Tests For Leptospirosis Research Articles

Characterization of the ompL1 gene of pathogenic Leptospira species in China and cross-immunogenicity of the OmpL1 protein

BackgroundThe usefulness of available vaccine and serological tests for leptospirosis is limited by the low cross-reactivity of antigens from numerous serovars of pathogenic Leptospira spp. Identification of genus-specific protein antigens (GP-Ag) of Leptospira would be important for development of universal vaccines and serodiagnostic methods. OmpL1, a transmembrane porin of pathogenic leptospires, was identified as a possible GP-Ag, but its sequence diversity and immune cross-reactivity among different serovars of pathogenic leptospires remains largely unknown.ResultsPCR analysis demonstrated that the ompL1 gene existed in all 15 official Chinese standard strains as well as 163 clinical strains of pathogenic leptospires isolated in China. In the standard strains, the ompL1 gene could be divided into three groups (ompL1/1, ompL1/2 and ompL1/3) according to their sequence identities. Immune electron microscopy demonstrated that all products of the different gene types of ompL1 are located on the surface of leptospires. The microscopic agglutination test revealed extensive yet distinct cross-immunoagglutination among the antisera against recombinant OmpL1 (rOmpL1) and leptospiral strains belonging to different ompL1 gene types. These cross-immunoreactions were further verified by ELISAs using the OmpL1 proteins as the coated antigens in serum samples from 385 leptospirosis patients. All the antisera against rOmpL1 proteins could inhibit L. interrogans strain Lai from adhering to J774A.1 cells. Furthermore, immunization of guinea pigs with each of the rOmpL1 proteins could cause cross-immunoprotection against lethal challenge with leptospires from different ompL1 gene types.ConclusionThree types of the ompL1 gene are present in pathogenic leptospires in China. OmpL1 is an immunoprotective GP-Ag which should be considered in the design of new universal vaccines and serodiagnostic methods against leptospirosis.

Evaluation of the Anti‐LipL32 Monoclonal Antibodies Potential for Use in Leptospirosis Immunodiagnostic Tests

LipL32 is the major lipoprotein in the membrane of pathogenic leptospira. In this work, we report on the production of monoclonal antibodies (MAbs) against recombinant LipL32 (rLipL32) and on the evaluation of their potential for use as reagents in diagnostic tests for leptospirosis. The MAbs were all of the IgG2b isotype and reacted specifically with native LipL32 in pathogenic serovars only. MAbs reacted in the same region of the rLipL32 molecule and their affinity constant was between 5×107 M−1 and 6×106 M−1. These results suggest that although the MAbs cannot be used together, they are well suited for diagnostic tests of leptospirosis based on LipL32 detection.

LEPTOSPIROSIS ON OAHU: AN OUTBREAK ASSOCIATED WITH FLOODING OF A UNIVERSITY CAMPUS

On October 31, 2004, a stream overflowed, flooding the University of Hawaii (UH) campus. On November 19, 2004, a possible flood-related leptospirosis case (Patient 1) was reported to the Hawaii State Department of Health (HDOH). Surveillance for febrile illness was established through an Internet questionnaire. Active case finding was conducted among groups involved in the flood clean-up. Free leptospirosis testing was offered by HDOH. Patient 1's illness was confirmed as leptospirosis by microscopic agglutination testing. A total of 271 persons responded to the Internet survey, of whom 90 (33%) reported a febrile illness within 30 days of contact with flood water. Forty-eight respondents (18%) were tested for leptospirosis. One additional acute leptospirosis case was identified. Patient 2 was epidemiologically linked to Patient 1. Health care providers should maintain a high level of suspicion for leptospirosis after flooding events, and local public health officials should promote leptospirosis awareness among flood-affected populations.

Rapid diagnostic tests for dengue and leptospirosis: antibody detection is insensitive at presentation

To determine the performance of rapid diagnostic tests for dengue and leptospirosis that rely on detecting antibodies that may not be produced when patients present for medical treatment. We prospectively enrolled 723 patients with undifferentiated febrile illness presenting to rural hospitals in northern and northeastern Thailand over a 1-year period. We evaluated rapid antibody detection diagnostic tests for dengue and leptospirosis on these patients. Sensitivity of the tests was low at the acute visit (7.6-21.5%). Sensitivity at the convalescent visit ranged from 25.8% to 81.5% and was significantly higher than at the acute visit for all tests (chi(2), P < 0.001). Low sensitivity of the rapid tests at presentation suggests that their utility in the acute phase of dengue and leptospirosis is limited.

