Epidemiological and space aspects of the schools of the National Leprosy Campaign: the case of Sobral – Ceará, Brazil

The objective of this study is to describe the epidemiological and spatial aspects of leprosy of the schoolchildren participating in the National Leprosy Campaign in the municipality of Sobral, Ceará, in the year 2016. This is a cross-sectional epidemiological study with spatial analysis of secondary data obtained in the records instruments used in the Campaign (self-image files), with public school schoolchildren from five to fourteen years old. From this population a sample was taken to be studied from the calculation of a standard error limit of 5%, confidence level of 99.99% and an expected frequency of 50%, resulting in 1,216 students, corresponding to 19.7% of a total of 6,169 schoolchildren who returned the completed self-indexed records. A descriptive analysis was performed for all the variables of interest of the study object and for the spatial analysis the QGIS program 2.18 was used. Of the 1,216 schoolchildren participating in the study, 31.7% had body spots and 18.1% (220/1126) of the total number of schoolchildren had leprosy cases in the study. Of the 1,216 students in the study, 31.7% (386/1). Among the schoolchildren with spots on the body, 6.2% (75/1126) reported having cases of leprosy in the family, 59.3% (195/329) are birthmarks, 20.7% Among children with spots suspected of leprosy (39.2%, 129/329), they were found to be dormant (9.3%) (31/329) and 10.6% (35/329) The strategies for the screening of new suspected leprosy cases developed through campaigns helped to mobilize around the epidemiological situation of leprosy, facilitating the dissemination of information to leprosy patients. the population on the recognition of signs and symptoms, treatment and cure of leprosy. AUTHOR SUMMARY Leprosy is an infectious and contagious, chronic disease caused by Mycobacterium leprae (M. leprae), which has high infectivity and low pathogenicity. Brazil is part of the group of three countries responsible for 80.2% of all new cases registered in the world in 2017 and in the Region of the Americas contributed with 92.3% of new cases. The National Leprosy Campaign aims to find new cases of leprosy in children 5 (five) to 14 years of age. Sobral, a city of Ceará, with high disease burden, has been joining the campaign every year since 2013. This study describes the epidemiological and spatial aspects of leprosy of students participating in the National Leprosy Campaign in the municipality of Sobral, Ceará, in 2016. Strategies for screening new suspected leprosy cases developed through Campaigns, in addition to contributing to the identification of new cases in the community, promote a mobilization around the epidemiological disease situation and dissemination of information to the population on the recognition of signs and symptoms, treatment and cure of leprosy.


INTRODUCTION
Leprosy is an infectious and contagious, chronic disease caused by Mycobacterium leprae (M. leprae), which has high infectivity and low pathogenicity.
Transmission in humans occurs mainly through the upper airways with the elimination of the M. leprae agent, which is preferentially installed in the skin and peripheral nerves ¹. Its multiplication in the organism is slow, which determines a long period of incubation of the disease, which can vary from two to seven years ², and the later the disease is diagnosed, the greater the risk of developing deformities and incapacities ³. As a measure to strengthen the fight against leprosy, since 1992, the World Health Organization (WHO) has been launching campaigns to eliminate the disease as a public health problem, as control strategies where the burden of disease is high. In 2016, the "Global Strategy for Leprosy: 2016-2020" was launched to accelerate action towards a world without leprosy, aiming at strategic changes in three areas: (1) elimination of Grade 2 disabilities in children with leprosy; (2) reduction of new cases of leprosy with Grade 2 disabilities to less than one case per million population; (3) that no country has laws that allow discrimination to those with leprosy 5,6 .
In Brazil, new strategies and intervention measures were introduced to achieve the elimination of neglected diseases by establishing the "Integrated Plan for Strategic Actions to Eliminate Leprosy, Filariasis, Schistosomiasis and Onchocerciasis as a Public Health Problem." In this plan, the active search for new cases of leprosy disease from the self-image files for leprosy, applied to schoolchildren ranging from five to fourteen years old, 7 from campaigns in public schools, which are characterized as interdisciplinary spaces of construction of knowledge, and that can enhance the insertion of new practices and habits, constituting the appropriate tool for the success of educational actions in health 8,9 .
The National Leprosy, Verminoses, Trachoma and Schistosomiasis Campaign has annual periocity and focuses on geographic areas with greater epidemiological risks for leprosy, with the search for new cases in children between five and 14 years old, aiming at the early detection through use of the "mirror method", which consists in the completion of a self-image record by parents or guardians indicating whether or not the child has suspicious spots of leprosy 8,10 .
Sobral, one of the priority municipalities in the state of Ceará for surveillance and leprosy control actions since 2013, has been joining the annual campaigns of Leprosy, Verminoses, Trachoma and Schistosomiasis of the Ministry of Health as a strategy for the early detection of new cases of leprosy, and to minimize the endemic load. This municipality, historically, presents high annual rates of detection of new cases of leprosy. Between 2005 and 2016, 1,163 new cases were registered in this municipality, with an average detection rate of 52.2 cases per 100,000 inhabitants. Of the total number of cases identified in the period, 89 were younger than 15 years, reaching an average detection rate of 10.2 cases per 100,000 inhabitants in this age group 11 . Mean values in the general population and in those under 15 indicate, according to the parameters of the Ministry of Health, as a hyperendemic municipality 10 .
This study aims to describe the epidemiological aspects of the students of the public school of Sobral, aged between five and 14 years old, who participated in the National Leprosy Campaign in 2016.

