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PubMed1981

Studies on the kidneys of pregnant hamsters infected with Leptospira canicola.

An electron microscopic study on the histopathological changes in the kidneys of pregnant hamsters resulting from infection with Leptospira canicola was undertaken. The experiment revealed damage to the glomeruli as well as the tubules. The severity of these lesions increased with the progress of the disease and examination of kidney sections showed leptospires in the tissue. It is suggested that the stress of pregnancy has some influence on the severity of the lesions seen in this disease.

Animals↗
PubMed1998

In vivo apoptosis of hepatocytes in guinea pigs infected with Leptospira interrogans serovar icterohaemorrhagiae.

To investigate the contribution of the previously demonstrated in vitro apoptosis to the pathogenesis of leptospirosis, guinea pigs were infected with Leptospira interrogans serovar icterohaemorrhagiae strain Verdun and sequentially killed to collect target organs involved in the natural history of the disease (liver, kidneys, lungs, spleen and heart). The combination of histopathological procedures and a specific TUNEL assay showed a significant Leptospira-induced programmed cell death of hepatocytes with a peak at 48 h post inoculation. Hepatocyte nuclei showed morphological changes including fragmented and condensed nuclei. This phenomenon occurred early in the course of the disease at a time where infecting leptospires were present at a low density between the liver parenchyma cells.

Animals↗
PubMed1997

Effects of experimental infection with Leptospira interrogans serovar balcanica on the health of brushtail possums (Trichosurus vulpecula).

Data on changes in the condition and feeding behaviour of captive brushtail possums (Trichosurus vulpecula) following an experimental infection with Leptospira interrogans serovar balcanica are presented. The daily food intake of nine experimentally infected possums was recorded for 47 days before and 24 days after balcanica inoculation (0.5 ml intraperitoneally containing about 10(8) organisms). Body weight was recorded seven times between 42 days before and 96 days after inoculation. The mean daily food intake of infected possums decreased significantly throughout the 24-day recording period after infection with balcanica. The mean body weight of infected possums had decreased significantly by day 26 after inoculation but had fully recovered by day 96 after inoculation. Uninfected and control possums showed no significant changes in mean daily food intake or mean body weight over the experimental period. These data suggest that the health of possums is temporarily affected by infection with balcanica, but that overt disease caused by balcanica is unlikely. These findings support previous research suggesting that balcanica has only subclinical effects on possums.

Journal Article↗
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↗
PubMed1996

Protective activity of rabbit polyclonal anti-idiotype antibody against Leptospira interrogans infection in hamsters.

We prepared an anti-idiotype (Id) antibody against leptospirosis. Serum from rabbit immunized with monoclonal antibody (MAb) LW2, which reacted to the main protective antigen prepared from Leptospira interrogans serovar lai, inhibited agglutination of the organism by MAb LW2. The immune rabbit serum was applied to a column coupled with normal mouse IgG as a ligand (first column), and the unbound fraction eluted was applied to a column coupled with MAb LW2 as a ligand (second column). The bound fraction (anti-Id antibody) eluted from the second column inhibited the binding of MAb LW2 to sonicated leptospiral cells in ELISA. Mice produced antibodies against Leptospira by intraperitoneal immunization with the anti-Id antibody at doses of 2 mu g/mouse or more. Hamsters were protected by immunization with the anti-Id antibody at doses of 2 and 20 mu g/hamster from the lethal infection of Leptospira. This is the first report concerning the use of an anti-Id antibody against leptospirosis.

Agglutination↗
PubMed1996

Presence of antigen and antibodies in serum and genital discharges of cows from dairy herds naturally infected with Leptospira interrogans serovar hardjo.

