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PubMed1981

The enzyme-linked immunosorbent assay (ELISA) as a serological test for detecting antibodies against Leptospira interrogans serovar hardjo in sheep.

The enzyme-liked immunosorbent assay (ELISA) was compared with the standard microscopic agglutination test (MAT) as a method for detecting antibodies against Leptospira interrogans serovar hardjo in sheep. Peak antibody levels detected by the 2 tests occurred at different times following experimental infection of sheep. In serums from flocks of sheep with naturally acquired infection there was a 95% correlation between MAT and ELISA with respect to the presence or absence of antibody to serovar hardjo, although the levels of correlation of the titres of the 2 tests was low. The 2 tests appeared to measure different antigen-antibody systems. The ELISA would be a useful test for screening large numbers of serums for antibodies to L. interrogans serovar hardjo.

Agglutination Tests↗
PubMed1982

Protection of pregnant swine by vaccination against Leptospira infection.

The protection conferred on pregnant gilts by 2 commercially available leptospira interrogans serovars pomona and tarassovi bacterins was evaluated. Gilts vaccinated either 3, 6 or 12 months prior to natural challenge with L. interrogans serovar pomona had significantly lower abortion rates (2% vs 69%) and foetal mortality rates (14% vs 57%) than unvaccinated controls. One vaccine was significantly superior to the other and contained approximately twice the number of L. interrogans serovar pomona organisms per vaccine dose. Neither vaccine protected against renal colonisation but vaccination reduced urinary excretion of leptospires. Both vaccines reduced agglutinating antibody response to infection, as measured by the microscopic agglutination (MA) test. This may prevent the detection of a carrier animal by serology. Foetal pigs did not develop specific MA titres. Cultural methods were not reliable in making a diagnosis of foetal infection. Histopathology of foetal liver and kidneys helped in making a diagnosis of foetal infection.

Animals↗
PubMed1983

Bovine abortion associated with Leptospira interrogans serovar hardjo infection.

During 1981, 265 bovine abortions were investigated by serological and histological methods for evidence of leptospiral infection. Leptospires were demonstrated in the tissues of 10 foetuses by a Levaditi silver impregnation technique. Serological testing of maternal sera indicated that Leptospira interrogans serovar hardjo was associated with 5 of the abortions while the remaining 5 were due to L. interrogans serovar pomona infection. In cases of abortion associated with L. interrogans serovar hardjo leptospires were readily demonstrated in foetal liver, kidney, intestine and heart. They were demonstrated less often in lung and placenta and could not be found in foetal brain. Autolysis did not appear to interfere with the demonstration of leptospires by silver impregnation. No lesions attributable to leptospiral infection were seen in placentas but mild interstitial nephritis was found in some of the foetuses. Fourteen other cows had serological evidence of recent leptospiral infection but leptospires were not detected in foetal tissues. Histological examination of silver impregnated foetal tissues in combination with the microscopic agglutination test was shown to be an effective method for diagnosing abortion associated with L. interrogans serovar hardjo in cattle.

Abortion, Veterinary↗
PubMed1984

The long term efficacy of a hardjo-pomona vaccine in preventing leptospiruria in cattle exposed to natural challenge with Leptospira interrogans serovar hardjo.

The long term efficacy of a commercially prepared bivalent vaccine against Leptospira interrogans serovar hardjo and L. interrogans serovar pomona was evaluated in a group of 82 dairy heifers exposed to natural challenge with L. interrogans serovar hardjo for up to 55 weeks after calfhood vaccination. Nineteen heifers were vaccinated twice with a one-month interval, at calfhood (9 to 10 months). A further 18 heifers received a similar calfhood vaccination regimen plus a third injection at adulthood (22 to 23 months), while 19 heifers were vaccinated twice at adulthood only and finally 22 heifers were used as unvaccinated controls. At 55 weeks after calfhood vaccination and prior to adulthood vaccination, only 2.7% of the vaccinated heifers were found to have leptospiruria compared with 58.5% of the unvaccinated heifers (p less than 0.0001). Microscopic agglutination (MA) titres at the same time in the unvaccinated heifers ranged from 32 to 4096 while those vaccinated at calfhood ranged from 32 to 64. Adult vaccination of infected animals did not significantly reduce leptospiruria . Prior to adulthood vaccination, 9 of 19 heifers had leptospiruria , in comparison to 4 of 15 after adulthood vaccination. At the same sampling periods 15 of 22 controls had leptospiruria in comparison to 4 of 9 subsequently tested.

