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Leptospiral antibodies in flying foxes in Australia.

The sera of 271 pteropid bats (or flying foxes) collected from Queensland, New South Wales, Western Australia, and the Northern Territory were screened against a reference panel of 21 Leptospira spp. using the microscopic agglutination test (MAT). Sera were collected from December 1997 through August 1999. The MAT panel represented those serovars previously isolated in Australia, as well as exotic serovars found in neighboring countries. Leptospiral antibodies were detected in 75 (28%) of the sera and represented seven serovars, one of which, L. interrogans serovar cynopteri has been regarded as exotic to Australia. Sixty sera were reactive to one serovar, 12 sera were reactive to two serovars, and three sera were reactive to three serovars. The L. kirschneri serovar australis was most frequently identified (60.2%). The findings suggest a previously unrecognized role of pteropid bats in the natural history of leptospirosis. The potential exists for establishment of infection in new host species, the transmission of new serovars to known host species, and for changes in virulence of leptospires as a result of passage through these species.

Agglutination Tests↗

Experiments with a homologous, inactivated canine parvovirus vaccine in vaccination programmers for dogs.

The significance of canine parvovirus (CPV) infections as a permanent threat susceptible dogs, in particular pups, made the authors develop three liquid homologous inactivated adjuvant CPV vaccines that were compatible with existing canine vaccines and could be incorporated in current vaccination programmes. On vaccine (Kavak Parvo) contained only the CPV component, the second product (Kavak i-LP) also contained two inactivated leptospiral antigens, and the third vaccine (Kavak i-HLP) contained in addition an inactivated canine hepatitis virus. This paper reports on the studies conducted to test the safety and efficacy of the three products. They were used as such and as diluents for freeze dried vaccines containing live attenuated measles, distemper, and hepatitis viruses. The study was performed in a breeding kennel where all dogs were free from CPV antibodies and the nonvaccinated sentinels remained so for the course of the study. All vaccines proved to be safe in dogs of all ages, including pregnant bitches. The efficacy of the CPV component was studied both by monitoring antibody titres for more than a year and by challenge exposure of some dogs to virulent CPV. The results obtained from these studies prove that the CPV component used in the three vaccines can be incorporated as indicated in the recommended canine vaccination programmes. The observations that the inactivated CPV and hepatitis components do induce an active immunity in pups that are still protected by low levels of maternally derived antibodies against these viruses, make those vaccines very suitable in breeding kennels. Additional studies on a comparative basis are being continued in edemically CPV infected breeding kennels to quantify the significance of these observations in these special conditions.

Adenoviruses, Canine↗

The chemiluminescent detection of leptospiral antigen.

The aim of this study was to investigate the feasibility of using enhanced chemiluminescence for the rapid detection of leptospiral antigen (L. interrogans serovar hardjo) in biological fluids, and to assess the suitability of such an assay for the early diagnosis of human leptospiral infections. The limit of detection for homologous antigen in phosphate buffered saline was 9 x 10(4) leptospires/ml. In human blood the sensitivity remained unchanged throughout the sampling time, (1.8 x 10(5) leptospires/ml), but decreased with time in human urine. The assay did not cross-react with other members of the Leptospira interrogans species, was unaffected by the presence of biological fluids but the sensitivity was reduced by contaminating bacteria. The assay was both rapid and sensitive, when compared with current cultural techniques, and offers a potentially valuable aid to the early diagnosis of leptospirosis.

Antigens, Bacterial↗

Intestinal spirochetosis: first cases reported in Brazil and the use of immunohistochemistry as an aid in histopathological diagnosis.

