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PubMed1991

Characterization of outer membrane and secreted proteins of Leptospira interrogans serovar pomona.

Outer membrane and secreted proteins were isolated from Leptospira interrogans serovar pomona and characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblot and radioimmunoprecipitation techniques. The L. interrogans outer membranes were extracted with Triton X-114 and contained several proteins. The major cellular protein with a molecular mass of 31 kDa was associated exclusively with the L. interrogans outer membrane. Using a whole cell immunoprecipitation method, five hydrophobic, Triton X-114 extractable proteins (22, 26, 31, 36 and 42 kDa) were exposed on the surface of L. interrogans. The 31 kDa protein was heat labile and was a potent antigen in animals experimentally infected with L. interrogans serovar pomona. Several proteins were secreted by L. interrogans including a 60 kDa protein tentatively identified as the L. interrogans hemolysin.

Animals↗
PubMed1986

In vitro studies of haemolysis by Leptospira interrogans serovars pomona and ballum.

Washed and unwashed red blood cells (RBC) from young calves, adult cattle, hamsters and humans were incubated with Leptospira interrogans serovars pomona and ballum. Washed cells suspended in saline were always haemolysed while unwashed cells and those which were washed and resuspended in plasma were never haemolysed, despite the presence of large numbers of organisms within the culture supernatant. Pomona produced greater haemolysis of cattle and human RBC than did ballum, but with hamster RBC ballum produced greater haemolysis than did pomona. A group of 6- to 9-month-old cattle infected with pomona showed no signs of clinical disease and RBC taken from them before infection and during the development of antibodies to pomona were haemolysed by pomona only after the cells were washed. Plasma therefore appears to have a protective function. This in vitro protective function of plasma even extended to plasma from young seronegative calves.

Animals↗
PubMed1999

Development of an ELISA to detect antibodies to a protective lipopolysaccharide fraction of Leptospira borgpetersenii serovar hardjo in cattle.

Monoclonal antibodies (Mabs) were produced against Leptospira borgpetersenii serovar hardjo-type Bovis antigens. A panel of 28 Mabs were characterised. Only the nine Mabs toward a lipopolysaccharide (LPS) fraction of 18, 24 kDa bands and a 26-28 kDa smear showed agglutinating, leptospiricidal and growth-inhibition activities, and passively protected hamsters against renal infection with hardjo. They also reacted strongly in the CH-ELISA, captured killed whole hardjo leptospires, gave good fluorescence in indirect FAT against smears of hardjo culture and exhibited no cross reactivity with strains in heterologous serogroups. On the basis of optimal activity in a range of tests, one IgG class Mab (designated 25) was selected for use in an antibody-capture ELISA system for the detection of bovine anti-hardjo antibodies. The system gave a wide separation of absorbance values between positive and negative sera at a 1:10 dilution. The antibodies detected by this assay are believed to be protective anti-LPS IgG.

Agglutination Tests↗
PubMed1986

Weil's syndrome in a zoologist.

Weil's syndrome is an unusual form of leptospirosis in Australia. A case of Weil's syndrome in a zoologist is described and an Australian native animal identified as the probable source of the infection. People who are in close contact with Australian native fauna should take precautions to minimize their exposure to leptospires.

Adult↗
PubMed1990

[Etiology and occurrence of periodic eye inflammation of horses in the area of Berlin].

Over 130 cases of equine periodic ophthalmia (p.o.), which were treated as in-patients at the Equine Clinic of the Free University of Berlin in the last 35 years, were examined statistically in relation to the age and gender of the animals involved as well as to the development of the illness and the season in which it arose. As regards aetiology, the extraction of 71 affected Trotters was investigated. Antibodies to toxoplasmosis, leptospirosis and intestinal parasites were found only in some of the patients. Younger animals, aged between one and four years, and male animals (63.6%) were predominantly affected. The results of the examinations of faeces showed no correlation between cases of p.o. and a vermination of the horses. The examinations for antibodies to toxoplasmosis gave no indication of a participation of the toxoplasmas in the aetiology of recurrent uveitis. In contrast, the results of the examinations for antibodies to leptospirosis, of which 58.8% were positive, showed a seven to ten times higher infection than in healthy horses in Berlin. Breed analysis showed that in certain breeds of Trotters and warm-blooded horses, p.o. illnesses were frequent, supporting the hypothesis that the occurrence of p.o. is due to a hereditary, allergic reaction, triggered by various factors, in particular an infection without clinical signs.

