Amoebiasis

Entamoeba species are endobiotic amoebae-colonizing animal primarily in the intestinal tract, where they divide and encyst. While most Entamoeba infections in humans appear to be caused by non-pathogenic species, Entamoeba histolytica can express virulence in human and is the causative agent of amoebiasis, responsible for dysentery and liver abscesses. Amoebiasis is the third parasitic disease, after malaria and schistosomiasis, causing death in the world, along with a significant gastrointestinal morbidity, malnutrition and mortality worldwide. According to the Global Burden of Disease Study 2010, the parasitosis was responsible for 2.2 million disability-adjusted life years, with an annual mortality estimated at 100,000 cases. Approximately 90% of infected individuals are asymptomatic carriers, but 1% of infected individuals develop the invasive form of the disease, which can be intestinal or extra-intestinal according to clinical presentation and districts involved in the infection. Vascular involvement was described in cases affected by amoebiasis, secondary to the histolytic features of the enzymes produced during the trophozoites invasion. Among these enzymes, the cysteine proteases produced by Entamoeba histolytica (E. histolytica) can amplify interleukin-1-mediated inflammation, attracting neutrophils and macrophages to the site of amoebic invasion. This mechanism suggests a potential contribution of the inflammatory damage to the vascular wall and aneurysm formation. Hepatic pseudo-aneurysm affecting patients with amoebic liver abscesses was described in occasional reports, but the aortic involvement co-occurring with intestinal amoebiasis and coronary aneurysm in paediatric patients with co-occurring Kawasaki diseases were also occasionally observed. The endovascular approach with pseudo-aneurysm embolization was described as effective in patients with hepatic involvement and a surgical indication. A timely parasitological diagnosis is essential to plan a good pharmacological and surgical management, emphasizing that clinicians must include amoebiasis in the differential diagnosis of patients with vascular presentation, intestinal symptoms and a positive history of potential exposure to Entamoeba. Further studies are needed to better understand this non-communicable vascular complication of a disease of parasitological interest.