Tropical anaemia can have multiple causes, whether socio-economic, dietary or infectious. In the Bolivian Chaco, soil-transmitted helminthiases (STH), malaria and Chagas disease are potential infectious causes of anaemia among school-aged children (SAC). Following years of preventive chemotherapy with mebendazole, the prevalence of STH among SAC living in that area is now negligible, while protozoan infections are still highly prevalent (81%); Hymenolepis nana is the most frequent intestinal helminth (~13%). We present results of haemoglobin (Hb) assessment and the association between parasitic infections and Hb levels of that SAC population. Overall, 511 SAC (girls:boys ratio 1:1, mean age 9.4 years (95%CI 9.3-9.5)) had Hb levels measured by using a portable Hb system HB 301+ (HemoCue1 AB, Angelhome, Sweden). The prevalence of anaemia was 23% (117/511), with mean and median Hb level = 12.2 g/dl (95%CI 12.1-12.3; range 9.2-15.4 g/dl). By multivariate analysis, H. nana infection was associated with an increased risk of anaemia (OR 2.9, 95%CI 1.5-5.7, p=0.002). Two samples (0.5%) were positive for T. cruzi and none for Plasmodium spp by polymerase chain reaction (PCR) of the 439 children tested.
Anaemia is still a concern among SAC living in the Bolivian Chaco. Our findings call for a greater attention to faecal-oral emerging pathogens, such as H. nana, and highlight the importance of water, sanitation and hygiene improvements for disadvantaged population such as those living in the Bolivian Chaco.