[Time characteristics of imported malaria cases in Yunnan Province]

Objective To investigate the time distribution characteristics and the epidemic trends of imported malaria cases in Yunnan Province. Methods The malaria case records and epidemiological history data of Yunnan Province were collected, and the local infection cases were excluded. The data were statistical analyzed. Results The imported malaria cases had a significantly seasonal periodicity (Q = 26.574, P < 0.05) and epidemic trends (Q = 35.487, P < 0.05). The imported peak was in May, while February was the lowest month of imported cases, and the difference was significant (Z = -2.619, P < 0.05). The simple seasonal prediction model was the best model (R² = 0.677, BIC = 4.867) for forecast while the residual sequence was white noise (Q = 14.226, P > 0.05). By using the model to predict the cases in January, February and March of 2016, the number (95% CI) were 29 (7-50), 22 (0-44) and 31 (8-54), and the actual number of imported malaria cases were 29, 24 and 38 cases respectively and all cases were included in the 95% CI. Conclusion The imported malaria cases in Yunnan Province had a significantly seasonal periodicity and epidemic trends, and the established model has good prediction on the recent cases.