Samples of cervico-vaginal mucus from 163 bulling cows (group 1) and post calving discharges from 59 newly calved cows (group 2) in five dairy herds naturally infected with Leptospira interrogans serovar hardjo were examined for the presence of antigen and IgG and IgA antibodies by using two ELISA systems which were protein or carbohydrate based. Corresponding serum samples were examined for systemic immune responses by using a microscopic agglutination test (MAT) and IgG-ELISA tests. Antigen was detected by direct immunofluorescence in six of the 163 samples of cervico-vaginal mucus. Both IgG and IgA antibodies were detected by ELISA in the genital discharges with a prevalence much higher than that obtained by the MAT but lower than that observed with the serum IgG-ELISA. Combining both groups, none of the MAT-positive cattle was negative by serum-ELISA. By using the protein or carbohydrate fraction serum IgG-ELISA assays, respectively, 29 or 41 per cent of the MAT-negative cows were positive at a titre of at least 1:40. Similarly, eight or 23 samples (10 or 27 per cent) had titres of at least 1:20 in the genital discharge ELISA for IgG and IgA antibodies, respectively. The serum IgG-ELISA was the most efficient in detecting hardjo antibodies, but in group 2 the IgG- and IgA-ELISA of the post calving discharge proved to be equally effective.

Animals↗
PubMed1997

[Investigation on the rate of urinary excretion of leptospires among cattle naturally infected with Leptospira interrogans].

Urine samples of Leptospires from cattle were detected by polymerase chain reaction (PCR) and isolation. Positive rates by Southern-blot and agarose gel electrophoresis of PCR amplification productions were 13% and 11% respectively. Positive rate of isolation was 3.1%. Various positive rates by PCR for cattle urine from different areas were discovered. Average rate of urinary excretion of Leptospires among cattle that naturally infected with Leptospira interrogans was 13.2%. Data showed that cattle was a major source of infection of Leptospirosis in some parts of China. According to the comparsion of results between PCR and isolation, we believe that PCR is a sensitive, rapid and simple method for the investigation on source of infection of Leptospirosis.

Animals↗
PubMed1991

The role of the common vole (Microtus arvalis) in the epidemiology of bovine infection with Leptospira interrogans serovar hardjo.

Control of leptospirosis in cattle depends on the presence of other possible maintenance hosts, with which cattle may have contact. Twenty-seven common voles (Microtus arvalis) were trapped on a dairy farm where the cattle were infected with Leptospira interrogans serovar hardjo (hardjo). In the sera of 11 voles, titres greater than or equal to 100 against serogroup Grippotyphosa were measured with the microscopical agglutination test (MAT). From 8 of these 11 voles, which also showed interstitial lymphoplasmacellular nephritis, Leptospira interrogans serovar grippotyphosa was isolated. We found no evidence that the common vole is a maintenance host for hardjo in this biotope.

Agglutination Tests↗
PubMedDate not supplied

Detection of pathogenic Leptospira spp. infections among mammals captured in the Peruvian Amazon basin region.

To identify potential zoonotic reservoirs of pathogenic leptospires in the Peruvian Amazon basin, wild mammals were trapped from July 1997 to December 1998 near the city of Iquitos. After extraction of nucleic acids from animal kidneys, DNA of pathogenic leptospires was identified by polymerase chain reaction (PCR) assays using one of two primer sets, one amplifying a region of the 23S rRNA gene, and the other amplifying a gene fragment specific for Leptospira spp (G1/G2 primers). Overall, 29% (40 of 136) of the mammals tested showed evidence of renal infection by Leptospira spp., including 20% (13 of 64) of the rodents, 39% (20 of 51) of the marsupials, and 35% (7 of 20) of the chiropterans (bats). Marsupials and chiropterans were implicated as more significant reservoir hosts of leptospires pathogenic to humans than previously recognized.

Animals↗
PubMed1990

Evaluation of an ELISA for the diagnosis of experimentally induced and naturally occurring Leptospira hardjo infections in cattle.

