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David A. Haake - One of the best experts on this subject based on the ideXlab platform.

  • Novel 45-Kilodalton Leptospiral Protein That Is Processed to a 31-Kilodalton Growth-Phase-Regulated Peripheral Membrane Protein
    Infection and immunity, 2002
    Co-Authors: James Matsunaga, Tracy A. Young, Jeanne K. Barnett, Dean Barnett, Carole A. Bolin, David A. Haake
    Abstract:

    Leptospiral protein antigens are of interest as potential virulence factors and as candidate serodiagnostic and immunoprotective reagents. We identified Leptospiral protein antigens by screening a genomic expression library with serum from a rabbit hyperimmunized with formalin-killed, virulent Leptospira kirschneri serovar grippotyphosa. Genes expressing known outer membrane lipoproteins LipL32 and LipL41, the heat shock protein GroEL, and the α, β, and β′ subunits of RNA polymerase were isolated from the library. In addition, a new Leptospiral gene that in Escherichia coli expressed a 45-kDa antigen with an amino-terminal signal peptide followed by the spirochetal lipobox Val−4-Phe−3-Asn−2-Ala−1↓Cys+1 was isolated. We designated this putative lipoprotein LipL45. Immunoblot analysis of a panel of Leptospira strains probed with LipL45 antiserum demonstrated that many low-passage strains expressed LipL45. In contrast, LipL45 was not detected in high-passage, culture-attenuated strains, suggesting that LipL45 is a virulence-associated protein. In addition, all Leptospiral strains tested, irrespective of culture passage, expressed a 31-kDa antigen that was recognized by LipL45 antiserum. Southern blot and peptide mapping studies indicated that this 31-kDa antigen was derived from the carboxy terminus of LipL45; therefore, it was designated P31LipL45. Membrane fractionation studies demonstrated that P31LipL45 is a peripheral membrane protein. Finally, we found that P31LipL45 levels increased as Leptospira entered the stationary phase, indicating that P31LipL45 levels were regulated. Hamsters infected with L. kirschneri formed an antibody response to LipL45, indicating that LipL45 was expressed during infection. Furthermore, the immunohistochemistry of kidneys from infected hamsters indicated that LipL45 was expressed by L. kirschneri that colonized the renal tubule. These observations suggest that expression of LipL45 responds to environmental cues, including those encountered during infection of a mammalian host.

  • An improved immunohistochemical diagnostic technique for canine leptospirosis using antiLeptospiral antibodies on renal tissue.
    Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians Inc, 2002
    Co-Authors: Chad J. Wild, Jeanne K. Barnett, Carole A. Bolin, David A. Haake, Justin J. Greenlee, Norman F. Cheville
    Abstract:

    The purpose of this study was to compare the immunoreactivity in canine renal tissues stained with antisera specific for 3 Leptospiral antigens and those processed with traditional staining methods. In addition, immunoglobulin staining was done on tissues with immunoreactivity to Leptospiral antigens. Formalin-fixed renal sections from 12 dogs with chronic interstitial nephritis suspected or proven to have leptospirosis (6 dogs with silver-stained leptospires and 6 dogs in which silver-stained leptospires were not detected) were used. Antibodies consisted of a monoclonal antibody to Leptospira kirschneri serovar grippotyphosa lipopolysaccharide (LPS) and 2 polyclonal antibodies to outer membrane proteins, including OmpL1, a Leptospiral porin, and LipL41, an outer membrane lipoprotein. The murine monoclonal antisera against LPS (F71C2-1) had the most abundant and consistent immunoreactivity. Immunoreactive areas were present in 6 of 6 sections positive by silver staining and included extracellular granular debris in intertubular areas, debris in macrophages, organisms in tubular lumina, and cytoplasmic granules in tubular epithelia. Antisera with specificity for the outer membrane proteins OmpL1 and LipL41 detected only intact organisms in tubular lumina. Immunoreactivity to OmpL1 (polyclonal 338) occurred in 4 of 5 sections positive by silver staining, but immunoreactivity to LipL41 (polyclonal 813) occurred in only 1 of 6 silver-positive sections. Each of the kidney sections in which Leptospiral antigens were detected by immunohistochemistry also was positive by silver staining. Sections negative by silver staining were also negative by immunostaining. Although immunohistochemistry did not enhance sensitivity, amplification of signal by secondary antibody and hematoxylin counterstaining improved the ease of diagnosis and allowed better evaluation of tissue morphology than did silver staining methods. IgG was the most abundant immunoglobulin. IgG immunoreactivity occurred predominantly in plasma cells within interstitial infiltrates. Interstitial infiltrates contained abundant immunoreactivity to LPS, but immunoreactivity to OmpL1 and LipL41 was not noted.