Colonization of the colon and rectum by intestinal spirochetes is detected for the first time in Brazil in 4 of 282 (1.41%) patients who had undergone sigmoidoscopy and/or colonoscopy with a histopathological diagnosis of chronic non specific-colitis. This frequency is probably underestimated, since surgically obtained specimens were not considered in the present study. Histopathological diagnosis was performed using routine stains like hematoxylin-eosin which showed the typical, of 3-microns thick hematoxyphilic fringe on the brush border of the surface epithelium, and by silver stains like the Warthin-Starry stain. Immunohistochemical procedures using two, polyclonal, primary antibodies, one against Treponema pallidum and the other against Leptospira interrogans serovar copenhageni serogroup Icterohaemorrhagiae cross-reacted with spirochetal antigen/s producing a marked contrast of the fringe over the colonic epithelium, preserving the spiral-shaped morphology of the parasite. In one case with marked diarrhea, immunohistochemistry detected spirochetal antigen/s within a cell in an intestinal crypt, thus demonstrating that the infection can be more widely disseminated than suspected using routine stains. Immunohistochemical procedures, thus, greatly facilitate the histological diagnosis of intestinal spirochetosis and may contribute to a better understanding of the pathogenesis of the disease. Transmission and scanning electron microscopy performed in one case showed that the spirochete closely resembled the species designated as Brachyspira aalborgi.

Adolescent↗

[Classification of spirochetes infecting man].

The systematics od spirochetes must from now own fulfil the genomic criteria recently laid down. Formerly, these parasites were classified on the basis of various phenotypic features, among which the pathogenicity and epidemiological criteria played the predominant role. At present, the order of Spirochaetales is divided into two families: Spirochaetaceae and Leptospiraceae. Two of the four genera of Spirochaetaceae, Treponema and Borrelia, include species that are pathogenic to man. Among Leptospiraceae, only one genus, Leptospira, has pathogenic species. The phenotypic characteristics of the various taxons are detailed, the role of each actor (causative agent, vector, reservoir) in the main pathological complexes and the progress of genotypic studies are briefly described.

Humans↗

A sero-epidemiological study of Haemophilus somnus infection in dairy cattle.

Five repeated cross-sectional serological surveys of 790 dairy cattle in 4 dairy herds between December 1985 and February 1987 provided an opportunity to study the changes in the seroprevalence of Haemophilus somnus across the 5 surveys and with respect to some demographic and disease variables. The demographic variables included were age (heifers or cows) and farm, representing two groups of herds (two herds in each group, located in the Central and Northern Valleys of California). The serological status of cattle as either negative or positive against H. somnus, Campylobacter fetus and Leptospira hardjo were determined with enzyme linked-immunosorbent assays. Logistic regression analysis was used to compute maximum likelihood estimates of adjusted odds ratios and their respective 95% confidence intervals. The baseline risk of being H. somnus seropositive in the cattle observed at first sampling did not vary significantly during the study period after adjustment for the effects of covariates. Only at first sampling were cows about twice as likely to be H. somnus seropositive than heifers. At samplings 1 and 3, but not at 2 and 5, being in the herds of the Central Valley appeared protective. In contrast, at sampling 4 the cattle in herds in the Central Valley were about 7 times more likely to be H. somnus seropositive. C. fetus-positive cattle were about 3 times more likely to be H. somnus seropositive at sampling 1 only. The relationship between H. somnus status and L. hardjo was not significant during the study period.

Animals↗

Usefulness of serologic analysis as a predictor of the infecting serovar in patients with severe leptospirosis.

The diagnosis of leptospirosis is often made using the microscopic agglutination test (MAT), in which live antigens representing >20 serogroups undergo reaction with patient serum samples to detect agglutinating antibodies. Data derived from this assay are often used to infer the identity of the infecting leptospiral serovar or serogroup; however, paradoxical reactions and cross-reactions between serogroups are common. To evaluate the usefulness of this approach, data on culture-proven cases of leptospirosis that occurred in Barbados from January 1980 through December 1998 were reviewed. A total of 151 isolates of 4 serovars were identified. The sensitivity of MAT for the prediction of the infecting serovar was determined. Overall, the predominant serogroup at a titer of >or=100 correctly predicted 46.4% of all serovars isolated. If a titer of >or=800 was used as the cutoff, sensitivity decreased slightly to 44.4%. The overall specificity for all serogroups was 64.8%. Serologic analysis appeared to be of little value for the identification of the infecting serovar in individual cases of leptospirosis in humans. Presumptive serogroup reactivity data should be used only to gain a broad idea of the serogroups present at the population level.

