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PubMed1998

Prevalence and geographic origin of pigs with serological evidence of infection with Leptospira interrogans serovar pomona slaughtered in abattoirs in Victoria, Australia.

A set of 10,440 sera was collected from pigs slaughtered at Victorian abattoirs. These sera were subjected to the microscopic agglutination test for antibodies to Leptospira interrogans serovar pomona. Identification of the herd of origin was possible for 6511 pigs, and these were derived from 167 herds in Victoria (84% of sera), from 32 herds in New South Wales (8% of sera) and 29 herds in South Australia (8% of sera). The overall prevalence of titres of 512 and above was 3.7%. This was higher (5.3%) among pigs for which the property of origin was unknown than among pigs with identified properties of origin. Among the latter the prevalence was 2.7% (Victoria 0.6%, New South Wales 1.3%, South Australia 25.2%.) Most of the pigs with unknown properties of origin were derived from market groups and were probably typically from smaller herds. Within Victoria a comparison of results with the known pig populations of the 12 statistical divisions indicated that infection was spread throughout the State. Of the 228 identified herds of origin sampled, 32 (14%) had at least one pig with a high titre. However, this may underestimate the proportion of infected herds, as in many cases only a few serum samples were obtained. Of 73 herds from which 25 or more serum samples were obtained, serological evidence of infection was obtained in 18 herds (25%).

Abattoirs↗
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↗
PubMed1999

Investigation on process parameters involved in preparation of poly-DL-lactide-poly(ethylene glycol) microspheres containing Leptospira Interrogans antigens.

Block copolymer, poly-DL-lactide-poly(ethylene glycol) (PELA) with 11.5% of poly(ethylene glycol) (PEG) content was prepared by bulk ring-opening polymerization using stannous chloride as initiator. PELA microspheres with entrapped Leptospira Interrogans antigens, outer membrane protein (OMP) were elaborated by solvent extraction method based on the formation of multiple w/o/w emulsion, and the resulting microspheres were characterized with respect to particle size, OMP entrapment and morphology characteristics. The purpose of the present study is to perform the optimization of preparative parameters for OMP-loaded PELA micropsheres to control particle size and improve the OMP encapsulation efficiency. Of all the parameters investigated, the polymer concentration of organic phase and the external aqueous phase volume play major roles on particle size, while the organic phase volume, internal aqueous phase volume and the addition of surfactant into the internal aqueous phase display considerable effects on OMP loading efficiency. A small volume of internal aqueous phase and intermediate volumes of organic phase and external aqueous phase were favorable to achieve micropsheres with a size of 1-2 microns and high antigen encapsulation efficiency (70-80%). In vitro OMP release profiles from PELA microspheres consist of a small burst release followed by a gradual release phase. The OMP release rate shows some relations with the porous and water-swollen inner structure of the microspheres matrix. The presence of surfactant in microspheres accelerates OMP release, but the OMP entrapment within microspheres shows limited effects on the release profile.

Antigens, Bacterial↗
PubMed2004

Production of tumor necrosis factor alpha by Treponema pallidum, Borrelia burgdorferi s.l., and Leptospira interrogans in isolated rat Kupffer cells.

Stimulation of isolated rat Kupffer cells by viable Leptospira interrogans, Treponema pallidum and Borrelia garinii elicited cellular responses resulting in the release of different tumor necrosis factor alpha (TNF-alpha) levels, depending on the spirochetes. L. interrogans induced TNF-alpha levels higher than those achieved with B. garinii and T. pallidum (in this order), but lower than the levels achieved with lipopolysaccharide (LPS). In contrast to L. interrogans, pretreatment of borreliae and treponemes with polymyxin B did not substantially diminish the ability of B. garinii and T. pallidum to stimulate Kupffer cells. Purified T. pallidum lipoproteins TpN47, TmpA, TpN15-TpN17, and B. garinii OspA induced TNF-alpha responses comparable to that achieved by LPS. This response was almost insensitive to the action of polymyxin B.

