Deforestation Increases the Risk of Scrub Typhus in Korea.

Min Min,Lee Lee,Cho Cho,So So

doi:10.3390/ijerph16091518

Min Min, Lee Lee + Show 2 more

Open Access

https://doi.org/10.3390/ijerph16091518

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Abstract

Background: Scrub typhus is an important public health issue in Korea. Risk factors for scrub typhus include both individual-level factors and environmental drivers, and some are related to the increased density of vector mites and rodents, the natural hosts of the mites. In this regard, deforestation is a potential risk factor, because the deforestation-induced secondary growth of scrub vegetation may increase the densities of mites and rodents. To examine this hypothesis, this study investigated the association between scrub typhus and deforestation. Methods: We acquired district-level data for 2006–2017, including the number of cases of scrub typhus reported annually, deforestation level, and other covariates. Deforestation was assessed using preprocessed remote-sensing satellite data. Bayesian regression models, including Poisson, negative binomial, zero-inflated Poisson, and zero-inflated negative binomial models, were examined, and spatial autocorrelation was considered in hierarchical models. A sensitivity analysis was conducted using different accumulation periods for the deforestation level to examine the robustness of the association. Results: The final models showed a significant association between deforestation and the incidence of scrub typhus (relative risk = 1.20, 95% credible interval = 1.15–1.24). The sensitivity analysis gave consistent results, and a potential long-term effect of deforestation for up to 5 years was shown. Conclusion: The results support the potential public health benefits of forest conservation by suppressing the risk of scrub typhus, implying the need for strong engagement of public health sectors in conservation issues from a One Health perspective.

Highlights

Scrub typhus is a mite-borne disease caused by Orientia tsutsugamushi that is transmitted mainly by trombiculid mites, such as Leptotrombidium pallidum and Leptotrombidium scutellare, in Korea [1].In the transmission dynamics, rodents play an important role, because the mites are mainly parasitic on rodents and become infected by feeding on infected rodents
Thistyphus study used from multiple examinethe theannual hypothesis, including the number of of scrub casesdata reported annuallysources by eachtodistrict, deforestation level, and other scrub typhus reported annually by each district, annual deforestation level, and other covariates thatcases are considered to be associated with scrub the typhus (Table covariates that are considered to be associated with scrub typhus (Table 1)
Our results showed only the potential effect of deforestation on scrub typhus, other vector-borne diseases such as severe fever with thrombocytopenia syndrome, hemorrhagic fever with renal syndrome, and malaria are likely associated with deforestation, because the underlying mechanism is applicable to these diseases

Summary

Introduction

Scrub typhus is a mite-borne disease caused by Orientia tsutsugamushi that is transmitted mainly by trombiculid mites, such as Leptotrombidium pallidum and Leptotrombidium scutellare, in Korea [1].In the transmission dynamics, rodents play an important role, because the mites are mainly parasitic on rodents and become infected by feeding on infected rodents. Risk factors for scrub typhus include both individual-level factors and environmental drivers, and some are related to the increased density of vector mites and rodents, the natural hosts of the mites. In this regard, deforestation is a potential risk factor, because the deforestation-induced secondary growth of scrub vegetation may increase the densities of mites and rodents. Deforestation is a potential risk factor, because the deforestation-induced secondary growth of scrub vegetation may increase the densities of mites and rodents To examine this hypothesis, this study investigated the association between scrub typhus and deforestation. A sensitivity analysis was conducted using different accumulation periods for the deforestation level to examine the robustness of the association

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Results

Discussion

Conclusion