Bacteriological Techniques↗

Possible role of leptospires of the Pomona serogroup in sporadic bovine abortion in the south west of England.

An investigation of a small outbreak of abortion in mixed-age cows in a dairy herd in Somerset produced circumstantial evidence that a leptospire belonging to the Pomona serogroup was the causative agent. Although the initial epidemic involved more than 30 per cent of the herd, agglutination titres did not persist in the majority of animals and bacteriological monitoring produced no evidence that this leptospire could establish endemic infection in dairy cattle. An isolate recovered from the kidney of a cow which aborted was found to be similar to mozdok, a serovar maintained by free-living species in continental Europe, and it is probable that free-living species also maintain the Pomona serogroup organisms that have been isolated in England. Clinical disease caused by infection of domestic stock with Pomona serogroup organisms other than pomona has not been recognised in other countries but this may be because of the presence of endemic infection with pomona, a serovar that causes a very similar clinical and serological response.

Abortion, Veterinary↗

[Seroepidemiological studies of the detection of leptospires of the sejroe group in cattle in middle Thuringia].

From 1983 to 1989 14,361 head of cattle from the middle Thuringia region were investigated by means of microagglutination test for the presence of Leptospira serovars hardjo, saxkoebing and sejroe. 4,484 samples from cattle with abortion (1983-1985) and a random sample of 5,284 cattle sera (1985) were investigated giving priority to L. hardjo. Furthermore 3,293 samples from cattle with abortion (1986/87) and a random samples test of 1,300 cattle sera (1989) were tested giving priority to L. saxkoebing. 2.5 percent of the cows having aborted and 10.3 percent of cattle tested out of the whole livestock showed antibodies against L. hardjo. The test for presence of L. saxkoebing demonstrated in cattle with abortion a seroprevalence of 14 percent and in the random samples tests a portion of reagents of 11.3 percent. The degree of infection differed regionally, the highest degree was found in livestocks of the northern part of the Thuringia forest. The prevalence of L. saxkoebing in cattle with abortion from large dairy farms was 18.6 percent, which is higher than the average in the region examined. Antibodies against hardjo and sejroe were interpreted as caused by cross reactivity.

Abortion, Veterinary↗

Broadly reacting precipitating and agglutinating antigen of leptospirae.

A saprophytic Leptospira biflexa strain of equine origin was found which cross-reacts with immune rabbit antisera to 14 pathogenic Leptospira interrogans serotypes. Sera from goats experimentally inoculated with the saprophyte showed multiple low-level cross-agglutination reactions against a battery of live L. interrogans serotypes. Sonically treated and saline-extracted suspensions of the L. biflexa strain and serotypes canicola, icterohaemorrhagiae, and pomona yielded a common precipitating protein antigen that was detected by immunodiffusion and immunoelectrophoresis with all of the antileptospiral sera examined. In cross-absorption and gel diffusion tests, the precipitinogen from each of the strains was shown to be identical. Formaldehyde treatments and heating at 100 degree C suggest that the cellular location of the common antigen is either somatic or subsurface, and Sephadex G-200 gel filtration enabled the isolation of the active fraction of the L. biflexa antigen. Monoprecipitin sera against the common antigen of L. biflexa were produced by immunizing rabbits with specific precipitates in agar. In gel diffusion and immunoelectrophoresis tests the antisera with each of the soluble antigens developed a single precipitin formation, and the antisera agglutinated formolized and heated whole-cell suspensions of serotypes canicola, icterohaemorrhagiae, and pomona at low dilutions. The soluble L. biflexa antigen was evaluated as an immunogen and in passive immunity tests for protection against death and kidney infection in hamsters. No cross-protection occurred when the hamsters were challenged with virulent leptospires. In contrast, the animals vaccinated or administered hamster immune serum before challenge died earlier than the control animals.

Animals↗

Treatment and outcome of dogs with leptospirosis: 36 cases (1990-1998).

