EO in Epidemio

Buruli Ulcer

Buruli Ulcer

Fact sheet

Buruli ulcer is one of the 17 neglected tropical diseases. The exact mode of transmission of M. ulcerans is still unknown. Since there is no knowledge of how Buruli ulcer is transmitted, preventive measures cannot be applied.

At least 33 countries with tropical, subtropical and temperate climates have reported Buruli ulcer. Between 5000–6000 cases are reported annually from 15 of the 33 countries. The disease occurs in Africa, South America and Western Pacific regions. Most patients are children under 15. (Source: WHO 2016)

Buruli Ulcer endemic countries, number of reported cases 2015 (Source: WHO, 2016)

Only case detection, reporting and clinic therapy exist so far. Environmental factors have not been investigated in depth until now. Satellite derived information support the identification of preventable risk factors and VecBorn could be an important contribution to reduce the risk of infection for the local, particular rural population.

Man-made environmental changes, in particular clearings, dam construction and the resulting changes of water body and wetland distribution are assessed within VecBorn.

Results of epidemiological studies have been correlated with earth observation data to exposure the association of the emergence and spatial pattern of M. ulcerans and the disease and to compare the spatial patterns of Buruli ulcer prevalence and the presence of different types of water bodies.

Map examples

LULC:

LULC maps are provided together with maps of major environmental changes (forest clearings, flood extend, new settlement / infrastructure, new agricultural areas) for 2 points in time (1987 and 2014/15/16).

LC Classification of 1987 before the Mapé dam construction in Cameroon.

LC Classification of 2015/16

The figures show LULC maps for the Buruli Ulcer test site in Cameroon, derived from Landsat satellite images from 1987 (before dam construction) and 2015/16.

The building of a dam in 1989 on the Mapé River profoundly modified the environment by creating an artificial lake of 3.2 billion m³ capacity.

 

Water surface extent and distance to water bodies:

The seasonality of the water surface of the Mbam river and the distribution of smaller water bodies has been mapped in the Mapé area in the course of nearly one year (04/2015 – 01/16).

Risk areas delineated by threshold Subset Lake Bankim and Mban River.

Risk area estimation:

The correlation of water bodies, farms and health cases underlines the assumption of prior research results, that the infection with Buruli Ulcer is related to the contact resp. distance to stagnate seasonal water bodies and agricultural activities of farmers.

Result of thresholding and classification of the floodplain Nyong River.

Detailed explorations of the tick occurrence risk and activity can be done within the interactive web map.

Link to the Web Map: WebGIS