Gastrointestinal parasite infections in Nepalese Gurkha recruits arriving in the United Kingdom from 2012–2020

Background: Gastrointestinal parasite (GIP) infections are a major cause of global morbidity, infecting hundreds of millions of people each year and potentially leading to lifelong infection and serious complications. Few data exist on screening for GIP infections in migrants entering the UK or on the current performance of different traditional diagnostic approaches. Methodology/Principal findings: We present a retrospective analysis of data from screening male adults (18–21 years) who arrived in the UK from Nepal between 2012 and 2020. Three separate faecal samples were obtained from participants at weekly intervals and processed for formalin-ethyl acetate (FEA) concentration/light microscopy and charcoal culture. Serum samples were analysed for IgG antibodies to Strongyloides stercoralis by ELISA. Conclusions/Significance: The level of potentially pathogenic GIP infection in young Nepalese men migrating to the UK is high (20.5%) and requires a combined diagnostic approach including serology and analysis of multiple stool samples incorporating specialised parasitological methods. Advances in molecular approaches may optimise and simplify the intensive screening strategy required. Author summary: Gastrointestinal parasite (GIP) infections caused by protozoa and helminths affect hundreds of millions of people worldwide, resulting in significant morbidity, but remain neglected in terms of diagnosis and management. Migrant and refugee populations are rarely offered screening for GIP infection in the UK, but providing this can create opportunities for treatment, as well as to gather valuable epidemiological data. We present a retrospective analysis of screening for gastrointestinal parasites in 2,263 young Nepalese men arriving in the UK as military Gurkha recruits, using a range of conventional diagnostic methods. The presented study is one of the largest reported and most complete approach to GIP screening in a homogeneous migrant population, finding high rates of GIP infection. When conventional diagnostic methods of light microscopy and charcoal culture are used, we found serial stool collection in combination with serological assessment for Strongyloides sp. is required to achieve satisfactory results, as opposed to a single stool examination.