OBJECTIVE: To characterize serologic and clinical features and outcome of dogs with leptospirosis that were treated conservatively (i.e., medical management alone) or with hemodialysis. DESIGN: Retrospective study. ANIMALS: 36 dogs with leptospirosis. PROCEDURE: History; results of physical examinations, ultrasonography, and serologic, hematologic, and serum biochemical analyses; time to resolution of azotemia; and outcome were obtained from medical records. Dogs were treated conservatively (n = 22) or with hemodialysis (14). RESULTS: Between 1990 and 1998, amount of rainfall was positively correlated with number of cases of leptospirosis identified per year. Serum antibodies against 6 Leptospira serovars were measured, and titers were highest to Leptospira pomona in 16 (44%) dogs, L bratislava in 9 (25%) dogs, and L hardjo in 1 (3%) dog. Eight (22%) dogs had equally high titers to L pomona and L bratislava, 1 (3%) had equally high titers to L grippotyphosa and L canicola, and 1 (3%) had high titers to L grippotyphosa, L pomona, L canicola, and L bratislava. During initial evaluation, all dogs were azotemic. Thirty (83%) dogs survived, including 12 of 14 (86%) dogs treated with hemodialysis and 18 of 22 (82%) treated conservatively. Serum creatinine concentration was similar in both groups after resolution of clinical signs. CONCLUSIONS AND CLINICAL RELEVANCE: Infection with L pomona and L bratislava was recognized as a cause of leptospirosis in dogs, and resulted in development of acute renal failure with various degrees of azotemia. Prognosis for dogs with mild to moderate azotemia was good with conservative treatment, whereas treatment with hemodialysis appeared to improve prognosis for dogs with severe azotemia.

Animals↗

The antibodies involved in the human immune response to leptospiral infection.

Antibody responses were studied in human patients from whom leptospiral serovars--mainly pomona or hardjo--had been isolated and identified. The antibody to the polysaccharide F4 antigen belonged exclusively to the IgM class, even as late as 10 months after infection. Human sera cross-reacted widely with F4 antigen from heterologous serovars. The antibodies involved in leptospiral agglutination were mainly IgM, but some patients also produced IgG agglutinins. The titres of IgM agglutinins were higher than those of IgG agglutinins and persisted for many months, regardless of the presence or absence of IgG agglutinins. Both types of immunoglobulin from patients with serovar pomona infection protected hamsters against lethal infections with homologous leptospires. The hamster-protective capacity of human sera correlated well with agglutinin titres. Sera from patients infected with serovars other than pomona protected hamsters against challenge with pomona only if they contained agglutinins to that organism.

Agglutination Tests↗

IS1533-based PCR assay for identification of Leptospira interrogans sensu lato serovars.

A PCR-based assay was developed for typing L. interrogans sensu lato serovars. The assay is designed to exploit the presence of many copies of the leptospiral insertion sequence IS1533 and IS1533-like sequences present in the genomes of most leptospiral serovars. The PCR primers were designed to amplify DNA of unknown sequence between closely placed IS1533 or IS1533-like sequences. Amplification reactions primed with IS1533-based primers generated products of different sizes. When few copies of IS1533 were present in the genome, amplification of a few products was still detected. These results suggest that IS1533 elements may be found close together. Analysis of DNA amplified from different serovars showed the presence of differently sized products, thus enabling the serovars to be identified. Genetic variation among isolates within the same serovar was also demonstrated with the IS1533-based primers. Amplification reactions using DNA extracted from the urine of infected animals generated specific products which were similar to the products generated from purified bacterial DNA. These results demonstrate that this assay is selective enough to be used for typing leptospiral serovars from clinical material and thus allows leptospiral typing without isolation of the bacteria in pure culture.

Animals↗

Human leptospirosis--a review of 50 cases.

