powderburn
Active member
TORONTO (CP) - They may be lovely to look at. But Canada geese are generally considered pests, walking feces factories that take over parks and ponds, leaving a slick of guano in their wake.
A new study suggests the problem may be more than cosmetic. Canada geese can pick up and shed antibiotic-resistant pathogens, potentially making them an effective winged delivery network for so-called superbugs.
Experts aren't ready to call out the troops. But they admit the research, to be published in the June issue of the journal Emerging Infectious Diseases, highlights a way of spreading antibiotic-resistant organisms that hitherto hasn't been studied.
"If you have a multi-drug resistant salmonella being shed by a horse in Georgia and a goose happens to eat in that pasture and then fly up to Kentucky or Ontario, then maybe you can get quick dissemination of these bugs," says Dr. Scott Weese, a veterinarian who specializes in antimicrobial resistance at the Ontario Veterinary College in Guelph.
"It's probably low priority in the grand scheme of things, but it still is a potential way to disseminate something - and disseminate it widely across North America."
The paper reports on the work of U.S. researchers who tested four different flocks of Canada geese to see if they could acquire and shed antibiotic-resistant E. coli. Sampling was done by collecting droppings and swabbing bird butts.
"We just wanted to test the hypothesis if they might be actual carriers," explains Dr. Dana Cole, a veterinarian with the Georgia division of public health in Atlanta.
"When you have geese hanging out in agricultural areas and exposed to (animal) waste sources or even human areas with (human) waste sources, what are they getting exposed to?"
The non-migratory flocks - from Georgia and North Carolina - had habitats representing different types of land use: recreational (a park), agricultural and industrial.
One of the North Carolina flocks had a disturbing habit of loitering around a nearby swine waste lagoon. Pig farms, like other livestock rearing operations, can use high levels of antibiotics to tamp down diseases.
When samples from that flock were run through laboratory testing, it was the veritable "Bingo!" moment.
Many of the isolates were found to harbour antibiotic-resistant strains of E. coli. Furthermore, 72 per cent of those isolates were resistant to more than one antibiotic; 48 per cent were resistant to three or more drugs.
Rates of antibiotic-resistant isolates were much lower in birds in another agricultural setting not close to a lagoon. The park birds tested clean.
The study doesn't look at whether the birds carry and shed the resistant bacteria long term or whether it's a case of short-term infection and shedding.
And while it proves the geese pose a theoretical risk, it doesn't confirm whether in reality they are part of a chain of transmission leading to human infection, says Dr. Todd Weber, director of the office of antimicrobial resistance at the U.S. Centers for Disease Control.
Weber says he knows too little about how much exposure Canada geese have to field crops to know whether it's likely the birds could inoculate produce which might then sicken people.
"Are they contaminating fields? I don't know," Weber admits.
"They're not like crop dusters, spraying feces over these crops - I assume. At least I've never seen Canada geese do that."
"There are a lot of pieces to this puzzle which could happen. But we don't know if it is happening," he says from Atlanta.
Weese sees other theoretical possibilities though.
The geese could spread antibiotic resistant bugs to livestock or domestic pets, which in turn could spread them to humans.
It's as easy as taking the family dog for a walk in the local park. A dog owner would step around the goose droppings. But would the dog?
"My dog would eat it. No doubt about that. Oh yeah," Weese says with a laugh.
"The dog's going to eat it and if it (the pathogen) is one that can colonize the dog, then the dog brings it into the household."
The study looked for E. coli, but there's no reason to believe geese couldn't pick up other antibiotic-resistant bugs as well.
"It depends on the organism, about its survivability and all that stuff. But if you're consuming drug-resistant bacteria, presumably you're going to defecate the same," Weber says.
Still, neither Weber nor Weese believes bug-infested birds are a huge player in the spread of antimicrobial resistance.
"Would I put Canada geese on the top of my list of things to figure out in the whole problem of drug resistance? No," says Weber.
But both say the findings underscore the fact that migratory birds and animals can play a role in moving antibiotic-resistant bugs around the globe and as such probably deserves more study.
Meanwhile, people might want to take note when they're in the presence of the lovely birds - or their droppings.
"It would be inappropriate to get people concerned about going into parks with geese around them. But it's just one of the things you need to think about," Weese says.
"It's a matter of how far you take all these (scientific) papers in terms of real risk. And probably if they're in a park and there are geese droppings around, is the risk real? Probably not. Is it worth general hand hygiene principles like washing your hands? Absolutely."
