Modelling Bluetongue Risk in Kazakhstan

2020

Full text Open access: Gold Metadata (CSL-JSON)
DOI 10.21203/rs.3.rs-76231/v1
Data confidence 70 medium
How this score is calculated

It is built from checkable properties of the record itself: whether the article has a DOI, how many independent sources confirmed its data, whether the required fields are filled in, and how recent the latest confirmation is. Disagreement between sources and a missing identifier lower it. A value of 80 or above means the record was published without further checking; 60 to 79 means it is published at reduced confidence, with a manual check advisable. A record verified by an editor by hand is never pushed below 90 by a recalculation. This scores our data about the article, not the article itself.

Abstract

Abstract Background: Bluetongue is a serious disease of ruminants transmitted by biting midges (Culicoides spp). Serological evidence from livestock and the presence of at least one vector competent spp of Culicoides suggests that transmission of bluetongue is possible and may have occurred in Kazakhstan. Methods: We estimated the relative risk of transmission using a mathematical model of the reproduction number R0 for bluetongue. This model depends on livestock density and climatic factors which affect vector density. Data on climate and livestock numbers from the 2778 local communities were used. This together with previously published model parameters was used to estimate R0 for each month of the year, which was rescaled to give a relative risk of transmission. These relative risks were mapped using kernal density estimates using R statistical software and mapping tools.Results: The results suggest that transmission of bluetongue in Kazakhstan is not possible in the winter from November to March. Assuming there are vector competent species of Culicoides endemic in Kazakhstan, then low levels of risk first appear in the south of Kazakhstan in April before spreading north and intensifying reaching maximum levels in northern Kazakhstan in August. The risk decline in September with only a low risk of transmission in October.Conclusion: These results should aid in surveillance efforts for the detection and control of bluetongue in Kazakhstan by indicating where and when outbreaks of bluetongue are most likely to occur.