Animals↗
PubMed1991

A comparative investigation and identification of Leptospira interrogans serogroup icterohaemorrhagiae strains by monoclonal antibody and DNA fingerprint analyses.

The identification of Leptospira interrogans icterohaemorrhagiae strains from a number of Reference Laboratories were confirmed using monoclonal antibody (MoAb) and DNA restriction endonuclease (EcoR1) analyses. With a few exceptions, strain fidelity was demonstrated. Three clinical isolates and one isolate from a rat (Rattus norvegicus) were identified on DNA fragment patterns and found to be similar to the reference strains, icterohaemorrhagiae copenhageni, I. "icterohaemorrhagiae" Ictero I and I. icterohaemorrhagiae RGA.

Animals↗
PubMed1991

Use of the enzyme linked immunosorbent assay (ELISA) to detect the IgM and IgG antibody response to Leptospira interrogans Serovar hardjo in pregnant ewes.

Fourteen pregnant ewes were inoculated with Leptospira interrogans serovar hardjo via intramuscular injection or inoculation via the conjunctiva. The serological response to inoculation detected by the microscopic agglutination test was compared to IgM and IgG antibody levels detected by enzyme linked immunosorbent assay. Intramuscular injection produced a better serological response than conjunctival inoculation. The mean IgM response was short lived whereas the IgG antibody response and the MAT persisted for much longer. The IgM antibody levels may be useful as an indicator of recent exposure. Although leptospiruria was not established in any of the animals, 6 of the 14 pregnant ewes failed to rear a healthy lamb.

Agglutination Tests↗
PubMed1993

Chromosomal rearrangement and serovar conversion in Leptospira biflexa strains.

A bacterial population change involving chromosomal rearrangement and phenotypic changes in antigens, proteins and lipopolysaccharides is described for strains of Leptospira biflexa that were previously grown in media containing homologous oligoclonal antibodies. The chromosomal rearrangement phenomenon showed that the variants differed from the parent strains, yet they were similar to phenotypically related serovars already occurring in nature. Accordingly, in vitro serovar conversion mediated by chromosomal rearrangement, due to as yet unknown genetic mechanisms, had occurred.

Animals↗
PubMed1990

Biological activities and endotoxic activities of protective antigens (PAgs) of Leptospira interrogans.

The biological and endotoxic activities of protective antigens (PAgs) prepared by the chloroform-methanol-water method from Leptospira interrogans serovars lai, copenhageni and canicola were examined. The PAg preparations did not show a local Shwartzman reaction in the rabbits at doses of 100 micrograms and 50 micrograms/site and lethal toxicity to galactosamine-sensitized mice at the dose of 12.5 micrograms to 50 micrograms/mouse. PAgs exhibited a weak cytotoxic action on peritoneal exudate macrophages of C3H/HeJ and C3H/HeN mice at the dose of 500 micrograms/ml in vitro, but did not show cytotoxicity for BHK-21 cells kidney cells of the Syrian hamster, CHO-K1, ovary cells of the Chinese hamster, and CHL, lung cells of the Chinese hamster, at doses of 5 and 500 micrograms/ml. Gelation activity in the Limulus test was only observed at PAg concentrations over 100 ng/ml, which dose was 10,000 times that of lipopolysaccharide (LPS) of Escherichia coli O55:B5. Furthermore, an adjuvant activity of PAgs was not observed in the production of anti-sheep red blood cell antibody in mice. Mitotic conversion of spleen cells from C3H/HeJ and C3H/HeN mice was observed by the addition of PAgs in vitro. These results indicated that the biological properties of PAgs were different from those of LPS prepared from gram-negative enterobacteria, that PAgs had no endotoxic activity and that the biological safety of PAgs as vaccine was proved.

Animals↗
PubMed1998

Morphological characterization of lung and kidney lesions in C3H/HeJ mice infected with Leptospira interrogans serovar icterohaemorrhagiae: defect of CD4+ and CD8+ T-cells are prognosticators of the disease progression.

