Abstract
ObjectivesTo summarise age- and intensity-stratified associations between human hookworm infection and anaemia and to quantify the impact of treatment with the benzimidazoles, albendazole and mebendazole, on haemoglobin and anaemia in non-pregnant populations.MethodsElectronic databases (MEDLINE, EMBASE, PubMed) were searched for relevant studies published between 1980 and 2009, regardless of language, and researchers contacted about potential data. Haemoglobin concentration (Hb) was compared between uninfected individuals and individuals harbouring hookworm infections of different intensities, expressed as standardised mean differences (SMD) and 95% confidence intervals (CI). Meta-analysis of randomised control trials (RCTs) investigated the impact of treatment on Hb and anaemia.ResultsTwenty-three cross-sectional studies, six pre- and post-intervention studies and 14 trials were included. Among cross-sectional studies, moderate- and heavy-intensity hookworm infections were associated with lower Hb in school-aged children, while all levels of infection intensity were associated with lower Hb in adults. Among RCTs using albendazole, impact of treatment corresponded to a 1.89 g/l increase (95%CI: 0.13–3.63) in mean Hb while mebendazole had no impact. There was a positive impact of 2.37 g/l (95%CI: 1.33–3.50) on mean Hb when albendazole was co-administered with praziquantel, but no apparent additional benefit of treatment with benzimidazoles combined with iron supplementation. The mean impact of treatment with benzimidazoles alone on moderate anaemia was small (relative risk (RR) 0.87) with a larger effect when combined with praziquantel (RR 0.61).ConclusionsAnaemia is most strongly associated with moderate and heavy hookworm infection. The impact of anthelmintic treatment is greatest when albendazole is co-administered with praziquantel.
Highlights
Hookworms (Necator americanus and Ancylostoma duodenale) reside in the small intestine of infected individuals where they attach themselves to the villi and feed on host blood
We summarise available data from randomised control trials (RCTs) and pre- and post-intervention observational studies that compared the effects of benzimidazole treatment, either alone or in combination with the anti-schistosomal drug praziquantel, on Haemoglobin concentration (Hb) and anaemia levels
Prevalence estimates for hookworm infection ranged from 0.3 to 96%, with 12.5% of the surveys having a mean intensity of infection >1000 epg and eight studies having no individuals with infection intensity >2000 epg
Summary
Hookworms (Necator americanus and Ancylostoma duodenale) reside in the small intestine of infected individuals where they attach themselves to the villi and feed on host blood. The link between hookworm and anaemia was first established in the nineteenth century (Perroncito 1880), and during the subsequent 130 years, there have been numerous reviews of the extensive literature in this area (Layrisse & Roche 1964; Miller 1979; Schad & Banwell 1984; Crompton & Stephenson 1990; Crompton & Whitehead 1993; Stoltzfus et al 1997; Brooker et al 2004; Hotez et al 2004). There is a direct relationship between the number of hookworms an individual harbours (the intensity of infection) and the amount of intestinal blood lost attributable to hookworm Brooker Impact of hookworm infection and deworming on anaemia volume 15 no 7 pp 776–795 july 2010
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