi sensu lato prevalence was favored by shrubby vegetation. Both results are probably because large amounts of edges or shrubs increase the abundance of small vertebrates as reservoir hosts. The Rickettsia sp. prevalence was maximal on pasture with medium forest fragmentation. Female ticks were more infected by B. burgdorferi sensu lato than males and nymphs in woodland sites, which suggests an interaction between the ticks and the bacteria. This study confirms the complexity of the tick-borne pathogen ecology. The findings support the importance of small vertebrates as reservoir hosts and make a case for further studies in Europe on the link between the composition of the reservoir host community and the infection prevalence in ticks.

scholarly journals Characterization of a Novel Bat Adenovirus Isolated from Straw-Colored Fruit Bat (Eidolon helvum)

Viruses ◽  
2017 ◽  
Vol 9 (12) ◽  
pp. 371 ◽  
Author(s):  
Hirohito Ogawa ◽  
Masahiro Kajihara ◽  
Naganori Nao ◽  
Asako Shigeno ◽  
Daisuke Fujikura ◽  
...  
Keyword(s):  
Fruit Bat ◽  
Eidolon Helvum

scholarly journals Foraging movements are density-independent among straw-coloured fruit bats

2020 ◽  
Vol 7 (5) ◽  
pp. 200274
Author(s):  
María C. Calderón-Capote ◽  
Dina K. N. Dechmann ◽  
Jakob Fahr ◽  
Martin Wikelski ◽  
Roland Kays ◽  
...  
Keyword(s):  
Intraspecific Competition ◽  
Colony Size ◽  
Resource Depletion ◽  
Central Place ◽  
Long Distance ◽  
Foraging Patterns ◽  
Fruit Bat ◽  
Foraging Movements ◽  
Productive Landscapes ◽  
Eidolon Helvum

Intraspecific competition in large aggregations of animals should generate density-dependent effects on foraging patterns. To test how large differences in colony size affect foraging movements, we tracked seasonal movements of the African straw-coloured fruit bat ( Eidolon helvum ) from four colonies that range from 4000 up to 10 million animals. Contrary to initial predictions, we found that mean distance flown per night (9–99 km), number of nightly foraging sites (2–3) and foraging and commuting times were largely independent of colony size. Bats showed classic central-place foraging and typically returned to the same day roost each night. However, roost switching was evident among individuals in three of the four colonies especially towards the onset of migration. The relatively consistent foraging patterns across seasons and colonies indicate that these bats seek out roosts close to highly productive landscapes. Once foraging effort starts to increase due to local resource depletion they migrate to landscapes with seasonally increasing resources. This minimizes high intraspecific competition and may help to explain why long-distance migration, otherwise rare in bats, evolved in this highly gregarious species.

Seasonal variations in the morphology of the seminal vesicles of the African straw‐coloured fruit bat ( Eidolon helvum )

2020 ◽  
Author(s):  
Clifford Nwabugwu Abiaezute ◽  
Innocent Chima Nwaogu ◽  
Ikechukwu Reginald Obidike ◽  
Udensi Maduabuchi Igwebuike
Keyword(s):  
Seasonal Variations ◽  
Seminal Vesicles ◽  
Fruit Bat ◽  
Eidolon Helvum

scholarly journals The Movement Ecology of the Straw-Colored Fruit Bat, Eidolon helvum, in Sub-Saharan Africa Assessed by Stable Isotope Ratios

PLoS ONE ◽  
2012 ◽  
Vol 7 (9) ◽  
pp. e45729 ◽  
Author(s):  
Gonzalo Ossa ◽  
Stephanie Kramer-Schadt ◽  
Alison J. Peel ◽  
Anne K. Scharf ◽  
Christian C. Voigt
Keyword(s):  
Stable Isotope ◽  
Movement Ecology ◽  
Isotope Ratios ◽  
Sub Saharan Africa ◽  
Stable Isotope Ratios ◽  
Fruit Bat ◽  
Sub Saharan ◽  
Eidolon Helvum

scholarly journals Diosgenin Exerts Antitumor Activity via Downregulation of Skp2 in Breast Cancer Cells