Neonates and young C3H/HeJ mice were highly susceptible to lethal infection with Leptospira interrogans serovar icterohaemorrhagiae. The main pathological changes were seen by light microscopy in the lung and kidneys of 3-week-old mice at 11 days after inoculation. Lung histological lesions included small and medium-sized vasculitis with fibrinoid changes, hemorrhages, moderate infiltrate of mononuclear inflammatory cells and fibrin thrombi. In the kidney there was mild to severe acute tubular necrosis associated with interstitial nephritis. Repair of damaged tubules in surviving mice was observed within 17 days after inoculation. Pathological findings of CD4+ and CD8+ cell-depleted mice were clearly more severe than that seen in untreated animals by 17 days after inoculation. Comparatively, CD4+/CD8+ cell-depleted mice had more marked lung and kidney lesions than in the CD8+ or CD4+ cell-depleted mice. A very high level of tubular alterations was seen in the kidneys of all treated groups. Increased degrees of interstitial nephritis also reflected the T-cell subsets depletion related events. Leptospires were clearly demonstrated by immunoperoxidase close to the sites of histological damage in all infected mice. C3H/HeJ mice represent a useful model for further studies in pathogenicity of leptospires and natural resistance of the host.

Animals↗
PubMed1999

Phylogenetic analysis of Leptospira strains of pathogenic serovars using 23S rDNA gene sequences.

The 23S ribosomal DNAs were amplified from 11 strains of Leptospira interrogans sensu lato by polymerase chain reaction (PCR) and sequenced. The PCR products of about 290-bp DNA fragments indicated more than 97% sequence similarity to each other. The phylogenetic tree based on the 23S ribosomal DNAs obtained in this study revealed that 11 strains of L. interrogans examined composed a cluster distinct to that of L. weilii and L. borgpetersenii, confirming that these strains were similar to strain Moulton of L. interrogans serovar canicola in 23S rDNA sequence.

Base Sequence↗
PubMed1997

Detection of an antigenic protein of Leptospira interrogans which shares epitopes with the equine cornea and lens.

A protein epitope which is involved in an antigenic relationship between equine ocular tissues and Leptospira interrogans was detected in homogenates of the bacterium. The antigenic determinant was harboured on a peptide structure which was shown to be sensitive to the action of denaturing and reducing agents by means of Western blotting. The outer surface of the leptospires appeared to be free of this epitope as was proved by dot-blot and electron microscopic studies.

Animals↗
PubMed2000

Overview of the epidemiology, microbiology, and pathogenesis of Leptospira spp. in humans.

Leptospirosis is probably the world's most widespread zoonosis. It remains underdiagnosed largely due to the broad spectrum of signs and symptoms attributable to this spirochetal pathogen. Leptospira spp. cause a diversity of diseases from flu-like illness to Weil's syndrome with multi-organ failure. Recent epidemics may herald a change in virulence or an alteration in the balance between humans and their interactions with other host species and the environment.

Animals↗
PubMed1987

Experimental infection of monkeys with Leptospira interrogans serovar hardjo.

Grivet monkeys experimentally infected with two different strains of Leptospira interrogans serovar hardjo showed no signs of severe clinical disease. There were no significant macroscopic lesions in any of the tissues examined, but the organisms were demonstrated in various tissues by immunofluorescent technique and were isolated from the blood and urine of two monkeys and the kidney of one. Abraded skin was shown to be a viable route of infection in non-human primates.

Animals↗
PubMed1987

A new serovar mogdeni of serogroup Tarassovi of Leptospira interrogans isolated from a sewage plant in England.

Among 30 strains of leptospires isolated from samples of sewage taken before and during treatment at two sewage plants in England, only one appeared to belong to Leptospira interrogans, the species that comprises the leptospires that are pathogenic to man and animals. That strain, Compton 746, was isolated from settled sewage, before treatment at a treatment plant that deals mainly with human sewage. It was shown serologically to belong to serogroup Tarassovi and appears to represent a new serovar that has been named mogdeni after the name of the sewage plant, Mogden, from which it was isolated.