Epidemiological and clinical aspects of 50 consecutive patients, 47 adults and three children, hospitalized between 1977 and 1987 for human leptospirosis, were reviewed. 45 (90%) of the patients were from rural regions. 32 (64%) cases occurred in individuals at occupational risk for the infection. 35 (70%) cases were registered in the warm season. The source of infection was known in 34 (68%) cases. Weil's disease was diagnosed in 31 (62%) patients, aseptic meningitis in 12 (24%) and acute unexplained fever in seven (14%). Haemodialysis was required for 11 (35%) patients with Weil's disease. Three (6%) patients died. Cause of death was massive gastrointestinal haemorrhage in two and renal failure in one. Leptospira icterohaemorrhagiae was responsible for 39 (78%) cases, Leptospira canicola for six (12%), Leptospira grippotyphosa for two (4%), and Leptospira australis, Leptospira ballum and Leptospira sejroe, for one case each. A muscle biopsy was performed in six patients and a renal biopsy in three. Focal necrotic muscular changes, with mild mononuclear infiltrate, were found. Pigmented casts in distal convoluted tubules, mild interstitial inflammatory infiltrate and mesangial enlargement of some glomeruli were observed in kidney biopsies. A good knowledge of the protean clinical manifestations of leptospirosis and an accurate laboratory study are required for a correct diagnosis.

Adolescent↗

Prevalence of leptospiral infection in Texas cattle: implications for transmission to humans.

Of 1193 Texas slaughterhouse cattle serum samples assayed for anti-leptospiral antibodies by microscopic agglutination testing, 262 (22%) reacted with serovar pomona and 179 (15%) with serovar hardjo. Of 300 urine samples tested for leptospiral DNA by a polymerase chain reaction assay, 106 (35%) were positive. The high prevalence of leptospiral infection of cattle represents potential threats to human health and agricultural economics.

Agglutination Tests↗

To the knowledge of the common hamster (Cricetus cricetus Linné, 1758; Rodentia) as host of leptospirosis in Czechoslovakia.

A total of 1288 hamsters (Cricetus cricetus), coming from two regions of Czechoslovakia, were serologically investigated on the presence of leptospirosis. In 1114 hamsters from eastern Slovakia, where an outbreak occurred and local populations lived quite atypically, there was 31.8% positivity, in 174 animals from central Moravia, where the populations were at higher levels but lived normally, the positivity amounted to 17.2%. The serological positivity increases proportionately to the weight, i.e. to the age of the animals. The serovar grippotyphosa was dominant in them (29.6% of examined hamsters), while 6.0% were positive for L. pomona, 1.0% for serovars from the serogroup Sejroe, 0.2% for L. sorex-jalna and L. bataviae respectively, and 0.1% for L. bratislava. The hamsters from central Moravia were positive only for the serovar grippotyphosa. Antibodies in lower titres against L. pomona, having the character of coagglutinations, were simultaneously detected in some hamsters positive for L. grippotyphosa. In Czechoslovakia the common hamster is one of the potential hosts of L. grippotyphosa, its importance increasing during severe outbreaks, when the incidence of infection with L. grippotyphosa in hamster populations increases and the animals inhabit most varied types of biotopes and transfer to synanthropic way of life.

Animals↗

Leptospirosis in Israel: a report of 14 cases caused by icterohaemorrhagiae serogroup (1968-82).

Fourteen cases of leptospirosis due to the Leptospira interrogans serogroup Icterohaemorrhagiae (Weil's disease) were serologically confirmed in the last 15 years. In two cases, Icterohaemorrhagiae was also isolated from the patients' blood. Both positive cultures were obtained in Korthof's medium by indirect passage through brain-heart infusion medium. One of the isolates was identified as serovar budapest, which has never been reported in Israel. In most of the cases, paradoxical cross-reactions with serovars of the Autumnalis, Hebdomadis and Canicola serogroups were observed in the early stages of the illness. In all cases, we suspected that the source of the infection was serovars of the Icterohaemorrhagiae serogroup shed in the urine of Rattus norvegicus rats. Thirteen of the affected persons were working and living in the Tel Aviv area, all in places not known to be Icterohaemorrhagiae endemic before 1968. One patient was working and living in the Hadera region. All patients were jaundiced, and one died. The illness was usually accompanied by pronounced and long-lasting elevation of blood bilirubin and urea levels.

Adolescent↗

Acute leptospirosis in a triathlete.

We report the case of a 38-year-old male patient with acute leptospirosis. The most probable cause of infection was repeated and prolonged exposure to contaminated river water (Neckar and Enz rivers) while preparing for participation in long-distance triathlon (swimming, biking, and running) competitions.

Acute Disease↗