Carl Kendall1, Ligia Regina Franco Sansigolo Kerr2, José Garcia Vivas Miranda3, Suani Tavares Rubin de Pinho3, Roberto Fernandes Silva Andrade3, Laura Cunha Rodrigues4, Cristiane Cunha Frota5, Rosa Maria Salani Mota6, Rosa Lívia Freitas de Almeida7, Fabio Brito Moreira3, Raoni Boaventura Cruz Gomes3, Naíla Alves de Almeida8, Lucas França9, Maria Araci de Andrade Pontes10, Hector Gonçalves11, Gerson Oliveira Penna12, Samira Bührer-Sékula8, Alden Klovdahl13, Maurício Lima Barreto14. 1. Tulane School of Public Health and Tropical Medicine, Department of Global Community Health and Behavioral Sciences, Universidade Federal do Ceará, Faculdade de Medicina, Departamento de Saúde Comunitária, R: Prof. Costa Mendes, 1608 - 5o. andar - Rodolfo Teófilo - CEP: 60.430-971 - Fortaleza - CE - Brazil. 2. Universidade Federal do Ceará, Faculdade de Medicina, Departamento de Saúde Comunitária, R: Prof. Costa Mendes, 1608 - 5o. andar - Rodolfo Teófilo - CEP: 60.430-971 - Fortaleza - CE - Brazil. 3. Universidade Federal da Bahia, Instituto de Física, Salvador, BA, Brazil. 4. London School of Hygiene and Tropical Medicine, Department of Infectious Disease Epidemiology, London, UK. 5. Universidade Federal do Ceará, Departamento de Patologia e Medicine Legal, Fortaleza, CE, Brazil. 6. Universidade Federal do Ceará, Departamento de Estatística e Matemática Aplicada, Fortaleza, CE, Brazil. 7. Universidade Federal do Ceará, Faculdade de Medicina, Departamento de Saúde Comunitária, Salvador, BA, Brazil. 8. Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brazil. 9. University College London, Institute of Neurology, London, UK. 10. Centro de Dermatologia Sanitária D. Libânia, Fortaleza, CD, Brazil. 11. Centro de Dermatologia Sanitária D. Libânia, Fortaleza, Brazil. 12. Núcleo de Medicina Tropical, Universidade de Brasília, Brasília, DF, Brazil. 13. School of Public Health, University of Texas, Houston, TX, USA. 14. Universidade Federal da Bahia, Instituto de Saúde Coletiva, Salvador, BA, Brazil.
Abstract
BACKGROUND: Mycobacterium leprae was the first microorganism directly associated with a disease, however, there are still important gaps in our understanding of transmission. Although household contacts are prioritized, there is evidence of the importance of extrahousehold contacts. The goal of this article is to contribute to our understanding of the transmission of leprosy ex-household. METHODS: We compare co-location data of 397 leprosy cases and 211 controls drawn from the Centro de Dermatologia Sanitária D. Libânia in Fortaleza, Brazil. We collected lifetime geolocation data related to residence, school attendance and workplace and developed novel methods to establish a critical distance (Rc) for exposure and evaluated the potential for transmission for residence, school and workplace. RESULTS: Our methods provide different threshold values of distance for residence, school and workplace. Residence networks demonstrate an Rc of about 500 m. Cases cluster in workplaces as well. Schools do not cluster cases. CONCLUSIONS: Our novel network approach offers a promising opportunity to explore leprosy transmission. Our networks confirm the importance of coresidence, provide a boundary and suggest a role for transmission in workplaces. Schools, on the other hand, do not demonstrate a clustering of cases. Our findings may have programmatic relevance.
BACKGROUND: Mycobacterium leprae was the first microorganism directly associated with a disease, however, there are still important gaps in our understanding of transmission. Although household contacts are prioritized, there is evidence of the importance of extrahousehold contacts. The goal of this article is to contribute to our understanding of the transmission of leprosy ex-household. METHODS: We compare co-location data of 397 leprosy cases and 211 controls drawn from the Centro de Dermatologia Sanitária D. Libânia in Fortaleza, Brazil. We collected lifetime geolocation data related to residence, school attendance and workplace and developed novel methods to establish a critical distance (Rc) for exposure and evaluated the potential for transmission for residence, school and workplace. RESULTS: Our methods provide different threshold values of distance for residence, school and workplace. Residence networks demonstrate an Rc of about 500 m. Cases cluster in workplaces as well. Schools do not cluster cases. CONCLUSIONS: Our novel network approach offers a promising opportunity to explore leprosy transmission. Our networks confirm the importance of coresidence, provide a boundary and suggest a role for transmission in workplaces. Schools, on the other hand, do not demonstrate a clustering of cases. Our findings may have programmatic relevance.