Animals↗
PubMed1989

Leptospira interrogans serovar hardjo is not a major cause of bovine abortion in Victoria.

The aim of this study was to determine whether evidence could be obtained of foetal infection with Leptospira interrogans serovar hardjo in aborted foetuses collected from dairy farms. Material from 197 abortions occurring over a wide area of Victoria was collected over 3 years. None of 195 foetal kidney cultures or 7 cultures from membranes was positive for leptospiral organisms. Immunogold silver staining for leptospires was performed on sections of kidneys, lungs or heart from 156 foetuses, with negative results. Evidence of transient leptospiral infection in 11 of 123 foetuses was obtained by foetal heart blood serology. Two isolates of L. interrogans serovar hardjo were obtained from the urine of milking cows. These strains were examined by restriction endonuclease analysis and both were shown to be of the genotype Hardjobovis, as have been all Australian isolates studied so far. It appears that foetal infection with serovar hardjo is not associated with any substantial proportion of bovine abortions in Victoria, in contrast to the situation in Northern Ireland. The apparent absence from Victoria of the pathogenic genotype Hardjoprajitno is a possible explanation.

Abortion, Veterinary↗
PubMed1991

The influence of maternal antibody and age of calves on effective vaccination against Leptospira interrogans serovar hardjo.

Twelve seronegative cows were vaccinated with an experimental bivalent Leptospira interrogans serovars hardjo and pomona vaccine late in their first pregnancy. Calves born of these dams were divided into 4 equal groups that received this vaccine at 4, 6, 10 and 18 weeks of age, respectively. Before vaccination the group geometric mean titres of maternally-derived circulating antibodies ranged from 2 to 25 for the microscopic agglutination (MA) test and 3 to 35 for enzyme-linked immunosorbent assay (ELISA) using a serovar hardjo outer envelope antigen. Post-vaccination peak titres were 645 to 1612 for MA and 562 to 1037 for ELISA, respectively. Calves vaccinated at the youngest age, had the highest pre-vaccination circulating maternal antibody titres, but showed the smallest rise in post-vaccination antibody titres. Circulating maternal antibody was detected in calves up to 13 weeks of age. All immunised calves were protected against a virulent challenge with serovar hardjo type Hardjobovis, regardless of their age or maternally-derived antibody titres. These findings indicate that calves as young as 4 weeks old, vaccinated in the presence of maternally-derived antibody, can be fully protected against homologous virulent challenge.

Age Factors↗
PubMed1992

Genetic diversity among Australian and New Zealand isolates of Leptospira interrogans serovar pomona.

Restriction endonuclease analysis of 16 Australian and 4 New Zealand isolates of Leptospira interrogans serovar pomona showed that they could be divided into 3 genetic groups. Most of the isolates closely resembled the serovar kennewicki reference strain, and they all differed from the reference strain of serovar pomona. Based on these findings, it is suggested that vaccine manufacturers re-evaluate their choice of serovar pomona vaccine strain.

Animals↗
PubMed1993

Restriction-endonuclease analysis of Australian isolates of Leptospira interrogans serovar hardjo from cattle with agalactia and abortion.

Polyacrylamide gel electrophoresis and agarose gel electrophoresis were used to resolve restriction endonuclease digests of 20 Australian Isolates of Leptospira interrogans cultured from urine samples of cattle with agalactia and abortion. The restriction endonuclease profiles of 19 isolates closely matched the profiles of L interrogans serovar hardjo subtype hardjobovis reference strains. The remaining isolate had a different restriction profile from subtype hardjobovis and subtype hardjoprajitno reference strains and was serologically identified as serovar pomona. Silver staining of polyacrylamide gels gave enhanced resolution of restriction fragments compared with the traditional method of ethidium bromide staining of agarose gels.

Abortion, Veterinary↗
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↗
PubMed1994

A review of laboratory techniques and their use in the diagnosis of Leptospira interrogans serovar hardjo infection in cattle.

