Dengue in Africa Franco, L; Cnops, L; Navascues, A ...
Tropical medicine & international health,
2015, Letnik:
20, Številka:
Suppl. 1
Journal Article
Recenzirano
Introduction: Dengue is caused by 4 different related viruses, DENV 1 to 4, transmitted to humans via Aedes mosquitoes. The disease is endemic in more than 100 countries. In Africa, the estimated ...dengue burden is 15 million of clinical cases and about 48 millions of inapparent infections. However, dengue remains largely unrecognized in Africa. Due to the lack of laboratory confirmation, a febrile syndrome is frequently misdiagnosed as malarial infection. The circulation of different dengue serotypes is also poorly documented. However, some information is provided by reports of dengue infections in travellers returning from Africa. In the present study we attempt the identification of dengue serotypes and genotypes circulating in Africa from 2010 to 2014 detected in travellers returning to Europe.
Methods: We collected samples from viraemic travellers returning from Africa who attended TropNet clinics in Europé from 2010 to 2014. Sequences of the Envelope gene were used to identify the serotype and genotype.
Results: During the study period we identified 3 DENV serotypes circulating in Africa. DENV 1 strains were detected in East Africa in 2010 (Eritrea) and in 2012 (Kenia), whereas in Central Africa in 2013(Angola and DRC). Strains from East Africa were grouped within Asian genotype, close to virus isolated in previous years in Djibouti and Kenia; we found American /African genotype in Central Africa. Both genotypes have circulated in West Africa for many years. DENV 2 strains were detected in West Africa (Senegal) and in East Africa (Tanzania) in 2014. Dengue 2 from Tanzania belongs to cosmopolitan genotype, but form a distinct clade different from the old African group. However, DENV 2 from Senegal surprisingly fell into genotype America /Asia. To our knowledge this is the first time identified in Africa. Finally, DENV 3 was detected in 2010 in Mali and Burkina Faso and again in Burkina Faso in 2013. All DENV 3 belong to genotype III and form a cluster with the African strains identified since 2008.
Conclusion: DENV 1 of both genotypes was identified previously in Africa indicating endemic transmission as well as with DENV 3. Meanwhile, a new DENV 2 appeared in Tanzania, introduced from South East Asia, and in Senegal from the Americas. These results confirm silent and sustained circulation of dengue in Africa and show the usefulness of travelers for sentinel surveillance to unmask the dengue problem in Africa.
Disclosure: Nothing to disclose.
Rapid bedside inactivation of Ebola virus would be a solution for the safety of medical and technical staff, risk containment, sample transport, and high-throughput or rapid diagnostic testing during ...an outbreak. We show that the commercially available Magna Pure lysis/binding buffer used for nucleic acid extraction inactivates Ebola virus. A rapid bedside inactivation method for nucleic acid tests is obtained by simply adding Magna Pure lysis/binding buffer directly into vacuum blood collection EDTA tubes using a thin needle and syringe prior to sampling. The ready-to-use inactivation vacuum tubes are stable for more than 4 months, and Ebola virus RNA is preserved in the Magna Pure lysis/binding buffer for at least 5 weeks independent of the storage temperature. We also show that Ebola virus RNA can be manually extracted from Magna Pure lysis/binding buffer-inactivated samples using the QIAamp viral RNA minikit. We present an easy and convenient method for bedside inactivation using available blood collection vacuum tubes and reagents. We propose to use this simple method for fast, safe, and easy bedside inactivation of Ebola virus for safe transport and routine nucleic acid detection.
Background
Countries in the World Health Organization (WHO) European Region are reporting more severe influenza activity in the 2015–2016 season compared to previous seasons.
Objectives
To conduct a ...rapid risk assessment to provide interim information on the severity of the current influenza season.
Methods
Using the WHO manual for rapid risk assessment of acute public health events and surveillance data available from Flu News Europe, an assessment of the current influenza season from 28 September 2015 (week 40/2015) up to 31 January 2016 (week 04/2016) was made compared with the four previous seasons.
Results
The current influenza season started around week 51/2015 with higher influenza activity reported in Eastern Europe compared to Western Europe. There is a strong predominance of influenza A(H1N1)pdm09 compared to previous seasons, but the virus is antigenically similar to the strain included in the seasonal influenza vaccine. Compared to the 2014/2015 season, there was a rapid increase in the number of severe cases in Eastern European countries with the majority of such cases occurring among adults aged <65 years.
Conclusions
The current influenza season is characterized by an early start in Eastern European countries, with indications of a more severe season. Currently circulating influenza A(H1N1)pdm09 viruses are antigenically similar to those included in the seasonal influenza vaccine, and the vaccine is expected to be effective. Authorities should provide information to the public and health providers about the current influenza season, recommendations for the treatment of severe disease and effective public health measures to prevent influenza transmission.
The objective of the study was to compare the mortality in HIV infected individuals to the general population, and to explore the relative contribution of HIV to mortality before and after the ...introduction of highly active antiretroviral therapy (HAART). All HIV patients attending Ullevål University Hospital, Oslo, Norway before (cohort 1) and after (cohort 2) the introduction of HAART were included. Causes of deaths were classified as HIV related or not. Mortality in the Norwegian general population was standardized according to the distribution of age and gender in our cohorts. Ratios between mortality in our cohorts and the standardized mortality were calculated. The risk ratio (RR) for 5-y mortality compared to the general population was 22.6 (95% confidence interval (CI), 19.5-26.4) in cohort 1 (n=782), and 3.96 (95% CI 2.25-6.97) in cohort 2 (n=398). The non-HIV related mortality RR was 4.42 (95% CI 3.18-6.13) in cohort1 and 0.89 (95% CI 0.29-2.76) in cohort 2. Higher age and low CD4 cell count were associated with increased mortality. Thus, in the HAART era the mortality in HIV patients was reduced by 80%. However, the mortality in the HAART era was still 4 times higher than in the general population.
