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At least 19 recordsLinked to original sources

Survey on the prevalence of leptospira infections in the Italian population.

This investigation is the first nationwide survey on the circulation of leptospira infections in human beings in Italy. In nine out of twenty Italian regions, representative samples of the population were investigated for the presence of leptospira infections. Unexpectedly, leptospira infections were found to be widespread, the number of cases being much higher than the diagnosed clinical cases. There were found to be high, medium, and low risk areas. On the whole, the risk for the rural population was no higher than the risk for urban dwellers; leisure activities, contact with animals and residence on the plain versus residence in the hills were important risk factors. There was an unidentified risk factor in urbanites which was absent in the rural population. A changing pattern in infecting serovars was observed, with infections from serogroups Sejroe, Javanica and Australis prevailing over infections from the Icterohaemorrhagiae and Bataviae serogroups, which were the main agents of human leptospirosis during the 1950s. The mechanisms of these changes, the need for epidemiological surveys and improved diagnostic methods of screening are discussed.

Adult↗

Doxycycline prophylaxis for experimental leptospira infection in non-human primates and hamsters.

Doxycycline was effective as a chemoprophylactic agent for experimental Leptospira infection in non-human primates and hamsters. Monkeys injected intraperitoneally with Leptospira bataviae, and receiving only diluent as treatment developed a leptospiremia during the first week and later leptospires were cultured from the cerebrospinal fluid and urine. Monkeys treated daily with oral doxycycline for 10 days beginning one day before infection had a shortened period of detectable leptospiremia, and organisms were never detected in the cerebrospinal fluid or urine. Even an oral dose of doxycycline 2 hours before infection and on day 7 prevented the later infection of the cerebrospinal fluid and urine. In hamsters, doxycycline treatment prevented deaths from acute Leptospira infection and when hamsters were treated daily for 4 or more days, renal infection was prevented. The results of animal studies, the susceptibility of LC0475 and the five other isolates to doxycycline in vitro, and lack of evidence for antibiotic resistance in culture suggests this antibiotic may be useful as a prophylactic drug for high risk groups and an effective treatment for leptospirosis in Thailand.

Animals↗

Treatment of human leptospira infections with semicillin (ampicillin) or with amoxil (amoxycillin).

Ampicillin (Semicillin) and Amoxycillin (Amoxil) have a strong leptospirocidal effect in vitro and also in vivo. We have tested these drugs on 28 patients suffering from Leptospira infection. The patients generally received per os 3 g Ampicillin (Semicillin) or 2 g Amoxycillin (Amoxil) per day over a period of 6 days. In the groups treated with Ampicillin and Amoxycillin the average durations of fever during the treatment were 1.6 and 1.2 days, respectively. In the first group (Ampicillin) a 'second wave of fever' occurred in one case (5%) and in the second group (Amoxycillin), in 0% (as compared to 22% after treatment with benzylpenicillin). On the basis of our experiences, Ampicillin and Amoxycillin are strongly recommended for the treatment of human Leptospira infections.

Adolescent↗

[Gene diagnostics of acute persistent Leptospira infection].

The results of clinical trials carried out in different foci have demonstrated high diagnostic value of analysis made with the use of the polymerase chain reaction (PCR) at early stages of Leptospira infection caused by infective agents of the serogroups Grippotyphosa, Canicola and Icterohaemorrhagiae. The possibility of leptospiremia lasting considerably longer than heretofore believed to be possible, as well as the persistence of leptospires in the liquor of patients after the acute phase of the disease is over, i.e. during the early and late convalescence periods, has been shown. This is indicative of good prospects of using the PCR analysis not only for early rapid diagnostics of Leptospira infections, but also for controlling the course of the infection, for prognosticating early and late complications of the disease, as well the mechanisms of pathogenesis.

Acute Disease↗

[Etiological structure and clinical epidemiological characteristics of Leptospira infection in Rostov Province based on data from therapeutic institutions from 1960 to 1983].

Changes in communal conditions, in economy, as well as in ecology and fauna, which took place in Rostov Province during the last decade (1973-1983) determined shifts in the etiological structure of Leptospira infection and in its course. The study revealed an increase in morbidity caused by L. icterohaemorrhagiae (up to 61%) and L. hebdomadis (up to 22%) with a simultaneous decrease in the isolation rate of L. grippotyphosa and L. pomona (up to 2-3%). In most cases (77%) the diseases caused by leptospires of different serogroups were found to take an icteric course accompanied by the development of hepatorenal insufficiency (46%). The similarity of clinical manifestations in different etiological forms of Leptospira infection was determined by common pathogenetic and pathophysiological features characteristic of the development of the leptospiral infectious process.

Age Factors↗

Antibody response to genus- and serovar-specific leptospiral antigens in Leptospira-infected cows.

