Structure of an H3N2 influenza virus nucleoprotein

Influenza A viruses of the H1N1 and H3N2 subtypes are responsible for seasonal epidemic events. The influenza nucleoprotein (NP) binds to the viral genomic RNA and is essential for its replication. Efforts are under way to produce therapeutics and vaccines targeting the NP. Despite this, no structure of an NP from an H3N2 virus has previously been determined. Here, the structure of the A/Northern Territory/60/1968 (H3N2) influenza virus NP is presented at 2.2 Å resolution. The structure is highly similar to those of the A/WSN/1933 (H1N1) and A/Hong Kong/483/97 (H5N1) NPs. Nonconserved amino acids are widely dispersed both at the sequence and structural levels. A movement of the 73–90 RNA-binding loop is observed to be the key difference between the structure determined here and previous structures. The data presented here increase the understanding of structural conservation amongst influenza NPs and may aid in the design of universal interventions against influenza.

Vaccination strategies for a seasonal epidemic: a simple SIR model

We model the effect of vaccination on an epidemic which, like the current one, exhibits a climate-induced seasonality. Our study is carried out using a simple SIR model. One important feature of our approach is that of recruitment: by gradually introducing susceptible individuals we mimic the spatial evolution of the epidemic, which is absent in the classic SIR. We focus on the effect of vaccination on the number of hospital admissions. We show that any delay in the vaccination campaign results in an increase of hospitalisations, and if one tries to palliate for the delay by increasing the vaccination rate, this results in an inflation of the number of necessary doses. Considering a multi-agegroup population we show that it is advantageous to prioritise the vaccination of the older groups (upholding thus the current practice). Finally, we investigate whether a vaccination of the younger population based on awareness can be an optimal strategy, concluding by a negative.

The impact of the COVID-19 pandemic on influenza, respiratory syncytial virus, and other seasonal respiratory virus circulation in Canada

BackgroundThe ongoing coronavirus disease 2019 (COVID-19) pandemic has resulted in implementation of public health measures worldwide to mitigate disease spread, including; travel restrictions, lockdowns, messaging on handwashing, use of face coverings and physical distancing. As the pandemic progresses, exceptional decreases in seasonal respiratory viruses are increasingly reported. We aimed to evaluate the impact of the pandemic on circulation of influenza, respiratory syncytial virus and other seasonal respiratory viruses in Canada.MethodsEpidemiologic data were obtained from the Canadian Respiratory Virus Detection Surveillance System. Weekly data from the week ending 30th August 2014 until the week ending the 13th February 2021 were analysed. We compared trends in laboratory detection and test volumes during the 2020/2021 influenza season with baseline pre-pandemic seasons from 2014 to 2019.FindingsWe observed a dramatically lower percentage of tests positive for all seasonal respiratory viruses during 2020-2021 compared to baseline. For influenza A and B the percent positive decreased to 0·0017 and 0·0061 times that of baseline respectively and for RSV, the percent positive dropped to 0·0145 times that of baseline. Ongoing detection of enterovirus/rhinovirus occurred, with regional variation in the epidemic patterns and intensity.InterpretationWe report an effective absence of the annual seasonal epidemic of most seasonal respiratory viruses in 2020/2021. This dramatic decrease is likely related to implementation of multi-layered public health measures during the pandemic. The impact of such measures may have relevance for public health practice in mitigating seasonal respiratory virus epidemics and for informing responses to future respiratory virus pandemics.FundingNo additional funding source was required for this study.Research in contextEvidence before this studyWe searched PubMed, preprint servers and country-specific public health rapid communications to identify surveillance and epidemiological studies on influenza, respiratory syncytial virus and other seasonal respiratory virus detection during the COVID-19 pandemic. A number of regional and national studies were identified worldwide. The majority of these studies focus on influenza epidemiology and all studies show consistent decreases in circulation of seasonal non-SARS-CoV-2 respiratory viruses. One previous study on the impact of non-pharmaceutical interventions on laboratory detections of influenza A and B in Canada included data for the 2019/2020 influenza season. Another recent study examined the effect of seasonal respiratory virus transmission on COVID-19 syndromic surveillance in the province of Ontario, Canada. No previous Canada-wide study has described the epidemiology of influenza, respiratory syncytial virus and other seasonal respiratory virus detection during the 2020/2021 influenza season.Added value of this studyThe Canadian Respiratory Virus Detection Surveillance System provides weekly respiratory virus detection reports from sentinel laboratories across Canada for influenza, respiratory syncytial virus, parainfluenza viruses, adenovirus, human metapneumovirus, enterovirus/rhinovirus and seasonal coronaviruses. Data have been collected continuously since 2004. Analysis of this dataset provides a comprehensive assessment of the impact of the COVID-19 pandemic on circulation of seasonal respiratory viruses in Canada and analysis of data from the Canadian Public Health Infobase on COVID-19 allowed comparison of SARS-CoV-2 epidemiology. This is the first country-wide study in the Northern hemisphere to describe the concurrent epidemiology of all major seasonal respiratory viruses and SARS-CoV-2 during the 2020/2021 influenza season.Implications of all the available evidenceThe effective absence of the annual seasonal epidemic for most non-SARS-CoV-2 respiratory viruses in 2020/2021 has important public health implications for informing ongoing and future responses to respiratory virus epidemics and pandemics.