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Yanling Liu ◽  
Zijun Zhou ◽  
Jingzhe Yan ◽  
Xuefeng Wu ◽  
Guiying Xu
Keyword(s):  
Breast Cancer ◽  
Antitumor Activity ◽  
Cell Viability ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Underlying Mechanism ◽  
High Morbidity ◽  
Novel Approach ◽  
Transwell Invasion Assay ◽  
Induced Apoptosis

Background. Breast cancer is the common malignancy with high morbidity and mortality in women. S-phase kinase-associated protein 2 (Skp2) has been characterized to play an oncogenic role in the breast carcinogenesis and progression. Therefore, inactivation of Skp2 in breast cancer might be a novel approach for fighting breast malignancy. A natural compound diosgenin has been reported to exert anticancer activity in a variety of human cancers. However, the underlying mechanism has not been fully determined. Methods. In this study, we aim to explore whether diosgenin performed antitumor activity via inhibition of Skp2 in breast cancer cells using several methods including MTT, Transwell invasion assay, RT-PCR, western blotting, and transfection. Results. We found that diosgenin inhibited cell viability and stimulated apoptosis. Moreover, we found that diosgenin reduced cell invasion in breast cancer cells. Furthermore, diosgenin inhibited the expression of Skp2 in breast cancer cells. Notably, diosgenin reduced cell viability and motility and induced apoptosis via suppression of Skp2 in breast cancer cells. Conclusion. Our findings revealed that diosgenin could be a potential inhibitor of Skp2 for treating breast cancer.

Estimation of population density of Eidolon helvum on the island of Príncipe, Gulf of Guinea / Estimation de densité de population de Eidolon helvum sur l'île de Príncipe, Golfe de Guinée

Mammalia ◽  
2006 ◽  
Vol 70 (1-2) ◽  
Author(s):  
Martin Dallimer ◽  
Tony King ◽  
David Cope ◽  
Manuel Borge Jiana
Keyword(s):  
Population Density ◽  
Food Resources ◽  
Gulf Of Guinea ◽  
Migratory Behaviour ◽  
Fruit Bat ◽  
Large Numbers ◽  
Eidolon Helvum

AbstractEidolon helvum is a widespread African fruit bat. It is migratory and can form colonies of millions of individuals. On Príncipe, in the Gulf of Guinea, there are seemingly large numbers of E. helvum . Here, they have lost their migratory behaviour and rely on the availability of the year-round food resources on the island, which is small (128 km

scholarly journals Evolution of Nipah Virus Infection: Past, Present, and Future Considerations

2021 ◽  
Vol 6 (1) ◽  
pp. 24
Author(s):  
Naomi Hauser ◽  
Alexis C. Gushiken ◽  
Shivakumar Narayanan ◽  
Shyam Kottilil ◽  
Joel V. Chua
Keyword(s):  
Case Fatality Rate ◽  
Nipah Virus ◽  
Case Fatality ◽  
Therapeutic Agents ◽  
Reservoir Host ◽  
Fruit Bats ◽  
Intermediate Hosts ◽  
Mode Of Transmission ◽  
Human Infections ◽  
Reservoir Hosts

Nipah virus (NiV) is a zoonotic paramyxovirus of the Henipavirus genus first identified in Malaysia in 1998. Henipaviruses have bat reservoir hosts and have been isolated from fruit bats found across Oceania, Asia, and Africa. Bat-to-human transmission is thought to be the primary mode of human NiV infection, although multiple intermediate hosts are described. Human infections with NiV were originally described as a syndrome of fever and rapid neurological decline following contact with swine. More recent outbreaks describe a syndrome with prominent respiratory symptoms and human-to-human transmission. Nearly annual outbreaks have been described since 1998 with case fatality rates reaching greater than 90%. The ubiquitous nature of the reservoir host, increasing deforestation, multiple mode of transmission, high case fatality rate, and lack of effective therapy or vaccines make NiV’s pandemic potential increasingly significant. Here we review the epidemiology and microbiology of NiV as well as the therapeutic agents and vaccines in development.

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