Our study investigated efficacy of combined school based antihelminthic treatment with Praziquantel and albendazole; prompt malaria treatment and health education in control of schistosomiasis, STHs, malaria and on suppression of helminths - Plasmodium co-infections. Results from our study demonstrate that two rounds of deworming and sustained prompt malaria treatment significantly reduce the proportions of children with helminths -Plasmodium falciparum co-infections. The observed low level of helminths-Plasmodium falciparum co-infection during the proceeding 21 months (almost 2 years) could have been due to the initial combined treatment intervention and school based health education leading to change of children's behaviour towards the preventive practices. Thus the intervention could be promising as it managed to reduce the proportion of helminths-Plasmodium falciparum co-infection, hence the multiplicative effect of co-infection on malaria clinical outcomes and morbidity [17, 20, 27, 28, 49, 50].
If similar but large scale intervention could demonstrate similar results to our study then application of such a strategy in helminths -Plasmodium falciparum co-endemic areas would result in reduction of morbidity associated with helminths Plasmodium falciparum co-infections or helminths co-infections [29, 30, 32–34]. Successful implementation of such a strategy at national level in endemic countries could be a cost effective way of delivering drugs for treatment of multiple diseases affecting primary school children. Reduction of morbidity due to polyparasitism resulting from combined school based drug administration and prompt malaria treatment could contribute towards achievement of the Millennium Development Goals number 2 and 6: Universal primary education and disease eradication, respectively [16, 36, 40]. The pragmatic target set by the World Health Organisation: to regularly treat at least 75% of primary school children at risk of morbidity due to schistosomiasis and STHs by the year 2010  could also be achieved. However the set target could be achieved later than 2010 since until only a few of the endemic countries has mapped areas with overlapping NTDs or helminths - Plasmodium falciparum co-infections for control [16, 37, 41, 52].
The observed higher prevalence of co-infection with schistosomes + STHs in Burma Valley farming area following 21 months of delayed treatment than that observed at pre-treatment survey as well as the unprecedented increase in prevalence of S. mansoni and hookworm light infections (figures 3 and 5) in Burma Valley farming area, are of concern. However they could have little impact on morbidity and hence school health since these are all helminths whose effect is dependent on infection intensity rather than prevalence [1, 3, 41]. The observed low levels of heavy infection intensities (Figures 1, 2, 3, 4 and 5) that is critical for morbidity due to helminthiasis [1, 3, 30] even when re-treatment was delayed by almost 2 years demonstrate that regular biannual de-worming could still be efficacious with regards to morbidity control especially in areas of low STHs infection intensities as observed Burma Valley farming area, a strategy also shown to decrease S. haematobium infection in Burkina Faso . This treatment interval could make national helminthiasis control programmes feasible in the developing world whose resources are limited.
Currently, conflicting suggestions on the timing of regular deworming do exist, with the World Health Organization recommending regular annual de-worming in areas where the prevalence of schistosomiasis is ≥ 50% and the prevalence of STHs ≥ 20%, whilst the best practice paper on deworming considers it cost effective if annual deworming is done when the prevalence of STHs is ≥ 40% [38, 41]. Empirical results from our study show that for a prevalence of 23.8% observed in the farming area at baseline (Table 2), the proportion of individuals with heavy infection was less than 1% (Figure 5). These results agree with Hall and Horton's calculated 0.01 proportions of individuals at risk of high STHs infection intensities when the prevalence is 20% [41, 51]. Thus the threshold prevalence of ≥ 20%, recommended by WHO for annual STHs de-worming could be none cost effective if Hall and Horton's economic calculations on treatment rounds based on prevalence are to be considered .
