The Frequency Distribution of Cases Affected by Influenza A (H1N1) Based on Demographic Characteristics During 2008 – 2009 in Yazd Province (Iran)

Background: Human influenza is an acute and self-limited disease that is caused by viruses including types A, B, C. These viruses are related to RNA viruses and belonging to the family of Orthomyxoviridae. They are divided into other sub-species based on surface antigens, including hemagglutinin (H) and neuraminidase (N). The new virus of the group that was isolated from swine was called as influenza A (H1N1) virus. Objectives: The purpose of this study is an investigation on the frequency distribution of cases affected by influenza A (H1N1) based on demographic characteristics during 2008–2009 in Yazd Province. Patients and Methods: This is a descriptive cross-sectional study that was done with the information related to patients that were available at the Health Center of Yazd Province . Of 1442 patients suspected to influenza, during 2008 – 2009 years, 253 throat samples were positive with RT-PCR (reverse transcriptase-polymerase chain reaction) method and were confirmed for viruses. Results: 111 female and 142 male were available from a total of 253 confirmed H1N1 cases. The minimum and maximum ages were 1.5 and 90 years, respectively. The most common symptoms were fever and cough. 144 cases had record of hospitalization, 100 cases were undergone outpatient treatment and nine cases have not recorded the treatment status. The most frequent underlying manifestation was hypertension. Conclusions: According to this study, due to higher hypertension frequency in patients, hypertension should be considered in other diseases in Iran for preventing influenza.