Review finds elevated rates of antibiotic resistance in aquatic animals

A review and meta-analysis of point-prevalence surveys conducted in Asia over the past two decades found concerning levels of resistance to first-line and last-resort antibiotics in foodborne pathogens isolated from aquatic animals, researchers reported late last week in Nature Communications.

The systematic review identified 749 point-prevalence surveys reporting antimicrobial resistance (AMR) in aquatic food animals (fish and shrimp) in Asia published from 2000 to 2019, a period that saw substantial growth in aquaculture. From 2000 to 2018, the percentage of antimicrobial compounds with resistance exceeding 50% (P50) in each survey plateaued at 33% in cultured aquatic animals and declined from 52% to 22% in wild-caught aquatic animals. The study authors suggest the decline in wild-caught aquatic animals could be associated with reduced exposure to human and livestock fecal pollution.

Among the foodborne pathogens isolated (Escherichia coli, Vibrio spp, Aeromonas spp, and Streptococcus spp), resistance was highest to penicillins (60.4%), macrolides (34.2%), sulfonamides (32.9%), and tetracyclines (21.5%). In Vibrio and Aeromonas species, resistance to colistin was 42.7% and 51.5%, respectively; carbapenem resistance in Vibrio climbed from 5.1% before 2010 to 51.1% after 2010.

Predicted hot spots of multidrug resistance in freshwater environments, based on geospatial modeling, included eastern Turkey, southern India, the Yangtze River in China, and the lower reaches of the Mekong River and its delta in southern Cambodia and Vietnam. In marine environments, the highest rates of AMR were identified in northeastern China on the Yellow and East China seas; southern China and Central Vietnam on the South China Sea; southern India on the Arabian Sea and the Bay of Bengal between southern India and northern Sri Lanka; and the eastern Mediterranean Sea on the coast of Lebanon.

“This study identified elevated rates of antimicrobial resistance in bacteria isolated from aquatic animals intended for human consumption in Asia,” the authors wrote. “A growing aquatic food animal production industry may serve as an important pathway for transmission of resistance along the food chain with potential consequences for human health.”

The authors say their findings could help direct the prioritization of future surveillance efforts and inform planning for the sustainable development of the aquaculture industry.
Sep 10 Nat Commun study


Research: CWD has spread fivefold in Kansas in 11 years

Researchers at the University of Missouri have found that chronic wasting disease (CWD) has spread fivefold among Kansas counties, expanding from 6 counties in 2009 to 32 counties with confirmed positive cases in 2020.

The information came from the University of Missouri’s Veterinary Medical Diagnostic Laboratory, which analyzed more than 1,900 samples from 2020’s deer hunting season. Those samples identified CWD in seven eastern Kansas counties where the disease was previously undetected.

The spread has several researchers and officials concerned. Students and professors at the University of Missouri said they will continue to sample deer across the state and test for CWD and solicit samples from taxidermists, wildlife biologists, game wardens, and individual hunters who collect and send the lymph nodes of hunted deer to the university.

“This project not only helps us track the spread of the disease, it also helps raise awareness for hunters because we want them and their families to stay as safe as possible,” said Zoe Koestel, a doctoral student, in a university press release. “Hunters are the world’s original conservationists, and they often ask how they can help our efforts. The more samples we receive from hunters, the better we can track the spread of chronic wasting disease.”

CWD is a deadly prion disease that affects cervids. It was first identified in North America in 1967 and has since spread across much of the United States and Canada. Though no humans have confirmed CWD infections related to consuming infected animals, some experts fear CWD could follow the trajectory of bovine spongiform encephalopathy, or mad cow disease.
Sep 13 University of Missouri press release


Measles cases prompt pause in Afghan refugee arrivals

After four measles cases were detected in evacuated Afghans who recently arrived in the United States, inbound refugee flights will be paused for at least until Sep 20, White House officials said yesterday, according to CNBC.

At press briefings yesterday, officials said those infected with measles will be housed separately and that the Centers for Disease Control and Prevention (CDC) is conducting contact tracing. They also added that the refugees from Afghanistan will be soon be given critical immunizations, including those against measles, mumps, and rubella (MMR), while they are overseas and awaiting transfer to other countries.

The United States expects to admit about 65,000 refugees through Operation Allies Welcome. All are required to be vaccinated against measles as an entry condition.

Measles is highly contagious, and infected people can spread the virus from 4 days before the rash appears. In 2019, the United States reported 1,282 cases, with outbreaks reported in pockets of undervaccinated people that were triggered by those who contracted the virus in foreign countries. COVID-19 measures and the impacts on surveillance resulted in few numbers of known cases. So far this year, the United States has reported only two cases.
Sep 13 CNBC story
CDC measles background


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