Toward Health Management of Major Labour Force Generation by Using Infection Control Countermeasures for Haematobium Schistosomiasis – assumed to be related to occupational risk-in the Republic of Malawi

Background In Malawi, haematobium schistosomiasis is highly endemic. According to previous studies, countermeasures have been conducted mainly in school-aged children. In this study, we focused on the age groups, which are assumed to be major labour force generation. Haematobium schistosomiasis is supposed to be related to occupational activities in schistosome endemic countries. Methods We chronologically followed the transition of schistosome egg positive prevalence before and after mass drug administration of praziquantel (MDA) by using a urine filtering examination. We also analyzed the effectiveness of urine reagent strips from the cost perspective. Findings The egg positive prevalence was 34.3% (95%CI: 28.5-40.5) just before MDA in June 2010 and the highest prevalence was in the age of twenties. The egg positive prevalence reduced to 12.7% (95%CI: 9.2-17.3, p<0.01) eight weeks after the first MDA and the prevalence reduced to 6.9% (95%CI: 4.6-10.0, p<0.01) after the second MDA in August 2011. The egg positive prevalence after MDA in 2013 was reduced from 3.8% (95%CI: 2.1-6.9) to 0.9% (95%CI: 0.3-3.4) and p value was 0.050. Using urine reagent strips after MDA, the positive predictive value decreased, but the negative predictive value remained high. The cost of one urine reagent strip and one tablet of praziquantel were US$0.06 and US$0.125 in 2013 in Malawi. If the egg positive prevalence is 40%, screening subjects for MDA using urine reagent strips, the cost reduction can be estimated to be about 24% -showing an overall cost reduction. Conclusion The combination of MDA and urine reagent strips could be both a practical and cost-effective countermeasure for haematobium schistosomiasis. It is key to recognize that haematobium schistosomiasis could be considered a disease that is assumed to have some concern with occupational risk in tropical agricultural countries such as Malawi. From this point of view, it is very important to protect the health of workers; the sound labour force generation is vital for economic growth and development in these countries. Author summary Schistosomiasis is widely endemic in the tropical and subtropical countries including Malawi, and it is related that more than 300 million people suffer from associated severe morbidity. The pathway of transmission is mainly contacting infested fresh water and it is inevitable to contact fresh water through their daily activities in Malawi. Then, they are routinely exposed to the risk of schistosome infection. Previously the main targets of schistosome control were school-aged children, but our research showed main population of schistosome infection was twenties that was presumed to be major labour force. Agriculture is the dominant industry in Malawi and it can be related to be at risk of schistosome infection during agricultural work. Schistosomiasis is presumed to have occupation-related risks, we consider that schistosome control will be a valuable step-up to economic development and make a social contribution in Malawi and many low-income tropical countries. Funding The Ministry of Education, Culture, Sports, Science and Technology of Japan’s scientific research grant (JSPS KAKENHI Grant Number JP23406025). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.


Introduction 68
Schistosomiasis, a trematode infectious disease, is widely distributed around the tropics and subtropics.

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This infectious disease is one of the world's three major parasitic infections. It is endemic in 74 70 developing countries; and approximately 800 million people are at risk of schistosome infection. More 71 than 300 million people suffer from associated severe morbidity [1]. Chronic and repeat infection of 72 schistosomiasis could result in irreversible damage to body organs and other diseases; for example,

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Schistosoma haematobium infection may lead to bladder cancer and cervical cancer [2,3]. In the 74 schistosome endemic regions, the most prevalent form of the disease is chronic schistosomiasis, resulting 75 from repeated exposure to infectious cercariae [4]. Schistosomiasis mortality rates rises substantially as 76 age increases [5]. Therefore, it is important for healthcare systems to consider not only children but also 77 young adults -assumed to be a major component of labour generation-as the subjects of schistosomiasis 78 control as related to occupational risk.

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Schistosomiasis is recognized as one of the neglected tropical diseases (NTDs) at present. Global 80 coverage rate of preventive chemotherapy against schistosomiasis is still low at 8.3%, while the rate 81 against onchocerciasis is 59.8% [1]. In sub-Saharan Africa, approximately 280,000 annual deaths have 82 been attributed to schistosomiasis [6]. Countermeasures have been globally to fight malaria, tuberculosis, 83 and HIV infection; however, we consider provisions against schistosomiasis are an important next step 84 for the sustainable growth and development in countries affected by schistosomiasis because of the 85 burden the disease places on those living in the affected region. This disease does not only cause 86 immediate morbidity in children, but it also has long-term health effects on the children's development 87 into adulthood. Although the earlier studies targeted school-aged children, but the disease may become a 88 matters of concern for the general public if the overall labour force suffers from schistosomiasis.

