A machine learning model of microscopic agglutination test for diagnosis of leptospirosis.

Leptospirosis is a zoonosis caused by the pathogenic bacterium Leptospira. The Microscopic Agglutination Test (MAT) is widely used as the gold standard for diagnosis of leptospirosis. In this method, diluted patient serum is mixed with serotype-determined Leptospires, and the presence or absence of aggregation is determined under a dark-field microscope to calculate the antibody titer. Problems of the current MAT method are 1) a requirement of examining many specimens per sample, and 2) a need of distinguishing contaminants from true aggregates to accurately identify positivity. Therefore, increasing efficiency and accuracy are the key to refine MAT. It is possible to achieve efficiency and standardize accuracy at the same time by automating the decision-making process. In this study, we built an automatic identification algorithm of MAT using a machine learning method to determine agglutination within microscopic images. The machine learned the features from 316 positive and 230 negative MAT images created with sera of Leptospira-infected (positive) and non-infected (negative) hamsters, respectively. In addition to the acquired original images, wavelet-transformed images were also considered as features. We utilized a support vector machine (SVM) as a proposed decision method. We validated the trained SVMs with 210 positive and 154 negative images. When the features were obtained from original or wavelet-transformed images, all negative images were misjudged as positive, and the classification performance was very low with sensitivity of 1 and specificity of 0. In contrast, when the histograms of wavelet coefficients were used as features, the performance was greatly improved with sensitivity of 0.99 and specificity of 0.99. We confirmed that the current algorithm judges the positive or negative of agglutinations in MAT images and gives the further possibility of automatizing MAT procedure.

Uncommon manifestation of leptospirosis: a diagnostic challenge.

Leptospirosis is a zoonotic disease commonly affecting the tropical countries. It may have protean clinical manifestations including hepatorenal dysfunction, myocarditis, pulmonary haemorrhage, meningitis, optic neuritis and rhabdomyolysis. Neurological manifestation of leptospirosis without the classical hepatorenal dysfunction is a rare entity. This complication of leptospirosis can present with diverse central and peripheral neurological presentations. The overlapping clinical manifestations with many common tropical pathogens often pose diagnostic dilemma and delay in definitive therapy may lead to adverse clinical consequences. We report a case of a 19-year-old man with no prior comorbidities presenting with high-grade fever and altered sensorium. He was diagnosed to be a probable case of leptospirosis, based on all available test results and by fulfilment of parameters under modified Faine's criteria. The patient was successfully managed and discharged in stable condition.

Leptospirosis presenting as haemolytic uraemic syndrome: a case report.

BACKGROUND: Leptospirosis is a rare infectious disease especially in Western Countries. Renal involvement is a recognised complication of leptospirosis but leptospirosis-associated haemolytic uraemic syndrome is extremely rare and to our knowledge has only been reported once, in 1985. CASE PRESENTATION: A 29-year-old male was transferred to our Renal Unit with fevers, myalgia and diarrhoeal illness. Laboratory investigations revealed an acute kidney injury, acute liver injury, significantly raised lactate dehydrogenase with marked anaemia, thrombocytopenia and schistocytes on a blood film. A diagnosis of haemolytic uraemic syndrome was made. Surprisingly, the stool culture was negative which led to a suspicion of leptospirosis as one of the differential diagnoses. This was subsequently confirmed by enzyme-linked immunosorbent assay and microscopic agglutination test. He received plasma exchange and antibiotics and made a complete recovery on discharge. CONCLUSION: Leptospirosis presenting as haemolytic uraemic syndrome is rare but should be considered in the differential diagnosis especially in the presence of significant liver injury, as current evidence suggests that the disease is re-emerging.

Prospective evaluation of abdominal ultrasonographic findings in 35 dogs with leptospirosis.

Despite the emergence of new serovars, a detailed and current abdominal ultrasonographic description of dogs with leptospirosis is lacking. The purpose of this prospective, observational, single cohort study was to illustrate abdominal ultrasonographic findings in 35 dogs with confirmed leptospirosis. At least one ultrasonographic abnormality was seen in all of the dogs. Ultrasound renal abnormalities were found in all the dogs and included increased renal cortical echogenicity (100%), increased medullary echogenicity (86%), reduced corticomedullary definition (80%), cortical thickening (74%), renomegaly (60%), pelvic dilation (31%), and medullary band (14%). Hepatic changes were identified in 83% of the dogs, with diffuse hypoechoic parenchyma (71%) and hepatomegaly (60%). Biliary gallbladder abnormalities were found in 60% of the dogs, with biliary sludge (46%), wall thickening (29%), mucocele (26%), and hyperechoic wall (20%). The other most frequently observed abdominal abnormalities were perirenal (60%) and peritoneal (46%) effusions, small intestinal wall thickening (49%), and lymphadenopathy (38%). Two dogs (6%) presented with a small intestinal intussusception. No association was found between serogroups and the presence of ultrasonographic findings. This study is the first to prospectively and exhaustively describe abdominal ultrasonographic findings in dogs with leptospirosis. Our results should prompt clinicians to systematically perform abdominal ultrasounds on dogs with suspected leptospirosis even in the absence of abnormal physical signs. The presence of a gallbladder mucocele could be a warning sign of leptospirosis in dogs.

