Illustrative case series of eosinophilia in UK Armed Forces personnel and recommended management for non-specialists

Peripheral eosinophilia (>0.5×10⁹/L) in the full blood count is caused by a variety of infectious and noninfectious aetiologies. Of particular importance to the UK military are parasitic infections, especially in individuals recruited from overseas and those who have deployed to areas that are highly endemic for schistosomiasis, strongyloidiasis and soil-transmitted helminths. These infections may persist for decades without causing symptoms. UK Armed Forces (UKAF) personnel have recently presented with more severe forms of strongyloidiasis, which can be fatal, especially following immunosuppression for chronic non-communicable diseases. Most uncomplicated infections respond to oral ivermectin or oral praziquantel, which are easy to take and generally well tolerated. We present the histories of three UKAF personnel to raise awareness of these infections, and we describe a framework for the initial investigation and management of people found to have eosinophilia in military primary care settings, together with indications for onward referral to infection or haematology specialists. Furthermore, given their relatively unknown prevalence in the UKAF Forces population, increased awareness and seroprevalence studies may be beneficial.