The prevalence of STHs > 50% was observed in school children attending Kinyasini and Chaani approximately 6 months after a decade of sustained regular school based de-worming . This was attributed to local risk factors that included socio-economic discrepancies, poor hygienic practices and soil composition . Many of the children who participated in our study were from unemployed subsistence farmers in the rural area or the lowly paid farm worker communities whose farming activities involved regular irrigation of banana plantations and tobacco, thus the soils in the farming communities are always moist enough to support survival of STHs eggs and larvae hence transmission. These risk factors associated with transmission of schistosomiasis and STHs  could have caused the exceptional resurgence of helminths light infections and schistosome + STHs co-infections observed in our study after almost two years of delayed treatment (Figures 1, 2, 3, 4 and 5).
The observed significant difference in prevalence of S. mansoni in Nyamaropa and Burma Valley commercial farming areas at 33 months follow up survey demonstrate the effect of heterogeneities in water contact patterns in different communities and the spatial heterogeneity in the distribution of infected snails on the epidemiology of schistosomiasis [55–57]. In areas where infected intermediate host snail population is limited as could be the case for Nyamaropa rural area, the transmission force of the disease is low and repeated treatment can reduce the disease to a level where its public health significance would be no more. However areas like Burma Valley farming area where intermediate host snails could be significantly populated and water reservoirs are perennial (personal observation), water contact activities will continue all year round resulting in resurgence of the disease if treatment is delayed by two years (Table 2). However only light infection rebounded after almost 2 years of delayed treatment in our study (Figure 3,), making the decision to de-worm biannually optimal and cost effective in similar endemic areas in the developing world where resources are already strained.
Although the research team and school teachers educated children about malaria disease, its signs and symptoms, a strategy implemented continuously through out the study to promote children to recognise malaria and seek prompt treatment, Table 2 shows that still a certain percentage of children could be found with Plasmodium falciparum parasites at each treatment point parasitologically. These could be a few asymptomatic malaria cases whose immunity could be able to control parasite load and tolerate parasitaemia without clinical manifestation of the disease . Thus in stable malaria endemic areas like Burma Valley farming area, additional active case finding is recommended to track and treat asymptomatic malaria cases as these may sustain transmission of the disease in the community although this has an implication on cost-effectiveness of the approach. Provision of LLINs and their effective use would complement the effort as IPT in schools [59, 60] could be irrational today given the cost of the new malaria drug compounds and the need to prevent rapid emergence of resistance resulting from drug abuse.
The health seeking behaviour of children for malaria treatment as demonstrated by records made at the clinic is difficult to attribute it to school health education intervention since the figures of children who reported for prompt malaria treatment were rather low at each follow up survey. There was also no control arm. We observed that at each follow up survey, some children harboured P. falciparum parasites but did not seek treatment. The three primary schools in Burma Valley are served with Burma Valley clinic that is located at the centre and is approximately 200 m away from Msapa primary school, and about 2 to 3 km away from Kaswa and Valhalla primary schools. The schools are therefore in close proximity to the clinic, thus distance can not be attributed to low compliance observed. More studies in diverse endemic communities are recommended in order to explore the role of school based health education on prompt malaria treatment. Although our study show that integrated school based parasite control can reach a wide population at risk of infection and resulted in reduction of prevalence of polyparasitism, teachers were not able to provide treatment since the local policy stipulates that only medically qualified personnel prescribe and administer drugs regardless of safety guaranteed. In order to realise maximum benefit from school based integrated treatment approach, school teachers need to be allowed to administer treatment in situations where drugs are declared safe like praziquantel and albendazole as this is not only cost effective but also a quick strategy for reaching children living in hard to reach areas who are most commonly overburdened with curable neglected tropical disease.
To our knowledge, this is the first study to investigate the efficacy of combined school based control strategy for helminths - Plasmodium co-infections. Whilst the results show some potential, it should be noted that the study did not have an untreated control arm due to ethical reasons, a weakness that begs for care in interpreting our results. Further, rigorous studies are therefore recommended in diverse areas in order to inform public health managers on appropriate and cost effective integrated control measures in areas co-endemic for NTDs and malaria.