Ethics statement
This study is part of a larger study entitled: Leprosy in children under 15 years: use of social networks and genetic tools in the study of the transmission of Mycobacterium leprae, which was approved by the Scientific Committee of the

Secretariat of Health and Social Action of Sobral and by the Human Research Ethics
Committee of the Federal University of Ceará (CEPSH-UFC), Nº. 624,393.
During the National Leprosy Campaign the parents received a consciously printed informational statement accompanying the self-image file for leprosy. In the end it is explained that the objective of the campaign is to protect children from diseases: leprosy, verminoses, trachoma and schistosomiasis. Parents who accepted, their respective children were evaluated for identification of suspected cases of leprosy.

National Leprosy Campaign
This is a cross-sectional epidemiological study with spatial analysis of secondary data obtained in the National Campaign on Leprosy, Verminoses, Trachoma and Schistosomiasis, with students from the public network of the municipality of Sobral, in the state of Ceará -Brazil, in 2016 The epidemiological scenario of leprosy in Sobral was one of the motivators for choosing the place for the present case study.
Epidemiological "cross-sectional" studies seek to give an idea of the cut in the historical flow of a disease, evidencing its characteristics and correlations at that moment, in a given population or community 12 . While the spatial analysis based on the use of the Geographic Information System (SIG) in epidemiology allows the analysis of the spatial distribution, predicting patterns, determinants and results directed to populations 13 . Allowing the understanding of the epidemiological dynamics of the territory from the design of a cartographic chart.
The population of the study are schoolchildren in the age range from five to fourteen years of the 31 schools in the municipal network, of which 22 are urban and nine are in the countryside. The schools that joined the campaign were selected based on two criteria: to include a higher concentration of students enrolled in the study's age range, and to be located in areas with high rates of leprosy cases.
The operation of the campaign in the schools comprised four stages: 1st Stepidentification of the Family Health Centers (CSF) of reference of the schools; Step 2 -CSF and school health professionals received guidelines and campaign materials, such as self-image files for leprosy; Step 3 -delivery of self-image files to schoolchildren and completion by the parents or persons in charge at home; Step 4 -return of the selfimage files to the health professionals of the responsible schools within a maximum of two days, and screening of schoolchildren with signs and symptoms suggestive of leprosy who need to be referred for medical referral in the school's reference CSF.
In the campaign, 19,415 self-image files were distributed to schoolchildren, and 6,169 of the files were returned by the schoolchildren. Considering the significant quantity of returned chips, the sample was calculated in the public domain software Epi Info ™, with a default error limit of 5%, a 99.99% confidence level and an expected frequency of 50%, resulting in 1,216 tokens of self-image selected by the random sampling technique, corresponding to 19.7% of the total of filled in received.
In order to access and use the data of the self-image files of the students of the National Leprosy Campaign in 2016, the Health Surveillance Coordination of the municipality of Sobral, local responsible for the Campaign, was requested by means of a Term of Commitment. Thus, as a criterion for the selection of self-image files, access was made to the self-image files returned and the correct completion. The records that showed inconsistencies were not selected for analysis.

