Abstract: Objective To identify the risk factors for malaria infection in migrant workers returned to Anhui from Africa countries. Methods Between January 2018 and December 2019, we conducted series of investigations on the risk factors for malaria infection among migrant workers returned to Anhui area from African countries by questionnaire on casecontrol study basis. Then the results were analyzed with univariate and multi-variate logistic regression model by using the outcome of infection as variate to identify the risks of malaria infection. Results A total of 396 subjects underwent the investigation, in whom 132 were malaria cases(129 males, 3 females) and 264 were controls(257 males, 7 females). The two groups were not significantly different in gender(P>0. 05) as well as average age[(43. 74±9. 16) years for malaria cases vs. (45. 05±7. 92) years for controls, t =1. 472,P>0. 05]. Univariate analysis indicated that malaria infection was associated with the age, educational background, occupation, types of residence abroad, house type, ecological environment around the dwellings, mosquito control measures, outdoor activity time and training on malaria knowledge abroad. Multivariate analysis showed that the risks of malaria infection were higher among workers in road construction or engineering, living on the open field, or in work shed or grass house[OR(95% CI) ]: 6. 493 (2. 932, 14. 380), 6. 250(2. 749, 14. 297)and
2. 191(1. 204, 3. 987). Malaria infection was increased by 1. 579 times with each level of prolonged outdoor activity time, yet use of mosquito nets and training on malaria knowledge abroad reduced the risk of infection by 82. 9% and 65. 1% , respectively. Conclusion Improved living conditions, strengthened mosquito control measures, regular malaria prevention education and reduced outdoor activity time can effectively reduce the risks of overseas malaria infection among migrant laborers, and the number of imported malaria cases in Anhui Province.

Key words: Africa, Imported malaria, Risk factors, Case-control study, Anhui Province