Age Factors↗
PubMed1999

Epidemiologic studies of leptospiroses in the Plovdiv region of Bulgaria.

BACKGROUND: The natural habitat of leptospira along the Maritsa river, the high level of development of the land-cultivation and cattle-raising underscore the importance of establishing the exact prevalence of leptospiroses ranking it among the highest in the country. The changes occurring in the economy and land-making of the country following 1990 are reflected in the prevalence of leptospiroses during this period. MATERIAL AND METHODS: We studied 95 patients of the Infectious Disease Clinic of the Higher Medical Institute of Plovdiv with serological evidence for leptospirosis for the period 1987-1998. The patients were analyzed based on the following criteria: morbidity, age, gender, season, etiologic structure, mechanism and factors for the transmission of disease etc. RESULTS: The morbidity rate of Leptospira has shown a clear tendency towards increase since 1992. In terms of etiology L. pomona ranked first accounting for 44.22% of the cases as compared with the prevalence of L. tsalapitsa--22.10%. The isolation rates of those who had been infected during contact with animals (swine predominantly) was 40.44%, during plant watering--38.95%, and 17.89% resulted from bathing in the Maritsa river or its tributaries. Patients in the high-risk groups were characteristically 20-39 years old, cattle-raisers, fishermen, land workers. The highest number of registered cases occurred in July through August. CONCLUSIONS: Based on these results from the epidemiologic study effective measures aimed at the reservoir, mechanism of transmission of the infection and the risk groups can be implemented so that the epidemiologic and epizootic control of leptospiroses can be improved.

Adolescent↗
PubMedDate not supplied

[Leptospirosis].

Leptospirosis is the most common zoonosis worldwide, although most cases occur in tropical countries. Leptospira interrogans, a spirochete, is the causative agent. Rats are the main reservoir. Most patients present a mild clinical form of the disease, which consists of a self-limited febrile process, without jaundice. Nevertheless, about 10% of patients suffer severe infections, with intense jaundice. Typically the disease manifests in two phases: acute or leptospiremic and immune or leptospiuric, although in many patients the two phases are indistinguishable, and in mild cases the second one is frequently absent. Diagnosis is carried out by serology or culture of the microorganism. Treatment consists of antibiotics such as penicillin G, ceftriaxone, doxycycline or amoxicillin.

Humans↗
PubMed1983

Leptospiral vaccines: immunogenicity of protein-free medium cultivated whole cell bacterins in swine.

Swine serologically negative for anti-Leptospira antibodies were given 2 doses of a pentavalent vaccine (3 weeks between doses) prepared from Leptospira serovars canicola, icterohaemorrhagiae, hardjo, pomona, and grip-potyphosa (0.2 mg/serovar/dose). Leptospires used for vaccinal production were cultivated in a protein-free medium or in a bovine albumin-containing medium. All vaccinated swine had demonstrable antibody titers within 1 week of the initial vaccination. Peak microscopic agglutination titers were between 256 and 1,024 after the 2nd vaccinal dose was given. After challenge exposure with serovar canicola, control swine had titers of at least 13,653 and the vaccinated swine had titers of 3,403 to 8,192, depending on the vaccine. Leptospiremia and kidney infections were not detected in any canicola Moulton immunized swine, but did appear in control swine. The Al(OH)3 adjuvant had no obvious influence of any of the vaccinal titers.

Adjuvants, Immunologic↗
PubMed1994

Seroprevalence to Leptospira interrogans serovar hardjo in merino stud rams in South Australia.

A serological survey of 2160 Merino stud rams on 36 farms detected positive reactions greater than or equal to 1/100 in 42% of animals using the microscopic agglutination test (MAT) to Leptospira interrogans serovar hardjo. Twenty flocks had seroprevalence values greater than 30% with 15 flocks having values > or = 60%. The enzyme-linked immunosorbent assays showed that 47% and 3% of rams on the 36 farms were positive for IgG and IgM antibodies, respectively. Forty-five percent of hardjo reactions were in rams that had not been exposed to cattle. Significant correlations were found between IgM reactors and creek/dam water pumped into troughs, and between MAT/IgG reactors and total flock size. No statistical relationships were detected between positive reactors and two different annual average rainfall gradients, the time of the year in which samples were obtained, or agricultural regions of South Australia. Infections with an organism of the Sejroe serogroup is widespread in Merino stud rams.

Agglutination Tests↗
PubMed2004

Potential application of low-stringency single specific primer-PCR in the identification of Leptospira in the serum of patients with suspected leptospirosis.

