Challenges in interpreting SARS-CoV-2 serological results in African countries

A diagnosis of COVID-19 is based on a positive PCR test for SARS-CoV-2. Over the past year, PCR testing capacity has varied globally due to the availability of tests, and testing strategies have targeted mainly symptomatic individuals. Therefore, the spread of the virus is probably wider than the numbers reported by official surveillance systems that are based on PCR results. Serology tests detect antibodies against SARS-CoV-2, which start being measurable around 1–2 weeks after infection. They are used in seroprevalence studies to estimate the proportion of people in a population that has been infected, including asymptomatic infection. These studies are of particular importance in African countries, where reported testing and incidence are among the lowest in the world.Peer Reviewe

The role of MscL amphipathic N terminus indicates a blueprint for bilayer-mediated gating of mechanosensitive channels

The bacterial mechanosensitive channel MscL gates in response to membrane tension as a result of mechanical force transmitted directly to the channel from the lipid bilayer. MscL represents an excellent model system to study the basic biophysical principles of mechanosensory transduction. However, understanding of the essential structural components that transduce bilayer tension into channel gating remains incomplete. Here using multiple experimental and computational approaches, we demonstrate that the amphipathic N-terminal helix of MscL acts as a crucial structural element during tension-induced gating, both stabilizing the closed state and coupling the channel to the membrane. We propose that this may also represent a common principle in the gating cycle of unrelated mechanosensitive ion channels, allowing the coupling of channel conformation to membrane dynamics

Population cycles and outbreaks of small rodents : ten essential questions we still need to solve

Correction: 10.1007/s00442-021-04856-4, Oecologia (2021)Most small rodent populations in the world have fascinating population dynamics. In the northern hemisphere, voles and lemmings tend to show population cycles with regular fluctuations in numbers. In the southern hemisphere, small rodents tend to have large amplitude outbreaks with less regular intervals. In the light of vast research and debate over almost a century, we here discuss the driving forces of these different rodent population dynamics. We highlight ten questions directly related to the various characteristics of relevant populations and ecosystems that still need to be answered. This overview is not intended as a complete list of questions but rather focuses on the most important issues that are essential for understanding the generality of small rodent population dynamics.Peer reviewe

The role of MscL amphipathic N terminus indicates a blueprint for bilayer-mediated gating of mechanosensitive channels

The bacterial mechanosensitive channel MscL gates in response to membrane tension as a result of mechanical force transmitted directly to the channel from the lipid bilayer. MscL represents an excellent model system to study the basic biophysical principles of mechanosensory transduction. However, understanding of the essential structural components that transduce bilayer tension into channel gating remains incomplete. Here using multiple experimental and computational approaches, we demonstrate that the amphipathic N-terminal helix of MscL acts as a crucial structural element during tension-induced gating, both stabilizing the closed state and coupling the channel to the membrane. We propose that this may also represent a common principle in the gating cycle of unrelated mechanosensitive ion channels, allowing the coupling of channel conformation to membrane dynamics

European code against cancer 4th edition: 12 ways to reduce your cancer risk

This overview describes the principles of the 4th edition of the European Code against Cancer and provides an introduction to the 12 recommendations to reduce cancer risk. Among the 504.6 million inhabitants of the member states of the European Union (EU28), there are annually 2.64 million new cancer cases and 1.28 million deaths from cancer. It is estimated that this cancer burden could be reduced by up to one half if scientific knowledge on causes of cancer could be translated into successful prevention. The Code is a preventive tool aimed to reduce the cancer burden by informing people how to avoid or reduce carcinogenic exposures, adopt behaviours to reduce the cancer risk, or to participate in organised intervention programmes. The Code should also form a base to guide national health policies in cancer prevention. The 12 recommendations are: not smoking or using other tobacco products; avoiding second-hand smoke; being a healthy body weight; encouraging physical activity; having a healthy diet; limiting alcohol consumption, with not drinking alcohol being better for cancer prevention; avoiding too much exposure to ultraviolet radiation; avoiding cancer-causing agents at the workplace; reducing exposure to high levels of radon; encouraging breastfeeding; limiting the use of hormone replacement therapy; participating in organised vaccination programmes against hepatitis B for newborns and human papillomavirus for girls; and participating in organised screening programmes for bowel cancer, breast cancer, and cervical cancer

Joachimmarien/MOSA: Twenty-nine years of continuous monthly capture-mark-recapture data of multimammate mice in Tanzania

<p>The dataset consists of twenty-nine years of continuous monthly capture-mark-recapture entries on a 3ha mosaic field (MOSA) in Morogoro, Tanzania. It is one of the most accurate and long-running (capture-recapture time series on a small mammal species worldwide and unique to Africa. From March 1994 until February 2023, the total dataset consisted of 49216 captures of 21927 unique individual rodents. The database is uploaded on Github and can be used by researchers to test hypotheses on the population dynamics of small mammals (e.g. to test the effect of climate change) or to validate new algorithms on real long-term field data (e.g. new survival analyses techniques). It is also useful for both scientists and decision-makers who want to optimize rodent control strategies and predict outbreaks of multimammate mice or the pathogens they carry (e.g. Lassa virus).</p&gt

A multicentre, propensity score matched analysis comparing a valve-sparing approach to valve replacement in aortic root aneurysm: Insight from the AVIATOR database

