An influenza A (H1N1) outbreak in a college, 2009, Guangxi.

Objective To explore the causes and characteristics of an influenza A(H1N1)outbreak in a college of Guangxi and provide scientific evidence for the disease control and prevention.Methods Field epidemiologic investigations were done among population in the college and pharyngeal swabs were tested to confirm influenza A(H1N1) infection.Results 98.7%(male 62.9%,female 37.1%) of the influenza A cases were new-enrolled students,who joined the college from 18 provinces.The incidence rates were 14.0% and 1.7% for new-enrolled and the other students respectively.The incidence rates of cases were ranged from 6% to 75%(average 37%)for students with close contact with influenza patients.The viral nucleic acid were tested positive in 7-15 days following the onset of illness.All patients showed only mild symptoms and recovered after appropriate medication or rest.The outbreak was over in 7 days after implementing isolation and the other intervention measures.Conclusion The risk of influenza came from close contact with patients.The isolation of patients and the prevention of transmission were efficient in the control of influenza outbreak.