Veno-Arterial Extracorporeal Membrane Oxygenation in Acute Respiratory Distress Syndrome Caused by Leptospire Sepsis

To the Editor: We present a case of severe acute respiratory distress syndrome caused by systemic leptospirosis that we successfully managed with veno-arterial extracorporeal membrane oxygenation. The most frequent zoonosis in the world (1), leptospirosis is endemic to tropical regions. It can also appear in developed countries (1,2) and is a possible cause of acute respiratory distress syndrome. Pulmonary involvement, usually consisting of hemorrhagic pneumonitis, varies from 20% to 70% (3) and can be fatal (4–8). One week after returning from Thailand, our patient's flu-like symptom required acute hospitalization. Three days later, he required endotracheal intubation and mechanical ventilation. Chest radiograms revealed diffuse bilateral infiltrates. Bronchoscopy showed diffuse endobronchial bleeding, possibly secondary to coagulopathy. His sepsis-related organ failure scores were 4 for respiration, coagulation, liver, cardiovascular system, and renal function and 1 for central nervous system. The patient was treated with amoxicillin/clavulanate (Augmentin) and clarithromycin. His respiratory status worsened, with progressive hypoxia and evidence of pulmonary hypertension. An echocardiogram showed atrial fibrillation with a frequency of 110–120 bpm. Cardiac ultrasound revealed right ventricular overload. His pulmonary artery pressure was estimated to be 60 mm Hg. Central venous pressure was 22 mm Hg, and the arterial blood pressure was 95 mm Hg. The pulmonary hypertension was unresponsive to inhaled nitric oxide and prostacyclin. We placed the patient on veno-arterial extracorporeal membrane oxygenation, which immediately improved his oxygenation and hemodynamic status. A subsequent microagglutination test confirmed a diagnosis of leptospirosis. The patient was treated with imipenem and ciprofloxacin. Acute renal failure required continuous hemofiltration for 3 days. The patient steadily improved, and he was weaned off extracorporeal membrane oxygenation after 60 h. His subsequent hospital course was unremarkable, and 26 days after admission the patient was discharged from the hospital. We recommend testing for leptospirosis to screen for infection of unknown origin. Early extracorporeal membrane oxygenation treatment may be lifesaving for patients with acute respiratory distress syndrome that does not respond to conventional therapy. Judith M. Kahn, MD Helmut M. Müller, MD Division of Surgery Department of Transplant Surgery Medical University of Graz [email protected] Alexander Kulier, MD Astrid Keusch-Preininger, MD Division of Anesthesiology Medical University of Graz Karl-Heinz Tscheliessnigg, MD Division of Surgery Department of Transplant Surgery Medical University of Graz

Japanese Encephalitis, Singapore

Japanese Encephalitis, Singapore

Leptospirosis among patients presenting with dengue-like illness in Puerto Rico

Leptospirosis is difficult to distinguish from dengue fever without laboratory confirmation. Sporadic cases/clusters of leptospirosis occur in Puerto Rico, but surveillance is passive and laboratory confirmation is rare. We tested for leptospirosis using an IgM ELISA on sera testing negative for dengue virus IgM antibody and conducted a case–control study assessing risk factors for leptospirosis, comparing clinical/laboratory findings between leptospirosis (case-patients) and dengue patients (controls). Among 730 dengue-negative sera, 36 (5%) were positive for leptospirosis. We performed post mortem testing for leptospirosis on 12 available specimens from suspected dengue-related fatalities; 10 (83%) tested positive. Among these 10 fatal cases, pulmonary hemorrhage and renal failure were the most common causes of death. We enrolled 42 case-patients and 84 controls. Jaundice, elevated BUN, hyperbilirubinemia, anemia, and leukocytosis were associated with leptospirosis ( p < .01 for all). Male sex, walking in puddles, rural habitation, and owning horses were independently associated with leptospirosis. Epidemiological, clinical, and laboratory criteria may help distinguish leptospirosis from dengue and identify patients who would benefit from early antibiotic treatment.

