Yersiniosis

Queensland Health Guidelines for Public Health Units

Revision History

Version Date Changes
 1.0 October 2024 Re-write based on updated guideline format

Infectious Agent

Yersiniosis is a collective term for zoonotic disease caused by the enteropathogenic bacteria Yersinia enterocolitica or Yersinia pseudotuberculosis. Y. enterocolitica is the species most often reported as causing human disease, while Y. pseudotuberculosis is infrequently diagnosed.1 Yersiniosis does not include illness caused by Yersinia pestis, the causative agent of plague.

Y. enterocolitica are classified phenotypically into six biotypes (1A, 1B and 2–5) (2) and more than 70 serotypes. Pathogenicity varies among the different bioserotypes. Biotypes 1B, 2, 3, 4, and 5 may carry the pYV virulence plasmid while biotype 1A lacks this plasmid and has long been regarded as non-pathogenic.3 However, recent studies have demonstrated that some Yersinia enterocolitica biotype 1A strains possess chromosomal based virulence genes that encode for enterotoxins and other factors that may cause a mild gastrointestinal illness.4-6

In Queensland, many notified cases do not have a biotype reported due to the frequency of diagnoses made via nucleic acid testing (NAT) only. For culture positive cases, the large majority (70-80%) are biotype 1A, with the remainder predominantly comprising biotype 3 strains and biotype 4 serotype O:3.7

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Case Definitions and Notification Criteria

Report confirmed cases only.

Confirmed case

A confirmed case requires laboratory definitive evidence only.

Laboratory definitive evidence

1. Isolation of Y. enterocolitica or Y. pseudotuberculosis from faeces, or blood and other normally sterile site (s)

OR

2. Detection of Y. enterocolitica or Y. pseudotuberculosis in faeces, blood, or other normally sterile site by nucleic acid testing.

Community outbreak criteria

Two or more cases epidemiologically linked to a common source by location and time of exposure.

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Notification Procedure

Pathology Laboratories

To notify on laboratory confirmation, by usual means.

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Objectives of surveillance

  1. To monitor the epidemiology of yersiniosis (Y. enterocolitica and Y. pseudotuberculosis).
  2. To identify outbreaks of yersiniosis (Y. enterocolitica and Y. pseudotuberculosis) and enable a prompt public health response.

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Public health significance and occurrence

Yersiniosis is not nationally notifiable in Australia. Routine reporting is conducted by only a few jurisdictions, including Queensland. In 2023, the notification and culture positive rates for yersiniosis in Queensland were 17.6 and 7.0 cases per 100,000 population respectively.7 This is higher than rates described elsewhere in Australia and both the European Union and United States8–10 but less than New Zealand.11

Most Y. enterocolitica and Y. pseudotuberculosis cases notified in Australia are considered sporadic with no identifiable source. Further, there is a lack of local source attribution information in Australia to guide interventions aimed at reducing disease incidence. Outbreaks due to yersiniosis remain uncommon. In 2023, an outbreak investigation in Queensland isolated Y. enterocolitica biotype 1A from milkshakes prepared in an aged-care facility.4 Internationally, outbreaks of Y. enterocolitica linked to raw salad vegetables, pasteurized milk, and pork products have also been described.12–14 Outbreaks of Y. pseudotuberculosis are rare but have been linked to raw vegetables.10,15

The ability of Yersinia bacteria to survive and grow at refrigeration temperatures (<4°C) and in vacuum-packed foods with a prolonged shelf-life is of considerable importance to food safety and public health.10,15,16

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Clinical Features

Acute yersiniosis

Yersiniosis commonly presents as an acute enterocolitis, characterised by abdominal pain, diarrhoea (occasionally bloody) and fever. Mesenteric adenitis may develop, accompanied by severe abdominal pain that mimics appendicitis.2,17 This ‘pseudo-appendicitis’ is more common in older children and adults and can lead to unnecessary appendectomy.17,18 Extra-intestinal infection such as bacteraemia is less common but may be seen among persons who are immunosuppressed or have iron loading disorders like haemochromatosis.17,18

Post-infectious sequelae

Several post-infectious sequalae are also associated with yersiniosis, most notably reactive arthritis and erythema nodosum. Reactive arthritis typically affects the wrists, knees and ankles, and usually occurs one month after the initial diarrhoeal illness, with resolution within 1–6 months.19 Erythema nodosum, manifesting as painful, raised red or purple lesions along the trunk and legs, can also occur, and usually resolves spontaneously within one month.19

