It can replicate at low temperatures which means that it can multiply in refrigerated foods. Heating food to 60o kills the organism.
Human infection is usually by one of the following routes :
Humans most often contract the infection from :
Human workers most at risk to contract this infection are :
People develop abdominal pain, diarrhoea, fever, septicaemia and skin rashes which are similar to, and therefore can be confused with, the clinical signs of appendicitis. With Yersinia pestis infection they also develop pneumonia , lymphadenopathy and disseminated intravascular coagulation (DIC).
Y. pseudotuberculosis causes diarrhoea in many species during winter and spring - the incidence of Yersinia infection seems to be more prevalent during cold weather.
In cats and dogs Y. enterocolitica is thought to be a non-pathogenic commensal, but it causes illness in people…possibly transmitted from household pets. This organism has been isolated occasionally from young dogs with clinical signs of colitis.
In cats pyogranulomatous lesions involving the intestinal tract, liver and lymph nodes has been described associated with Y.pseudotuberculosis, and this may be progressive and fatal.
Feline plague caused by Y.pestis occurs in many countries in Africa, Asia and the Americas, including the Western States of the USA. Rodents including ground and rock squirrels and prairie dogs are the natural hosts. In addition, rodent fleas (eg rabbit fleas) may transmit the organism to cats and people. Fleas can remain infected for many months. Following the bite of an infected flea the incubation period of the disease in the cat is 2-6 days, whereas it is 1-3 days following the ingestion of an infected rodent.
Clinical signs include :
In Guinea pigs - Y. pseudotuberculosis causes an illness which may either :
In humans Yersiniosis causes :
Isolation of the organism from faeces does not necessarily confirm it is a cause of disease as it is often found in normal animals. Isolation from deep tissues (lymph nodes, wounds) urine or blood is much more likely to be significant. A special culture medium is needed to grow Yersinia.
Dogs - postmortem - chronic enteritis with mononuclear and plasma cell infiltration
Cats - postmortem- focal microabscesses and microthrombosis in the liver and spleen.
Guinea pigs - culture of Y.pseudotuberculosis from blood (septicaemia) or lymph nodes. At post-mortem get enlarged lymph nodes (mesenteric and abdominal) and focal necrosis of the liver and spleen.
Guinea pigs - because of the zoonosis risk , euthanasia is recommended. Sterilise habitat if it is to be re-used.
Long term problems
Updated October 2013