What is swine influenza?
Swine Influenza is a highly contagious acute respiratory disease of pigs caused by type A influenza virus. Influenza in pigs is characterised by high morbidity and low mortality. Swine influenza in pigs occurs in most other pig-producing countries in the world, and is considered endemic in the United States of America and Mexico. Internationally pig influenza outbreaks occur year round and many countries routinely vaccinate swine populations against swine influenza. Normally Swine influenza viruses are species specific but sometimes swine influenza will cause disease in people. International outbreaks and sporadic infections in people (swine to people) have been reported occasionally in the past, but rarely has infection been reported to spread from person to person.
Swine influenza (also referred to as Swine influenza viruses or SIV) is caused by Orthomyxoviruses which are endemic among pig populations. Wild pigs can carry the virus intestinally, without being affected. Swine influenza can be highly contagious among pigs, but most outbreaks cause high levels of illness and low death rates in pigs. Swine flu infects a number of human beings every year, and there have been increasing numbers of reports of person-to-person spread in recent years. Analysis of the various virus sub-types found in swine flu in pigs suggests a pooling of DNA, incuding genes from swine, avian and human influenza. Until recently, influenza viruses had been thought to be largely ‘species specific’, with little risk to other species, but it has now been established that the great epidemic of 1918 was a strain of avian flu. Some of the cases in the 2009 outbreak in Mexico and the USA have been confirmed by the World Health Organization to be due to a new genetic strain of H1N