OBJECTIVES: Our goal was to evaluate the outcome of valve-sparing root replacement (VSRR) and to compare the outcomes to those of patients having composite valve-graft conduit aortic root replacement (CVG-ARR) in a cohort of patients with aortic root aneurysm ± valve insufficiency, without valvular stenosis. Although valve-sparing procedures are preferable in young patients, there is a lack of comparative data in comparable patients. METHODS: The VSRR procedures were performed in 2005 patients, and 218 patients underwent a CVG-ARR procedure. Exclusion criteria included aortic dissection, endocarditis and valvular stenosis. Propensity score matching (3:1 ratio) was applied to compare VSRR (reimplantation 33% and remodelling 67%) and CVG-ARR. RESULTS: We matched 218 patients with CVG-ARR to 654 patients with VSRR (median age, 56.0; median follow-up was 4 years in both groups; interquartile range 1-5 years). Early mortality was 1.1% of those who had VSRR versus 2.3% in those who had CVG-ARR. Survival was 95.4% [95% confidence interval (CI) 94-97%] at 5 years in patients who had VSRR versus 85.4% (95% CI 82-92%) in those who had CVG-ARR; P = 0.002. Freedom from reintervention at 5 years was 96.8% (95% CI 95-98%) with VSRR and 95.4% (95% CI 91-99%) with CVG-ARR (P = 0.98). Additionally, there were more thromboembolic, endocarditis and bleeding events in the patients who had CVG-ARR (P = 0.02). CONCLUSIONS: This multicentre study shows excellent results after valve-sparing root replacement in patients with an ascending aortic aneurysm with or without valve insufficiency. Compared to composite valve-graft aortic root replacement, survival is better and valve-related events are fewer. Consequently, valve-sparing procedures should be considered whenever a durable repair is feasible. We advocate a valve-sparing strategy even in more complex cases when performed in experienced centres

A multicenter, propensity-score matched analysis comparing valve-sparing approach to valve replacement in aortic root aneurysm: Insight from AVIATOR database

OBJECTIVES: The study objective is to evaluate outcome of valve-sparing root replacement(VSRR) and its comparison to composite valve-graft conduit aortic root replacement(CVG-ARR), in a cohort of patients with aortic root aneurysm +/- valve insufficiency, without valvular stenosis. Although valve-sparing procedures are preferable in young patients, there is a lack of comparative data in comparable patients. METHODS: The VSRR procedures were performed in 2005 patients and 218 patients underwent a CVG-ARR procedure. Exclusion criteria: aortic dissection, endocarditis and valvular-stenosis. Propensity score matching (3:1 ratio) was applied to compare VSRR (reimplantation 33% and remodelling 67%) and CVG-ARR. RESULTS: We matched 218 CVG-ARR patients to 654 VSRR patients (median age, 56.0; median follow-up was 4 years in both, IQR 1-5 years). Early mortality was 1.1% in VSRR versus 2.3% in CVG-ARR. Survival was 95.4% (95% CI 94-97%) at 5 years in VSRR versus 85.4% (95% CI 82-92%) in CVG-ARR, p = 0.002. Freedom from reintervention at 5 years was 96.8% (95% CI 95-98%) in VSRR and 95.4% (95% CI 91-99%) in CVG-ARR, p = 0.98. Additionally, there were more thromboembolism, endocarditis and bleeding events in CVG-ARR (p = 0.02). CONCLUSIONS: This multicentre study shows excellent results after valve-sparing root replacement in patients with ascending aortic aneurysm with or without valve insufficiency. Compared to composite valve-graft aortic root replacement, survival is better and valve-related event are fewer. Consequently, valve-sparing procedures should be considered whenever a durable repair is feasible. We advocate a valve-sparing strategy even in more complex cases when performed in experienced centers

Molecular characterization of chikungunya virus during the 2019 outbreak in the Democratic Republic of the Congo

Early 2019, a chikungunya virus (CHIKV) outbreak hit the Democratic Republic of the Congo (DRC). Though seldomly deadly, this mosquito-borne disease presents as an acute febrile (poly)arthralgia often followed by long-term sequelae. Although Aedes aegypti is the primary vector, an amino acid substitution in the viral envelope gene E1 (A226V) is causing concern as it results in increased transmission by Aedes albopictus, a mosquito with a much wider geographical distribution. Between January and March 2019, we collected human and mosquito samples in Kinshasa and Kongo Central province (Kasangulu and Matadi). Of the patients that were tested within 7 days of symptom onset, 49.7% (87/175) were RT–qPCR positive, while in the mosquito samples CHIKV was found in 1/2 pools in Kinshasa, 5/6 pools in Kasangulu, and 8/26 pools in Matadi. Phylogenetic analysis on whole-genome sequences showed that the circulating strain formed a monophyletic group within the ECSA2 lineage and harboured the A226V mutation. Our sequences did not cluster with sequences from previously reported outbreaks in the DRC nor with other known A226V-containing ECSA2 strains. This indicates a scenario of convergent evolution where A226V was acquired independently in response to a similar selection pressure for transmission by Ae. albopictus. This is in line with our entomological data where we detected Ae. albopictus more frequently than Ae. aegypti in two out of three affected areas. In conclusion, our findings suggest that CHIKV is adapting to the increased presence of Aedes albopictus in DRC