Dynamics of bacterial blight disease in resistant and susceptible rice varieties

Bacterial blight (X. oryzae pv. oryzae) is a serious disease in rice across the world. To better control the disease, it is important to understand its epidemiology and how key aspects of this (e.g. infection efficiency, and spatial spread) change according to environment (e.g. local site conditions and season), management, and in particular, variety resistance. To explore this, we analysed data on the disease progress on resistant and susceptible varieties of rice grown at four sites in the Philippines across five seasons using a combination of mechanistic modelling and statistical analysis. Disease incidence was generally lower in the resistant variety. However, we found no evidence that the primary infection efficiency was lower in resistant varieties, suggesting that differences were largely due to reduced secondary spread. Despite secondary spread being attributed to splash dispersal which is exacerbated by wind and rain, the wetter sites of Pila and Victoria in south Luzon tended to have lower infection rates than the drier sites in central Luzon. Likewise, we found spread in the dry season can be substantial and should therefore not be ignored. In fact, we found site to be a greater determinant of the number of infection attempts suggesting that other environmental and management factors had greater effect on the disease than climate. Primary infection was characterised by spatially-random observations of disease incidence. As the season progressed, we observed an emerging short-range (1.6 m–4 m) spatial structure suggesting secondary spread was predominantly short-range, particularly where the resistant variety was grown.

Cydalima perspectalis in Poland—8 Years of Invasion against the Background of Three Other Invasive Species

The box tree moth (Cydalima perspectalis) origins from East Asia. In Europe, it was recorded for the first time in 2007, and in Poland in 2012. By the end of 2020, it was found all over Poland. There are no published data on the range of C. perspectalis occurrence in Poland because it is not a quarantine pest in the European Union and is not subject to official monitoring. Data collected in 2018–2020 via a website dedicated to monitoring, for the first time, illustrate the current range and its largest concentrations in southern and central Poland. The monitoring confirmed that the main directions of the invasion are related to the main communication routes of Poland (south-north) and are of a long-distance character. The dispersal pattern corresponds to the model developed for Cameraria ohridella: a stratified dispersal model that considers long-distance road/rail transport. The second important factor contributing to the invasion of C. perspectalis are large human communities enabling rapid local dispersion (a diffusion model). Comparing its invasion with the monitoring data from 2007–2013 of two other invasive pests of Poland: Ostrinia nubilalis and Diabrotica virgifera, shows that a diffusion model best describes the spatial spread of these pests only to uninhabited neighboring areas.

Using Moran’s I For Detection And Monitoring Of The Covid-19 Spreading Stage In Thailand During The Third Wave Of The Pandemic

Spatial distribution and spreading patterns of COVID-19 in Thailand were investigated in this study for the 1 April – 23 July 2021 period by analyzing COVID-19 incidence’s spatial autocorrelation and clustering patterns in connection to population density, adult population, mean income, hospital beds, doctors and nurses. Clustering analysis indicated that Bangkok is a significant hotspot for incidence rates, whereas other cities across the region have been less affected. Bivariate Moran’s I showed a low relationship between COVID-19 incidences and the number of adults (Moran’s I = 0.1023- 0.1985), whereas a strong positive relationship was found between COVID-19 incidences and population density (Moran’s I = 0.2776-0.6022). Moreover, the difference Moran’s I value in each parameter demonstrated the transmission level of infectious COVID-19, particularly in the Early (first phase) and Spreading stages (second and third phases). Spatial association in the early stage of the COVID-19 outbreak in Thailand was measured in this study, which is described as a spatio-temporal pattern. The results showed that all of the models indicate a significant positive spatial association of COVID-19 infections from around 10 April 2021. To avoid an exponential spread over Thailand, it was important to detect the spatial spread in the early stages. Finally, these findings could be used to create monitoring tools and policy prevention planning in future.

Areas Of Socio-Geographical Study Of The Covid-19 Pandemic In Russia And The World

The natural and socio-economic characteristics of the territory play a decisive role in the spread of the pandemic of COVID-19. It provoked a restructuring process in practically all fields of the social life. Its main areas were laid before the pandemic, but the changes were sharply accelerated by the pandemic. In analyzing a number of Russian and foreign publications, the authors discuss the main areas and methods of human-geographical study of the development and consequences of the pandemic. The constantly growing flow of publications in this field can be divided into three major parts: studies of the spatial spread of infection on the different stages; analysis of demographic, (geo) political and economic implications of the pandemic, and attempts to forecast the impact of social and technological changes accelerated by it on territorial structures. The authors note in particular that the geopolitical picture of the world with the division of countries into developed and developing, rich and poor, authoritarian and democratic, Eastern and Western, became much less clear. The most obvious geopolitical consequence of the pandemic is the further fragmentation of the political and socio-economic space. Not only state, but often also administrative boundaries have turned into almost insurmountable barriers for people and trade. The COVID crisis has opened new opportunities for a reasonable combination of the concentration of social life in the «archipelago» of large cities and the development of other territories.

