Does lock-down of Wuhan effectively restrict early geographic spread of novel coronavirus epidemic during chunyun in China? A spatial model study.

BACKGROUND: Prior to Wuhan lock-down in 2020, chunyun, the largest population mobility on this planet, had begun. We quantified impact of Wuhan lock-down on COVID-19 spread during chunyun across the nation. METHODS: During the period of January 1 to February 9, 2020, a total of 40,278 confirmed COVID-19 cases from 319 municipalities in mainland China were considered in this study. The cross-coupled meta-population methods were employed using between-city Baidu migration index. We modelled four scenarios of geographic spread of COVID-19 including the presence of both chunyun and lock-down (baseline); lock-down without chunyun (scenario 1); chunyun without lock-down (scenario 2); and the absence of both chunyun and lock-down (scenario 3). RESULTS: Compared with the baseline, scenario 1 resulted in 3.84% less cases by February 9 while scenario 2 and 3 resulted in 20.22 and 32.46% more cases by February 9. The geographic distribution of cases revealed that chunyun facilitated the COVID-19 spread in the majority but not all cities, and the effectiveness of Wuhan lock-down was offset by chunyun. Impacts of Wuhan lock-down during chunyun on the COVID-19 spread demonstrated heterogenetic geographic patterns. CONCLUSION: Our results strongly supported the travel restriction as one of the effective responses and highlighted the importance of developing area-specific rather than universal countermeasures.

Phenology in a warming world: differences between native and non-native plant species.

Phenology is a harbinger of climate change, with many species advancing flowering in response to rising temperatures. However, there is tremendous variation among species in phenological response to warming, and any phenological differences between native and non-native species may influence invasion outcomes under global warming. We simulated global warming in the field and found that non-native species flowered earlier and were more phenologically plastic to temperature than natives, which did not accelerate flowering in response to warming. Non-native species' flowering also became more synchronous with other community members under warming. Earlier flowering was associated with greater geographic spread of non-native species, implicating phenology as a potential trait associated with the successful establishment of non-native species across large geographic regions. Such phenological differences in both timing and plasticity between native and non-natives are hypothesised to promote invasion success and population persistence, potentially benefiting non-native over native species under climate change.

Prevalence of CCR5delta32 in Northeastern Iran.

BACKGROUND: A 32-base pair deletion (∆32) in the open reading frame (ORF) of C-C motif chemokine receptor 5 (CCR5) seems to be a protective variant against immune system diseases, especially human immunodeficiency virus type 1 (HIV-1). We aimed to assess the frequency of CCR5∆32 in the healthy Iranian population. METHODS: In this study, 400 normal samples from Khorasan, northeastern Iran, were randomly selected. The frequency of CCR5∆32 carriers was investigated using PCR analysis. Allele prevalence and the fit to the Hardy-Weinberg equilibrium were analyzed. RESULTS: The prevalence of CCR5∆32 in the northeastern population of Iran was 0.016. Four hundred samples were studied, among which one with CCR5∆32/∆32 and 11 with CCR5Wild/∆32 genotype were detected. CONCLUSION: This study was the first investigation for an assessment of the prevalence of CCR5∆32 in northeastern Iran. The low prevalence of CCR5∆32 allele in the Iranian population may result in the increased susceptibility to HIV-1. In addition, this prevalence is the same as that of reported in East Asia, while is lower than that in the Europeans.

Reconstruction and prediction of viral disease epidemics.

A growing number of infectious pathogens are spreading among geographic regions. Some pathogens that were previously not considered to pose a general threat to human health have emerged at regional and global scales, such as Zika and Ebola Virus Disease. Other pathogens, such as yellow fever virus, were previously thought to be under control but have recently re-emerged, causing new challenges to public health organisations. A wide array of new modelling techniques, aided by increased computing capabilities, novel diagnostic tools, and the increased speed and availability of genomic sequencing allow researchers to identify new pathogens more rapidly, assess the likelihood of geographic spread, and quantify the speed of human-to-human transmission. Despite some initial successes in predicting the spread of acute viral infections, the practicalities and sustainability of such approaches will need to be evaluated in the context of public health responses.

Seasonality and geographical spread of respiratory syncytial virus epidemics in 15 European countries, 2010 to 2016.

