NoBaSURV-PWN is a tool for assessing the confidence in pest freedom gained in official pine wood nematode (PWN, Bursaphelenchus xylophilus ) surveys.
NoBaSURV-PWN can be used to assess 1) the confidence of each year’s survey separately, and 2) the confidence accumulated in all years’ surveys. The first is referred to as “the sensitivity of annual surveys” , and the latter as “the probability of pest freedom after the last annual survey” .
Detailed guidance on how to assess the statistical confidence of past PWN surveys using NoBaSURV-PWN is given in Hannunen et al. (2023) . Also the methodology used in NoBaSURV-PWN is described in detail in Hannunen et al. (2023) .
NoBaSURV-PWN was developed in the Risk Assessment Unit of the Finnish Food Authority as part of a project 'Assessing the confidence in pest freedom gained in the past pine wood nematode surveys'. The project was a co-operation between the Finnish Food Authority, the Estonian Agriculture and Food Board (EAFB), the State Plant Service under the Ministry of Agriculture of the Republic of Lithuania (SPSMoA), the Norwegian Scientific Committee for Food and Environment (VKM), and the Swedish University of Agricultural Sciences (SLU), and it was co-funded by the European Food Safety Authority (EFSA) Partnering grant (GP/EFSA/ENCO/2020/03).
NoBaSURV-PWN reflects only the author’s view, and EFSA is not responsible for any use that may be made of the information it contains.
How to prepare the files to be uploaded?
Data must be uploaded as comma separated csv files in which data for regions is in columns, and data for years is in rows. Data must be provided for at least two regions and two years.
The first row must have the names of the regions, and the first column must indicate the years covered. The names of the regions must be written without special characters. The regions must be in the same order in all the files, and the years must be in ascending order. Every year between the first and the last must be in a separate row, even if the survey was not done in all years.
When the number of inspected sites or the number of samples is zero, that must be indicated by 0. Even if the area of entry sites or target population was the same for some (or all) of the considered years, data must be given separately for all years.
Point must be used as a decimal separator.
Design prevalence = Roughly, design prevalence determines the minimum prevalence that the survey is aimed to detect. If the pest prevalence is equal to or greater than the design prevalence, at least one infested inspection unit will be detected in the survey, with the probability equal to the sensitivity of the survey.
Detection survey = A survey conducted to determine the presence or absence of pests
Early detection survey = A detection survey that aims to detect possible PWN invasions early enough to enable successful eradication
Entry site = A site where the probability of PWN introduction is considered to be elevated, i.e., harbours, industrial areas and landfills
Initial prior probability of freedom = The probability that the prevalence of the pest is below the design prevalence before the first survey
Inspection unit = The plants, plant parts or pest vectors that could potentially host the pest and that are scrutinised to detect the pest
Method sensitivity = The probability that the pest is detected in the laboratory analysis, given that it was present in the inspection units form which the sample was collected
Trade facilitation survey = A detection survey that aims to provide evidence to justify import requirements related to PWN and to facilitate export to countries with corresponding requirements
Probability of freedom = The probability that the prevalence of the pest is below the design prevalence if the pest is not detected in the surveys
Sensitivity = Roughly, sensitivity determines the probability with which a survey is expected to succeed in its aim. If the pest prevalence is equal to or greater than the design prevalence, at least one infested inspection unit will be detected in the survey, with the probability equal to the sensitivity of the survey.
Target population = The population to which the results of the survey will be generalised
For a comprehensive glossary, see Hannunen et al. (2023) .
Hannunen S and Tuomola J 2023. NoBaSURV-PWN - A tool for assessing the confidence in pest freedom gained in official pine wood nematode surveys. Finnish Food Authority, Helsinki, Finland. Available at https://nobasurv-pwn.rahtiapp.fi/
The source code for NoBaSURV-PWN is published at https://zenodo.org/record/7766617 under the GNU General Public License version 3.