Prediction of the Hazard Rate of CTX s First Occurrence

Culex tritaeniorhynchus (CTX) is a well-known mosquito which transmits Japanese encephalitis. To prevent Japanese encephalitis, we need to know the time and the places where Culex tritaeniorhynchus may occur. If we could predict the time when the mosquito will appear first in Korea, we can set up an excellent surveillance system and get facilities ready to treat Japanese encephalitis. In addition we may need the hazard rate of occurrence of the mosquito, which might depend on the period when the mosquito is absent, so that if the hazard rate becomes significantly high, we may activate an alarm of pre-caution in advance. This research intends to estimate the hazard rate for the first occurrence of Culex tritaeniorhynchus with the Cox regression model with the covariate, temperature corresponding to trapping time. We conclude that the hazard rate increases about 25% as the average temperature rises one degree in Celsius. In addition, if the mosquitos were not detected by the 35th week, the hazard rate of occurring is about 11%. So we suggest that an alarm system against Japanese encephalitis start from the 35th week.