RESUMO
As part of a prospective study of leptospirosis and biodiversity of Leptospira in the Peruvian Amazon, a new Leptospira species was isolated from humans with acute febrile illness. Field trapping identified this leptospire in peridomestic rats (Rattus norvegicus, six isolates; R. rattus, two isolates) obtained in urban, peri-urban, and rural areas of the Iquitos region. Novelty of this species was proven by serological typing, 16S ribosomal RNA gene sequencing, pulsed-field gel electrophoresis, and DNA-DNA hybridization analysis. We have named this species "Leptospira licerasiae" serovar Varillal, and have determined that it is phylogenetically related to, but genetically distinct from, other intermediate Leptospira such as L. fainei and L. inadai. The type strain is serovar Varillal strain VAR 010(T), which has been deposited into internationally accessible culture collections. By microscopic agglutination test, "Leptospira licerasiae" serovar Varillal was antigenically distinct from all known serogroups of Leptospira except for low level cross-reaction with rabbit anti-L. fainei serovar Hurstbridge at a titer of 1:100. LipL32, although not detectable by PCR, was detectable in "Leptospira licerasiae" serovar Varillal by both Southern blot hybridization and Western immunoblot, although on immunoblot, the predicted protein was significantly smaller (27 kDa) than that of L. interrogans and L. kirschneri (32 kDa). Isolation was rare from humans (2/45 Leptospira isolates from 881 febrile patients sampled), but high titers of MAT antibodies against "Leptospira licerasiae" serovar Varillal were common (30%) among patients fulfilling serological criteria for acute leptospirosis in the Iquitos region, and uncommon (7%) elsewhere in Peru. This new leptospiral species reflects Amazonian biodiversity and has evolved to become an important cause of leptospirosis in the Peruvian Amazon.
Assuntos
Leptospira/genética , Leptospira/imunologia , Adulto , Animais , Antígenos de Bactérias/imunologia , Técnicas de Tipagem Bacteriana , Southern Blotting , Western Blotting , Cricetinae , Eletroforese em Gel de Campo Pulsado , Feminino , Humanos , Leptospira/classificação , Leptospirose/microbiologia , Mesocricetus , Dados de Sequência Molecular , Peru , Reação em Cadeia da Polimerase , Estudos Prospectivos , RNA Ribossômico 16S/genética , Ratos , Sorotipagem , Adulto JovemRESUMO
A stool and serosurvey for Strongyloides stercoralis was conducted in a community in the Peruvian Amazon region. Strongyloidiasis stercoralis was identified in the stool of 69 (8.7%) of 792 participants. Six hundred nine sera were tested using by an enzyme-linked immunosorbent assay (ELISA), which had a sensitivity of 92% and a specificity of 94%; 442 (72%) were positive. In multivariable logistic regression models, having S. stercoralis in stool was associated with hookworm in the same specimen (odds ratio [OR] = 4.44, 95% confidence interval [CI] = 2.02-9.79), occasionally or never wearing shoes (OR = 1.89, 95% CI = 1.10-3.27), and increasing age (OR = 1.012 for each one-year increase, 95% CI = 1.00-1.03). Similarly, occasionally or never wearing shoes (OR = 1.54, 95% CI = 1.01-2.37) and increasing age (OR = 1.04 for each one-year increase, 95% CI = 1.02-1.06) were associated with an increased risk of a positive S. stercoralis ELISA result. The ELISA had a negative predictive value of 98% and is an excellent screening test for strongyloidiasis.