THE DIFFERENTIAL LEUKOCYTE COUNT ASSOCIATED WITH HOOKWORM INFECTION

Although there is ample evidence to support the widespread belief that eosinophilia occurs in cases of hookworm infection, there is equally valid evidence that infections with this parasite may occur without any increase in the number of eosinophils in the peripheral circulation. The most striking instances of eosinophilia have been associated with acute infections. Ashford, Payne and Payne¹ reported percentages of eosinophils ranging from 62 to 91 in cases of acute massive infections with the European (Old World) hookworm, Ancylostoma duodenale, in previously well nourished, normal white children and adults in Puerto Rico. These patients were effectively treated with hexylresorcinol, and within a year after infection the eosinophil counts had dropped to as low as 6 per cent and in no case were above 33 per cent. Likewise, Boycott and Haldane² reported percentages of eosinophils ranging from 17 to 72 for English miners with relatively recent infections with