There have long been many good reasons for keeping wild birds away from poultry farms and now, it would seem, there is another.
Research across eight countries in the Americas, Asia, and Europe has found that wild birds, such as ducks and crows, living close to humans, are likely to carry bacteria with antimicrobial resistance (AMR).
The study was conducted by the U.K.’s Ineos Oxford Institute for antimicrobial research at Oxford University. It examined 700 samples of bacteria taken from the guts of 30 wild bird species. In particular, the researchers looked for Campylobacter jejuni.
The diversity of C. jejuni strains was looked at, along with the presence of genes associated with AMR, and a novel statistical model was developed to study the relationship between these and various factors including bird behavior and location.
Contamination from human waste
Genetic markers associated with AMR were found across all bird species studied. Wild birds living close to humans contained a wide range or bacterial strains, and up to three times more AMR genes than birds living in more isolated environments, such as mountain.
Wild birds may pick up antimicrobial resistant bacteria in a number of ways. Gulls and crows, for example, are known to frequent landfill sites, while ducks may pick up resistant bacteria from rivers contaminated with human wastewater.
As human populations continue to grow, urbanization disrupts the existing environment, along with the birds that live there. This not only increases the opportunities for contact between birds and humans, but also the opportunities for antibiotic resistant bacteria that have emerged in urban settings to find their way back to farms and then back to consumers.
Let us not forget that birds can travel long distances. The poultry industry is more than aware of the increase in risk when seasonal migrations occur, or even when a notifiable disease is reported locally or nationally. Just as birds may carry avian influenza (AI), for example, they can as easily spread antibiotic resistant bacteria to a farm. The potential risk is obvious.
Who's risking food security, safety?
The industry has made great strides in reducing its antibiotic use, and this has not always been replicated in human medicine. Fingers have too often been pointed as poor prescribing practices in animal agriculture, when, in many parts of the world, antibiotics for human health can be bought - prescription-free - in street markets.
Various studies have found that antibiotic resistant bacteria resulting from non-farming activities do find their way into the countryside, but perhaps given the danger that wild birds contaminated in an urban setting could, it might be time the industry to be at the giving end of the pointing finger, rather than the receiving.