In cows inoculated with Leptospira interrogans serovar pomona or hardjo, the 2-mercaptoethanol-sensitive microscopic agglutination test (MAT) antibody to the serovar appeared 3 to 8 days after inoculation and peaked at 10 to 20 days, whereas the 2-mercaptoethanol-resistant MAT antibody was predominant at 35 to 80 days. A persistent antibody response, probably associated with serovar-specific leptospiral antigens, was detected in the cows inoculated with serovar pomona, using a sonicated or an alkaline-extracted antigen derived from serovar pomona in the enzyme-linked immunosorbent assay (ELISA). In contrast, a short-lived antibody response to the same antigens was demonstrated in cows inoculated with serovar hardjo, probably more typical of the response to genus-specific leptospiral antigens. Antigens derived from L biflexa serovar patoc only detected the latter type of antibody response in cows inoculated with serovar pomona or hardjo. Correlative studies revealed that the antigens derived from serovar patoc seem to be genus specific and serologically closely related, but not identical. The antigens derived from serovar pomona were genus specific on the basis of the early antibody response to leptospiral inoculation in the cows, but serovar specific based on the subsequent more persistent response to leptospiral inoculation. These antigens were also serologically closely related, but not identical. Examination of sera from cows that aborted and were MAT-positive for serovar pomona or hardjo revealed a more serovar-specific antibody response, indicating that there may have been a less recent leptospiral antigenic stimulus, thus emphasizing the caution with which results of the ELISA and other serologic assays for the detection of bovine leptospirosis must be interpreted.

Agglutination Tests↗

[The use of nonpathogenic leptospira as diagnostic antigens for the diagnosis of leptospira infections in cattle].

The seroprevalence of leptospira antibodies was determined in 4377 bovine sera by microagglutination assay using 11 Leptospira interrogans serovars. In 10% (439 samples) of the sera, a positive reaction was detected. These included 275 sera (62.6%) with reaction to L. grippotyphosa, 159 (36.2%) to L. saxkoebing and 5 (1.1%) sera with reactions to other serovars. Multiple reactions were found in 9.8% of the 439 positive sera, whereby the Sejroe group dominated (65%) within the possible combinations of crossreactions. To determine the suitability of nonpathogenic strains as polyvalent diagnostic antigens, two L. biflexa serovar patoc strains were compared with the above-mentioned 11 L. interrogans serovars in microagglutination testing of 1995 screen sera. The sensitivity of the test was found to be 0.3% and the specificity was 80.3%. Using the two L. patoc strains, all of the 415 positive field sera and 11 positive control sera yielded negative reactions. Based on these results, the use of L. biflexa serovar patoc cannot be recommended as polyvalent antigen in the diagnosis of bovine leptospirosis by microagglutination.

Agglutination Tests↗

The coypu as a rodent reservoir of leptospira infection in Great Britain.

The coypu (Myocastor coypus Molina) is an aquatic rodent that has become a widespread pest in the south-east of England. Since the natural habitat of this animal is aquatic, the possibility of infection with leptospires was investigated. Twenty-nine coypu were trapped and examined by serological, histological and cultural methods. Of these, there was serological evidence of infection in seven coypus and Leptospira interrogans var. Wolffii was isolated from a further animal. This appears to be the first report of the isolation of leptospira from a coypu in Great Britain.

Animals↗

Immunohistochemical investigations of leptospira-infected golden hamsters in potency tests.

Golden hamsters taken from routine potency testing of leptospirosis vaccines were investigated for leptospirae after a challenge infection. Kidneys, livers, and spleens were examined immunohistochemically by the unlabelled antibody enzyme (PAP) method, and samples of these organs were additionally cultured for the evidence of living leptospirae. In non-vaccinated animals the recultivation method indicated leptospirae during the bacteraemic phase, beginning immediately after infection. Both methods resulted in positive reactions after organ manifestations. Intravascular evidence of leptospirae in the kidneys could be seen first on day 3 after infection. On day 7, there was intracellular and intratubular evidence as well, combined with tubulo-interstitial alterations. In vaccinated animals the bacteraemia after infection was reduced. Organ manifestations were seen rarely; there were less severe or no pathohistological alterations.

Animals↗

[Leptospira infected rat population as probable cause of a fatal case of Weil's disease].

In the summer of 1992 a patient died of a leptospiral infection which he probably had contracted while he was swimming in an artificial lake in the region of Tübingen/Reutlingen. Regarding the epidemiological role of leptospirosis the rodent population was investigated, because rats and mice were often seen in the surrounding area. 11 rats and 20 mice could be trapped. From their urine or kidneys two leptospiral serovars were isolated: Serovar copenhageni from Rattus norvegicus and serovar saxkoebing from Clethrionomys glareolus. Leptospiral antibody titers were not detected in one of these infected animals. It may be supposed that the Leptospira interrogans serovar copenhageni out of the Serogroup Icterohaemorrhagiae had caused the leptospiral infection of the patient.

Animals↗

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↗

Evidence of rickettsial and leptospira infections in Andean northern Peru.

Between May and October 2002, a cluster of acute febrile illnesses occurred in the subtropical Andean foothills of Peru. Serologic evidence in villages where disease had been documented showed that the prevalence of IgM antibody to Leptospira ranged from 6% to 52%, that of IgM antibody to spotted fever group (SFG) rickettsia ranged from 10% to 19%, and that of IgM antibody to Coxiella burnetii from 1% to 15%. Measurement of IgG antibodies for SFG rickettsiae suggested that this disease was endemic. In contrast, IgG antibodies against C. burnetii were largely absent. In humans, microagglutination tests identified pathogenic variants of Leptospira. The presence of an SFG rickettsial infection was confirmed in four febrile patients following polymerase chain reaction and sequencing of the conserved 17-kD common antigen gene (htrA). Collectively, these analyses indicated that Rickettsia sp., C. burnetii, and Leptospira sp. were circulating in the region during the time of disease outbreak and implicate the involvement of an as yet undetermined SFG rickettsia in northwestern Peru.

Adolescent↗