  • Characterization of the Leptospiral Outer Membrane and Description of Three Novel Leptospiral Membrane Proteins
    Infection and immunity, 2002
    Co-Authors: David A. Haake, James Matsunaga
    Abstract:

    Identification and characterization of outer membrane (OM) components are essential in the development of a molecular understanding of bacterial structure and function. Development of techniques for isolation of the OM from Leptospira species and other spirochetes has been difficult because of their unique architecture and a lack of sensitive markers for the cytoplasmic membrane. Like enteric gram-negative bacteria, spirochetes have both an OM and a cytoplasmic membrane, separated by a periplasmic space. However, spirochetal architecture differs significantly from that of gram-negative bacteria in that the peptidoglycan layer of spirochetes is associated with the cytoplasmic membrane rather than the OM (22, 24). For this reason, techniques developed for isolation of the gram-negative OM from components of the underlying cell wall and cytoplasmic membrane are unlikely to be useful in spirochetes. Several approaches have been used in the isolation of the Leptospiral OM, including sodium dodecyl sulfate (SDS) treatment of salt-altered cells (2, 7, 25, 28), Sarkosyl (27), and Triton X-114 extraction and phase partitioning (20, 45). On the basis of these approaches, three classes of Leptospiral OM proteins (OMPs) have been described: transmembrane, lipoprotein, and peripheral membrane proteins. OmpL1 was the first Leptospiral OMP to be described (16). The structure of OmpL1 is predicted to contain at least 10 β-sheet transmembrane segments, which probably accounts for its heat-modifiable electrophoretic mobility. Its transmembrane structure is also supported by evidence that purified OmpL1 creates porin channels in the planar lipid bilayer assay (36). A second class of Leptospiral OMPs are the lipoproteins that are anchored to the OM by fatty acids attached to an amino-terminal cysteine (15). Analysis of the detergent phase of Triton X-114 extracts of Leptospira kirschneri intrinsically labeled with tritiated palmitate indicates that the Leptospiral OM contains at least five lipoproteins (37). The genes encoding three Leptospiral OM lipoproteins, LipL32, LipL36, and LipL41, have been described (17, 18, 37). LipL32 is known to be the most prominent protein in the Leptospiral protein profile and is an immunodominant antigen during human leptospirosis (10, 14, 17). LipL41 is a surface-exposed lipoprotein that provides synergistic immunoprotection with OmpL1 (19, 37). Recently, the peripheral membrane protein P31LipL45 was described, which represents a third type of Leptospiral OMP (J. Matsunaga, T. A. Young, J. Croda, J. Lima, A. I. Ko, and D. A. Haake, 101st Gen. Meet. Am. Soc. Microbiol. 2001, abstr. D-229, p. 324, 2001). P31LipL45 is exported as a 45-kDa lipoprotein and processed to a 31-kDa C-terminal form that is associated with the OM. Evidence that P31LipL45 is a peripheral OMP, rather than an integral OMP, comes from studies showing that it is released from membranes by urea and that it partitions into the Triton X-114 detergent and aqueous phases. In the absence of a detergent-independent technique for isolation of the Leptospiral OM, it has not been possible to confirm that proteins, such as lipoproteins, are actually OM components or rather cytoplasmic membrane proteins selectively extracted by detergents. An example of the aberrant behavior of spirochetal cytoplasmic membrane lipoproteins in detergent extraction methods is TpN47 of Treponema pallidum, which is readily extracted by Triton X-114 (32) yet has been shown to be virtually absent from T. pallidum OM vesicles (OMVs) isolated and purified by isopycnic sucrose gradient ultracentrifugation (4, 34). Another caveat about detergent-based methods of isolating spirochetal OMs was brought to light by the finding that LipL32 is selectively degraded during Triton X-114 phase partitioning (17, 45). Notably lacking from previous studies of the Leptospiral OM are controls to assess contamination of the OM fraction with cytoplasmic membrane components. We have developed antisera to two Leptospiral cytoplasmic membrane proteins that serve as sensitive markers of the cytoplasmic membrane. Leptospiral lipopolysaccharide (LPS) serves as a specific marker for the OM. By using these cytoplasmic membrane and OM detection tools, we have developed a method for isolation of the Leptospiral OM in the form of membrane vesicles. Our method is a modification of techniques that use buffers that destabilize the spirochetal OM and facilitate its release in the form of OMVs (4, 5, 33, 34, 38). These OM isolation techniques take advantage of the structural lability of the spirochetal OM to produce OMVs that can be separated from protoplasmic-cylinder (PC)components by isopycnic sucrose gradient density ultracentrifugation. We believe that the method presented here provides the most accurate assessment of a protein's representation in the Leptospiral OM.

