Consistent clinical signs include fever, lethargy and lymphodenopathy. Haematological changes during the acute phase include elevated blood urea
concentrations, decreased plasma protein, leucopenia mainly due to a lymphopenia, eosinopenia, and thrombocytopenia Soesanto et al. 1990. The
mortality rate in the experimentally infected cattle was 17 Soeharsono et al. 1996
a
. The mechanism of transmission of JD is poorly understood. There is
evidence of direct transmission from acutely affected animals in close contact with susceptible cattle, possibly by virus in these secretions infecting cattle by
conjunctival, intranasal or oral routes. During the acute disease the titer of infectious virus in blood is high and can be detected in saliva and milk. It is
probable that the virus is also transmitted mechanically by Haematophagous arthropods Soeharsono et al. 1995
b
. The blood sucking insect could transmit JDV from infected animal during fever to susceptible animal Putra and
Sulistyana 1995. Recovered cattle are also a potential source of infection. Recovered cattle are persistently viraemic but the titre of infectious virus in blood
by 60 days after recovery from the acute disease is only about 10
1
IDml Soeharsono et al. 1996
b
. Commonly, JD can be diagnosed by enzyme-linked immunosorbent assay
ELISA and Western Blotting WB to detect the JD antibody. Antibody was not detected by ELISA in majority of infected cattle until 11 weeks after infection and
a maximum antibody response was detected 23 to 33 weeks after infection. Antibody was still detectable 59 weeks after infection Hartaningsih et al. 1994.
Another technique is polymerase chain reaction PCR that can be used to confirm both field and laboratory diagnosis of JD in Bali cattle Tenaya and Hartaningsih
2005.
2.2 Spatial Analysis using Geographic Information System
GIS stands for geographic information system is a computerized system that helps in maintaining and displaying data about geographic space. GIS
provides four capabilities in data capture and preparation, data management storage and maintenance, data manipulation and analysis, and data presentation
de By 2004. GIS is computer-based system specially designed and implemented for two subtle but interrelate purposes: managing geospatial data and using these
data to solve spatial problems Lo and Yeung 2007. GIS is capable of assembling, storing, manipulating, and displaying map and database information.
GIS allows us to view, understand, question, interpret, and visualize data in a very informative way. Data management is more effective in order to support any
management in any sector by decision and policy makers Wicaksono et al. 2010. The construction and functions of GIS were explained by dividing them
into subsystems of input, processing, analysis, and output. GIS is made up of four components, namely, data, technology, application, and people. Geospatial data
record the locations and characteristics of natural features or human activities that occur on earth’s surface. GIS technology can be explained in terms of hardware
and software. The application component of GIS can be explained from three perspectives: areas of application, nature of application, and approaches of
implementation. The people component is defined as GIS users Lo and Yeung 2007.
Spatial analysis using GIS includes a wide range of operations. Typically they relate to analyses within or between layers of geographical data provided by
the GIS. In spatial analysis three different types of spatial data can be analyzed: point data, geostatistical data, and lattice data Pfeiffer et al. 1994. Point patterns
are the data set may consist of locations only, or it may be a marked point process, with data values associated with each location. Geostatistical data represents
continuous variation of a feature attribute such as rainfall or temperature Allepuz 2008. Lattice data represents discrete variation in space based on regular or
irregular units. These units can be for example farm or administrative boundaries Pfeiffer et al. 1994.
2.3 Spatial Analysis in Veterinary Epidemiology
