Anemia, leukocytosis and eosinophilia in a resource-poor population with helmintho-ectoparasitic coinfection.

INTRODUCTION Eosinophilia and anemia are very common hematological alterations in the tropics but population-based studies scrutinizing their value for diagnosing parasitic infections are rare. METHODOLOGY A cross-sectional study was conducted in a rural district in northeast Brazil where parasitic infections are common. Stool and blood samples were collected and individuals were clinically examined for the presence of ectoparasites. RESULTS In total, 874 individuals were examined. Infection with intestinal helminths occurred in 70% (95% CI 67 - 75), infestation with ectoparasites in 45% (95% CI 42 - 49) and co-infection with both helminths and ectoparasites was found in 33% (95% CI 29% - 36%) of all inhabitants. Eosinophil counts ranged from 40/µl to 13.800/µl (median: 900/µl). Haemoglobin levels ranged from 4.8 g/dl to 16.8 g/dl (median: 12.5 g/dl), and anemia was present in 24% of the participants. Leukocytosis was found in 13%, eosinophilia in 74%, and hypereosinophilia in 44% of the participants. Eosinophilia was more pronounced in individuals co-infected with intestinal helminths and ectoparasites (p < 0.001) and correctly predicted parasitic infection in 87% (95% CI 84%-90.7%) of all cases. CONCLUSIONS Eosinophilia is strongly associated with the presence of intestinal helminthiases and accentuated by co-infestation with ectoparasites. Our study confirms in a population with high prevalence of intestinal helminthiases and ectoparasites that eosinophilia can be used to accurately diagnose current parasitic infection and initiate treatment.