Abstract. We enrolled consecutive febrile admissions to two hospitals in Moshi, Tanzania. Confirmed leptospirosis was defined as a ≥ 4-fold increase in microscopic agglutination test (MAT) titer; probable leptospirosis as reciprocal MAT titer ≥ 800; and exposure to pathogenic leptospires as titer ≥ 100. Among 870 patients enrolled in the study, 453 (52.1%) had paired sera available, and 40 (8.8%) of these met the definition for confirmed leptospirosis. Of 832 patients with ≥ 1 serum sample available, 30 (3.6%) had probable leptospirosis and an additional 277 (33.3%) had evidence of exposure to pathogenic leptospires. Among those with leptospirosis the most common clinical diagnoses were malaria in 31 (44.3%) and pneumonia in 18 (25.7%). Leptospirosis was associated with living in a rural area (odds ratio [OR] 3.4, P < 0.001). Among those with confirmed leptospirosis, the predominant reactive serogroups were Mini and Australis. Leptospirosis is a major yet underdiagnosed cause of febrile illness in northern Tanzania, where it appears to be endemic. Laboratory methods. Leptospirosis laboratory diagnosis was made using the standard MAT performed at the CDC. 10 Live leptospiral cell suspensions representing 20 serovars and 17 serogroups were incubated with serially diluted serum specimens. Resulting agglutination titers were read using darkfield microscopy. The reported titer was the highest dilution of serum that agglutinated at least 50% of the cells for each serovar tested. 10 The serogroups (serovars) included in the antigen panel were Australis ( Leptospira interrogans serovar Australis, L. interrogans serovar Bratislava), Autumnalis ( L. interrogans serovar Autumnalis), Ballum ( Leptospira borgpetersenii serovar Ballum), Bataviae ( L. interrogans serovar Bataviae), Canicola ( L. interrogans serovar Canicola), Celledoni ( Leptospira weilii serovar Celledoni), Cynopteri ( Leptospira kirschneri sero-interrogans serovar Wolffi), and Tarassovi ( L. borgpetersenii serovar Tarassovi).Study definitions. Confirmed leptospirosis was defined as a ≥ 4-fold rise in the agglutination titer between acute and convalescent serum samples.11 Probable leptospirosis was defined as a single reciprocal MAT titer ≥ 800.3, 12, 13 Exposure to pathogenic leptospires was defined as any reciprocal MAT titer ≥ 100.3, 12 Predominant reactive serogroup was defined as the serogroup for the reacting serovar with the highest MAT titer. Rural or urban residence, based on the 2002 Tanzania Population and Housing Census, was determined on a village level for all those with complete residence demographics available.14 Statistical analysis. Data were entered using the Cardiff Teleform system (Cardiff, Inc ., Vista, CA) into an Access database (Microsoft Corp., Redmond, WA). Descriptive statistics are presented as proportions, medians, ranges and interquartile ranges (IQR). Pearson's χ 2 was used to compare categorical data; Fisher's exact test was used when any cell contained fewer than 10 observations. Wilcoxon rank sum was used to compare categor...

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Abstract. In 2009, an increased proportion of suspected dengue cases reported to the surveillance system in Puerto Rico were laboratory negative. As a result, enhanced acute febrile illness (AFI) surveillance was initiated in a tertiary care hospital. Patients with fever of unknown origin for 2-7 days duration were tested for Leptospira, enteroviruses, influenza, and dengue virus. Among the 284 enrolled patients, 31 dengue, 136 influenza, and 3 enterovirus cases were confirmed. Nearly half (48%) of the confirmed dengue cases met clinical criteria for influenza. Dengue patients were more likely than influenza patients to have hemorrhage (81% versus 26%), rash (39% versus 9%), and a positive tourniquet test (52% versus 18%). Mean platelet and white blood cell count were lower among dengue patients. Clinical diagnosis can be particularly difficult when outbreaks of other AFI occur during dengue season. A complete blood count and tourniquet test may be useful to differentiate dengue from other AFIs. BACKGROUND