Respiratory Manifestations of Leptospirosis: A Retrospective Study

We retrospectively reviewed 34 consecutive patients with serologically confirmed leptospirosis admitted during years 1992-2002. Nine patients (26.5%) had respiratory symptoms on admission including cough (n = 4), shortness of breath (n = 4), cyanosis (n = 2), and hemoptysis (n = 1). Six patients had pulmonary radiographic findings including (1) diffuse, ill-defined, ground-glass density (n = 3); (2) diffuse alveolar opacities (n = 2); and (3) small nodular density (n = 1). Male/female ratio was 8/1 and mean age was 47 years. Seven patients reported their exposure source including hunting (n = 2), fishing (n = 2), fresh water swimming (n = 2), and canoeing (n = 1). All patients had fever (mean = 40.1 degrees C). Other common symptoms were headache (n = 4), vomiting (n = 3), and myalgia (n = 3). Biological abnormalities included elevated liver enzymes (n = 8), proteinuria (n = 7), lymphopenia (n = 6), hematuria (n = 5), renal failure (n = 4), anemia (n = 4), and elevated neutrophil count (n = 4). PaO(2 )was measured for 3 patients while they were breathing room air (32, 55, and 66 mmHg). Suspected diagnosis on admission included leptospirosis (n = 2), bacterial pneumonia (n = 2), intoxication, influenza, viral hepatitis, biliary tract lithiasis, and rapidly progressive glomerulonephritis (one patient each). The first serologic testing for leptospirosis was positive for 5 patients (55%). Serovar was presumptively identified for 7 patients: Australis (n = 3), Grippotyphosa (n = 2), and Icterohaemorrhagiae (n = 2). Seven patients were treated with penicillin; two patients received no antibiotics. All patients were cured. In conclusion, patients with leptospirosis may present predominantly with nonspecific pulmonary symptoms. In these patients, leptospirosis must be suspected when there is a potential exposure to rats, especially in case of high-grade fever, myalgia, hepatitis, and renal abnormalities.

Monoclonal antibodies against an outer membrane protein from pathogenic Leptospira

Two hybridomas secreting monoclonal antibodies (MAbs) that react with a lipoprotein (LipL32) of the outermembrane of pathogenic Leptospira were obtained. For hybridoma production, spleen cells from BALB/cmice imunized with recombinant LipL32 (rLipL32) were fused to SP2/O-Ag14 cells, selected in HAT mediumand screened in an indirect ELISA. One MAb produced was of the IgG2b isotype and the other was an IgM.MAbs specificity was confirmed by indirect ELISA and immunoblotting using purified rLipL32 and whole-cellantigen preparations from Escherichia coli (E. coli) expressing LipL32 and from pathogenic and non-pathogenic serovars. Both Mabs reacted with most of the pathogenic serovars tested and none reacted withnon-pathogenic Leptospira. The MAbs described have potential for use in diagnostic tests for leptospirosis.

Leptospirosis mimicking acute cholecystitis among athletes participating in a triathlon

Leptospirosis, a disease acquired by exposure to contaminated water, is characterized by fever accompanied by various symptoms, including abdominal pain. An acute febrile illness occurred in athletes who participated in an Illinois triathlon in which the swimming event took place in a freshwater lake. Of 876 athletes, 120 sought medical care and 22 were hospitalized. Two of the athletes had their gallbladders removed because of abdominal pain and clinical suspicion of acute cholecystitis. We applied an immunohistochemical test for leptospirosis to these gallbladders and demonstrated bacterial antigens staining (granular and filamentous patterns) around blood vessels of the serosa and muscle layer. Rare intact bacteria were seen in 1 case. These results show that leptospirosis can mimic the clinical symptoms of acute cholecystitis. If a cholecystectomy is performed in febrile patients with suspicious environmental or animal exposure, pathologic studies for leptospirosis on formalin-fixed, paraffin-embedded tissues may be of great value. HUM PATHOL 32:750-752. This is a US government work. There are no restrictions on its use.