Malaria trends in Ethiopian highlands track the 2000 ‘slowdown’ in global warming

A counterargument to the importance of climate change for malaria transmission has been that regions where an effect of warmer temperatures is expected, have experienced a marked decrease in seasonal epidemic size since the turn of the new century. This decline has been observed in the densely populated highlands of East Africa at the center of the earlier debate on causes of the pronounced increase in epidemic size from the 1970s to the 1990s. The turnaround of the incidence trend around 2000 is documented here with an extensive temporal record for malaria cases for both Plasmodium falciparum and Plasmodium vivax in an Ethiopian highland. With statistical analyses and a process-based transmission model, we show that this decline was driven by the transient slowdown in global warming and associated changes in climate variability, especially ENSO. Decadal changes in temperature and concurrent climate variability facilitated rather than opposed the effect of interventions.

Implications of climatic and demographic change for seasonal influenza dynamics and evolution

Seasonal influenza causes a substantial public health burden, as well as being a key substrate for pandemic emergence. Future climatic and demographic changes may alter both the magnitude, frequency and timing of influenza epidemics and the prospects for pathogen evolution, however, these issues have not been addressed systematically. Here, we use a parsimonious influenza model, grounded in theoretical understanding of the link between climate, demography and transmission to project future changes globally. We find that climate change generally acts to reduce the intensity of influenza epidemics as specific humidity increases. However, this reduction in intensity is accompanied by increased seasonal epidemic persistence with latitude, which may increase suitability for year-round local influenza evolution. Using a range of population growth scenarios, we find that the number of global locations with high evolution suitability may double by 2050. High population growth in tropical Africa could thus make this region a locus of novel strain emergence, shifting the current focus from South East Asia.

The epidemiology of foot-and-mouth disease outbreaks and its history in Iraq

Background and Aims: Foot-and-mouth disease (FMD) is reported in Iraq since 1937 and occurs as a devastating seasonal epidemic. This study intended to explore the epidemiology of FMD in Iraq during 2011-2016, through assessment of outbreak reports among cow, buffalo, and small ruminants (sheep and goat) in 15 Iraqi governorates except for Kurdistan region. Materials and Methods: The reported data regarding FMD cases were collected from veterinary hospitals in 15 Iraqi governorates and were analyzed. Results: The results revealed annual FMD outbreaks in cow, buffalo, and small ruminants in Iraqi governorates with variability in the numbers of the infected and dead animals. The total number of infected animals increased in 2016 compared to 2015 due to the illegal importation of FMD-infected cows at the end of 2015. The prevalence rates of FMD were 68.7%, 46.6%, and 30.3% in cattle, buffalo, and small ruminants, respectively, in 2016, while this was 18.4%, 19.9%, and 17.3%, respectively, in 2015. Conclusion: This study approved the reemergence and endemic nature of FMD in Iraqi livestock. Prompt procedures and a new future strategy need to be implemented to control the increasing incidences of FMD in Iraq.