New data from the United Kingdom show that sales of antibiotics for use in food-producing animals remain at decade-low levels.

The data from the latest the UK-Veterinary Antimicrobial Resistance and Sales Surveillance (UK-VARSS) report show that sales of veterinary antibiotics for use in livestock and poultry, adjusted by animal population, were unchanged from 2022 to 2023 but were 59% lower than in 2014.  Veterinary sales of highest priority critically important antibiotics, which includes fluoroquinolones, third-generation cephalosporins, and colistin, fell slightly from 2022 and were 84% lower than in 2014.

The amount of antibiotics prescribed or administered fell across several food-animal and farmed-fish species in 2022, but increases were observed in pigs, gamebirds, ducks, and salmon compared with 2023. Still, all species except for salmon have seen reductions in antibiotic usage ranging from 50% to 97% over the last decade. UK officials say the upticks in use in some sectors need to be monitored.

Declining levels of resistance

The report also shows declining levels of antimicrobial resistance (AMR) in UK livestock and poultry. The proportion of Escherichia coli isolates from healthy pigs and chickens at slaughter that were fully susceptible to a panel of antibiotics is at a new high of 43%, which is more than double the proportion found in 2014-2015.  The percentage of multidrug-resistant E coli in pigs and chickens is at a new low of 27%.

UK officials say the reductions in antibiotic use and AMR on UK farms demonstrate the dedication of UK farmers and veterinarians to responsible antibiotic use in animals.

"Today’s report, which is published during World AMR Awareness Week, highlights ongoing progress but also the vital need for continued action in this space," UK Animal and Plant Health Agency Director Jenny Stewart, PhD, MBA, said in an agency press release. "We will continue to work closely with UK vets and farmers, as well as international partners, to address the threat of AMR."

Four states reported more H5N1 avian flu outbreaks in poultry, including a second detection in Hawaiian backyard poultry and outbreaks on commercial farms in California, according to the latest confirmations from the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS).

Hawaii reported its first outbreak on November 17 in a backyard flock of 70 birds in Honolulu County on Oahu island. According to APHIS, the virus also turned up at another backyard facility in the same county, which involves a location that has nine birds.

California, which has been hit hard by outbreaks in dairy cows and poultry, has three more outbreaks from three different counties. They include a commercial broiler farm in Fresno County that has 172,800 birds, a turkey farm in Merced County that has 38,200 birds, and a turkey farm in Stanislaus County that has 22,400 birds.

Two states—Minnesota and Washington—reported outbreaks in backyard poultry. Minnesota reported two events in Martin County, its first since July. Taken together, the sites have 70 birds. Washington’s outbreak occurred at a location in Whatcom County that has 40 birds.

More confirmations in wild birds, dairy farm developments

In other virus developments, APHIS reported more than 100 H5N1 detections in wild birds, most with October and November sample collection dates. Most of the detections were from western states and many were raptors found dead or hunter-harvested waterfowl. Some of the detections were from Midwestern states including Illinois, Kansas, and Minnesota, and the APHIS list also included captive black vultures from Florida’s Brevard County.

The group also included some agency harvested wild birds in California counties experiencing outbreaks in dairy cattle.

Regarding outbreaks in dairy cattle, APHIS confirmed one more detection from a California farm, raising the state’s total to 336 and the national total to 550.

Elsewhere, the Pennsylvania Department of Agriculture today announced mandatory bulk milk tank testing as an added measure to prevent the spread of avian flu in dairy cattle. So far, Pennsylvania has not reported any outbreaks on dairy farms. The order goes into effect today and will be done at no cost to farmers. Pennsylvania is now one of four states that haven’t been affected by outbreaks to order bulk milk tank testing. The others are Arkansas, Oklahoma, and Massachusetts.

Two randomized control trials conducted in the Netherlands show text messages can increase COVID-19 vaccine uptake, especially if they are formulated with a message using ownership words, such as "your vaccine is ready."

The study, published this week in Vaccine, analyzed outcomes after different types of text messages were sent to 140,973 study participants. All participants were eligible for the COVID-19 booster but did not yet obtain it from the Dutch Public Health Service by January 24, 2022.

The authors established that text messages sent with an ownership frame, "your [vaccine] is ready for you," were associated with more vaccine uptake compared to no texts (odds ratio [OR], 1.28; 99% confidence interval [CI], 1.03 to 1.59). 

Adding specifics helps

Uptake improved further if the ownership frame texts included specifics, such as when and where vaccines were currently available. 

"Text message reminders are able to increase vaccine uptake. Based on this study, a tailored text message reminder ('dear [name]'), with an ownership frame ('your [vaccine] is ready for you') and a specific date, time and location is more effective than no message, and often a basic message, also on a longer-term," the authors said. 

The authors also found that text messages that prompted a "yes" or "no" response—indicating an intention to take the vaccine—moderated the effect of message variant on actual vaccine uptake, (OR, 2.86; 99% CI, 2.14 to 3.82).

Because text messages demonstrate no notable disadvantages, we advise Public Health authorities to include this effective intervention in their vaccination campaign strategies.

"Because text messages demonstrate no notable disadvantages, we advise Public Health authorities to include this effective intervention in their vaccination campaign strategies," the authors concluded. 

Of 47 animals tested at a zoo in Brazil, 9 were positive for SARS-CoV-2 RNA on reverse transcription-polymerase chain reaction (RT-PCR), with phylogenetic analysis suggesting they may have been infected by people, according to a report published yesterday in Virology Journal.

A team led by researchers from the Universidade Federal de Minas Gerais obtained oropharyngeal, rectal, and nasal swabs from 47 animals of different species at Belo Horizonte Zoo from November 2021 to March 2023.

"Zoos are unique in terms of the epidemiology of human-animal interactions," the authors wrote. "They shelter multiple species of wildlife from a wide range of taxonomic groups in relative proximity, and interactions between animals and humans are frequent, especially for animal caregivers."

Alpha, Omicron found in wolf, deer, gorilla

Roughly one fifth (19.1%) of the animals tested positive for SARS-CoV-2. Of 147 swabs, SARS-CoV-2 RNA was found in 5 rectal (10.6%), 3 oropharyngeal (6.3%), and 2 nasal (5.8%) samples.

Three genome sequences identified two variants of concern: Alpha in a maned wolf and a fallow deer and Omicron in a western lowland gorilla. Animal-genome clustering close to human samples from the same region suggested potential human-to-animal viral transmission.

The detection of different variants suggests ongoing viral evolution and adaptation in new hosts.

From November 2021 to January 2022, although the zoo restricted visitor access as an infection-control measure, three animals tested positive for SARS-CoV-2, which the researchers said suggests that infection could have occurred through contact with zookeepers.

But after the zoo reopened to visitors in February 2022, more animals tested positive, raising the question of whether visitors increased the risk of transmission to zookeepers, who may have then infected the animals through direct contact or aerosol exposure. 

"The detection of different variants suggests ongoing viral evolution and adaptation in new hosts," the researchers wrote. "Continuous monitoring and genomic surveillance of SARS-CoV-2 in wildlife are essential for understanding its transmission dynamics and preventing future zoonotic outbreaks. These findings underscore the need for integrated public health strategies that include wildlife monitoring to mitigate the risks posed by emerging infectious diseases."