A review of human alveolar echinococcosis in the Republic of Armenia from 2008 to 2020

BACKGROUND: Since the 90s' Echinococcus multilocularis infection has expanded the geographical area and central-eastern European countries had seen first alveolar echinococcosis (AE) human cases. AE is considered to be a very rare disease in Europe with average incidences of 0.03–0.2/100,000 inhabitants/year. Because of a suitable orography, this study aims to confirm whether there are human AE cases in Armenia, identify areas at risk, and also estimate AE annual incidence. METHODS: Retrospective AE case finding was carried out at main multi-profile medical centers equipped with the modern diagnostic means. The medical records of all patients with liver surgery admitted between January 2008 and June 2020 were reviewed. A specific form was developed in EpiInfo v.7.2. Annual national incidence was estimated using population denominators provided by the National Institute of Statistics. RESULTS: Overall, 11 AE cases have been identified. All patients were diagnosed at advanced stages, with subsequent poor prognosis and costly treatment. Confirmation was based on tissue biopsy and medical imaging results. Age ranged from 12 to 58 years with a median of 33 yrs. Patients were from rural communities, mostly in the Gegharkunik region (6 cases, 55%). Annual average incidence of AE was 0.033/100,000 varying between 0.032 in 2008 and 0.1 in 2017. CONCLUSIONS: There are human AE cases happening in Armenia since more a decade ago. In the absence of an AE surveillance system, the burden of AE disease is difficult to estimate. Development of national AE guidelines with a case definition should help enforcing registry of all cases, early diagnosis and also clinical and public awareness.