RESULTS
Of the 1,216 schoolchildren in the study, 31 (Table 3).  showed that: 29.2% (7/24) of the neighborhoods have a profile hyperendemic for leprosy; 12.5% (3/24) have a very high rate and have the same high rate percentage; 8.3% (2/24) have an average rate for leprosy; and 37.5% (9/24) did not present any case of leprosy registered in 2016.
In Figure 1, the group of schoolchildren who had spots on the body (34.9%, 317/909) (Map1A), the linear distance matrix among schoolchildren who have cases of leprosy in the family has a minimum distance of 0.0km and the maximum of ± 6.03km; and distance for schoolchildren with spots and cases of leprosy in the family (19.6%, 178/909) (Map 1B) is 0.0km the minimum distance, and the maximum distance is ± 0.041km. The distance between schoolchildren with spots and cases of leprosy in the family (65,1; 592/909) (Map1C) and schoolchildren without spots, the minimum distance is ± 0.0km and the maximum ± 9.1km. The minimum distance between schoolchildren with different characteristics, such as having spots or presenting cases of leprosy in the family, corresponded from 0.0 km to 10 km.
Schoolchildren with spotting who presented cases of leprosy in the family (Map1C), have a neighborhood index of ± 0.6km, and are concentrated the distribution in the neighborhoods that present hyperendemic rates, very high and high leprosy. Only three of the cases with cases of leprosy cases in the family are distributed in three regions where the incidence rate for leprosy was zero, and the respective neighborhoods are: Colina da Boa Vista, Cohab I and Derby.

DISCUSSION
The National Leprosy Campaign is a successful strategy worldwide referenced by the WHO to act in the active search for new cases of leprosy with schoolchildren in the age group of five to fourteen years old of the public education network residing in areas at highest risk for the disease 15 . The active search strategy consists of epidemiological investigation actions, such as campaigns and surveys 16 . In the analysis of the sample, it was also possible to investigate some epidemiological aspects of the t schoolchildren in relation to cases of leprosy in the family nucleus. When children are exposed to M. leprae in the family environment, they have a 60% higher chance of developing leprosy. If the child has contact with cases of leprosy in the environment outside the home is four times more likely to develop leprosy, although the development of the disease depends on the relationship of the bacillus and host 15,21,22 . In an active search campaign of new leprosy cases in Manaus

CONCLUSION
The active search strategy adopted by the National Leprosy Campaign is an effective methodology for screening suspected cases among schoolchildren and early detection of new cases of leprosy, preventing physical disabilities resulting from late diagnosis. Early detection of leprosy and immediate treatment to avoid disability minimizes stigma associated with leprosy such as discrimination, as many patients continue to suffer from social exclusion resulting from leprosy injury.
It should be noted that, in the Sobral Leprosy Campaign, no new cases of leprosy were found in children under 15 years of age in the campaign, despite the schoolchildren of the students with dormant and suspicious spots, a profile of suspected schoolchildren with cases of leprosy in the family residing in areas with high rates of leprosy. However, the campaign allowed to establish the epidemiological characteristics of the participating students, such as stratification of groups residing in areas with high endemic rates.
This study had several limitations, first because it is a study with a secondary data source, being only possible the access of the self-image files returned by the students to the school officials during the period of the National Leprosy Campaign.
Second, in addition to the losses of return of the self-image files for leprosy, an expressive quantity of fichas was not correctly filled, being excluded from the study and reducing the sample for analysis. Thus, there is a need to raise the awareness of those responsible for the importance of returning the self-image record, in order to evaluate new cases suspected of leprosy in <15 years.

Supporting Information Legends
 Table 1 Socio-demographic characteristics of the students of the IV National Leprosy Campaign in Sobral -Ceará, Brazil, 2018.
 Table 2 Distribution of the characteristics of the spots of the students of the IV National Leprosy Campaign according to sex, age group, level of schooling and location, in the municipality of Sobral -Ceará, Brazil, 2018.
 Table 3 Clinical and epidemiological characteristics of students with suspected leprosy in the IV National Leprosy Campaign in Sobral, Ceará, Brazil, 2018.