Inference for epidemic models with time varying infection rates: tracking the dynamics of oak processionary moth in the UK

2021 ◽  
Author(s):  
Laura E Wadkin ◽  
Julia Branson ◽  
Andrew Hoppit ◽  
Nick G Parker ◽  
Andrew Golightly ◽  
...  

Invasive pests pose a great threat to forest, woodland and urban tree ecosystems. The oak processionary moth (OPM) is a destructive pest of oak trees, first reported in the UK in 2006. Despite great efforts to contain the outbreak within the original infested area of South-East England, OPM continues to spread. Here we analyse data of the numbers of OPM nests removed each year from two parks in London between 2013 and 2020. Using a state-of-the-art Bayesian inference scheme we estimate the parameters for a stochastic compartmental SIR (susceptible, infested, removed) model with a time varying infestation rate to describe the spread of OPM. We find that the infestation rate and subsequent basic reproduction number have remained constant since 2013 (with R_0 between one and two). This shows further controls must be taken to reduce R_0 below one and stop the advance of OPM into other areas of England. Our findings demonstrate the applicability of the SIR model to describing OPM spread and show that further controls are needed to reduce the infestation rate. The proposed statistical methodology is a powerful tool to explore the nature of a time varying infestation rate, applicable to other partially observed time series epidemic data.spread and show that further controls are needed to reduce the infestation rate. The proposed statistical methodology is a powerful tool to explore the nature of a time varying infestation rate, applicable to other partially observed time series epidemic data.

Author(s):  
Yevhen F. Suprunenko ◽  
Matthew D. Castle ◽  
Cerian R. Webb ◽  
Julia Branson ◽  
Andrew Hoppit ◽  
...  

2021 ◽  
Author(s):  
Claire Beverley

Abstract T. processionea, commonly known as the oak processionary moth, is a major pest in many European countries and threatens the health of oak trees. The common and scientific names of T. processionea refer to the behaviour of the larvae to form long processions. The larvae cause severe defoliation, reducing the viability of oak trees. They also pose a risk to both human and animal health because they shed poisonous hairs, which can result in severe allergic reactions, amongst other health problems. The moth is native to central and southern Europe but is now present in almost all European countries and also in parts of the Middle East. EPPO issued a Pest Risk Analysis in 2007 for the UK in response to infestations of the species in Europe from 2006. At this time, infestations of the moth were observed on a range of oak (Quercus) species in London. The adult males are strong fliers and can fly long distances, such as from France to the UK (Evans, 2007). Host plants of this pest include many species of deciduous Quercus, and to a much lesser degree, Betula, Carpinus, Castanea, Corylus, Crataegus, Robinia and Fagus; plants commonly found in forests, woods or ornamental plantations in the UK, for example (Evans, 2007). Therefore, areas where these plants are present and offer a suitable climate for pest development are likely to be under threat from T. processionea. Various pines have been reported as hosts, but such records are suspect and are probably the result of confusion with the pine processionary (Thaumetopoea pityocampa).


Public Health ◽  
2012 ◽  
Vol 126 (9) ◽  
pp. 778-781 ◽  
Author(s):  
M.J. Mindlin ◽  
O. le Polain de Waroux ◽  
S. Case ◽  
B. Walsh

2015 ◽  
Author(s):  
James JN Kitson ◽  
Christoph Hahn ◽  
Richard J Sands ◽  
Nigel A Straw ◽  
Darren M Evans ◽  
...  

AbstractDetermining the host-parasitoid interactions and parasitism rates for invasive species entering novel environments is an important first step in assessing potential routes for biocontrol and integrated pest management. Conventional insect rearing techniques followed by taxonomic identification are widely used to obtain such data, but this can be time consuming and prone to biases. Here we present a Next Generation Sequencing approach for use in ecological studies which allows for individual level metadata tracking of large numbers of invertebrate samples through the use of hierarchically organised molecular identification tags. We demonstrate its utility using a sample data set examining both species identity and levels of parasitism in late larval stages of the Oak Processionary Moth (Thaumetopoea processionea - Linn. 1758), an invasive species recently established in the UK. Overall we find that there are two main species exploiting the late larval stages of Oak Processionary Moth in the UK with the main parasitoid (Carcelia iliaca-Ratzeburg, 1840) parasitising 45.7% of caterpillars, while a rare secondary parasitoid (Compsilura conccinata-Meigen, 1824) was also detected in 0.4% of caterpillars. Using this approach on all life stages of the Oak Processionary Moth may demonstrate additional parasitoid diversity. We discuss the wider potential of nested tagging DNA-metabarcoding for constructing large, highly-resolved species interaction networks.


