Abstract

In the 1970’s, a global increase in Salmonellosis was noticed, initially in the USA , but shortly followed by UK and Europe. The increase was determined to be associated with a single serovar, Salmonella Enteritidis, and specific to global regions certain phage types of this serovar became prevalent. In the earliest outbreaks reported from the USA , phage type 8 (PT 8) Enteritidis was determined as the pathogen in the majority of outbreaks; in the UK phage type 4 (PT 4) accounted for the majority of outbreaks. In a large proportion of investigated outbreaks the vehicle of infection was attributed to either eggs or poultry. In the UK, the `epidemic’ started in the mid 1980’s, reaching a peak in 1993. In December 1988, Edwina Currie the Junior Minister for Health made a public statement on television stating that “most of the egg production in this country, sadly, is now affected with salmonella” resulting in her resignation. The end result of such a public statement ensured government interventions were introduced. The interventions primarily involved cleaning up the poultry industry and introducing vaccination schemes, improved farm management including controls for bio-security, pests (vermin) and feeds in addition to National Control Plans for Salmonella in Poultry (part of EU wide strategy). Interventions involved both the British Egg Industry and national government (MAFF / DEFRA ) and public health. Following the introduction of interventions between 1993 and 1998, the reported numbers of PT 4 Enteritidis declined. At the peak of the epidemic, 17,257 PT 4 reports were recorded (1993), dropping to 6,744 in 1999, 1,915 in 2005 and 271 in 2011 (0.006% of 1993 figures). In 2011, the reported numbers of Salmonella Enteritidis PT 4 were 35% below those reported pre epidemic in 1982. In the USA , no such interventions were put in place, and improved farm management used instead. In 2009, the USA issued the largest recall of shell-eggs, calling for the removal of half a billion eggs from the market.