Respiratory syncytial virus (RSV) is considered the most common pathogen causing severe lower respiratory tract infections among infants and young children. We describe the seasonality and geographical spread of RSV infection in 15 countries of the European Union and European Economic Area. We performed a retrospective descriptive study of weekly laboratory-confirmed RSV detections between weeks 40/2010 and 20/2016, in patients investigated for influenza-like illness, acute respiratory infection or following the clinician's judgment. Six countries reported 4,230 sentinel RSV laboratory diagnoses from primary care and 14 countries reported 156,188 non-sentinel laboratory diagnoses from primary care or hospitals. The median length of the RSV season based on sentinel and non-sentinel surveillance was 16 (range: 9-24) and 18 (range: 8-24) weeks, respectively. The median peak weeks for sentinel and non-sentinel detections were week 4 (range: 48 to 11) and week 4.5 (range: 49 to 17), respectively. RSV detections peaked later (r = 0.56; p = 0.0360) and seasons lasted longer with increasing latitude (r = 0.57; p = 0.0329). Our data demonstrated regular seasonality with moderate correlation between timing of the epidemic and increasing latitude of the country. This study supports the use of RSV diagnostics within influenza or other surveillance systems to monitor RSV seasonality and geographical spread.

Distribution of non-native suckermouth armoured catfish Pterygoplichthys ambrosettii in the upper Paraná River basin, Brazil.

This study describes the invasion of the upper Paraná River basin by Pterygoplichthys ambrosettii based on a literature review and field samples. Pterygoplichthys ambrosettii has been reported in 42 localities throughout the upper Paraná River basin, including the Tietê, Paranapanema, Paraná, Grande and Aguapeí rivers. The ascent of P. ambrosettii after the inundation of the Sete Quedas Falls on the Paraná River and the release of individuals by aquarium hobbyists were the primary drivers of this invasion.

Early signs of geographic spread of COVID-19: lessons learnt from outbreaks in Wuhan 2020 and Nanjing 2021.

BACKGROUND: Knowing the spatiotemporal pattern of the early geographic spread of coronavirus disease 2019 (COVID-19) would inform the preparedness for a possible recurrence of COVID-19. METHODS: We ascertained the number of confirmed cases during the early spread of COVID-19 during the Wuhan outbreak in 2020 and the Nanjing outbreak in 2021. RESULTS: We observed a speeding-up pattern of geographic spread, in particular to cities of no particular orientation then outflowing to commercial cities during the first month of both the Wuhan and Nanjing outbreaks. CONCLUSION: Re-emergence of COVID-19 indicates it is becoming endemic, with new outbreaks and a risk of increased transmission remaining a challenge to local public health institutions. Social distancing and lockdowns should continue in response to any potential widespread and focal outbreaks.

Modeling the transmission dynamics and control of rabies in China.

Human rabies was first recorded in ancient China in about 556 BC and is still one of the major public-health problems in China. From 1950 to 2015, 130,494 human rabies cases were reported in Mainland China with an average of 1977 cases per year. It is estimated that 95% of these human rabies cases are due to dog bites. The purpose of this article is to provide a review about the models, results, and simulations that we have obtained recently on studying the transmission of rabies in China. We first construct a basic susceptible, exposed, infectious, and recovered (SEIR) type model for the spread of rabies virus among dogs and from dogs to humans and use the model to simulate the human rabies data in China from 1996 to 2010. Then we modify the basic model by including both domestic and stray dogs and apply the model to simulate the human rabies data from Guangdong Province, China. To study the seasonality of rabies, in Section 4 we further propose a SEIR model with periodic transmission rates and employ the model to simulate the monthly data of human rabies cases reported by the Chinese Ministry of Health from January 2004 to December 2010. To understand the spatial spread of rabies, in Section 5 we add diffusion to the dog population in the basic SEIR model to obtain a reaction-diffusion equation model and determine the minimum wave speed connecting the disease-free equilibrium to the endemic equilibrium. Finally, in order to investigate how the movement of dogs affects the geographically inter-provincial spread of rabies in Mainland China, in Section 6 we propose a multi-patch model to describe the transmission dynamics of rabies between dogs and humans and use the two-patch submodel to investigate the rabies virus clades lineages and to simulate the human rabies data from Guizhou and Guangxi, Hebei and Fujian, and Sichuan and Shaanxi, respectively. Some discussions are provided in Section 7.