This paper reviews the laboratory diagnosis of Leptospira hardjo infection in cattle. Two genotypes of L hardjo, Hardjoprajitno and Hardjobovis, have been identified in cattle, but only Hardjobovis has been isolated in Australia. There are problems with diagnosis and control of bovine leptospirosis. Infection is usually subclinical and the serological titres vary greatly in peak and duration. Leptospires may be excreted in urine for up to 18 months. Low microscopic agglutination test titres may be significant in unvaccinated herds as indicators of endemic infection. Vaccines differ in their composition, and their efficacy is difficult to evaluate. The serological response after vaccination is difficult to differentiate from the response after infection. Pregnant cows that become infected may abort, but this is usually after the serological response has peaked. Therefore, paired serum samples are of little use in diagnosing abortion caused by L hardjo. Fluorescent antibody techniques are more sensitive than dark field microscopy for detection of leptospires in urine and tissue samples. Techniques for culture have improved but are still difficult to perform and take 3 months or longer for results to be known. DNA probes and polymerase chain reaction tests are very sensitive and specific, quick to perform, and can be used on fluid and tissue samples.

Agglutination Tests↗
PubMed1997

Amoxycillin as an alternative to dihydrostreptomycin sulphate for treating cattle infected with Leptospira borgpetersenii serovar hardjo.

OBJECTIVE: To assess the effect of amoxycillin treatment on urinary excretion of leptospires from cattle infected with Leptospira borgpetersenii serovar hardjo. DESIGN: A chemotherapy trial with controls. PROCEDURE: Fourteen heifers serologically negative to L hardjo were inoculated with L hardjo via the conjunctival route and assessed for evidence of infection by serological, fluorescent antibody and microbiological tests. Two injections (48 h apart) of amoxycillin at a dose of 15 mg/kg were administered intramuscularly to seven heifers 6.5 weeks after infection; the remaining heifers acted as untreated controls. Later, these seven control group heifers were treated with a single dose of amoxycillin (15 mg/kg). Samples of urine were collected before and after amoxycillin treatments; kidneys were collected at slaughter, and examined by fluorescent antibody test and microbiological culture. RESULTS: Leptospires were isolated from the urine of 11 of 14 heifers inoculated with L hardjo. After treatment of six of these with two injections of amoxycillin, leptospires were not isolated. Of the controls, four of the five initially leptospiruric heifers continued to shed leptospires; after a single injection of amoxycillin, no leptospires were detected in the kidneys of these four. CONCLUSION: Amoxycillin may be an acceptable alternative to dihydrostreptomycin sulphate for the treatment of cattle infected with L hardjo.

Amoxicillin↗
PubMed1997

Experimental Leptospira borgpetersenii serovar hardjo infection of pregnant cattle.

OBJECTIVE: To observe the effect upon the foetus of experimental infection of pregnant cattle with Leptospira borgpetersenii serovar hardjo. DESIGN: A disease transmission study using pregnant cattle. PROCEDURE: Fourteen heifers serologically negative to L hardjo were artificially inseminated and later challenged with a north-Queensland isolate of L hardjo by conjunctival inoculation. The heifers were serologically monitored and their urine examined for the presence of leptospires using culture and fluorescent-antibody tests at appropriate intervals. Elective caesarean sections were performed on pregnant heifers at 6.5 weeks after the challenge. Foetuses were examined using serological, histopathological, microbiological and fluorescent-antibody tests. RESULTS: Ten of the heifers became pregnant, but three subsequently aborted before challenge. After challenge, all 14 heifers seroconverted and L hardjo was isolated from the urine of 6 of the 7 pregnant heifers. No evidence of foetal L hardjo infection was detected. Two of the foetuses had histopatho-logical lesions consistent with Neospora sp infection. CONCLUSION: It is likely that the isolate of L hardjo used in this study does not normally infect the foetus. Neospora sp may be a more significant cause of bovine reproductive wastage.

Animals↗
PubMed2005

[A case of leptospirosis caused by Leptospira borgpetersenii serovar sejroe infected in Bali Island, Indonesia].