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Leptospira is a global pathogen of emerging public health importance in both developing and industrialized nations and can infect almost all mammalian species, including humans. As suburbanization and the popularity of outdoor recreational activities increases, so do human-wildlife and companion animal-wildlife interfaces. Florida offers a tropical climate favorable for outdoor activities and a semirural landscape that sustains an abundant feral hog population. Because no survey ofleptospirosis in feral hogs (Sus scrofa) in Florida has been published to our knowledge, we sought to establish preliminary seroprevalence ofleptospirosis exposure in feral hogs in Florida. Blood samples were collected opportunistically from 158 male and 166 female feral hogs taken at managed hunts and by permitted trappers in the northern, central, and southern regions of Florida. Samples were then analyzed using the microscopic agglutination test (MAT) for antibody titers to 20 Leptospira serovars representing 17 serogroups. A titer of > 1:100 was considered positive; 33% (107/324 total samples) were positive to at least one serovar, and 46% of those were positive to multiple serovars. Antibodies to L. interrogans serovar Bratislava strain Jez Bratislava (serogroup Australis) was the most common, with 18% (58/324) testing positive for antibodies. These initial data indicate that there is a significant possibility of feral hogs having a larger role in the complex etiology of leptospirosis in Florida than historically estimated and that further investigation is warranted.

Background: Leptospirosis and human immunodeficiency virus (HIV) infection are prevalent in many areas, including northern Tanzania, yet little is known about their interaction. Methods: We enrolled febrile inpatients at two hospitals in Moshi, Tanzania, over 1 year and performed HIV antibody testing and the microscopic agglutination test (MAT) for leptospirosis. Confirmed leptospirosis was defined as ‡ four-fold rise in MAT titer between acute and convalescent serum samples, and probable leptospirosis was defined as any reciprocal MAT titer ‡ 800.

Abstract. Leptospira spp. isolated from patients during a multiyear outbreak in Thailand were genotyped using multilocus sequence typing and a majority were identified as ST34, especially in earlier years. We tested whether ST34 isolates were better adapted to survive in various pH levels, temperatures, and water sources. Motility and growth were monitored over a 12-week period. Early year ST34 isolates did not appear to have a significant fitness advantage over non-ST34, however, this may have been because a majority of the isolates survived to the termination of the study, with the exception being at high temperature (37 C) and/or basic pH (8.65). Failure to detect a significant fitness advantage of ST34 may be a result of the length of the study or the small sample size. Lengthening the study and looking at virulence and maintenance in the host could yield additional information about this outbreak.Leptospirosis has a broad range of symptoms, from mild flu-like illness to acute renal failure and pulmonary hemorrhage.1,2 The disease is found worldwide, but is more common in countries with a rainy season and warmer climate that promotes the survival of leptospires in the environment. 3 The outbreak could not be explained by climate or regional flooding; the authors hypothesized that the increased incidence may have been caused by the presence of a biologically successful strain of pathogenic Leptospira.3 In this study, we tested whether early year ST34 isolates (2001 and 2003) were better adapted than later year ST34 and/or non-ST34 isolates (2005 and 2006) from this outbreak for survival in water from different sources and at variable pH and temperature.Isolates representing four of the 11 STs from various years of the outbreak were selected (Table 1). Isolates had been maintained at 25-30 C and had gone through 18-23 passages in Ellinghausen, McCullough, Johnson, and Harris (EMJH) semisoild media. Isolates were inoculated into liquid EMJH, grown at 30 C to the logarithmic phase, and adjusted to a McFarland standard of 0.5. [5][6][7][8][9] Spiking was performed by centrifuging 12 mL of the adjusted culture, discarding the supernatant, and then resuspending with 12 mL of suspending fluid. Rice field water and pond water from the outbreak location in Thailand were autoclaved before use. For each suspending fluid, conditions were tested in duplicate with various temperatures (25 C, 30 C, or 37 C) and pH (unadjusted, 5.65 or 8.65) combinations. The unadjusted pH was found to be pH 6.95 in rice field water and pH 7.79 in pond water. Once the Leptospira were resuspended, tubes were placed in a dark incubator at the appropriate temperature for 12 weeks. For each test combination, growth and viability of the Leptospira isolates were determined by measuring optical density (OD), leptospiral motility, and growth in semisolid EMJH (Figure 1).The OD at 400 nm was measured twice each week as a method of monitoring viable Leptospira ( Figure 1A). 10,11 Repeated measures analysis of variance and Wilks test were performed to...