Simple leptospirosis test

An easy-to-perform, cost-effective test for leptospirosis, which can be performed in rural, medically underserved areas, could have great benefit for the management of infected children. The Lepto dri-dot test, developed by the Royal Tropical Institute in Amsterdam, detects IgM antibodies to leptospirosis. It requires 10 ml of serum to be added to a card on which latex particles are coated with leptospiral antigen. Appearance of a visible granular agglutination within 30 secs indicates a positive result and can be detected by 7–10 days after infection. The Lepto dri-dot test has been shown to be more effective than the conventional ELISA IgM serological test. CK

Simple latex agglutination assay for rapid serodiagnosis of human leptospirosis.

A newly developed latex agglutination assay for the detection of genus-specific Leptospira antibodies in human sera was evaluated. The assay is performed by mixing, on an agglutination card, serum with equal volumes of stabilized antigen-coated, dyed test and control latex beads and is read within 2 min. The latex agglutination test was evaluated with groups of serum samples from patients with leptospirosis and control patients from Hawaii, the Seychelles, Thailand, and The Netherlands. The mean overall sensitivity was 82.3%, and the mean overall specificity was 94.6%. The assay is easy to perform and does not require special skills or equipment. The reagents have a long shelf life, even at tropical temperatures. Together, these factors make the assay suitable for use even at the peripheral level of a health care system as a rapid screening test for leptospirosis.

International multi-centre evaluation of a dipstick assay for human leptospirosis.

A dipstick assay for the detection of Leptospira-specific immunoglobulin M (IgM) antibodies in human sera was evaluated in 27 laboratories in 23 countries. 873 serum samples from 711 patients including 329 laboratory-confirmed leptospirosis case patients, 239 noncase patients and 69 patients with viral infections causing heamorrhagic fever were tested. Relative to the results of the reference leptospirosis test, the sensitivity of the dipstick assay was 84.5% for serum samples collected during the first 10 days of the disease and 92.1% for serum samples collected 10-30 days after the onset of disease. The specificity was 87.5% and 94.4%, respectively. Similar to viral haemorrhagic fevers, leptospirosis may cause bleeding. A small number of serum samples from patients with haemorrhagic viral infections gave a weak (1 +) stain. All other samples were negative. In conclusion, the dipstick assay is sensitive and specific and reacts well with serum samples from patients infected with a range of leptospiral strains. It is also easy to use and does not require special equipment or refrigeration. Therefore the assay is ideal for use in developing countries and rural settings.

Diversidade antigênica entre amostras de Arcobacter spp isoladas de suínos no Rio Grande do Sul e presença de anticorpos aglutinantes em amostras de soro de porcas com problemas reprodutivos

O teste de aglutinação microscópica, usando a técnica descrita para o diagnóstico de leptospirose, foi utilizado para verificar a antigenicidade de 47 amostras de Arcobacter cryaerophilus e duas amostras de Arcobacter butzleri isoladas de suínos no Rio Grande do Sul, Brasil, em frente a soros hiperimunes produzidos em coelhos a partir de amostras padrões das bactérias. Verificou-se grande heterogeneidade antigênica e apenas quatro amostras provocaram títulos acima de 1.600 com os anti-soros padrões. A classificação genética dos microorganismos foi confirmada no teste em 48,97% dos antígenos. Igualmente, utilizando a técnica de aglutinação microscópica, foram testadas amostras de soro de porcas que apresentaram problemas reprodutivos, procedentes de granjas de onde foram isoladas amostras de Arcobacter spp. Não existe registro anterior na literatura sobre o uso do referido teste em infecções por Arcobacter spp. Os exames sorológicos em fêmeas suínas reprodutoras revelaram títulos de até 1.600, possibilitando indicar que houve a presença de aglutininas para Arcobacter spp.

Leptospirosis

Leptospirosis, a waterborne spirochetal illness, is common in tropical climates. Rodents and wild animals are the most common reservoirs for this widespread zoonosis. Human disease is acquired by contact with urine or tissues of an infected animal or through contaminated water and soil. Systemic leptospirosis is characterized by its multisystem involvement, protean manifestation, and varying severity. The clinical presentation ranges from occult infection to fatal complications like hepatorenal failure. Early diagnosis is important to halt the fulminate course. The microagglutination test is considered the gold standard serological test for leptospirosis, although molecular techniques are now under study. Treatment of systemic leptospirosis includes penicillin or tetracycline in addition to supportive treatment. Ocular involvement occurs during the immunological phase of the disease. One or both eyes may be involved, typically with a panuveitis often accompanied by retinal periphlebitis and hypopyon. In general, leptospiral uveitis has a good prognosis and the patient recovers full vision in spite of severe panuveal inflammation. Awareness of this infectious uveitic entity is essential not only in order to differentiate it from other severe autoimmune uveitides, but also to reduce the percentage of idiopathic uveitis in endemic areas.