Reservoir

The primary reservoir for Y. enterocolitica is thought to be pigs. Healthy pigs have been shown to be frequently colonised with pathogenic Y. enterocolitica, particularly their tonsils, but may also excrete the organism in their faeces.20 Occasionally pathogenic Y. enterocolitica strains have been isolated from other animals, including cats, dogs, cattle, horses and sheep.21 Water sources have been widely investigated, including lakes, streams and drinking water, although most strains from these sources are regarded as non-pathogenic.20Y. pseudotuberculosis is widespread among many avian and mammalian hosts, particularly rodents and other small mammals.17

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Mode of Transmission

Transmission occurs primarily via the faecal-oral route. Ingestion of bacteria may occur through:

  • Consumption of contaminated food and water
    • The main sources of human infection are assumed to be pork and pork products primarily due to the association between Y. enterocolitica and pigs.20 Occasionally, pathogenic Y. enterocolitica has been detected in vegetables and environmental water; thus, raw vegetables and untreated water are also potential sources of human yersiniosis.16
  • Direct contact with infected animals, including pigs and domestic pets is a suspected route of transmission but rarely reported in the literature.
  • Direct person to person contact is uncommon but possible if basic hand hygiene and hand washing habits are inadequate.
  • Indirect person to person transmission via blood transfusions has been documented following multiplication of bacteria in donated blood held in refrigerated storage.22

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Incubation Period

The incubation period is variable but usually between 4–6 days (range 1–14 days). Symptom onset may be more gradual compared with infections caused by other enteric pathogens.19

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Period of Communicability

There is faecal shedding for at least as long as symptoms exist, usually for 2 to 3 weeks. Untreated cases may excrete the organism for 2 to 3 months. Prolonged asymptomatic carriage has been reported in both adults and children.17

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Susceptibility

There is universal susceptibility to infection. While infectious dose is not clearly understood, it is thought to be high (>104 CFU)(1). Y enterocolitica appears to equally affect females and males. Diarrhoeal illness may be more severe in children, while reactive arthritis is more severe in adolescents and older adults, particularly those carrying the HLA-B27 gene.2,17 Systemic disease, while uncommon, occurs more often in persons who are immunocompromised or who have iron overload disorders such as haemochromatosis.2,17

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Management

Cases

Investigation

Routine case investigation is not recommended unless in the context of a public health response such as an outbreak investigation.

Management & Restriction

Adults should not return to work until diarrhoea has ceased for 24 hours. Children should not return to childcare or school until diarrhoea has ceased for 24 hours. People who work in the food industry or health care professionals should not return to work until diarrhoea has ceased for 48 hours.

Persons diagnosed with yersiniosis and experiencing gastrointestinal symptoms should avoid the following until symptoms have resolved:

  • swimming in public swimming pools
  • donating blood
  • contact with people at risk of severe disease, especially people with weakened immune systems.

Exclusion criteria need not be applied for asymptomatic cases. However, the importance of good personal hygiene should be emphasised, particularly proper handwashing among food handlers.

Treatment

Most infections are self-limiting. Antimicrobial drug therapy has not been shown to shorten the duration of uncomplicated enterocolitis or to alter the likelihood of postinfectious sequelae. Antibiotic use should be restricted to moderate to severe cases of disease.Y. enterocolitica isolates are usually susceptible to aminoglycosides, third generation cephalosporins, fluoroquinolones, tetracyclines, and trimethoprim-sulfamethoxazole and are typically resistant to first-generation cephalosporins and most penicillins.19

Contacts

Contact tracing and contact management is generally not indicated unless a common exposure source is identified.

Community outbreaks/epidemics:

Outbreaks due to yersiniosis are rare but any clusters of acute enterocolitis or appendicitis / pseudo-appendicitis should be investigated to identify a potential common exposure source. This action should be undertaken in conjunction with Environmental Health, OzFoodNet, Public and Environmental Health Reference Laboratory (PEHRL) and other agencies. Investigators should be aware that up to 21 days should be allowed for initial ‘cold’ culturing of clinical, food and environmental samples.

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Preventive measures

The preventive measures include handwashing after animal exposure, safe food handling and processing, avoiding consumption of raw pork and pork products, routine water treatment and disinfection, and screening for the pathogen in blood and blood products.

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Other resources

Yersiniosis | Health and wellbeing | Queensland Government (www.qld.gov.au)

Queensland Health Guideline for the investigation and management of suspected foodborne illness outbreaks December 2018

References

1.       Drummond N, Murphy BP, Ringwood T, Prentice MB, Buckley JF, Fanning S. Yersinia enterocolitica: a brief review of the issues relating to the zoonotic pathogen, public health challenges, and the pork production chain. Foodborne Pathog Dis. 2012;9(3):179-89.