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Malawi is one of the poorest countries in the world and was ranked as the ninth poorest country in  schistosome transmission notably affects farmers, fishermen, irrigation workers, and those whose daily 107 activities involve contact with infested freshwater. Contact with freshwater is the inextricable part of the 108 daily activities of many inhabitants in the area. Malawi is predominantly an agricultural country and 109 agriculture accounts for about 35% of GDP. Moreover agricultural activities provide more than 80% of 110 the employment in this country [7]; therefore, the vast majority of the population is routinely exposed to 111 the possibility of schistosome infection while working. As a result of this situation, we need to recognize 112 that there could be the occupational risk in suffering from schistosomiasis. The prevalence of the disease 113 in the country is estimated between 40% and 50%; school-aged children are a highly infected group and 114 are intensely affected [9]. It was previously reported that although all sections of the population in the endemic areas can be infected with schistosomiasis, the most vulnerable groups are pre-school (under 5 116 years old) and school-aged children, adolescent girls, and women of childbearing age [10,11].

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Haematobium schistosomiasis is likely to impact child growth and possibly can cause anemia in all age 118 groups; this would call for the inclusion of the entire populations into future control programs [12].

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In this study, which looks at schistosomiasis that could have relation to occupational risk, we targeted 120 residents of all generations, including major segments of the labour force to check the current status of 121 residents in our surveyed areas using mass drug administration of praziquantel (MDA) and urinalysis.

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Protecting the health of the labour force can be expected to contribute to the economic growth and

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These four target areas were Chisindo, Mtika, Mapiri, and Chisaka in Lilongwe. The total population was 140 1,393 people in these four areas, and around 300 subjects were selected by random sampling from among 141 all age groups. The target areas were located near the capital Lilongwe, the basic infrastructure was being 142 developed to some extent. Health education for schistosome infection had been provided at the schools.

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Information about schistosomiasis was also provided via broadcast media.

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A signed consent form was obtained from both the new and old participants in the study. The consent form contained the following information: general introduction of the study, usefulness of the study, and 192 purpose of the study. The participants were allowed to withdraw at any point during the project whenever

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Those in the twenties belonged to the labour force. To alleviate poverty, and cases of schistosomiasis 311 related to poverty, it is important for the economic growth and development of this country to protect the 312 health of the labour force. In the older-than-20 age group, the egg positive prevalence decreased ten 313 months after the first MDA (Fig 2-b). In general, providing health information about schistosomiasis may 314 bring about behavioral changes in the population that would improve the overall health in the country.

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An increase in the egg positive prevalence was observed in the under-15-age group one year after 316 MDA in June 2011. Among under-15-age group, the gradient of the increasing line of under-5 age-group 317 was steepest (Fig 2a). Positive egg prevalence of each age group in 2013 was lower than the average in 318 Malawi, and the highest was 8.8% in the under-5-age group (Table 3). There is a high risk of infection for

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In only 15-19 age group, elevation of the egg positive prevalence was confirmed after MDA in August 332 2013 (Fig 4b). Therefore, those who graduated from schools -who are in the 15-19 age group-belong to 333 the high-risk group for repeat schistosome repeated.

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Although it is expected that urgent schistosomiasis countermeasures will make a great social contribution in affected tropical countries, it can be easily imagined that the budgeting for countermeasures will be 418 quite difficult in those countries. Thus, it is considered essential to prioritize to the implementation of 419 countermeasures. School-aged children were the main targets for schistosomiasis countermeasure in the 420 past, but this research shows that both the infection rate and the recurrence rate were higher in the labour 421 force and that may have a direct influence on economic development. Agricultural work is the main form 422 of labour in many developing countries, including Malawi, and contact with freshwater areas is inevitable 423 as long as the residents are engaged in agricultural activities. Therefore, schistosomiasis should be 424 considered to have concerning with occupational risks. Good health is positively related to economic 425 growth or output [16]. Based on the results of this study, we believe that reasonable countermeasures and 426 well-targeted treatment could reduce the prevalence of haematobium schistosomiasis; and this could lead 427 to an improvement in morbidity and mortality, reducing the prevalence of schistosomiasis in Malawi and 428 other schistosome endemic countries. It will be resulted to protect health of labour force, too.

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Furthermore, since schistosomiasis is presumed to have occupation-related risks, we consider that 430 schistosome control will be a valuable step-up to economic development and make a social contribution 431 in Malawi and many low-income tropical countries.