[Establishment and application of ascariasis transmission mathematical models in China]

To establish ascariasis transmission mathematical models and apply them to predict field status.

Cuiping District in Sichuan Province, Jinxian County in Jiangxi Province and Yueyang County in Hunan Province were selected as the investigation sites. The Ascaris lumbricoides infection rates and mean worm burdens of baseline, 1 month and 1 year later after deworming were acquired by field surveys. The transmission models on population dynamics, distribution and infection rate were developed. The model parameters obtained through the field data were substituted into models to predict the infection level one year after deworming. The predicted values were compared with the actual survey data, and the sensitivity analysis was performed to analyze factors related to the chemotherapy measures.

The infection rates of Cuiping, Jinxian and Yueyang at baseline were 28.79%, 20.35% and 20.72%, respectively, with mean worm burdens of 1.32, 0.65 and 0.48, respectively. Those one year after chemotherapy were 30.10%, 7.51% and 0.94%, respectively, with mean worm burdens of 1.04, 0.56 and 0.34, respectively. The predict values were all in the range of the 95% confidence interval of the actual values. The sensitivity analysis showed that the treatment coverage rate and the treatment frequency were the important factors influencing the disease benefits (infection rate and mean worm burden).

The ascariasis transmission mathematical models have been established which fit the actual field data well. Therefore, they can provide theoretical basis for setting ascariasis control specifications and optimizing the control strategies.