Seven E. coli and 13 Cryptosporidium outbreak investigations in England and Wales required APHA assistance in 2024, according to a recent report.
The Animal and Plant Health Agency (APHA) was part of seven Shiga toxin-producing E. coli (STEC) investigations with two each in the first and second quarters of 2024, and three during the third quarter. There were three STEC O26 and two STEC O157 investigations epidemiologically linked to open farms; and two STEC O145 incidents traced to high-risk foods.
An STEC O26 outbreak, which began in early 2024, was caused by animal contact at a farm visitor attraction. E. coli O26 was detected in animal feces samples, which on further characterization with sequencing, was found to be the same strain as human isolates. Sampling was done for a STEC O157 outbreak in the third quarter, which detected the human outbreak strain in four animal feces samples.
An STEC O145 outbreak was caused by domestic apollo lettuce in pre-packed sandwiches. Almost 290 people fell sick and seven developed a serious kidney condition called Hemolytic Uremic Syndrome (HUS). Another STEC O145 outbreak was linked to unpasteurized milk but officials have not made public how many people fell ill.
For outbreaks linked to milk and milk products, APHA advises that the farmer ensure milking routines and dairy hygiene are improved. Unpasteurized, raw milk can be a source of a range of microorganisms, so optimized routines and hygiene in the handling of milk, including all equipment and bottles, are important.
Cryptosporidium incidents
During 2024, APHA assisted with 13 cryptosporidiosis investigations including 12 during the second quarter and one in the fourth quarter, which was a premises that was investigated in the second quarter. Two outbreaks had both Cryptosporidiosis and STEC cases. One involved STEC O157, the other STEC O26.
Eleven outbreaks were epidemiologically linked to farms in England and one to a farm in Wales. There were four APHA advisory visits and three involved sampling.
For the combined outbreaks, 10 E. coli O157 isolates from animal feces samples were identical to the human outbreak strain.
Some farm visitor attractions were offering cuddling of young lambs and piglets to visitors. This involves close contact, with potential for clothing and footwear contamination. APHA said activities like these increase the risk of transmission of a range of organisms.
April to June is traditionally the busiest time for cryptosporidiosis investigations and is related to the frequency of open farm visits by families or school groups around Easter and bank holidays.
In 2024, the UK Health Security Agency (UKHSA) investigated 16 outbreaks of Cryptosporidium linked to farm visits, which resulted in hundreds of infections. One large outbreak in the South East affected more than 400 people who visited a lamb handling and feeding event.
Contact with young lambs either through bottle-feeding or handling is a high-risk activity for the spread of Cryptosporidium parvum. APHA said the availability of appropriate and suitably located handwashing facilities including soap, rather than antimicrobial gel, which is not effective for this pathogen, is extremely important.
The most frequently identified deficiencies at animal contact attractions include poor handwashing facilities; suboptimal supervision of animal contact; contamination of walkways with soiled animal bedding or feces; and unclear marking of animal contact versus non-contact areas.
For Coxiella burnetii, which causes Q fever, APHA provided advice during one incident management team meeting regarding a dairy farm that was selling unpasteurized milk. There were no human outbreaks of Q fever epidemiologically linked to farms in 2024.
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