  • the Leptospiral major outer membrane protein lipl32 is a lipoprotein expressed during mammalian infection
    Infection and Immunity, 2000
    Co-Authors: David A. Haake, James Matsunaga, Jeanne K. Barnett, Dean Barnett, Richard L Zuerner, Garlo Chao, Mary Mazel, Paul N Levett, Carole A. Bolin
    Abstract:

    We report the cloning of the gene encoding the 32-kDa lipoprotein, designated LipL32, the most prominent protein in the Leptospiral protein profile. We obtained the N-terminal amino acid sequence of a staphylococcal V8 proteolytic-digest fragment to design an oligonucleotide probe. A Lambda-Zap II library containing EcoRI fragments of Leptospira kirschneri DNA was screened, and a 5.0-kb DNA fragment which contained the entire structural lipL32 gene was identified. Several lines of evidence indicate that LipL32 is lipid modified in a manner similar to that of other procaryotic lipoproteins. The deduced amino acid sequence of LipL32 would encode a 272-amino-acid polypeptide with a 19-amino-acid signal peptide, followed by a lipoprotein signal peptidase cleavage site. LipL32 is intrinsically labeled during incubation of L. kirschneri in media containing [(3)H]palmitate. The linkage of palmitate and the amino-terminal cysteine of LipL32 is acid labile. LipL32 is completely solubilized by Triton X-114 extraction of L. kirschneri; phase separation results in partitioning of LipL32 exclusively into the hydrophobic, detergent phase, indicating that it is a component of the Leptospiral outer membrane. CaCl(2) (20 mM) must be present during phase separation for recovery of LipL32. LipL32 is expressed not only during cultivation but also during mammalian infection. Immunohistochemistry demonstrated intense LipL32 reactivity with L. kirschneri infecting proximal tubules of hamster kidneys. LipL32 is also a prominent immunogen during human leptospirosis. The sequence and expression of LipL32 is highly conserved among pathogenic Leptospira species. These findings indicate that LipL32 may be important in the pathogenesis, diagnosis, and prevention of leptospirosis.