Agglutination Tests↗
PubMed2003

Molecular characterization of Leptospira spp. strains isolated from small rodents in Croatia.

We report the isolation and characterization of 16 Leptospira spp. strains isolated from small rodents captured in 11 different regions of inland Croatia. Large NotI and SgrAI restriction fragment allowed us to assign 10 isolates to the serovar istrica, 5 isolates to the serovar tsaratsovo and 1 isolate to the serovar lora. The phylogenetic analysis conducted from the sequences of the first 330 bp from the 16S rDNA gene revealed that the strains belonged to three different species, L. borgpetersenii, L. kirschneri and L. interrogans. Carrier rates in eight rodent species varied from 0 to 71.4%. Mus musculus showed the highest infection level and confirmed its role as a major reservoir of the serogroup Sejroë. For the first time we reported the occurrence of serovars tsaratsovo and lora in Croatia.

Animals↗
PubMed2004

A unique strain of Leptospira isolated from a patient with pulmonary haemorrhages in the Andaman Islands: a proposal of serovar portblairi of serogroup Sehgali.

Leptospirosis is endemic in the Andaman Islands, often occurring as outbreaks during the post-monsoon period. Pulmonary involvement is common and associated with high morbidity and mortality. During the investigation of an outbreak in North Andaman in 1996 an isolate was recovered from the blood of a patient with fever, headache, body aches and haemoptysis with respiratory distress as presenting symptoms. The isolate was characterized using the cross-agglutination absorption test (CAAT) and monoclonal antibodies (mAbs). The isolate showed typical morphology and characteristic motility of the genus Leptospira. Growth was inhibited at 13 degrees C and in the presence of 8-azaguanine. The isolate could not be identified with grouping sera representing 25 serogroups, CAAT and mAbs. A new serovar of a new serogroup is proposed. Genetic characterization using polymerase chain reaction (PCR) followed by sequencing of the PCR product and randomly amplified polymorphic DNA fingerprinting (RAPD) showed that the isolate was genetically similar to L. interrogans sensu stricto.

Adult↗
PubMed1998

Serological titres to Leptospira fainei serovar hurstbridge in human sera in Australia.

A set of 723 diagnostic sera from human patients, submitted for the microscopic agglutination test (MAT) for antibodies to a group of 6 leptospiral serovars, was also tested by MAT for antibodies to the recently-discovered Leptospira fainei serovar hurstbridge. MAT titres of > or = 128 to serovar hurstbridge were detected in 13.4% of these sera, and titres of > or = 512 in 7.2%. In contrast, none of 62 sera obtained from a control population of laboratory staff gave titres of > or = 128. The difference between the number of titres of > or = 128 given by the two groups of sera was highly significant (P < 0.01). The titres observed may have been due to cross-reactions with other leptospiral serovars, but this could not be demonstrated. An alternative explanation is that serovar hurstbridge is present in the human population.

Agglutination Tests↗
PubMed1998

Infection rate of Leptospira interrogans in the field rodent, Apodemus agrarius, in Korea.

Leptospirosis has significantly decreased in Korea since 1988, following the leptospiral vaccination programme initiated in 1988. Whether this wholly explains the decreased incidence is uncertain. As an initial step to answer this question, infection rates of Leptospira interrogans in field rodents, Apodemis agrarius, were examined and compared with previous data. Two hundred and twenty-two A. agrarius were captured during October-December 1996. Spirochaetes were isolated from 22 (9.9%) and leptospiral DNA was detected in an additional 6 rodents (12.6%). Subsequent microscopic agglutination tests (MAT) classified all these isolates as L. interrogans serogroup Icterohaemorrhagiae serovar lai. The above data did not significantly differ from previous surveys in 1984-7. There was no significant change of L. interrogans infection in field rodents following the introduction of the vaccination programme in Korea. Further studies are needed to determine the role of human vaccination in reducing incidence.

Animals↗