Viral drug resistance Dudman, Susanne Gjeruldsen; Stene-Johansen, Kathrine; Vik, Inger Sofie Samdal
Tidsskrift for den Norske Lægeforening,
2008-Nov-20, Letnik:
128, Številka:
22
Journal Article
Recenzirano
More and more viral infections are treated with antiviral drugs, and resistance against these drugs is steadily increasing. Our aim is to give a general understanding of viral resistance and its ...clinical significance.
This article is based on review of published literature on the subject, international recommendations and our own experience as a national reference laboratory for hepatitis viruses.
Development of viral resistance is an increasing problem with long-term treatment of both latent and chronic viral infections and may be one of the reasons for clinical treatment failure. Susceptibility testing is therefore an important diagnostic tool in cases of suspected failure during antiviral treatment, and is also necessary for customising of treatment to each individual patient. In Norway, susceptibility testing is offered for HIV, HBV, CMV and influenza, whereas systematic surveillance for the time being is only performed on HIV and influenza resistance. Surveillance on viral resistance is necessary in order to choose the adequate empirical therapy and to monitor the spread of resistant virus in the population. Prevalence of resistance can be limited with infection control measures and appropriate antiviral treatment, especially used in combinations of effective drugs directed at different enzymes and proteins within the virus.
Progressive depletion of midbrain dopamine neurons (PDD) is associated with deficits in the initiation, speed, and fluidity of voluntary movement. Models of basal ganglia function focus on initiation ...deficits; however, it is unclear how they account for deficits in the speed or amplitude of movement (vigor). Using an effort-based operant conditioning task for head-fixed mice, we discovered distinct functional classes of neurons in the dorsal striatum that represent movement vigor. Mice with PDD exhibited a progressive reduction in vigor, along with a selective impairment of its neural representation in striatum. Restoration of dopaminergic tone with a synthetic precursor ameliorated deficits in movement vigor and its neural representation, while suppression of striatal activity during movement was sufficient to reduce vigor. Thus, dopaminergic input to the dorsal striatum is indispensable for the emergence of striatal activity that mediates adaptive changes in movement vigor. These results suggest refined intervention strategies for Parkinson’s disease.
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•A mouse model of Parkinson’s disease produces a persistent reduction in effort•The neural representation of movement vigor in striatum requires dopamine•Acute suppression of striatal activity during execution enervates movement•Dopamine repletion is sufficient to restore striatal activity and invigorate movement
Movement vigor, reduced in Parkinson’s disease, is regulated by dopamine-dependent activity in the striatum.
Animals adapt their behavior in response to informative sensory cues using multiple brain circuits. The activity of midbrain dopaminergic neurons is thought to convey a critical teaching signal: ...reward-prediction error. Although reward-prediction error signals are thought to be essential to learning, little is known about the dynamic changes in the activity of midbrain dopaminergic neurons as animals learn about novel sensory cues and appetitive rewards. Here we describe a large dataset of cell-attached recordings of identified dopaminergic neurons as naive mice learned a novel cue-reward association. During learning midbrain dopaminergic neuron activity results from the summation of sensory cue-related and movement initiation-related response components. These components are both a function of reward expectation yet they are dissociable. Learning produces an increasingly precise coordination of action initiation following sensory cues that results in apparent reward-prediction error correlates. Our data thus provide new insights into the circuit mechanisms that underlie a critical computation in a highly conserved learning circuit.
For goal-directed behaviour it is critical that we can both select the appropriate action and learn to modify the underlying movements (for example, the pitch of a note or velocity of a reach) to ...improve outcomes. The basal ganglia are a critical nexus where circuits necessary for the production of behaviour, such as the neocortex and thalamus, are integrated with reward signalling to reinforce successful, purposive actions. The dorsal striatum, a major input structure of basal ganglia, is composed of two opponent pathways, direct and indirect, thought to select actions that elicit positive outcomes and suppress actions that do not, respectively. Activity-dependent plasticity modulated by reward is thought to be sufficient for selecting actions in the striatum. Although perturbations of basal ganglia function produce profound changes in movement, it remains unknown whether activity-dependent plasticity is sufficient to produce learned changes in movement kinematics, such as velocity. Here we use cell-type-specific stimulation in mice delivered in closed loop during movement to demonstrate that activity in either the direct or indirect pathway is sufficient to produce specific and sustained increases or decreases in velocity, without affecting action selection or motivation. These behavioural changes were a form of learning that accumulated over trials, persisted after the cessation of stimulation, and were abolished in the presence of dopamine antagonists. Our results reveal that the direct and indirect pathways can each bidirectionally control movement velocity, demonstrating unprecedented specificity and flexibility in the control of volition by the basal ganglia.
Animals infer when and where a reward is available from experience with informative sensory stimuli and their own actions. In vertebrates, this is thought to depend upon the release of dopamine from ...midbrain dopaminergic neurons. Studies of the role of dopamine have focused almost exclusively on their encoding of informative sensory stimuli; however, many dopaminergic neurons are active just prior to movement initiation, even in the absence of sensory stimuli. How should current frameworks for understanding the role of dopamine incorporate these observations? To address this question, we review recent anatomical and functional evidence for action-related dopamine signaling. We conclude by proposing a framework in which dopaminergic neurons encode subjective signals of action initiation to solve an internal credit assignment problem.
Coddington and Dudman review evidence for movement-related signaling in midbrain dopamine neurons. They outline a framework for understanding such signals in the context of anatomical connectivity with descending motor systems and propose roles of phasic dopamine activity in modulating action.
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