In this study we tested the potential use of low-stringency single specific primer-PCR (LSSP-PCR) for genetically typing Leptospira directly from biological samples. Serum samples obtained from 29 patients with clinically suspected leptospirosis were amplified by specific PCR, using the previously selected G1 and G2 primers. The PCR products of approximately 300 bp were subsequently used as a template for LSSP-PCR analysis. We were able to produce genetic signatures from the leptospires present in the human samples, which permitted us to make a preliminary identification of the infective serovar by comparing the LSSP-PCR profiles obtained directly from serum samples with those from reference leptospires. Thus, LSSP-PCR has the potential to become a useful diagnostic tool for identifying leptospires in biological samples without the need for bacteria isolation and culture.

Bacterial Typing Techniques↗
PubMed2002

A quantitative PCR (TaqMan) assay for pathogenic Leptospira spp.

BACKGROUND: Leptospirosis is an emerging infectious disease. The differential diagnosis of leptospirosis is difficult due to the varied and often "flu like" symptoms which may result in a missed or delayed diagnosis. There are over 230 known serovars in the genus Leptospira. Confirmatory serological diagnosis of leptospirosis is usually made using the microscopic agglutination test (MAT) which relies on the use of live cultures as the source of antigen, often performed using a panel of antigens representative of local serovars. Other techniques, such as the enzyme linked immunosorbent assay (ELISA) and slide agglutination test (SAT), can detect different classes of antibody but may be subject to false positive reactions and require confirmation of these results by the MAT. METHODS: The polymerase chain reaction (PCR) has been used to detect a large number of microorganisms, including those of clinical significance. The sensitivity of PCR often precludes the need for isolation and culture, thus making it ideal for the rapid detection of organisms involved in acute infections. We employed real-time (quantitative) PCR using TaqMan chemistry to detect leptospires in clinical and environmental samples. RESULTS AND CONCLUSIONS: The PCR assay can be applied to either blood or urine samples and does not rely on the isolation and culture of the organism. Capability exists for automation and high throughput testing in a clinical laboratory. It is specific for Leptospira and may discriminate pathogenic and non-pathogenic species. The limit of detection is as low as two cells.

Blood Specimen Collection↗
PubMed1983

Leptospiral infection in horses in Northern Ireland: serological and microbiological findings.

Thirteen strains of pathogenic leptospires were isolated from 12 of 91 horses; seven strains belonged to the Australis serogroup (serotype bratislava) with three, two and one strains belonging to the Icterohaemorrhagiae, Hebdomadis (serotype hardjo) and Autumnalis serogroups respectively. Using leptospires isolated from horses and others representing the known parasitic Leptospira serogroups, a sample of 650 mares' sera was tested for agglutinating antibodies. Antibodies were found in 89.1 per cent of sera. The predominant reaction was to serotype bratislava, strain S/1334/79, isolated in this study, antibodies to which were detected in 81.8 per cent of sera. It is suggested that serotype bratislava may be adapted to, and maintained by, the horse population in Northern Ireland.

Animals↗
PubMed1975

Immunizing effects of structural components of Leptospira icterohaemorrhagiae.

The protective attributes of the structural components of Leptospira icterohaemorrhagiae strain Shibaura were examined. Guinea pigs were immunized with the outer envelope, the cell wall, the type-specific main antigen, and the protein constituent of the outer envelope respectively. Of the 4 preparations, the outer envelope, the cell wall and the type-specific main antigen showed a considerable protective effect in this order. The protein constituent of the outer envelope was less effective. Immunization with 200 mug of the outer envelope protected guinea pigs from lethal infection but no completely from the renal carrier state. The rate of protection from renal leptospirosis by the preparations of leptospiral components and lyophilized whole cells was always inferior to the survivor rate.

Animals↗
PubMed1993

Prevalence of leptospiral agglutinins among conservancy workers in Madras City, India.

In a study of 584 Corporation conservancy (sanitation) workers who lived mostly in slums, and who worked in four Corporation Circles of Madras City, India, 192 (32.9%) were found to be positive for agglutinins to Leptospira interrogans. Seropositivity prevalence increased with age, but was similar in males and females except in the youngest age group, where males predominated. Prevalence in the four study areas ranged between 17.8 and 40.5% (P < 0.01). Among 152 sera in which one serogroup predominated, Autumnalis was the most commonly recorded (33.6%), followed by Icterohaemorrhagiae (15.1%), Panama (15.1%), Sejroe (14.5%) and others (21.7%). Forty sera reacted to two or more serogroups at the same (highest) titre, most frequently to the first three serogroups above. The titre range was 1:50-1:3200 (geometric mean titre 149). Among a group of 46 male automobile industry workers who lived in middle-class housing, seropositivity prevalence (17.4%) was approximately half that of the sanitation workers (P < 0.05), and the titre range was lower (1:50-1:200, GMT 84). The predominating serogroups were those found in the sanitation workers. Bearing in mind that sanitation workers are the urban group probably at highest risk of leptospiral infection, the prevalence rate (< 33%) found in our study is not considered to be particularly high.

