GSTM1 and schistosomiasis: On the other hand, the difference in anemia prevalence (Hb < 11 g/dL) was significant between the two groups 6 months after the net distribution in the Uganda study, but the effect was weaker later except in the areas where OlysetPlus was distributed.21 The inconsistency may be due to various factors, such as coinfection with schistosomiasis, which is particularly common in the present study area and the lake region of Uganda.59,60 Nevertheless, the results from the three studies confirmed that use of PBO-LLINs also improves anemia related to Plasmodium parasite infection.