Agriculture Reference
In-Depth Information
unknown, it has been established that antibiotics in hog feed
increase gene transfer.
How do infections spread from animals to humans? It isn't
just through the animal's meat. Using manure as a fertilizer
can contaminate vegetables. Farmworkers can carry the bacte-
ria with them as they leave the farm. Food activists love to tell
the story of Russ Kremer, a swine farmer who routinely gave
his hogs antibiotics at a low dose, only to personally acquire
an antibiotic-resistant infection after his skin was pierced by a
boar. Kremer is now a spokesperson for the movement to curb
antibiotic use in pigs. Is his experience highly unlikely, or does
it portend trouble? Hard to tell, but studies have found that
workers on farms using antibiotics do carry antibiotic-resistant
bacteria with them as they leave the farm, while those work-
ing on antibiotic-free farms are less likely to do so.
There is a benefit to antibiotic use in livestock, other than
lower meat prices. Humans can become sick from all bacteria,
not just those resistant to antibiotics. If hogs are healthier when
they receive regular, low doses of antibiotics, then there will be
fewer bacteria overall, and perhaps fewer human infections. For
instance, one study found that hogs raised in an antibiotic-free
setting were infected with salmonella at a greater rate than hogs
on farms regularly prescribing antibiotics.
Conceptually, it is impossible to say whether antibiotic use
in cattle, pig, and broiler production heightens or reduces
human health threats. It is an empirical question, which
requires one to guess the likelihood that bacteria will transfer
genes, horizontally, between each other. Many scientists and
most health organizations conclude a real human health threat
exists and that antibiotics should only be used therapeutically
and at appropriately high dosages to treat observed infections,
and many held this opinion even in the 1970s. The American
Medical Association openly opposes the regular use of anti-
biotics, and the World Health Organization considers antibi-
otic resistance one of the top three threats to human health.
The European Union went so far in 2006 as to ban the use of
