Clinical and epidemiological studies of Visceral Leishmaniasis in Bihar, India
|Project type:||Short Term RTD|
|Time frame:||2008 - 2009|
|Geographic keyword: Asia | India | Bihar|
|General keyword: Remote sensing|
|Specific keyword: Visceral Leishmaniasis | sand flies | habitat mapping|
Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is a chronic systemic disease that is fatal unless treated. The main clinical symptoms are an enlarged spleen and prolonged irregular fever. The parasite L. donovani is inoculated in the human host by the bite of peri-domestic sand flies and rapidly invades the macrophages. Approximately 500,000 new cases of human VL occur annually according to WHO estimations . The disease is mainly found in Brazil, East Africa and on the Indian sub-continent where devastating outbreaks have occurred and from where most VL cases are reported world wide . India, Nepal, Bangladesh, Sudan and Brazil harbour 90% of the worldwide reported VL cases. In India, millions are at risk, the state of Bihar accounts for nearly 90% of Indian cases, followed by the states of West Bengal, Jharkhand and Eastern Uttar Pradesh . Neighboring countries Nepal (the low land Terai region) and Bangladesh also report a significant number of VL cases.
VL is known to have occurred in the Indian subcontinent for centuries, but after extensive insecticide spraying in the 1950s by the National Malaria Eradication Programme, there was a dramatic decline in the incidence of VL. However, resurgence was noted from the early seventies onwards in a small area of North Bihar, and in the next 10-15 years the entire state of Bihar, a few districts of the newly created state Jharkhand, and of adjoining states West Bengal, plus the Eastern districts of Uttar Pradesh became endemic for VL. Neighboring countries Nepal and Bangladesh were also affected. For more than three decades now there has been incessant transmission of the disease with several million people at risk, several hundred thousand suffering from it every year and several thousands dying each year.
In the TMRC project, Avia-GIS is responsible for the high and low resolution remote sensing processing. Remote sensing data will be collected for the entire study area as follows. In the project, the data/indices from two types of remote sensors, MODIS and Landsat, will be derived and integrated. A database of 5 years of MODIS imagery will be set up. From this time series the Normalised Differencing Vegetation Index and the Land Surface Temperature will be derived on a daily basis. These data will then be aggregated to remove cloud contamination into 8-day composites. Next to this, seasonal parameters of LST (1km) and NDVI (250m) will be extracted using Fourier analysis. This will yield the amplitude and the phase for the different parameters. In a final stage eco-climatic zones will be delineated based on an unsupervised classification.
On local level the risk factors will be identified based on Landsat ETM or TM data (30m). The land cover/land use will be classified using a supervised classification approach based on Gaussian maximum likelihood classifier. Relevant land use/land cover classes will be identified. A second phase will include the determination of vegetation indices and texture in order to determine the suitable habitat for the vector.
Legend to the figures:
Figure 1: Location of study site in Bihar, India