Pulmonary Leptospirosis With Diffuse Alveolar Hemorrhage: High-Resolution Computed Tomographic Findings in 16 Patients.

OBJECTIVE: The aim of this study was to evaluate the high-resolution computed tomographic (HRCT) findings from patients with leptospirosis and diffuse alveolar hemorrhage (DAH). MATERIALS AND METHODS: We retrospectively reviewed HRCT findings from 16 patients diagnosed as having leptospirosis causing DAH. The patient sample was composed of 13 men and 3 women aged 22 to 53 years (mean age, 34.5 years). Diagnosis was established with confirmation of leptospirosis infection by serologic microagglutination test. Histopathological study was performed in 8 patients. Two chest radiologists analyzed the HRCT images and reached decisions by consensus. RESULTS: The predominant HRCT findings were ground-glass opacities and airspace nodules (both n = 12, 75%), ground-glass nodules (n = 9, 56.25%), consolidations (n = 7, 43.75%), "crazy-paving" pattern (n = 3, 18.75%), and interlobular septal thickening without ground-glass opacity (n = 3, 18.75%). Bilateral pleural effusion was an associated finding in 2 (12.5%) patients. Analysis of the axial distribution of the lesions revealed diffuse distribution in 11 (68.75%) patients and peripheral lung zone predominance in 5 (31.25%) patients. Abnormalities were bilateral in all 16 (100%) patients. Analysis of the craniocaudal distribution of the lesions revealed lower zone predominance in 9 (56.25%) patients, diffuse distribution in 5 (31.25%) patients, middle zone predominance in 1 (6.25%) patient, and upper zone predominance in 1 (6.25%) patient. CONCLUSIONS: The most frequent HRCT findings in patients with leptospirosis causing DAH were ground-glass opacities, airspace nodules, ground-glass nodules, and consolidations. The lesions showed symmetrical distribution with lower zone predominance in most cases.

Myocarditis causing severe heart failure--an unusual early manifestation of leptospirosis: a case report.

BACKGROUND: Leptospirosis is the most widespread zoonosis in the world. Cardiac involvement is a frequent complication of leptospirosis although significant left ventricular dysfunction is rare. We report a case of fatal leptospira myocarditis leading to cardiogenic shock on the second day of illness. This early occurrence of myocarditis is not previously reported. CASE PRESENTATION: A 36-yr-old previously healthy Sri Lankan male who takes care of a horse presented to the medical casualty ward with a one day history of fever, arthralgia and severe myalgia. He developed hypotension on the second day of illness. Electrocardiogram showed sinus tachycardia with ST segment depression in lateral leads which evolved in to rapid atrial fibrillation in the subsequent days. 2D echocardiogram showed dilated cardiac chambers with severe global hypokinesia and an ejection fraction of 20%. His renal and liver functions were within normal limits. He developed multi organ dysfunction syndrome and refractory shock, later in the course of illness. Leptospirosis was confirmed by positive leptospira IgM and negative IgG. Patient died on the fifth day of illness despite optimal medical treatment with intravenous penicillin, meropenem, levofloxacin, inotropes and supportive care in the intensive care unit. CONCLUSIONS: We describe a rare and unusual early complication of leptospirosis which has not been reported before. It is important to bear in mind that leptospirosis could present as myocarditis during the early phase of illness.

Leptospirosis in pregnancy with pathological fetal cardiotocography changes.

We report the case of a 33-year-old primigravida who presented at 37 weeks of gestation with symptoms suggestive of acute fatty liver of pregnancy, but was later diagnosed with leptospirosis (i.e. Weil's disease or syndrome) on serological testing. Cardiotocography showed fetal distress, and an emergency Caesarean section was performed. A healthy neonate with no evidence of congenital leptospirosis was delivered. The patient was treated with intravenous ceftriaxone and discharged well 13 days after admission. Herein, we discuss the patient's clinical presentation and the cardiotocography changes observed in leptospiral infection, and review the current literature.

Serial CT features of pulmonary leptospirosis in 10 dogs.

Leptospirosis pulmonary haemorrhage syndrome (LPHS) is a frequent manifestation of Leptospira infection in dogs and is associated with a high morbidity and mortality. Three helical 16-slice thoracic CT scans were performed in 10 dogs naturally infected with Leptospira, within 24 hours of admission, and three and seven days later. Patients were sedated and scanned without breathhold, with a protocol adapted for rapid scanning. One dog died of respiratory failure on the morning following the first scan. On the initial scan, imaging features of LPHS included ground-glass nodules (10/10), peribronchovascular interstitial thickening (10/10), diffuse or patchy ground-glass opacity (9/10), solid nodules (8/10) and consolidation (7/10). Temporary bronchiolar dilation was observed in all dogs in association with peribronchovascular interstitial thickening, which had completely resolved at day 7. Nodules were with few exceptions assigned to the centrilobular region. Regression of lesion severity was observed after each subsequent scan. Consolidation and solid nodules changed over time into lesions of ground-glass attenuation. Pleural effusion (3/10) and mediastinal effusion (2/10) were mild and transient. Lesion severity appeared unassociated with survival to discharge.