Georeferencing of COVID-19 Positive Nasopharyngeal Swabs to Support Emergency Management in an Area of Northern Italy

Spatial distribution heterogeneity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been observed in several countries. While previous studies have covered vast geographic areas, detailed analyses on smaller territories are not available to date. The aim of our study was to understand the spatial spread of SARS-CoV-2 in a province of Northern Italy through the analysis of positive nasopharyngeal (NP) swabs. The study was conducted on subjects who lived in the province of Alessandria with at least one positive NP swab between 2 March and 22 December 2020. To investigate if clustering occurred, the proportion of SARS-CoV-2 positive subjects over the total number of residents in each small administrative subregion was calculated and then mapped. A total of 17,260 subjects with at least one positive NP swab were included; the median age was 54 years (Interquartile range 38–72) and 54.9% (n = 9478) of our study population were female. Among the 192 towns scanned, 26 showed a prevalence between 5% and 7.5%, one between 7.5% and 10% and two with more than 10% positive swabs. The territories with a higher prevalence of positive subjects were located in areas with at least one nursing home and potential clusters were observed within these structures. The maps produced may be considered a useful and important monitoring system to identify areas with a significant and relevant diffusion of SARS-CoV-2.

Feline sporotrichosis

Over the past two decades, many Brazilian cities have been reporting an increasing incidence and spread of feline sporotrichosis. The disease is neglected, and little is known about the causal processes underlying its epidemic occurrence. This study characterized the spatiotemporal dynamics of feline sporotrichosis in Guarulhos. Moreover, we proposed and tested a causal explanation for its occurrence and zoonotic transmission, giving a key role to social vulnerability. A direct acyclic graph represented the causal explanation, while Bayesian spatial models supported its test as well as the attribution of a risk-based priority index to the census tracts of the city. Between 2011 and 2017, the disease grew exponentially and the spatial spread increased. The model findings showed a dose-response pattern between an index of social vulnerability and the incidence of feline sporotrichosis. This pattern was not strictly monotonic, so some census tracts received a higher priority index than others with higher vulnerability. According to our causal explanation, there will not be effective prevention of feline and zoonotic sporotrichosis as long as social inequities continue imposing precarious livelihoods.

The spread of cholera in western Democratic Republic of the Congo is not unidirectional from East–West: a spatiotemporal analysis, 1973–2018

Background Cholera outbreaks in western Democratic Republic of the Congo (DRC) are thought to be primarily the result of westward spread of cases from the Great Lakes Region. However, other patterns of spatial spread in this part of the country should not be excluded. The aim of this study was to explore alternative routes of spatial spread in western DRC. Methods A literature review was conducted to reconstruct major outbreak expansions of cholera in western DRC since its introduction in 1973. We also collected data on cholera cases reported at the health zone (HZ) scale by the national surveillance system during 2000–2018. Based on data from routine disease surveillance, we identified two subperiods (week 45, 2012–week 42, 2013 and week 40, 2017–week 52, 2018) for which the retrospective space–time permutation scan statistic was implemented to detect spatiotemporal clusters of cholera cases and then to infer the spread patterns in western DRC other than that described in the literature. Results Beyond westward and cross-border spread in the West Congo Basin from the Great Lakes Region, other dynamics of cholera epidemic propagation were observed from neighboring countries, such as Angola, to non-endemic provinces of southwestern DRC. Space–time clustering analyses sequentially detected clusters of cholera cases from southwestern DRC to the northern provinces, demonstrating a downstream-to-upstream spread along the Congo River. Conclusions The spread of cholera in western DRC is not one-sided. There are other patterns of spatial spread, including a propagation from downstream to upstream areas along the Congo River, to be considered as preferential trajectories of cholera in western DRC.

Demographic feedbacks can hamper the spatial spread of a gene drive

This paper is concerned with a reactionddiffusion system modeling the fixation and the invasion in a population of a gene drive (an allele biasing inheritance, increasing its own transmission to offspring). In our model, the gene drive has a negative effect on the fitness of individuals carrying it, and is therefore susceptible of decreasing the total carrying capacity of the population locally in space. This tends to generate an opposing demographic advection that the gene drive has to overcome in order to invade. While previous reaction-diffusion models neglected this aspect, here we focus on it and try to predict the sign of the traveling wave speed. It turns out to be an analytical challenge, only partial results being within reach, and we complete our theoretical analysis by numerical simulations. Our results indicate that taking into account the interplay between population dynamics and population genetics might actually be crucial, as it can effectively reverse the direction of the invasion and lead to failure. Our findings can be extended to other bistable systems, such as the spread of cytoplasmic incompatibilities caused by Wolbachia.