  • Leptospiral Outer Membrane Proteins OmpL1 and LipL41 Exhibit Synergistic Immunoprotection
    Infection and immunity, 1999
    Co-Authors: David A. Haake, James Matsunaga, Garlo Chao, Mary K. Mazel, Adam M. Mccoy, Frank Milward, Elizabeth A. Wagar
    Abstract:

    New vaccine strategies are needed for prevention of leptospirosis, a widespread human and veterinary disease caused by invasive spirochetes belonging to the genus Leptospira. We have examined the immunoprotective capacity of the Leptospiral porin OmpL1 and the Leptospiral outer membrane lipoprotein LipL41 in the Golden Syrian hamster model of leptospirosis. Specialized expression plasmids were developed to facilitate expression of Leptospiral proteins in Escherichia coli as the membrane-associated proteins OmpL1-M and LipL41-M. Although OmpL1-M expression is highly toxic in E. coli, this was accomplished by using plasmid pMMB66-OmpL1, which has undetectable background expression without induction. LipL41-M expression and processing were enhanced by altering its lipoprotein signal peptidase cleavage site to mimic that of the murein lipoprotein. Active immunization of hamsters with E. coli membrane fractions containing a combination of OmpL1-M and LipL41-M was found to provide significant protection against homologous challenge with Leptospira kirschneri serovar grippotyphosa. At 28 days after intraperitoneal inoculation, survival in animals vaccinated with both proteins was 71% (95% confidence interval [CI], 53 to 89%), compared with only 25% (95% CI, 8 to 42%) in the control group (P < 0.001). On the basis of serological, histological, and microbiological assays, no evidence of infection was found in the vaccinated survivors. The protective effects of immunization with OmpL1-M and LipL41-M were synergistic, since significant levels of protection were not observed in animals immunized with either OmpL1-M or LipL41-M alone. In contrast to immunization with the membrane-associated forms of Leptospiral proteins, hamsters immunized with His(6)-OmpL1 and His(6)-LipL41 fusion proteins, either alone or in combination, were not protected. These data indicate that the manner in which OmpL1 and LipL41 associates with membranes is an important determinant of immunoprotection.

Anne Mayer-scholl - One of the best experts on this subject based on the ideXlab platform.

  • Survival time of Leptospira kirschneri on strawberries.
    PloS one, 2020
    Co-Authors: Duygu Tekemen, Enno Luge, Nadja Bier, Karsten Nöckler, Mathias Franz, Martin H. Richter, Anne Mayer-scholl
    Abstract:

    In the past decade, two leptospirosis outbreaks occurred among strawberry harvesters in Germany, with 13, and 45 reported cases respectively. In both outbreaks, common voles (Microtus arvalis) infected with Leptospira kischneri serovar Grippotyphosa were identified as the most likely outbreak source. In an univariate analysis, eating unwashed strawberries was identified as one of the risk factors associated with Leptospira infection. The aim of this study was to evaluate the survival time of L. kirschneri serovar Grippotyphosa on strawberries under varying conditions. Strawberries were spiked with 5x109 of both a laboratory reference strain (strain Moskva V) and an outbreak field strain (94-6/2007) of L. kirschneri serovar Grippotyphosa sequence type 110. Survival times were investigated in a fully crossed design with three incubation times (2h, 4h, 6h and 8h) and three temperatures (15°C, 21°C and 25°C) with three replicated for each condition. A wash protocol was developed and recovered Leptospira were determined by qPCR, dark field microscopy and culturing. Viable L. kirschneri of both the reference strain and the field strain were identified in all samples at 25°C and an incubation time of 2h, but only 1/9 (11%) and 4/9 (44%) of the samples incubated at 15°C were positive, respectively. Both reference and field strain were viable only in 2/9 (22%) at 25° after 6h. After an 8h incubation, viable Leptospira could not be identified on the surface of the strawberries or within the fruit for any of the tested conditions. Based on these results, the exposure risk of consumers to viable Leptospira spp. through the consumption of strawberries bought at the retail level is most likely very low. However, there is a potential risk of Leptospira infection by consumption of strawberries on pick-your-own farms.

