Biomedical subjects

F M Danson

Publications and source records attributed to F M Danson.

4 recordsLinked to original sources

PubMed2004

Spatial analysis for epidemiology.

Remote sensing, geographical information systems (GIS) and spatial analysis provide important tools that are as yet under-exploited in the fight against disease. As the use of such tools becomes more accepted and prevalent in epidemiological studies, so our understanding of the mechanisms of disease systems has the potential to increase. This paper introduces a range of techniques used in remote sensing, GIS and spatial analysis that are relevant to epidemiology. Possible future directions for the application of remote sensing, GIS and spatial analysis are also suggested.

Animals↗

PubMed2004

Modelling the spatial distribution of Echinococcus multilocularis infection in foxes.

Alveolar echinococcosis is a rare but fatal disease in humans and is caused by the fox tapeworm Echinococcus multilocularis. The densities of fox and grassland rodent populations and the interactions between them influence E. multilocularis transmission rates in Europe. Successful rabies control has caused fox populations and E. multilocularis prevalence rates to increase in many European countries. The potential increase of the infection pressure on the human population motivates the monitoring of the infection status of foxes over space and time. Detection of E. multilocularis antigen levels in fox faecal samples collected in the field might provide a pragmatic methodology for epidemiological surveillance of the infection status in wildlife hosts across large areas, as well as providing an indication of the spatial distribution of infected faeces contaminating the environment. In this paper, a spatial analysis of antigen levels detected in faeces collected in the Franche-Comté region of eastern France is presented. In Franche-Comté, rodent outbreaks have been observed to originate in areas rich in grassland. Spatial trends in fox infection levels were modelled here as a function of the composition ratio of grassland in the landscape derived from the CORINE land-cover map. Kriging models incorporating the grassland trend term were compared to a variety of models in which five alternative trend expressions were used: the alternative trend expressions included linear and quadratic polynomials on the x and y coordinates with and without a grassland term, and a constant mean model. Leave-one-out cross-validation indicated that the estimation errors of kriging with a trend models were significantly lower when the trend expression contained the grassland index term only. The relationship between observed and predicted antigen levels was strongest when the estimated range of autocorrelation was within the home range size of a single fox. The over-dispersion of E. multilocularis in foxes may therefore account for the majority of spatial autocorrelation locally, while regional trends can be successfully modelled as a function of habitat availability for intermediate hosts.

Animals↗

PubMed2004

Ecological epidemiology: landscape metrics and human alveolar echinococossis.

The larval form of the fox tapeworm Echinococcus multilocularis can cause a potentially fatal liver infection in human hosts. Globally rare, the disease has a high prevalence focus in western China. Recent research has linked landscape to the presence and prevalence of the disease. This paper discusses the epidemiology of E. multilocularis in terms of landscape and disease transmission ecology. Landscape form was defined using satellite imagery to create a land cover classification for a study site in Zhang County (Gansu Province, China). Following the analysis of many landscape metrics, mean shape index was found to be related to the prevalence of infection for 31 villages in 1975 and 1997, at two spatial intervals, suggesting that habitat form is a correlate of disease. A temporal difference shows that the landscape is no longer suitable for transmission. These results indicate the possibility of identifying future hotspots which could aid the management of the disease.

China↗

PubMed2003

Multi-scale spatial analysis of human alveolar echinococcosis risk in China.

Risk factors for the transmission of Echinococcus multilocularis to humans operate at a range of spatial scales. Over a large area, such as China, regional scale risk is correlated with variation in climatic conditions because of its effect on the spatial distribution of landscapes that can support E. multilocularis transmission in wildlife hosts and the probability of egg survival. At a local scale of a few kilometres, or tens of kilometres, transmission risk is related to the spatial proximity of human populations and landscapes with active transmission. At the patch scale, when considering individual villages or households, human behavioural factors are important and for individuals genetic and immunological factors play a role. Satellite remote sensing can provide landscape information at a range of spatial scales and provide a spatial framework within which to examine transmission patterns. This paper reviews the application of remotely sensed data and spatial data analysis to develop a better understanding of disease transmission and shows how such data have been used to examine human alveolar echinococcosis infection patterns, at a range of spatial scales, in an endemic area in central China.

Animals↗