A case-control study of the epidemic factors of an outbreak of paratyphoid A

Objective The present study was conducted to ascertain the epidemic factors of paratyphoid A for the effective prevention and control of the epidemic．Methods A questionnaire investigation was done among 31 cases of paratyphoid A and a control group of 93 normal subjects involved in the 1 to 3 proportional case-control study．The odds ratio (OR)and itS 95％ confidence interval (CL) were calculated．Results The single-factor analysis showed that the OR value was 3.12 among those using river water with a statistically significant difference between the study group and the control group (X2=4.50，P<0.05)．It was believed that the local prevalence of paratyphoid was caused by using river water．Conclusion The use of the polluted river water was the main factor contributing to the prevalence of paratyphoid among the villagers．The surveillance of water quality is to be taken seriously by the authorities concerned to guarantee the supply of pipe water，making sure that the residents are provided with clean and sanitary drinking water．