title: Leptospirosis among patients presenting with dengue-like illness in Puerto Rico.
abstract: Leptospirosis is difficult to distinguish from dengue fever without laboratory confirmation. Sporadic cases/clusters of leptospirosis occur in Puerto Rico, but surveillance is passive and laboratory confirmation is rare. We tested for leptospirosis using an IgM ELISA on sera testing negative for dengue virus IgM antibody and conducted a case-control study assessing risk factors for leptospirosis, comparing clinical/laboratory findings between leptospirosis (case-patients) and dengue patients (controls). Among 730 dengue-negative sera, 36 (5%) were positive for leptospirosis. We performed post mortem testing for leptospirosis on 12 available specimens from suspected dengue-related fatalities; 10 (83%) tested positive. Among these 10 fatal cases, pulmonary hemorrhage and renal failure were the most common causes of death. We enrolled 42 case-patients and 84 controls. Jaundice, elevated BUN, hyperbilirubinemia, anemia, and leukocytosis were associated with leptospirosis (p < .01 for all). Male sex, walking in puddles, rural habitation, and owning horses were independently associated with leptospirosis. Epidemiological, clinical, and laboratory criteria may help distinguish leptospirosis from dengue and identify patients who would benefit from early antibiotic treatment.
authors.affiliation: Arctic Investigations Program, National Center for Infectious Diseases, Centers for Disease Control and Prevention (CDC), Anchorage, Alaska 99508, USA. zwa8@cdc.gov
authors.forename: Michael G
authors.initials: MG
authors.lastname: Bruce
authors.forename: E J
authors.initials: EJ
authors.lastname: Sanders
authors.forename: J A D
authors.initials: JA
authors.lastname: Leake
authors.forename: O
authors.initials: O
authors.lastname: Zaidel
authors.forename: S L
authors.initials: SL
authors.lastname: Bragg
authors.forename: T
authors.initials: T
authors.lastname: Aye
authors.forename: K A
authors.initials: KA
authors.lastname: Shutt
authors.forename: C C
authors.initials: CC
authors.lastname: Deseda
authors.forename: J G
authors.initials: JG
authors.lastname: Rigau-Perez
authors.forename: J W
authors.initials: JW
authors.lastname: Tappero
authors.forename: B A
authors.initials: BA
authors.lastname: Perkins
authors.forename: R A
authors.initials: RA
authors.lastname: Spiegel
authors.forename: D A
authors.initials: DA
authors.lastname: Ashford
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003715:Dengue / Q000175:diagnosis* / Q000209:etiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007922:Leptospirosis / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods*; D011647:Puerto Rico / Q000453:epidemiology; D012307:Risk Factors