  • Survival time of Leptospira kirschneri serovar Grippotyphosa under different environmental conditions.
    PloS one, 2020
    Co-Authors: L. H. Nau, Anne Mayer-scholl, Anna Obiegala, Nina Król, Martin Pfeffer
    Abstract:

    Leptospirosis is a re-emerging zoonotic disease of high medical importance that affects humans worldwide. Humans or animals acquire an infection with pathogenic leptospires either by direct contact with infected animals or by indirect contact to contaminated environment. Survival of Leptospira spp. in the environment after having been shed via animal urine is thus a key factor to estimate the risk of infection, but not much is known about the tenacity of pathogenic leptospires. Here, the survival time of both a laboratory strain and a field strain of L. kirschneri serovar Grippotyphosa in animal urine and their tenacity while drying was investigated and compared at different temperatures (15°C-37°C). Leptospira spp. are also often found in rivers and ponds. As the infection risk for humans and animals also depends on the spreading and survival of Leptospira spp. in these environments, the survival of L. kirschneri serovar Grippotyphosa was investigated using a 50-meter-long hose system simulating a water stream. Both strains did not survive in undiluted cattle or dog urine. Comparing different temperatures and dilution media, the laboratory strain survived the longest in diluted cattle urine with a slightly alkaline pH value (3 days), whilst the field strain survived in diluted dog urine with a slightly acid pH value up to a maximum of 24 h. Both strains did not survive drying on a solid surface. In a water stream, leptospires were able to move faster or slower than the average velocity of the water due to their intrinsic mobility but were not able to survive the mechanical damage caused by running water in the hose system. From our results we conclude, that once excreted via animal urine, the leptospires immediately need moisture or a water body to survive and stay infectious.

  • Leptospira spp. in Rodents and Shrews from Afghanistan.
    Journal of wildlife diseases, 2018
    Co-Authors: Anne Mayer-scholl, Jens Peter Teifke, Niclas Huber, Enno Luge, Nadja Bier, Karsten Nöckler, Rainer G. Ulrich
    Abstract:

    Leptospirosis is an occupational risk for military personnel and many cases have been reported worldwide. Rodents are the most important maintenance hosts for Leptospira spp. and may infect both animals and humans. To determine the occurrence and identity of pathogenic Leptospira spp. in rodent and shrew populations in German military camps in Afghanistan, we examined 751 animals (Mus musculus, Cricetulus migratorius, Meriones libycus, Rattus tanezumi, Crocidura cf. suaveolens, and Suncus etruscus) from four military camps in Northern Afghanistan from 2009–12. Leptospiral DNA was found in 1.1% of the animals and only in Mus musculus. Partial secY sequencing identified Leptospira borgpetersenii and Leptospira kirschneri as infecting genomospecies. Multilocus sequence typing was successful in the L. borgpetersenii samples, which were identified as sequence type 155. The low prevalence we observed suggested that the exposure risk of military personnel to infectious Leptospira spp. in the region is low.

  • Leptospirosis in dogs - Current aspects regarding clinical signs, diagnosis, therapy and prevention
    2012
    Co-Authors: B. Kohn, Anne Mayer-scholl, C. Weingart, Karsten Nöckler
    Abstract:

    Canine leptospirosis is a re-emerging zoonotic infectious disease which is primarily caused by Leptospiral spirochetes of the genomospecies Leptospira interrogans and Leptospira kirschneri. Indirect transmission of leptospires mainly occurs through the exposure of susceptible animals to a contaminated environment (urine of reservoir hosts). The leptospires enter the organism via intact mucous membranes or skin lesions. The course of the disease is dependent on the host's immunity, the infecting dose and the virulence of the organism. In dogs with low or absent antibody titres, leptospires can spread and replicate in many tissues. Acute renal failure is the most common clinical feature, but other organs such as liver, lung (haemorrhage), eyes and muscles are also involved. Common laboratory abnormalities include renal azotaemia, altered liver parameters, thrombocytopenia, leucocytosis, anaemia, proteinuria, glucosuria, and bilirubinuria. The diagnosis is based on a combination of clinical signs/laboratory abnormalities and indirect (microscopic agglutination test, ELISA) and direct (PCR, culture) tests. Dogs with acute leptospirosis require intensive care management. In addition to a biphasic anti-infective therapy (amoxicillin and doxycycline), affected dogs require individually adjusted fluid therapy, antiemetics, gastric protectants and analgesics according to their clinical signs. An intensive monitoring is needed mainly because of the risk of anuric renal failure and pulmonary haemorrhage. Haemodialysis may be life-saving.The prognosis is dependent on the severity of the clinical signs and associated complications; the mortality rate is higher in dogs with pulmonary involvement. Since leptospirosis is a zoonotic disease strict hygiene measures have to be taken. In Germany bivalent vaccines and recently tri- and tetravalent vaccines are available

Bruna Palmas - One of the best experts on this subject based on the ideXlab platform.

  • Presence of pathogenic Leptospira spp. in the reproductive system and fetuses of wild boars (Sus scrofa) in Italy.
    PLoS neglected tropical diseases, 2020
    Co-Authors: Giovanni Cilia, Fabrizio Bertelloni, Ivana Piredda, Maria Nicoletta Ponti, Barbara Turchi, Carlo Cantile, Francesca Parisi, Paolo Pinzauti, Andrea Armani, Bruna Palmas
    Abstract:

    Leptospirosis is a re-emerging and globally spread zoonosis caused by pathogenic genomospecies of Leptospira. Wild boar (Sus scrofa) are an important Leptospira host and are increasing in population all over Europe. The aim of this investigation was to evaluate Leptospira spp. infection in the reproductive systems of wild boar hunted in two Italian regions: Tuscany and Sardinia. From 231 animals, reproductive system tissue samples (testicles, epididymides, uteri) as well as placentas and fetuses were collected. Bacteriological examination and Real-Time PCR were performed to detect pathogenic Leptospira (lipL32 gene). Leptospires were isolated from the testicles and epididymides of one adult and two subadult wild boar. Four isolates from the two subadult males were identified as Leptospira interrogans serogroup Australis by MLST, whereas Leptospira kirschneri serogroup Grippotyphosa was identified from the adult testicles and epididymis. Using Real-Time PCR, 70 samples were positive: 22 testicles (23.16%) and 22 epididymides (23.16%), 10 uteri (7.35%), 3 placentas (6.66%), and 13 fetuses (28.88%). Amplification of the rrs2 gene identified L. interrogans and L. kirschneri species. The results from this investigation confirmed that wild boar represent a potential source of pathogenic Leptospira spp. Isolation of Leptospira serogroups Australis and Grippotyphosa from the male reproductive system and the positive Real-Time PCR results from both male and female samples could suggest venereal transmission, as already demonstrated in pigs. Furthermore, placentas and fetuses were positive for the lipL32 target, and this finding may be related to a possible vertical transmission of pathogenic Leptospira.

Fabrice Merien - One of the best experts on this subject based on the ideXlab platform.

  • Update on the status of leptospirosis in New Zealand.
    Acta tropica, 2018
    Co-Authors: Wael F. El-tras, Mieghan Bruce, Hannah R. Holt, Mahmoud Eltholth, Fabrice Merien
    Abstract:

    Leptospirosis is a zoonotic disease that poses public health and ecological threats worldwide. In New Zealand (NZ), incidence of the disease is relatively high compared to other developed countries. The aim of this review was to describe the epidemiological status, ecological risk of leptospirosis and prevention in NZ. Disease notification data for leptospirosis in humans in NZ from 2010 to 2015 were collected from the Institute of Environmental Science and Research database. These data were supported by a literature review of epidemiological studies in human and animal populations. During this six-year period, exotic serovars of Leptospira interrogans sv Australis and Leptospira kirschneri sv Grippotyphosa were identified in patients who had travelled abroad to Samoa (Pacific Ocean) and Thailand, respectively. Most cases of leptospirosis were recorded in New Zealanders of European ethnicity, followed by Māori people. Males had a nine-fold increased risk compared to females mostly due to occupation. The risk of leptospirosis increased gradually with the age, with a peak in the 40 to 49-year-old age group, after which it decreased. Workers in meat-processing and farming industries appeared at highest-risk of occupational exposure compared with other risky occupations such as hunters, veterinarians, technicians, stock truck drivers and lake workers. Other cases were also attributed to outdoor exposures or travelling overseas. Highest disease notification rates occurred in the West Coast region of the South Island (average annual incidence 9.7 per 100,000 people), followed by Whanganui region (8.2 per 100,000) and Hawke's Bay region (8 per 100,000) in the North Island. Vaccines currently available for animals are specific for cattle, sheep, deer and dogs and do protect against all serovars present in NZ. The development and use of molecular diagnostics is crucial for specific identification of Leptospira isolates and informing deployment of efficient vaccines.

  • application of multilocus variable number tandem repeat analysis for molecular typing of the agent of leptospirosis
    Journal of Clinical Microbiology, 2006
    Co-Authors: Laurence Salaun, Fabrice Merien, Svetlana Gurianova, Guy Baranton, Mathieu Picardeau
    Abstract:

    Leptospirosis is a worldwide-distributed zoonosis, endemic in tropical areas. Epidemiologic investigations of leptospirosis still rely on tedious serological identification tests. Recently, molecular typing systems based on variable-number tandem-repeat (VNTR) analysis have been described and have been used to identify Leptospira interrogans strains. Although L. interrogans is the most common Leptospira species encountered in human infections around the world, other pathogenic species, such as Leptospira kirschneri and Leptospira borgpetersenii, are also frequently associated with human leptospirosis. In this study, we aimed to extend multilocus VNTR analysis (MLVA) identification of strains to species other than L. interrogans. We designed primers for VNTR loci found in L. interrogans, L. kirschneri, and L. borgpetersenii. The discriminatory power of the redefined primers was evaluated on collection strains and then on clinical strains. We also carried out a retrospective study on 156 strains isolated from patients and animals from New Caledonia, an area of high endemicity in the South Pacific. Our results show that this simple PCR-based MLVA typing technique is a powerful methodology for the epidemiology of leptospirosis.

Joseph M. Vinetz - One of the best experts on this subject based on the ideXlab platform.

  • Regional Differences of Leptospirosis in Sri Lanka: Observations from a Flood-Associated Outbreak in 2011
    2016
    Co-Authors: Suneth B. Agampodi, Niroshan J. Dahanayaka, Manoj Perera, Sumudu Priyankara, Prasanna Weerawansa, Michael A. Matthias, Anoma K. B, Joseph M. Vinetz
    Abstract:

    Leptospirosis is known to be an important cause of weather disaster-related infectious disease epidemics. In 2011, an outbreak of leptospirosis occurred in the relatively dry district of Anuradhapura, Sri Lanka where diagnosis was resisted by local practitioners because leptospirosis was not known in the area and the clinical presentation was considered atypical. To identify the causative Leptospira associated with this outbreak, we carried out a cross-sectional study. Consecutive clinically suspected cases in this district were studied during a two-and-a-half-month period. Of 96 clinically suspected cases, 32 (33.3%) were confirmed by qPCR, of which the etiological cause in 26 cases was identified using 16S rDNA sequencing to the species level. Median bacterial load was 4.16102/mL (inter-quartile range 3.1–6.16102/mL). In contrast to a 2008 Sri Lankan leptospirosis outbreak in the districts of Kegalle, Kandy, and Matale, in which a predominance of Leptospira interrogans serovars Lai and Geyaweera was found, most cases in the 2011 outbreak were caused by Leptospira kirschneri. Seven (21.9%) confirmed cases had acute renal failure; five (15.6%) had myocarditis; severe thrombocytopenia (,20,000/uL) was seen in five (15.6%) cases. This outbreak of leptospirosis in the relatively dry zone of Sri Lanka due primarily to L