Author(s):  
Olga Perski ◽  
Aleksandra Herbec ◽  
Lion Shahab ◽  
Jamie Brown

BACKGROUND The SARS-CoV-2 outbreak may motivate smokers to attempt to stop in greater numbers. However, given the temporary closure of UK stop smoking services and vape shops, smokers attempting to quit may instead seek out digital support, such as websites and smartphone apps. OBJECTIVE We examined, using an interrupted time series approach, whether the SARS-CoV-2 outbreak has been associated with a step change or increasing trend in UK downloads of an otherwise popular smoking cessation app, Smoke Free. METHODS Data were from daily and non-daily adult smokers in the UK who had downloaded the Smoke Free app between 1 January 2020 and 31 March 2020 (primary analysis) and 1 January 2019 and 31 March 2020 (secondary analysis). The outcome variable was the number of downloads aggregated at the 12-hourly (primary analysis) or daily level (secondary analysis). The explanatory variable was the start of the SARS-CoV-2 outbreak, operationalised as 1 March 2020 (primary analysis) and 15 January 2020 (secondary analysis). Generalised Additive Mixed Models adjusted for relevant covariates were fitted. RESULTS Data were collected on 45,105 (primary analysis) and 119,881 (secondary analysis) users. In both analyses, there was no evidence for a step change or increasing trend in downloads attributable to the start of the SARS-CoV-2 outbreak. CONCLUSIONS In the UK, between 1 January 2020 and 31 March 2020, and between 1 January 2019 and 31 March 2020, there was no evidence that the SARS-CoV-2 outbreak has been associated with a surge in downloads of a popular smoking cessation app. CLINICALTRIAL osf.io/zan2s


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Laura A. Tugwell ◽  
Marion E. England ◽  
Simon Gubbins ◽  
Christopher J. Sanders ◽  
Jessica E. Stokes ◽  
...  

Abstract Background Culicoides biting midges (Diptera: Ceratopogonidae) are biological vectors of internationally important arboviruses and inflict biting nuisance on humans, companion animals and livestock. In temperate regions, transmission of arboviruses is limited by temperature thresholds, in both replication and dissemination of arboviruses within the vector and in the flight activity of adult Culicoides. This study aims to determine the cold-temperature thresholds for flight activity of Culicoides from the UK under laboratory conditions. Methods Over 18,000 Culicoides adults were collected from the field using 4 W down-draught miniature ultraviolet Centers for Disease Control traps. Populations of Culicoides were sampled at three different geographical locations within the UK during the summer months and again in the autumn at one geographical location. Activity at constant temperatures was assessed using a bioassay that detected movement of adult Culicoides towards an ultraviolet light source over a 24-h period. Results The proportion of active adult Culicoides increased with temperature but cold temperature thresholds for activity varied significantly according to collection season and location. Populations dominated by the subgenus Avaritia collected in South East England had a lower activity threshold temperature in the autumn (4 °C) compared with populations collected in the summer (10 °C). Within the subgenus Avaritia, Culicoides scoticus was significantly more active across all temperatures tested than Culicoides obsoletus within the experimental setup. Populations of Culicoides impunctatus collected in the North East of England were only active once temperatures reached 14 °C. Preliminary data suggested flight activity of the subgenus Avaritia does not differ between populations in South East England and those in the Scottish Borders. Conclusions These findings demonstrate seasonal changes in temperature thresholds for flight and across different populations of Culicoides. These data, alongside that defining thresholds for virus replication within Culicoides, provide a primary tool for risk assessment of arbovirus transmission in temperate regions. In addition, the study also provides a comparison with thermal limits derived directly from light-suction trapping data, which is currently used as the main method to define adult Culicoides activity during surveillance.


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