Salmonella species are the second most common cause of food poisoning
in man after Campylobacter spp, affecting over 13,400 people in the UK
each year, but the latest report on Salmonella in Livestock Production in Great
Britain (VLA, 2007) shows that only a small fraction (<1.8%) of human
infections can be associated with pig isolates.
Salmonella species are
the second most common cause of food poisoning in man after Campylobacter
spp, affecting over 13,400 people in the UK each year, but the latest report on
Salmonella in Livestock Production in Great Britain (VLA, 2007) shows that only
a small fraction of human infections can be associated with pig
The top five species of Salmonella found in human cases are S.
Enteritidis, S. Typhimurium, S. Virchow, S. Newport
and S. Infantis (see Figure 1).
Figure 1. Most
common Salmonella serotypes found in man in GB (2006).
Enteritidis is primarily associated with chickens,
both meat and eggs, although the UK has dramatically reduced the incidence of
this infection in its flocks through vaccination, and it may be associated more
with imported products and infections picked up while travelling
Typhimurium is the most common species (66.2%)
of isolates and therefore pigs are frequently blamed for this particular
infection in man.
The second most
common Salmonella infection in pigs is S.
Derby (13.9%), and this
species does not appear in the top 10 human list, so is as below 0.7% of
infections. In simple proportional terms, one would expect, therefore, S.
from pigs to account for below 3.3% of human cases, which is a surprisingly
Typhimurium is found in all animal and avian species but if we look at the
different definitive types of S.
Typhimurium, we can make a further assessment (see Figure
Figure 2. Top ten definitive
types (DT) of S. typhimurium
found in man and animals.
pigs were responsible for all of the human DT104, DT193 and DTU302 cases it
would add up to 3.58% of all of the human cases. If we assumed that they were
responsible for only one third of the DT104, as poultry and cattle also have a
strong involvement, but assume that pigs are mainly responsible for DT193 and
DTU302, then the number of human cases that is attributable to pigs can be
calculated as 1.84% or below.
As England is considered one of the 'dirty'
countries of Europe, as far as Salmonella in pigs is concerned, according to our
meat juice ELISA test results, it is possibly surprising that the figure is so
Possibly, legislators should take this into
account and not penalise pig producers but focus their attentions and resources
more on the areas where it can make a major difference.
One other snippet
of good news was that none of the pig isolates were resistant to ciprofloxacin
(fluoroquinolone), cefotaxime or ceftazidime (cephalosporins) and amikacin
(aminoglycoside), considered critically important antimicrobials for human