2.       Bottone EJ. Yersinia enterocolitica: overview and epidemiologic correlates. Microbes Infect. 1999;1(4):323-33.

3.       Tennant SM, Grant TH, Robins-Browne RM. Pathogenicity of Yersinia enterocolitica biotype 1A. FEMS Immunol Med Microbiol.  2003;38(2):127-37.

4.       Colbran C, May F, Alexander K, Hunter I, Stafford R, Bell R, et al. Yersiniosis outbreaks in Gold Coast residential aged care facilities linked to nutritionally-supplemented milkshakes, January-April 2023. Commun Dis Intell (2018). 2024;48.

5.       Palau R, Bloomfield SJ, Jenkins C, Greig DR, Jorgensen F, Mather AE. Yersinia enterocolitica biovar 1A: An underappreciated potential pathogen in the food chain. Int J Food Microbiol. 2024;412:110554.

6.       Platt-Samoraj A. Toxigenic Properties of Yersinia enterocolitica Biotype 1A. Toxins (Basel). 2022;14(2).

7.       Public Health Intelligence Branch. Queensland OzFoodNet Annual Surveillance Report 2023. Queensland: Department of Health;      2023.

8.       Chakraborty A, Komatsu K, Roberts M, Collins J, Beggs J, Turabelidze G, et al. The descriptive epidemiology of yersiniosis: a multistate study, 2005-2011. Public Health Rep. 2015;130(3):269-77.

9.       Disease Surveillance & Investigation Section. 2021 Annual Report. Adelaide: Communicable Disease Control Branch, SA Health.;    2023.

10.     European Centre for Disease Prevention and Control (ECDC). Yersiniosis. In ECDC Annual Epidemiological Report for 2022. Stockholm: ECDC; 2024.

11.     The Institute of Environmental Science and Research Ltd (ESR). Notifiable Diseases in New Zealand: Annual Report 2022. Porirua, New Zealand: ESR; 2024.

12.     Grahek-Ogden D, Schimmer B, Cudjoe KS, Nygard K, Kapperud G. Outbreak of Yersinia enterocolitica serogroup O:9 infection and processed pork, Norway. Emerg Infect Dis. 2007;13(5):754-6.

13.     Gruber JF, Morris S, Warren KA, Kline KE, Schroeder B, Dettinger L, et al. Yersinia enterocolitica Outbreak Associated with Pasteurized Milk. Foodborne Pathog Dis. 2021;18(7):448-54.

14.     MacDonald E, Heier BT, Nygard K, Stalheim T, Cudjoe KS, Skjerdal T, et al. Yersinia enterocolitica outbreak associated with ready-to-eat salad mix, Norway, 2011. Emerg Infect Dis. 2012;18(9):1496-9.

15.     Williamson DA, Baines SL, Carter GP, da Silva AG, Ren X, Sherwood J, et al. Genomic Insights into a Sustained National Outbreak of Yersinia pseudotuberculosis. Genome Biol Evol. 2016;8(12):3806-14.

16.     Bari ML, Hossain MA, Isshiki K, Ukuku D. Behavior of Yersinia enterocolitica in Foods. J Pathog. 2011;2011:420732.

17.     Gould LH., Griffin P. Yersiniosis. In: Heymann D, editor. Control of Communicable Diseases Manual. 20th ed. Washington: American Public Health Association; 2015.

18.     Fonnes S, Rasmussen T, Brunchmann A, Holzknecht BJ, Rosenberg J. Mesenteric Lymphadenitis and Terminal Ileitis is Associated With Yersinia Infection: A Meta-analysis. J Surg Res. 2022;270:12-21.

19.     Nemhauser J, LaRocque R, Alvarado-Ramy F, Angelo K, Ericsson C, Gertz A, et al. CDC Yellow Book 2024: Health Information for International Travel. In: Nemhauser JB, editor. CDC Yellow Book 2024: Health Information for International Travel: Oxford University Press; 2023. p. 0.

20.     Fredriksson-Ahomaa M, Stolle A, Korkeala H. Molecular epidemiology of Yersinia enterocolitica infections. FEMS Immunol Med Microbiol. 2006;47(3):315-29.

21.     Fredriksson-Ahomaa M, Korte T, Korkeala H. Transmission of Yersinia enterocolitica 4/O:3 to pets via contaminated pork. Lett Appl Microbiol. 2001;32(6):375-8.

22.     Guinet F, Carniel E, Leclercq A. Transfusion-transmitted Yersinia enterocolitica sepsis. Clin Infect Dis. 2011;53(6):583-91.


Last updated: 18 February 2025