Adult↗
PubMed1999

Leptospiral outer membrane proteins OmpL1 and LipL41 exhibit synergistic immunoprotection.

New vaccine strategies are needed for prevention of leptospirosis, a widespread human and veterinary disease caused by invasive spirochetes belonging to the genus Leptospira. We have examined the immunoprotective capacity of the leptospiral porin OmpL1 and the leptospiral outer membrane lipoprotein LipL41 in the Golden Syrian hamster model of leptospirosis. Specialized expression plasmids were developed to facilitate expression of leptospiral proteins in Escherichia coli as the membrane-associated proteins OmpL1-M and LipL41-M. Although OmpL1-M expression is highly toxic in E. coli, this was accomplished by using plasmid pMMB66-OmpL1, which has undetectable background expression without induction. LipL41-M expression and processing were enhanced by altering its lipoprotein signal peptidase cleavage site to mimic that of the murein lipoprotein. Active immunization of hamsters with E. coli membrane fractions containing a combination of OmpL1-M and LipL41-M was found to provide significant protection against homologous challenge with Leptospira kirschneri serovar grippotyphosa. At 28 days after intraperitoneal inoculation, survival in animals vaccinated with both proteins was 71% (95% confidence interval [CI], 53 to 89%), compared with only 25% (95% CI, 8 to 42%) in the control group (P < 0.001). On the basis of serological, histological, and microbiological assays, no evidence of infection was found in the vaccinated survivors. The protective effects of immunization with OmpL1-M and LipL41-M were synergistic, since significant levels of protection were not observed in animals immunized with either OmpL1-M or LipL41-M alone. In contrast to immunization with the membrane-associated forms of leptospiral proteins, hamsters immunized with His(6)-OmpL1 and His(6)-LipL41 fusion proteins, either alone or in combination, were not protected. These data indicate that the manner in which OmpL1 and LipL41 associates with membranes is an important determinant of immunoprotection.

Animals↗
PubMed2006

Determining risk for severe leptospirosis by molecular analysis of environmental surface waters for pathogenic Leptospira.

BACKGROUND: Although previous data indicate that the overall incidence of human leptospirosis in the Peruvian Amazon is similar in urban and rural sites, severe leptospirosis has been observed only in the urban context. As a potential explanation for this epidemiological observation, we tested the hypothesis that concentrations of more virulent Leptospira would be higher in urban than in rural environmental surface waters. METHODS AND FINDINGS: A quantitative real-time PCR assay was used to compare levels of Leptospira in urban and rural environmental surface waters in sites in the Peruvian Amazon region of Iquitos. Molecular taxonomic analysis of a 1,200-bp segment of the leptospiral 16S ribosomal RNA gene was used to identify Leptospira to the species level. Pathogenic Leptospira species were found only in urban slum water sources (Fisher's exact test; p = 0.013). The concentration of pathogen-related Leptospira was higher in urban than rural water sources (approximately 10(3) leptospires/ml versus 0.5 x 10(2) leptospires/ml; F = 8.406, p < 0.05). Identical 16S rRNA gene sequences from Leptospira interrogans serovar Icterohaemorrhagiae were found in urban slum market area gutter water and in human isolates, suggesting a specific mode of transmission from rats to humans. In a prospective, population-based study of patients presenting with acute febrile illness, isolation of L. interrogans-related leptospires from humans was significantly associated with urban acquisition (75% of urban isolates); human isolates of other leptospiral species were associated with rural acquisition (78% of rural isolates) (chi-square analysis; p < 0.01). This distribution of human leptospiral isolates mirrored the distribution of leptospiral 16S ribosomal gene sequences in urban and rural water sources. CONCLUSIONS: Our findings data support the hypothesis that urban severe leptospirosis in the Peruvian Amazon is associated with higher concentrations of more pathogenic leptospires at sites of exposure and transmission. This combined quantitative and molecular taxonomical risk assessment of environmental surface waters is globally applicable for assessing risk for leptospiral infection and severe disease in leptospirosis-endemic regions.

Environment↗