Asymptomatic Peripheral Blood Eosinophilia Redux: Common Parasitic Infections Presenting Frequently in Refugees and Immigrants

Abstract

Although the causes of peripheral blood eosinophilia are myriad, eosinophilia in refugees or immigrants from many parts of the world is most often a reflection of parasitic helminth (worm) infection. Soiltransmitted helminth infection affects more than 1.5 billion persons worldwide. If schistosome and filarial infections are added into the equation—even accounting for polyparasitism—this number reaches 12 billion persons. Thus, it stands to reason that many refugees and immigrants from areas where parasitic helminth infections are endemic present to clinicians with eosinophilia. The number of refugees (defined as individuals seeking refuge or asylum from their native country, typically because of persecution or fear of persecution) who came to the United States increased dramatically between 1980 and 2000 [1]. Although the number of refugees who come to the United States has diminished slightly in the past 5 years, the total number of all immigrants has increased, particularly the number of those from Africa and the tropical and subtropical regions of Asia. As a consequence, the health concerns of the immigrant and refugee populations have fallen on the shoulders of the community health systems in the cities and nearby regions that harbor these newly arrived people. The health problems likely to be encountered in this population include not only infectious diseases (e.g., latent tuberculosis, hepatitis B, intestinal parasites, and HIV infection), but also depression, other psychological disorders, anemia, dermatological conditions, dental problems, and trauma-induced injuries [2‐6]. This information has been widely disseminated, and those who screen refugees and immigrants have become quite aware of which medical conditions they need to monitor routinely.