As I said in my opening remarks, the scientific evidence suggests the major contributions to antimicrobial resistance problems in people, which arise from animals and animal uses of these drugs, are the food-borne enteric bacteria. They're common food-borne pathogens like salmonella and E. coli, which have campylobacter, which tend to have an animal reservoir. That's the best documented set of organisms for which we identify the resistance flowing through the animal production and food chain system, but there are others that are there.
Recently, over the past eight to 10 years, there has been an emergence of methicillin-resistant Staphylococcus aureus, which is a common human pathogen, but there is an animal-adapted strain that's spread around the world and is becoming more prevalent in production animal species as well as in horses and sometimes in pets.
There is recent data that just came out from Europe this week that indicates it's increasing its presence in human disease in Europe. So there are some other pathogens that flow from farm animals and from pets and horses, but there is a large component of resistance, which is a bit of a black box. It includes an environmental reservoir, as well as organisms that we don't monitor in our surveillance programs that well, which harbour resistance genes, and which act as donors of those genes for pathogens of animals and people.
As I said, I don't think we'll ever find out what the actual magnitude of the impact is from the animal sector on people, but it contributes through those various ways.