Overall findings of Salmonella in livestock in the United Kingdom in 2020 went up, according to a report.

Data covers Salmonella reports from livestock in England, Wales and Scotland collected by the Animal and Plant Health Agency (APHA) during 2020. Samples were taken from premises including farms, hatcheries, veterinary practices, zoos and slaughterhouses.

The rise came despite a reduction in non-statutory surveillance and clinical diagnosis submissions in many species because of the COVID-19 pandemic and associated lockdown measures.

The document revealed 5,263 lab reports of Salmonella from humans were sent to Public Health England, Public Health Wales and Public Health Scotland in 2020. This is 45 percent lower than the 9,588 isolations in 2019 and 48 percent down from 10,143 in 2018.

Salmonella by animal and type
In 2020, the number of Salmonella isolations overall from cattle, sheep, pigs and poultry increased by 7.6 percent compared with 2019 to 3,279 from 3,046 isolations but decreased by 7.3 percent on 2018 numbers.

Compared to 2019, fewer isolations from cattle, sheep, turkeys and ducks were recorded, but those for pigs and chickens rose. Most Salmonella reports from cattle, sheep and pigs are because of clinically diseased animals wheras those from chickens and turkeys are mostly from surveillance.

There were 52 isolations of Salmonella Newport in chickens, which is more than 10 times the number in 2019. Many of these were from an ongoing outbreak investigation in the layer sector. A single isolate of Salmonella Mikawasima — not related to a human outbreak strain — was isolated from chickens in the UK for the first time. The presence of one strain of Salmonella indicates others may be present.

There were two and a half times more isolations of Salmonella Agona with 103 in 2020 versus 40 in 2019, twice as many of Salmonella Bovismorbificans from 20 to 43 and almost three times as many Salmonella Newport isolations to 66. Salmonella Kedougou also went up. Isolations of Salmonella Typhimurium increased from 124 in 2019 to 159.

There were fewer isolations of Salmonella Derby from 183 to 39, Salmonella Indiana fell from 101 to 65 and Salmonella Mbandaka dropped from 451 to 326. Reports of Salmonella Enteritidis were at 34 in 2020 compared with 50 in 2019.

A total of 3,527 isolations of Salmonella from livestock in 2020 were noted, which is up almost 3 percent from 2019. They mostly came from chickens, followed by cattle, ducks, turkeys, pigs, sheep and horses.

Two isolations were found in geese compared with none the year before. The figure went down for horses to 41. There were only a few from pheasants and partridge and none from quail, guinea fowl, deer, goats or rabbits. Almost 180 isolations were made from non-statutory species such as cats, dogs and reptiles.

Feed findings
Surveillance data for 2020 shows that only 23.1 percent of the isolations of Salmonella reported to APHA resulted from samples taken because of clinical disease in livestock. This is lower than during both 2019 and 2018. It contrasts with data for Salmonella in humans wher reports usually originate from cases of clinical disease.

There were 756 isolations of Salmonella from animal feeding stuffs in 2020, including from compound feed and feed ingredients or products associated with testing under animal by-products regulations. This is an increase of 6 percent compared with 2019 and up from 627 isolations in 2018.

In total, 107 isolations of regulated Salmonella serovars were detected in animal feed and related products. This is higher than the 88 in 2019 and 63 in 2018.

There were 273 isolations of Salmonella from pet food intended to be fed raw during 2020. This is 11.4 percent higher than 2019 and 45.2 percent higher than 2018. A total of 62 isolations were of regulated serovars from raw pet food, which is up from 38 in 2019 and 35 in 2018. Pet food, especially raw foods, can infect people through cross-contamination of utensils and surfaces, as well as inadequate hand washing.

Of the more than 4,200 Salmonella isolates examined during 2020, 68.3 percent were susceptible to all 16 antimicrobial compounds tested. The percentage of isolates resistant to ciprofloxacin in 2020 was 0.5 percent.