The Impact Of Habitat Fragmentation On The Spread Of Animal Infectious Diseases

Infectious diseases are a major challenge to the progress and survival of human beings.The complex transmission mechanism still needs to be understood.Currently,there is a general consensus in the field of epidemiology that climate and landscape factors have impacts on disease risks,but little is known about the underlying mechanisms and regional differences.The purpose of this paper is to provide new insights into the transmission mechanism of infectious diseases through two completely different experiments.First,we tested the fitness and resistance of Drosophila melanogaster for 2 kinds of bacteria under the laboratory conditions found that the pupae production of Drosophila melanogaster in the fragmented setups was higher than that in a relatively big habitat.However,in some fragmentation environments,the resistance of drosophila to lethal bacteria was lower than that in other habitats,and there was no significant difference in other aspects.This study provides a basis for testing the effects of infectious diseases occurred in fragmentation in laboratory conditions.Subsequently,we focused on Lyme disease,which is recognized as one of the most important vector-borne diseases worldwide,has been increasing in incidence and spatial extend in United States.In the Northeast and Upper Midwest,Lyme disease is transmitted by Ixodes scapularis.Currently,many studies have been conducted to identify factors influencing Lyme disease risk in the Northeast,however,relatively few studies focused on the Upper Midwest.In this study,we explored and compared the climatic and landscape factors that shape the spatial patterns of human Lyme cases in these two regions,using the generalized linear mixed models.Our results showed that climatic variables generally had opposite correlations with Lyme disease risk in two different regions,while landscape factors usually had similar effects in these two regions.High precipitation and low temperature were correlated with high Lyme disease risk in the Upper Midwest,while with low Lyme disease risk in the Northeast.In both regions,size and fragmentation related factors of residential area showed positive correlations with Lyme disease risk.In general,this study provides new insight into understanding the differences of risk factors of human Lyme disease risk in these two regions.