Several species of bacteria in the genus Yersinia are known to cause infections in humans. These illnesses can be referred to by the collective name yersiniosis.
The bacterium Yersinia enterocolitica is responsible for the majority of yersiniosis cases in the United States. The bacterium usually enters the body from contaminated meat, milk or water. The infection is most often diagnosed in young children.
There’s some evidence that Yersinia bacteria have contributed to the onset of Crohn’s disease (an autoimmune condition of the gut) in some patients. A Yersinia bacteria infection may also lead to reactive arthritis, which occurs when the inflammation caused by the bacteria spreads to the joints from other tissues.
Nevertheless, yersiniosis isn’t limited to humans. It can also affect a variety of animals, including cattle, deer, pigs and some birds.
Signs and Symptoms of Yersinia Bacteria Infection
Yersiniosis can manifest in a number of ways. The exact symptoms depend largely on the patient’s age. Children normally present with fever, abdominal pain and diarrhoea, which often contains blood.
The first signs of the infection tend to develop within four to seven days after exposure to the bacteria. Symptoms usually last between one to three weeks, although in some cases they take longer to completely go away.
Some people with yersiniosis also experience nausea, vomiting and mesenteric lymphadenitis (an inflammation of the lymph nodes). Since stomach aches are often felt more strongly on the right side, it’s common for the illness to be misdiagnosed as appendicitis.
Complications of yersiniosis are rare. A few patients develop a skin rash, joint pains, ileitis (an inflammation of the ileum, a part of the small intestine) or erythema nodosum (swollen fat under the skin causing red patches and lumps). An extremely small proportion of patients experience sepsis, which is a life-threatening overreaction of the immune system to an infection.
Abdominal pain is a common symptom of Yersinia bacteria infection in both children and adults.
How To Treat Yersinia Bacteria Infection
In the majority of cases, treatment for symptoms of gastroenteritis (abdominal pain, diarrhoea and vomiting) isn’t needed. If the infection persists for longer than three weeks or if there are any serious complications, antibiotic therapy may be necessary.
Drugs of choice are typically doxycycline and aminoglycoside. Alternatives include cefotaxime, fluoroquinolones and co-trimoxazole.
Diagnosing Yersinia Infection
The conventional diagnostic test for yersiniosis is a stool culture. The aim of this method is to determine whether the bacteria are present in the patient’s faeces.
Other traditional tests include tube agglutination, radioimmunoassays, enzyme-linked immunosorbent assays, colonoscopy and computed tomography (CT) scans. Doctors sometimes consider joint aspiration when suspecting that a joint disorder may be the result of a Yersinia infection.
A modern and highly effective diagnostic technique is ELISpot. This test gives doctors a more accurate picture of the infection by determining the activity levels of any Yersinia bacteria present in the body.
The Connection Between Yersinia Bacteria and Lyme Disease
Yersinia bacteria and Lyme are related in that yersiniosis is a possible co-infection, as well as differential diagnosis, of Lyme disease. Also known as Lyme borreliosis, it’s an infectious disease caused by the bacterium Borrelia burgdorferi. It’s one of the most common tick-transmitted illnesses in the world.
The infection is the easiest to recognise when a distinctive rash called ‘erythema migrans’ appears at the site of the bite. The rash usually presents as a slowly expanding red area in the shape of a bull’s eye. It tends to appear within the first few weeks after the infecting tick bite. However, in approximately 20–30% of Lyme patients no rash is observed, making the illness difficult to diagnose.
If left untreated for a long time, Lyme disease may lead to serious neurological, heart and joint symptoms. The earlier it’s diagnosed, the easier it is to cure completely with a course of oral antibiotics.
One tick can carry more than one infection. Therefore, the same parasite that transmits Lyme-causing bacteria may also pass on other illnesses at the same time.
The clinical impact of these co-infections has been well-documented since the 1990s. Still, they’re often overlooked, because they can imitate the symptoms of Lyme disease. Patients may acquire co-infections via routes other than a tick bite, such as contaminated food and water, like in the case of yersiniosis.
Contaminated food and water can also transmit Yersinia bacteria infections, as well as ticks.
Yersiniosis As a Differential Diagnosis of Lyme Disease
Lyme disease may be mistaken for yersiniosis, and vice versa. The two conditions share some symptoms, such as joint pain, swelling and stiffness.
Although reactive arthritis is quite rare in yersiniosis patients, it does sometimes occur. Borrelia burgdorferi can also spread to the joints when the infection isn’t recognised in time. Lyme disease may become chronic if the bacteria travel to different tissues and organs when the immune system weakens due to another illness, stress or other environmental factors.
Thyroiditis may also present as a complication of yersiniosis. It has also been seen in patients with chronic Lyme disease, as a result of a widespread inflammation that can affect the thyroid gland.
It’s important to see your doctor if you experience any of the symptoms of Yersinia bacteria infection or Lyme disease. They will assess your likelihood of having contracted the infections and carry out any appropriate diagnostic tests.