An enzyme-linked immunosorbent assay (ELISA) for the diagnosis of Leptospira interrogans serovar hardjo (hardjo) infection in cattle was compared with the microscopic agglutination test (MAT). Glutardialdehyde was used in the ELISA to couple sonicated hardjo antigen to the microtiter plate. Mouse monoclonal anti-bovine IgG1 coupled to peroxidase was used as conjugate. Sera from calves experimentally inoculated with hardjo reacted positively in the MAT as early as 10 days after inoculation; these sera did not react positively in the ELISA until 25 days after the first inoculation. Positive and negative field sera from 704 adult cattle on 90 farms were examined by the MAT and the ELISA; a 90% correlation between the two tests was demonstrated. Eighty-six sera from calves inoculated with four Leptospira serogroups other than hardjo and 227 field sera from adult cattle with naturally occurring leptospirosis other than hardjo were examined by the ELISA. Fewer than 1% of these heterologous sera reacted with hardjo antigen in the ELISA. We concluded that the ELISA described in this report is an advantageous alternative to the MAT for diagnosing leptospirosis.

Agglutination Tests↗
PubMed2005

Changes in lipopolysaccharide O antigen distinguish acute versus chronic Leptospira interrogans infections.

Leptospirosis is the most geographically widespread zoonotic disease in the world. A severe pulmonary form of leptospirosis (SPFL) is being recognized with increased frequency. We have reported that human SPFL isolates of Leptospira cause acute lethal infection with prominent pulmonary hemorrhage in guinea pigs. We have found that the same SPFL strains cause asymptomatic infection and chronic renal shedding in rats, where infection is restricted to the renal tubules. To address the antigenic composition of host tissue-derived Leptospira (HTL), motile leptospires were purified from guinea pig liver by centrifugation on Percoll density gradients and compared to Percoll-purified in vitro-cultivated Leptospira (IVCL). The lipopolysaccharide O antigen (Oag) content of guinea pig liver-derived HTL was markedly reduced compared to that of IVCL, as demonstrated both by immunoblotting with a monoclonal antibody that was serovar specific for Oag and by periodate-silver staining. Confocal microscopy of HTL in guinea pig liver and kidney with the Oag-specific monoclonal antibody provided further evidence that diminution of the Oag content occurred in situ during lethal infection. In contrast, the Oag content of HTL in chronically infected rat renal tubules was indistinguishable from that of IVCL. These findings suggest that there may be regulation of Oag synthesis by Leptospira specific to the animal host infected. The hypothesis that the Oag content is related to whether lethal infection or chronic renal tubular colonization occurs remains to be tested.

Acute Disease↗
PubMed2003

Guillain-Barre syndrome in a pediatric patient following infection due to Leptospira.

Leptospirosis is a disease with protean manifestations. We report a case of Guillain-Barre syndrome (GBS) in a pediatric patient following infection with Leptospira. Infecting Leptospira presumably belonged to serovar Copenhageni. The patient recovered completely. The possibility of GBS developing as a result of antecedent leptospiral infection should be kept in mind.

Agglutination Tests↗
PubMed2006

A histopathological study of hearts and spleens of hamsters (Mesocricetus auratus) infected with Leptospira interrogans, serovar pyrogenes.

The effects of Leptospira interrogans on the heart and spleen of hamsters were studied histopathologically. Infected hamsters were sacrificed at 1 hour, 6 hours and on days 1, 2, 3, 4, 5 and 6 after inoculation with Leptospira interrogans serovar pyrogenes. The heart and spleen of each of the sacrificed animals were removed and processed for routine conventional light microscopy. Infected hearts showed degenerative change of the cardiac muscle cells composed of cellular swelling, condensation of chromatin granules, pyknotic nuclei and acidophilic cytoplasm. Congestion of the cardiac blood vessels and hemorrhagic areas were found. Necrosis of the cardiac muscle cells was surrounded by numerous inflammatory cells. In the spleen, cellular necrosis was found scattered throughout the splenic cord. The splenic sinusoids were dilated and congested with many hemorrhagic areas. Inflammatory cell infiltration was also noted in the splenic parenchyma and the splenic sinusoids.

Animals↗