The epidemiology of hookworm infection and its contribution to anaemia among pre-school children on the Kenyan coast

Abstract

Intestinal nematode infections are recognized as a major public health problem, and helminth control is currently being directed towards school-aged children who are known to harbour the heaviest infections and are most likely to suffer from associated morbidity. However, few data are available for the epidemiology of intestinal nematodes in pre-school children in Africa, and the contribution of hookworm infection to the aetiology and severity of anaemia among pre-school children remains poorly understood. This paper investigates the epidemiology of parasitic infections in 460 pre-school children who were part of a larger case-control study of severe malaria in Kilifi on the Kenyan coast. Almost one-third (28.7%) were infected with hookworm, 20.2% with Ascaris lumbricoides and 15.0% with Trichuris trichiura. Infection prevalence of each species rose with age, and the prevalence of heavy infection with hookworm and mean intensity of hookworm were markedly age-dependent. One-third (34.3%) of children had malaria. Overall, 76.3% of children were anaemic (haemoglobin < 110 g/L), with the prevalence decreasing with age. Anaemia was significantly worst in children with heavy hookworm infection (> 200 eggs per gram). This relationship held for all ages, both sexes, and was independent of socioeconomic factors. The application of attributable morbidity methods confirmed the contribution of hookworm infection to anaemia.

Intestinal parasitic infections among under-five children and maternal awareness about the infections in Shesha Kekele, Wondo Genet, Southern Ethiopia

“…However, in contrast to a previous study conducted in other intestinal schistosomiasis endemic areas of Ethiopia (18), the present study revealed high prevalence of Schistosoma mansoni infection among under-five children. The trend of infections with the different parasites was found to increase with age, in agreement with the observation among under-five children in Kenya (21).…”

Hemoglobin concentration in children in a malaria holoendemic area is determined by cumulated Plasmodium falciparum parasite densities.

“…35 Light hookworm infections have been implicated as a cause of anemia in populations with poor iron status, but in children Ͻ 3 years, hookworm egg counts rarely reach the concentration known to affect Hb concentration. 3,5 Although additional stool samples may have detected a few more infected children, in this cohort of anemic children hookworm infection was most likely of inferior importance.…”

“…Blood was collected on 1,540 occasions in the 211 study subjects, corresponding to a median of seven observations per child (range [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. A median of four (IQR 3-4) blood collections were made in children with no clinical malaria episodes recorded during the study.…”

“…1 The main contributory causes of anemia are infectious diseases, nutritional disorders, and hemoglobinopathies. 2 Some investigators cite an iron-deficient diet, hookworm infection, or schistosomiasis as important causes for anemia, [3][4][5] while others have identified malaria as the primary cause. Cross-sectional data have shown deterioration in hemoglobin (Hb) concentration during malaria transmission and an improvement in Hb with the administration of malaria chemoprophylaxis or insecticide-treated bed nets.…”

Relative prevalence of the human hookworm species, Necator americanus and Ancylostoma duodenale in an urban community in Ogun State, Nigeria

“…However, the rational design of hookworm control strategies requires, among other things, knowledge of the species infecting a particular human population in order for treatment to be successful in the long term. Most studies do not attempt to speciate hookworm infections and rely on past epidemiological data, which indicate the predominance of one species over the other (Brooker et al, 1999), because the eggs of the 2 species are similar and not readily distinguishable from one another by classical parasitological methods (Hawdon, 1996).…”