We report a patient with leptospirosis caused by Leptospira borgpetersenii serovar Sejroe infection on Bali Island, Indonesia. This 33-year-old Japanese man had stayed at a resort hotel on the island from July 8 to July 13 2004. At the hotel, he swam in the pool, walked barefoot, and lied down in the grass. He developed a high fever and headache 7 days after completing his trip, and was admitted to our hospital on July 23. On admission he showed conjunctival suffusion and complained of myalgias. Laboratory findings included granulocytosis and elevated CRP. Plasmodium spp. were not found in blood smears, and no pathogenic bacteria were isolated from blood or fecal cultures. We diagnosed the patient as leptospirosis upon detection of slender coiled organisms with characteristic morphology by darkfield examination of blood sample. Minocycline 100 mg i.v.b.i.d. showed excellent efficacy. A microscopic agglutination test (MAT) during the convalescent stage demonstrated a significant increase in antibodies against L. borgpetersenii serovar Sejroe, confirming the diagnosis of leptospirosis. Despite occurrence of a pandemic of leptospirosis in certain Southeast Asian countries including Indonesia, information concerning pandemic disease is limited. In addition serovars of "imported" cases representing infection in pandemic areas differ widely from those in domestic cases. Adequate laboratory support therefore is crucial for accurate diagnosis of leptospirosis.

Adult↗
PubMed1983

In vitro susceptibilities of five Leptospira strains to 16 antimicrobial agents.

The in vitro activities of 16 antibiotics against five serovar strains of the genus Leptospira were determined. Five of the antibiotics (ampicillin, cefmetazole, moxalactam, ceftizoxime, and cefotaxime) exhibited a lower minimal inhibitory concentration than did penicillin G. In tests for minimal bactericidal concentration, ceftizoxime and cefotaxime were found to be more effective than penicillin G, streptomycin, tetracycline, ampicillin, and cefmetazole.

Anti-Bacterial Agents↗
PubMed1989

Efficacy of ciprofloxacin against Leptospira interrogans serogroup icterohaemorrhagiae.

Ciprofloxacin activity against Leptospira interrogans serogroup icterohaemorrhagiae was studied in vitro and in an animal model. The MBC of ciprofloxacin was 0.6 microgram/ml. Three of three Syrian hamsters died 8 to 9 days after intraperitoneal challenge with 10(6) leptospires. In contrast, five of six animals given ciprofloxacin 3 or 5 days after challenge survived.

Animals↗
PubMed1993

Antimicrobial effects of a new carboxyquinolone drug, Q-35, on five serogroups of Leptospira interrogans.

New carboxyquinolone drugs, including the recently developed Q-35, were evaluated for their in vitro potency against five serogroups of Leptospira interrogans. Q-35, ofloxacin, ciprofloxacin, and tosufloxacin showed MICs (0.05 to 0.20 microgram/ml) comparable to those of tetracycline. However, MBCs of these drugs varied between 10- and 100-fold above the MIC for most strains tested. Q-35 was shown to be active against L. interrogans in vitro as judged by the MICs obtained.

Anti-Infective Agents↗
PubMed2001

Penicillin-binding proteins in Leptospira interrogans.

The Leptospira interrogans ponA and pbpB genes were isolated and characterized. ponA and pbpB encode the penicillin-binding proteins (PBPs) 1 and 3, respectively. There is little sequence variation between the PBP genes from two L. interrogans strains (serovar icterohaemorrhagiae strain Verdun and serovar pomona strain RZ11). The deduced L. interrogans PBP 1 and PBP 3 protein sequences from the two strains shared over 50% similarity to homologous proteins from Escherichia coli. It was demonstrated for strain Verdun that ponA and pbpB are transcribed individually from their own promoter. The ponA and pbpB genes from both strains are separated by 8 to 10 kb and oriented such that their transcription is convergent. The L. interrogans PBP 1 and PBP 3 proteins were synthesized in E. coli and were modified with ampicillin using a digoxigenin-ampicillin conjugate. These data show that both genes encode functional PBPs.

Adenosine Monophosphate↗
PubMed2003

In vitro susceptibilities of seven Leptospira species to traditional and newer antibiotics.

Human leptospirosis is generally treated with penicillin or doxycycline. We studied the susceptibilities of 11 serovars (seven species) of Leptospira to 14 antibiotics. With the exception of chloramphenicol, all tested agents were at least as potent as penicillin and doxycycline, with the macrolide and ketolide drugs producing the lowest MICs (and minimal bactericidal concentrations).

Anti-Bacterial Agents↗