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Seroprevalence of leptospirosis in an endemic mixed urban and semi-urban setting-A community-based study in the district of Colombo, Sri Lanka.
Rajapakse, Senaka; Weeratunga, Praveen N; Balaji, Krishan; Ramchandani, Kyra Charmaine; de Silva, Udani Savbhagya; Ranasinghe, Shenali Avishka; Gunarathne, Dinesh; Wijerathne, Pasindu P B; Fernando, Narmada; Handunnetti, Shiroma M; Fernando, Sumadhya Deepika.
Afiliação
  • Rajapakse S; Department of Clinical Medicine, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka.
  • Weeratunga PN; Department of Clinical Medicine, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka.
  • Balaji K; Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
  • Ramchandani KC; Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
  • de Silva US; Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
  • Ranasinghe SA; Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
  • Gunarathne D; Smallholder Tea and Rubber Revitalization (STARR) Project, Ministry of Plantation Industries, Colombo, Sri Lanka.
  • Wijerathne PPB; Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
  • Fernando N; Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
  • Handunnetti SM; Institute of Biochemistry, Molecular Biology and Biotechnology, University of Colombo, Colombo, Sri Lanka.
  • Fernando SD; Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka.
PLoS Negl Trop Dis ; 14(5): e0008309, 2020 05.
Article em En | MEDLINE | ID: mdl-32428003
Leptospirosis is endemic in Sri Lanka. There is a need for updated seroprevalence studies in endemic areas, to improve the understanding of disease dynamics, risk factors, control methods, and for clinical diagnosis. The cut-off titres for the microscopic agglutination test (MAT) for diagnosis of acute leptospirosis depend on community seroprevalence, and can vary based on locality and serovar. This study aimed to identify the seroprevalence, geographical determinants, and associations of seropositivity of leptospirosis in the district of Colombo in Sri Lanka, and to determine diagnostic cut-off titres for MAT in the community studied. This study utilized a stratified cluster sampling model in the Colombo district of Sri Lanka, to sample individuals living in urban and semi-urban areas. Serovar specific MAT titres were measured on recruited individuals using a panel of saprophytic (Leptospira biflexa) and 11 pathogenic Leptospira spp. serovars. Associations between environmental risk factors and MAT positivity were examined, with location mapping using GIS software. A total of 810 individuals were included. The mean age was 51.71 years (SD 14.02) with male predominance (60%). A total of 429 (53%) tested positive at a titer of 1/40 or more for the saprophytic Leptospira biflexa serovar Patoc. Pathogenic serovar MAT was positive at a titer of 1/40 or more for at least one serovar in 269 (33.2%) individuals. From the perspective of screening for clinical disease, serovar-specific cut-off titres of 1/80 for Leptospira spp. serovars Hebdomadis, Icterohaemorrhagiae, Pomona, Ratnapura and Patoc, 1/160 for serovars Pyrogenes and Cynopteri, and 1/40 for other serovars were determined, based on the 75th quartile MAT titre for each serovar. Serovar Pyrogenes (15.9%) had the highest seroprevalence, with serovars Ratnapura, Bankinang and Australis accounting for 9.9%, 9.6% and 9.3% respectively. When the proposed new cut-offs were applied, Bankinang(9.6%) Australis(9.3%), Pyrogenes(6.9%) and Ratnapura(6.9%) were the most prevalent serovars. No significant differences in seroprevalence or serovar patterns were noted between urban and semi-urban settings. Individuals seropositive for Australis, Ratnapura and Icterohaemorrhagiae were clustered around main water bodies as well as around smaller tributaries and paddy fields. Those positive for the serovar Pyrogenes were clustered around inland tributaries, smaller water sources and paddy fields. Associations of MAT positivity included high risk occupational exposure, environmental exposure including exposure to floods, bathing in rivers and lakes, using well-water for bathing, contact with stagnant water, propensity to skin injuries, presence of rats in the vicinity, and proximity to water sources. For pathogenic serovars, high-risk occupational exposure remained statistically significant following adjustment for other factors (adjusted OR = 2.408, CI 1.711 to 3.388; p<0.0001; Nagelkerke R2 = 0.546). High risk occupational exposure was determined to be independently associated with seropositivity. Baseline community MAT titres vary according to serovar, and presumably the locality. Testing against saprophytic serovars is unreliable. Thus, diagnostic MAT titre cut-offs should be determined based on region and serovar, and the use of a single diagnostic MAT cut-off for all populations is likely to result in false negatives.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: População Suburbana / População Urbana / Doenças Endêmicas / Aglutininas / Leptospira / Leptospirose Limite: Adolescent / Adult / Aged / Aged80 / Female / Humans / Male / Middle aged País/Região como assunto: Asia Idioma: En Revista: PLoS Negl Trop Dis Assunto da revista: MEDICINA TROPICAL Ano de publicação: 2020 Tipo de documento: Article País de afiliação: Sri Lanka País de publicação: Estados Unidos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: População Suburbana / População Urbana / Doenças Endêmicas / Aglutininas / Leptospira / Leptospirose Limite: Adolescent / Adult / Aged / Aged80 / Female / Humans / Male / Middle aged País/Região como assunto: Asia Idioma: En Revista: PLoS Negl Trop Dis Assunto da revista: MEDICINA TROPICAL Ano de publicação: 2020 Tipo de documento: Article País de afiliação: Sri Lanka País de publicação: Estados Unidos