title: Serovar prevalence of Leptospira in semirural India and the development of an IgM-based indirect ELISA.
abstract: BACKGROUND
  Leptospirosis is a major public health problem in India. However, it has been underreported and under-diagnosed due to a lack of awareness of the disease, a functional surveillance system, and appropriate laboratory diagnostic facilities.
  
  
  METHODS
  This multicenter study aimed to understand the Leptospira serovars causing leptospirosis in seven secondary-level hospitals in six states in India. Since early and accurate diagnosis of leptospirosis is one of the challenges faced by clinicians in India due to the poor specificity and sensitivity of commercially available diagnostic systems, an in-house indirect enzyme-linked immunosorbent assay (ELISA) was developed. Genomic DNA from L. interrogans serovar Canicola was used for polymerase chain reaction amplification, cloning, and expression of the lipL32 gene in E. coli to amplify, clone, and express the lipL32 gene.
  
  
  RESULTS
  Australis was the common serovar seen at all the study centers. Serovar Icterohaemorrhagiae was seen in samples from Tamil Nadu and Assam. In-house ELISA was standardized using the purified recombinant LipL32 polypeptide and was used to evaluate serum. Subsequently, acute serum samples from leptospirosis patients (n = 60) were screened. Compared to the gold standard, the microscopic agglutination test, sensitivity and specificity of the in-house ELISA was 95% and 90%, respectively.
  
  
  CONCLUSIONS
  Understanding Leptospira serovars circulating in leptospirosis-endemic areas will help to formulate better vaccines. LipL32-based ELISA may serve as a valuable tool for early diagnosis of leptospirosis.
authors.affiliation: Pushpagiri Research Center, Pushpagiri Institute of Medical Sciences, Tiruvalla, India. sarachandy@yahoo.co.in.
authors.forename: Sara
authors.initials: S
authors.lastname: Chandy
authors.forename: Lokeshwaran
authors.initials: L
authors.lastname: Kirubanandhan
authors.forename: Priya
authors.initials: P
authors.lastname: Hemavathy
authors.forename: Anees Mohammad
authors.initials: AM
authors.lastname: Khadeeja
authors.forename: Siby Jacob
authors.initials: SJ
authors.lastname: Kurian
authors.forename: Krishnan
authors.initials: K
authors.lastname: Venkataraman
authors.forename: Kristine
authors.initials: K
authors.lastname: Mørch
authors.forename: Dilip
authors.initials: D
authors.lastname: Mathai
authors.forename: Anand
authors.initials: A
authors.lastname: Manoharan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology; D002648:Child; D003955:Diagnostic Tests, Routine / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood*; D007194:India / Q000453:epidemiology; D007919:Leptospira / Q000145:classification* / Q000302:isolation & purification*; D007922:Leptospirosis / Q000175:diagnosis* / Q000453:epidemiology; D008074:Lipoproteins / Q000235:genetics / Q000276:immunology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D012680:Sensitivity and Specificity; D065288:Serogroup; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D007075:Immunoglobulin M; C406589:LipL32 protein, Leptospira; D008074:Lipoproteins; D011994:Recombinant Proteins