Studies On Epidemic Situation And Prevention And Control Strategy Of Influenza A(H1N1) In Jilin Province In 2009

Background:In March 2009, a large number of flu cases were reported in Mexico and the United States and other parts of the world also reported similar cases. The H1N1flu is caused by a mutated influenza virus H1N1 and will cause acute respiratory infections. Most people are susceptible to this strain of virus. The already infected H1N1 flu patients were the main source for infection. The H1N1 flu virus can be easily transmitted from person to person and is more infectious than the typical seasonal flu virus. The flu outbreak was the largest since 1968. WHO (World Health Organization) raised the influenza spread level to 6 which indicated that it is pandemic. The first case of H1N1 flu in China was reported in Hong Kong, China on May 1, 2009 and the first such case in mainland China was reported only 10 days later.. As the flu epidemic spread was fast and could led to a large number of infections in a short time, the flu case was reported in every province in China in a very short period. It was threatening the public health and safety especially when the public had little knowledge of the emerging epidemic and had not effective self-protective and preventive measures against it. The lack of effective measures against the outbreak of such flu infection has caused a certain degree of panic in the society in China in the beginning. The H1N1 flu was initially classified into the Class B infectious diseases in"Communicable Disease Prevention Act in China" and appropriate preventive and control measures were taken according to Class A infectious diseases. As information is getting increasingly more transparent, the public's awareness of this flu is significantly improved and some self-protective and preventive measures are taught to the public, the public panic has been alleviated. In addition, the appropriate prevention and treatment measures have been adopted on the key groups of people which greatly helped the prevention and control of the H1N1 influenza. The quick recovery of patients who were infected with H1N1 and the low death rate caused by H1N1 also slowed down the epidemic's trend and allow the flu epidemic to enter in a relatively stable period. On July 2009, China moved the H1N1 influenza back to the Class B infectious diseases. With the outbreak and spread of the H1N1 flu, China has made its prevention and treatment strategies in coping with the endemic and adjusted the strategies as the flu is under control. As the H1N1 is highly contagious, long lasting, widespread and infecting a large amount of people, it is very important and beneficial to establish a prevention and treatment framework which can also serve for better development of the flu treatment measures and a platform for treatments of other contagious diseases.Objective :We analyzed 1,054 flu cases reported in Jilin Province in 2009, characterized the H1N1 flu stages, summarize the flu symptoms and treatment measures adopted in different stages and propose a frame for the H1N1 prevention and treatment in the hope it can help improve the overall H1N1 treatment and provide some experiences for other clinical researchers.Materials and Methods:The data we used for Jilin province were from the China Disease Prevention and Control System (direct reporting system over the Internet) which collects the reported H1N1 diagnosed cases and other relevant information until December 31, 2009. The nationwide H1N1 flu cases and statistics were the data published on the website of the Ministry of Health in China. We adopted descriptive statistical analysis and used the analysis software SPSS and analyze 1,054 diagnosed H1N1 cases reported in Jilin province and charted the H1N1 incidence curve for different regions, different periods and different age groups. In addition, we analyzed the H1N1 patients'occupations and death rate and summarized the appropriate prevention and control measures.Results:As of December 31, 2009, 1,054 diagnosed H1N1 cases were reported and 1,011 cases were cured in Jilin Province. Five patients are in hospital for treatment. 22 patients are recovering at home. 16 deaths were associated from the H1N1 flu.The diagnosed H1N1 cases in Jilin province account for 0.875% of the total cases nationwide over the same period. The flu incidence rate is 3.86/100,000 in Jilin province which is lower than the national average which is at 9.01/100,000.The male/female ratio is 1.4:1 in the H1N1 cases reported in Jilin province. The predominant age group is the young people who are between 10 and 24 who account for 56.31% of all cases. The predominant occupation in the infected people was students.Among the 16 deaths, 6 of them were men and 10 were women. Three people who died are the children under the age five (including two infants who are under 3). Nine people who died are between 15 and 39. Three people who died are between 45 and 69. A person who died is above 65 years old. Seven people who died were peasants and 2 people who died are children who do not live with parents. Two people who died are factory workers. 2 people who died are unemployed. 1 person who died is cadre. Another 2 people who died are in other occupations. Four people who died have chronic disease and 6 people who died are pregnant. 1 person who died has obesity. 81% of the people were in the five high-risk groups of people. All the people who died have no prior H1N1 vaccine history. The deaths mainly occurred in the second peak of the epidemic and there was no death in the first peak of the epidemic.On December 2009, the percentage of H1N1 flu cases accounted for 85.9% in the total flu cases reported in the nation. In Jilin province, the percentage of H1N1 flu cases accounted for 55.72% in the total flu cases reported.Conclusion:1. Jilin Province has reported a total of 1,054 confirmed H1N1 flu cases with at least 1 case reported in every town and counties (cities, districts) in 2009. There were more men who were infected with H1N1 than women and the majority of the patients were students and the age of most patients was between the ages of 15 and 24.2. The number of the H1N1 infection cases and the percentage of H1N1 infection cases in all flu cases in Jilin Province in 2009 are both lower than the national averages as the H1N1 epidemic is under effective control in Jilin province.3. Severe complications and deaths caused by H1N1 virus mainly happened in five high-risk groups of people which are the chronically ill, pregnant women, obese people, infants and the elderly respectively. They altogether accounted for 69.78 percent of all severe complication cases and 81% of deaths.4. The H1N1 epidemic in Jilin Province has been under stable control with a low occurrence rate in 2009. The "moderate and rigorous prevention first " prevention and control strategy has played an important role in limiting the H1N1's spread in Jilin province and reduced the incidence of severe complications and deaths caused by the H1N1 virus.5. Although there are many factors affecting the H1N1 flu epidemic, we can keep the epidemic under control as long as we pay sufficient attention to it and adopt and adjust comprehensive prevention and control measures based on the epidemic development stage. With this established framework, we will be more confident and capable to respond to any possible flu epidemic in the future.