< Back to previous page

Publication

Plague in tanzania - a landscape ecological approach

Journal Contribution - Journal Article Conference Contribution

Plague remains a public health threat in many parts of the world, but particularly insub-Saharan Africa. In general, it occurs seasonally and shows a clear geographicallydisjunct distribution in circumscribed foci. In spite of plague’s highly focal nature, theunderlying ecology remains often unknown and Ecological Niche Modeling suggeststhat plague can occur in highly diverse landscapes under wide ranges of environmentalconditions (Neerinckx et al. in press). In 1980 a persistent focus of human plague wasdiscovered in Lushoto, northeastern Tanzania. By 2004 >7000 cases had been reportedfrom this region and a strong variation in plague frequency and incidence is seenamong neighboring villages in the plague endemic area (Davis et al. 2006). Earlierstudies, which focused mainly on the host-vector-parasite system, demonstrated thatthis striking variation could not be explained by differences in fauna composition orhuman domestic behavior. Therefore, landscape ecological factors are suspected todetermine plague’s local persistence and=or to act as disease-provoking factors. In thepresent study, we report on the link between human plague incidence in Lushoto anddata on climate, landforms, land cover, soils and vegetation. We performed a comparativefield survey in a number of plague-positive and -negative villages in Lushotoand gathered the collected information in a GIS database, including an elevationmodel, weather data time series (rainfall and temperature), landform and land coverdescriptions, soil physical and chemical properties, and concentrations of chemicalelements in the common plant Rumex usambarensis. We found a positive correlationbetween plague incidence and altitude, and the endemic plague area appeared tocoincide with an area that had been totally deforested in the early 1960s. Moreover,POSTER ABSTRACTS: ECOLOGY OF PLAGUE 101first observations suggest that villages with a high plague incidence are connectedthrough typical fertile valley bottoms, i.e. Gleysols and Fluvisols, and that hamlets(part of a village) in this valley bottom have had more human plague cases. Soil andplant samples are being analyzed to test if factors that define the microclimate (in thisstudy, bulk density, soil texture, pH, and organic carbon, and concentrations of chemicalelements in soil and plant) are linked with plague occurrence in Lushoto. Ourresults give an indication that a landscape ecological study approach can provideinsights into the persistence of plague and how its distribution can be affected bylandscape features, and therefore in this case, might open the track towards a betterunderstanding of the underlying ecology of plague’s distribution in Lushoto.
Journal: Vector-Borne and Zoonotic Diseases
ISSN: 1530-3667
Issue: 1
Volume: 10
Pages: 101 - 102
Publication year:2010