A new study suggests the problem may be more than cosmetic. Canada geese can pick up and shed antibiotic-resistant pathogens, potentially making them an effective winged delivery network for so-called superbugs.
Experts aren't ready to call out the troops. But they admit the research, to be published in the June issue of the journal Emerging Infectious Diseases, highlights a way of spreading antibiotic-resistant organisms that hitherto hasn't been studied.
"If you have a multi-drug resistant salmonella being shed by a horse in Georgia and a goose happens to eat in that pasture and then fly up to Kentucky or Ontario, then maybe you can get quick dissemination of these bugs," says Dr. Scott Weese, a veterinarian who specializes in antimicrobial resistance at the Ontario Veterinary College in Guelph.
"It's probably low priority in the grand scheme of things, but it still is a potential way to disseminate something - and disseminate it widely across North America."
The paper reports on the work of U.S. researchers who tested four different flocks of Canada geese to see if they could acquire and shed antibiotic-resistant E. coli. Sampling was done by collecting droppings and swabbing bird butts.
"We just wanted to test the hypothesis if they might be actual carriers," explains Dr. Dana Cole, a veterinarian with the Georgia division of public health in Atlanta.
"When you have geese hanging out in agricultural areas and exposed to (animal) waste sources or even human areas with (human) waste sources, what are they getting exposed to?"
The non-migratory flocks - from Georgia and North Carolina - had habitats representing different types of land use: recreational (a park), agricultural and industrial.
One of the North Carolina flocks had a disturbing habit of loitering around a nearby swine waste lagoon. Pig farms, like other livestock rearing operations, can use high levels of antibiotics to tamp down diseases.
When samples from that flock were run through laboratory testing, it was the veritable "Bingo!" moment.
Many of the isolates were found to harbour antibiotic-resistant strains of E. coli. Furthermore, 72 per cent of those isolates were resistant to more than one antibiotic; 48 per cent were resistant to three or more drugs.
Rates of antibiotic-resistant isolates were much lower in birds in another agricultural setting not close to a lagoon. The park birds tested clean.
The study doesn't look at whether the birds carry and shed the resistant bacteria long term or whether it's a case of short-term infection and shedding.
And while it proves the geese pose a theoretical risk, it doesn't confirm whether in reality they are part of a chain of transmission leading to human infection, says Dr. Todd Weber, director of the office of antimicrobial resistance at the U.S. Centers for Disease Control.
Weber says he knows too little about how much exposure Canada geese have to field crops to know whether it's likely the birds could inoculate produce which might then sicken people.
"Are they contaminating fields? I don't know," Weber admits.
"They're not like crop dusters, spraying feces over these crops - I assume. At least I've never seen Canada geese do that."
"There are a lot of pieces to this puzzle which could happen. But we don't know if it is happening," he says from Atlanta.
Weese sees other theoretical possibilities though.
The geese could spread antibiotic resistant bugs to livestock or domestic pets, which in turn could spread them to humans.
It's as easy as taking the family dog for a walk in the local park. A dog owner would step around the goose droppings. But would the dog?
"My dog would eat it. No doubt about that. Oh yeah," Weese says with a laugh.
"The dog's going to eat it and if it (the pathogen) is one that can colonize the dog, then the dog brings it into the household."
The study looked for E. coli, but there's no reason to believe geese couldn't pick up other antibiotic-resistant bugs as well.
"It depends on the organism, about its survivability and all that stuff. But if you're consuming drug-resistant bacteria, presumably you're going to defecate the same," Weber says.
Still, neither Weber nor Weese believes bug-infested birds are a huge player in the spread of antimicrobial resistance.
"Would I put Canada geese on the top of my list of things to figure out in the whole problem of drug resistance? No," says Weber.
But both say the findings underscore the fact that migratory birds and animals can play a role in moving antibiotic-resistant bugs around the globe and as such probably deserves more study.
Meanwhile, people might want to take note when they're in the presence of the lovely birds - or their droppings.
"It would be inappropriate to get people concerned about going into parks with geese around them. But it's just one of the things you need to think about," Weese says.
"It's a matter of how far you take all these (scientific) papers in terms of real risk. And probably if they're in a park and there are geese droppings around, is the risk real? Probably not. Is it worth general hand hygiene principles like washing your hands? Absolutely."
