Application of Remote Sensing and Geographic Information System for Vector-Borne Disease in Humans Through Rice Agroeco System
Results
The average temperature is 22-290C in 3 years in the northern region of Thailand. And the precipitate occurs with high precipitate in June-August. The correlation between mosquito abandance data and precipitate is 0.9116 as shown in fig .4. the most type of mosquitoes are related to JE about 63.7-93.2% of total mosquitoes. In Chaingrai Province, the density of mosquitoes is maximum in July and Culex triaeniorhynchus is the dominant species that very high potential for vinous to grow. In addition, no dynamic of JE vector mosquitoes that are the high peaks of vector found in July for 3 consecutive years ( fig 4). However, the density of vectors decrease every year that the average number of maximum in 1992, 1993 and 1994 are 12,050 ( July ), 7,443 ( July ) and 896 ( July ) mosquitoes per trap per night respectively. The relationship between the density of JE vectors and number of JE case rates that are including rainfall, temperature and humidity during 1992 shown in fig 5.
Figure 4: the correlation between mosquito abandance data and precipitate
Fig 5: The relationships between the density of JE vectors and No. of JE case rates that are including rainfall. Temperature and humidity during 1992.
Recommendation
During 1981-1994, the incidence cases of JE in Thailand are 700-2,084 per year respectively. The case rates decreased in 1986 but in the northern regions was still higher than the other regions in Thailand. The reason that the northern part was the highest because the influence of environmental factors and the others such as the climatic condition, misquote density, potential of vectors and population's immunity. The suitable temperature for JE virus growth in mosquito is equal to or more than 280C ( Mogi, 1975). And occurrence of JE outbreaks consistently corresponds with paddy field cultivation in the rainy season. In addition, culex traeniorhynchus is a dominant species that is the highest potential vectors of JE disease, feeding mainly on pigs . Pigs are raised in large numbers in northern Thailand reflected secular amplifying hosts. However, the reduction of JE cases in the northern Thailand reflected secular changes, such as modification in land utilization and increasing urbanization, that have concurrently led to a gradual declined in risk. According to9 the vacination program may be decrease the JE case rates that is not true because the case decrease before vaccine program begin. The vaccine program started in 1987 but the cases decrease in 1986. it can be concluded that the JE cases decreased because the density of JE vector mosquitoes decreased.