  • Redefining Gold Standard Testing for Diagnosing Leptospirosis: Further Evidence from a Well-Characterized, Flood-Related Outbreak in Sri Lanka
    The American journal of tropical medicine and hygiene, 2016
    Co-Authors: Suneth Agampodi, Karsten Nöckler, Niroshan J. Dahanayaka, Mayer-scholl Anne, Joseph M. Vinetz
    Abstract:

    A gap in the leptospirosis field remains the lack of well-characterized sample collections that allow for comparison of new methods to standard ones. In the context of a flood-related outbreak of leptospirosis evaluated in Anuradhapura, Sri Lanka, a specimen bank was obtained with detailed metadata accompanied by gold standard diagnostic test results. Blood samples collected on admission and 14 days later from suspected cases of leptospirosis were tested using microscopic agglutination test (MAT) (17 serovars), an in-house enzyme-linked immunosorbent assay (ELISA) using a locally obtained strain of Leptospira kirschneri as sonicated antigen, a commercially available ELISA based on sonicated Leptospira biflexa, and a quantitative polymerase chain reaction (qPCR) assay targeting the pathogenic Leptospira-specific 16S rRNA gene. Of 62 patients presenting within the first 2 days of illness, 31 had confirmed leptospirosis based either on paired-sample MAT or qPCR. During the acute phase, qPCR was most sensitive, detecting 74% of definitively diagnosed cases; immunoglobulin G (IgG) ELISA (in-house), IgG ELISA (commercial), and MAT had sensitivities of 35.5%, 12.0%, and 22.6%, respectively, in detecting definitively diagnosed cases using acute phase serum. Of 40 patients with paired sera, 10 were qPCR positive. Of these, five samples were negative by paired-sample MAT. Of the 11 MAT-positive samples, only five were detected using qPCR confirming that both tests are needed for maximal sensitivity. Regional Leptospiral serovar-specific IgG ELISA was superior to MAT. Knowing the regionally dominant serovars improves serological sensitivity in the analysis of acute specimens by ELISA, but qPCR was most sensitive in this patient population.

  • Regional Differences of Leptospirosis in Sri Lanka: Observations from a Flood-Associated Outbreak in 2011
    PLoS neglected tropical diseases, 2014
    Co-Authors: Suneth Agampodi, Niroshan J. Dahanayaka, Anoma Kumari Bandaranayaka, Manoj Perera, Sumudu Priyankara, Prasanna Weerawansa, Michael A. Matthias, Joseph M. Vinetz
    Abstract:

    Leptospirosis is known to be an important cause of weather disaster-related infectious disease epidemics. In 2011, an outbreak of leptospirosis occurred in the relatively dry district of Anuradhapura, Sri Lanka where diagnosis was resisted by local practitioners because leptospirosis was not known in the area and the clinical presentation was considered atypical. To identify the causative Leptospira associated with this outbreak, we carried out a cross-sectional study. Consecutive clinically suspected cases in this district were studied during a two-and-a-half-month period. Of 96 clinically suspected cases, 32 (33.3%) were confirmed by qPCR, of which the etiological cause in 26 cases was identified using 16S rDNA sequencing to the species level. Median bacterial load was 4.1×102/mL (inter-quartile range 3.1–6.1×102/mL). In contrast to a 2008 Sri Lankan leptospirosis outbreak in the districts of Kegalle, Kandy, and Matale, in which a predominance of Leptospira interrogans serovars Lai and Geyaweera was found, most cases in the 2011 outbreak were caused by Leptospira kirschneri. Seven (21.9%) confirmed cases had acute renal failure; five (15.6%) had myocarditis; severe thrombocytopenia (