Involvement of the nervous system in leptospirosis. II. Cerebrospinal fluid evaluation

From January 1st up to September 30th 1990, 77 patients with leptospirosis diagnosis confirmed by laboratory studies were admitted at the Infectious and Parasitic Disease Service of the Hospital das Clínicas of the Universidade Federal de Pernambuco. The neurological exam was abnormal in 70 of the patients (90.91%). The cerebrospinal fluid (CSF) examination was carried out on 67 (87%) of the patients; it was abnormal in 64 (95.52%) yielding hypercytosis in the majority of cases. There was no difference in the CSF behavior in report to the several neurological forms nor in relation to the icteric or non-icteric forms of the disease. Significant were the results for the microscopic agglutination tests for leptospirosis in the CSF.

Evaluation of a passive microcapsule agglutination test for the screening of human leptospirosis.

Microcapsules, absorbed with two mixed antigens--each composed of 3 sonicated leptospira serovars--were developed in the past as a microcapsule agglutination test (MCA-LS) for the screening of clinical leptospirosis. For this study, fifty serum samples, taken at an earlier and at a later stage of illness from 25 Italian in-patients with clinical symptoms of leptospirosis, were tested with both the MCA-LS one-dilution test and the microscopic agglutination (MA) test, the confirmatory test for leptospirosis, with 18 leptospira strains circulating in Italy. Compared with MA, MCA-LS showed a sensitivity of 91.7%, and a specificity of 92.3%, including leptospirosis not sustained by the diagnostic strains used in the MCA-LS kit.

Leptospiral cerebral arteritis: report of 4 autopsy cases.

This paper presents the autoptical findings of 4 cases of leptospiral cerebral arteritis involving predominantly large arteries at the base of the brain, especially the middle and anterior cerebral arteries. The main pathological change of this basal cerebral polyarteritis is a proliferative endarteritis which may be classified into three types: acute, chronic and oblitero-sclerous. Specific serological tests for leptospirosis were positive in two cases and in one of these two patients spirochetes were found while in the other, immuno-fluorescence positive substance was demonstrated in the involved cerebral arteries. These findings, together with the clinico-epidemiological data, strongly suggest that the cerebral arteritis in our cases should be the result from leptospirochetic infection.

Urinary excretion of an unidentified treponeme in a case of leptospirosis

Two kinds of spirochetes were observed by dark-field microscopy in the urine of a leptospirosis patient on day 26 after the onset of the disease. The spirochetes were identified as treponemes and leptospires. A classification of the treponemes on basis of their morphology was attempted by means of electron microscopy with no conclusive result. Cultivation of the spirochetes was unsuccessful. Sera obtained prior to, during and after the excretion of spirochetes were tested for antibodies in routine serology tests for leptospirosis and syphilis. The diagnosis leptospirosis was confirmed by a rise and subsequent fall in antibody titres. The sera were nonreactive in syphilis serology tests, but showed a weak fluorescence in a fluorescent treponemal antibody absorption (FTA-ABS) test when Treponema calligyrum was used as antigen. It could not be determined whether this reaction was due to antibodies raised in response to antigens of the excreted treponemes.

Polymorphism of Blood Serum Amylase and Transferrin and Leptospirosis in Large White Polish Pigs

The aim of this study was to ascertain any connection between the polymorphism of blood serum amylase and transferrins and the occurrence of leptospirosis in pigs. In the population of pigs studied showing serologically positive results to the leptospirosis test there was found to be a statistically significant greater frequency of Tf AA + Am AA and Tf AB + Am AA phenotypes and a statistically significant lesser frequency of Tf AA + Am BB and Tf BB + Am AB phenotypes compared with the frequencies of those combinations of loci in the serologically negative group of pigs.