Severe acute pancreatitis - a serious complication of leptospirosis.

Leptospirosis is a disease caused by pathogenic spirochetes of genus Leptospira. It is considered the most common zoonosis in the world. Acute pancreatitis is a rare complication of leptospirosis (25%). We present the case of a 34-year-old male patient with severe leptospirosis complicated with acute renal failure. After 9 days from the onset of the disease, the patient developed acute necrotizing pancreatitis, infected from the very beginning, associated with multiple organ failure, septic shock and severe anemia. The diagnosis was clinically and biologically stated and confirmed by CT-scan. The patient underwent surgery for infected necrotizing acute pancreatitis of the head and neck of the pancreas, with left retroperitoneal expansion down to the left iliac fossa. We performed a necrosectomy with the evacuation of the tisular debris, multiple drainage of the peritoneal cavity, followed by an open abdomen with synthetic mesh. The postoperative evolution was difficult but constantly progressive. Two reinterventions were necessary. The patient left the hospital in good condition after 75 days postoperatively.

[Intra-alveolar hemorrhage associated with dengue and leptospirosis]. / Hémorragie intra-alvéolaire associée à une dengue et à une leptospirose.

The intra-alveolar hemorrhage syndrome is defined by the presence of red cells in the alveolar lumen and can lead to acute respiratory failure. Among the infectious etiologies of this syndrome, leptospirosis is a common cause, whereas in dengue, the intra-alveolar hemorrhage is exceptional. We report a patient aged 46 years, with no particular history, who presented a clinical picture involving acute respiratory failure, hemoptysis, bilateral alveolar images and anemia. The intra-alveolar hemorrhage has been authenticated by bronchoalveolar lavage. The etiological showed infection by both dengue and leptospirosis.

Lemierre's syndrome mimicking leptospirosis.

Lemierre's syndrome is a suppurative thrombophlebitis involving the internal jugular vein, most commonly associated with Fusobacterium necrophorum, usually a complication of oropharyngeal infections. This syndrome is rare and is often overlooked. We present a case of sepsis mimicking initially severe leptospirosis (Weil's disease) due to acute febrile illness with multiorgan failure and hyperbilirubinemia. Finally, blood cultures revealed Fusobacterium necrophorum and computed tomography (CT) demonstrated bilateral pulmonary nodules and a thrombus in the right internal jugular vein. Early clinical suspicion is crucial so that appropriate diagnostic investigation and antibiotic therapy can be initiated to minimize the risk of life-threatening complications.

Radiographic chest findings and clinical correlations in leptospirosis.

OBJECTIVE: To determine the clinical presentations, radiographic chest findings, and their correlation in patients with leptospirosis. DESIGN: A cross sectional study. SETTING: Between July 2001- December 2002 at 3 hospitals in North Eastern Thailand. MATERIAL AND METHOD: Two hundred and forty patients with laboratory confirmed leptospirosis. RESULTS: Two hundred and nine (87.1%) patients were males. The mean age was 37.53 years (range 13-76). The median duration of fever was 3 days (range 1-13). Overall, 154 patients (64.2%) had respiratory symptoms and 26 (10.8%) patients had hemoptysis. Jaundice was detected in 76 (31.7%) patients, hypotension in 50 (20.8%), renal dysfunction in 80 (30%), and multiorgan dysfunction in 62 (25.8%) on admission. One hundred and fifty-four (64.17%) patients had abnormal chest radiographs on admission (classified as cardiovascular, pulmonary, and mixed cardio-pulmonary involvement in 40 (25.97%), 41 (26.62%), and 73 (47.4%) patients, respectively). Jaundice was significantly associated with the likelihood of having abnormal chest radiography on admission. Air- space nodules detected on the chest radiograph were significantly more common in patients with renal dysfunction and patients who required mechanical ventilation. CONCLUSION: Pulmonary and cardiovascular involvements are common in leptospirosis. Air-space nodules detected by chest radiography may indicate severe leptospirosis.

Thoracic radiology of infections emerging after natural disasters.

When natural disasters demolish shelter, destroy sources of clean drinking water, and disrupt the availability of medical care, vast numbers of people are placed at increased risk of disease. The infectious diseases that propagate under these conditions are usually common ones. Occasionally, a natural disaster alters the local environment in ways that markedly increase the prevalence of a disease that is endemic to a geographic region, occurring only as isolated cases under normal conditions. Many of these infections may affect the thorax. In this article, we discuss the radiologic findings of 4 infectious diseases, coccidioidomycosis, leptospirosis, melioidosis, and Chagas disease, which may flourish after natural disasters strike areas where they are endemic.