Swine- Origin Influenza A (H1N1) Pandemic Revisited

Since the beginning of January 2008 sporadic cases of infections in humans caused by influenza A (H1N1) virus- resistant to available anti-influenza drugs have been reported worldwide [1,2]. The World Health Organization (WHO) in its report published on 18 March 2009 indicated that during weeks 1- 4 (28 December 08-24 January 09), the level of overall influenza activity in the world increased. During this period, 1291 of 1362 A (H1N1) cases from 30 countries showed resistance to the antiviral drug osaltamivir. [3]. In Canada, United States of America, Japan, Republic of Korea, Hong Kong, France, Germany, Ireland, Sweden and United Kingdom the prevalence of oseltamivir resistance was reported to be more than 95% [3]. On 24 April WHO released the first alert indicating the occurrence of confirmed human cases of swine influenza (H1N1) in Mexico and the United States [4]. Subsequently the Centre for Disease Control and Prevention (CDC), in the United States confirmed that these human influenza cases were caused by a new strain of influenza A virus subtype (H1N1) [5].