Causative Agent The World Health Organization notes that acute respiratory illness known as influenza has afflicted human beings from ancient civilizations to date (Gerdil, 2003). Swine flu is a strain of influenza A viruses in the family Orthomyxoviridae (OIE, 2009). This strain is most commonly found in pigs. Influenza A viruses are further characterized by subtypes, a relatively stable subtype of which is the H1N1 virus. H1N1 is the etiologic agent of most swine influenza and for this reason, this is the strain most commonly associated with “classical swine influenza”. Swine Flu was first proposed to be related to human influenza during the 1918 flu pandemic which resulted in the subsequent death of 40-50 million people throughout the world (Zimmer & Burke, 2009). During this pandemic, pigs became sick at the same time as humans, therefore, leading to an investigation as to the relationship. Smith Andrewes identified a virus as being the causative agent for influenza. H1N1 viruses are readily transmitted and a host will begin excreting swine influenza viruses within 24 hours of infection and the shedding will go on for up to 7 to 10 days post-infection (OIE, 2009). The World Health Organization (2009) reveals that novel influenza A(H1N1) which appeared in 2009 is spread in the same manner as seasonal flu and can survive for up to 3 hours outside of a host in dry mucus. Populations Affected The World Health Organization reported that as of February this year, 213 countries had reported laboratory-confirmed cases of the H1N1 virus in their territories (Reuters, 2010). Reports by CDC (2009) show that H1N1 flu fatalities were highest in the 25 to 49 age bracket which accounted for 39% of the deaths by H1N1. The second age group most affected by H1N1 was the 50 to 64 age bracket which accounted for 25% of the fatalities. Young people aged 5 to 24 were reported to be the third most susceptible accounting for 16% of the affected. This preferential infection of younger people by swine flu is a significant difference of the virus from the seasonal flu which causes fatalities mostly in the older population (65 years and over). The World Health Organization has identified the following individuals as being at greater risk from the virus: pregnant women, children under the age of 5, chronic disease sufferers, and patients with immunosuppression (WHO, 2009). These are the people most likely to exhibit severe manifestations of the H1N1 virus. Owing to the classification of these groups as being high risk, it was recommended that they be given priority in vaccination when the vaccine was first made available. A course of the Disease Novel H1N1 is contagious from the first day before symptoms appear through to 7 days after the symptoms appear. The virus is shed in nasal secretions of the infected party and is disseminated through droplets or sneezing. According to the World Health organization, most people who have contracted the H1N1 virus experience influenza-like symptoms which include; sudden-onset high fever, sore throat, cough, runny nose, fever, malaise, headache and joint muscle. 25% of the infected people may also experience nausea, vomiting and diarrhea. The virus may result in respiratory tract disease which may result in the respiratory failure of the victim. Pregnant women and people with