Leptospirosis, a common cause of febrile illness in the Peruvian Amazon Region of Iquitos, associated with a novel leptospiral isolate and reservoir host

JESSICA RICALDI; MICHAEL MATTHIAS; K.J. CAMPOS; CESPEDES, M.J.; CHUQUIPIONDO, N.; ESTRADA, C.; BAUTISTA, C.T.; M. MÓNICA DÍAZ; LEVETT, P.N.; R.L. GALLOWAY; E. GOTUZZO; MICHAEL R. WILLIG; ROBERT GILMAN; J.M. VINETZ

Filadelfia, Estados Unidos

Congreso; 2003 Annual Meeting ASTMH (The American Society of Tropical Medicine and Hygiene); 2003

ASTMH (The American Society of Tropical Medicine and Hygiene)

Leptospirosis is endemic in the Peruvian Amazon although clinical disease is infrequently recognized. We estimated rates of clinical leptospirosis by studying patients presenting with undifferentiated fever enrolled at 4 healthposts in and around Iquitos, Peru. 174 malaria smear-negative patients were enrolled over 6 months (92 (52.8%) females, ages 2 to 77). Blood and urine were cultured for Leptospira; serologic tests for leptospirosis were done (MAT, IgM ELISA). Essentially all patients presented solely with undifferentiated fever. Physical exams were mostly unremarkable, although 15 (9%) had rash, 9 (5%) jaundice, 7 (4%) conjunctival suffusion. Six (3.4%) had a positive blood smear for malaria after enrollment; 1 (0.4%) had confirmed dengue. Regarding potential risk factors, 143 (82%) had various domestic animals, most commonly dogs; 78 (49%) reported exposure to rats, 7 (4%) to bats. 146 (83%) were frequently exposed to natural fresh-water (recreational swimming, bathing, washing clothes); 8 (4.6%) worked barefoot. Serological results available for 132 (75%) showed 44 IgM or MAT positives indicating acute infection. Because culture was likely suboptimal for obtaining an etiologic diagnosis, we are using a quantitative real time PCR method using an on-site MJ Research DNA Engine Opticon* 2 Continuous Fluorescence Detection System to analyze culture-negative serum and urine specimens; these experiments are in progress. Seropositivity was not associated with clinical findings or known risk factors for leptospirosis. Two (1.2%) positive cultures were obtained, 1 from an acute blood sample and one from a follow-up urine culture. Molecular analysis of one isolate suggested a possibly novel leptospiral serovar, the pattern of which was also found in a peridomestic rat. Leptospirosis is a common but frequently undiagnosed cause of undifferentiated febrile illness in the Peruvian Amazon. The discovery of a possibly novel leptospiral isolate both in a human and a mammalian reservoir host suggest a transmission mechanism.