Recreational 'mud fever': Leptospira interrogans induced diffuse alveolar hemorrhage and severe acute respiratory distress syndrome in a U.S. Navy seaman following 'mud-run' in Hawaii

Antibiotic Chemoprophylaxis for Leptospirosis: Previous Shortcomings and Future Needs

Leptospirosis is a neglected tropical disease that remains potentially life threatening and hard to diagnose. Climate change combined with overlapping reservoir and human habitats will likely lead to increasing incidence, outbreaks, and mortality in the future. Preventative vaccines are either of limited scope and availability, or under development. Antibiotic chemoprophylaxis for prevention has been the subject of numerous clinical trials. However, despite 40 years of effort, clinical trials to better define protective efficacy, dosing, and the preferred medication are of poor quality and offer limited evidence. We reviewed the literature and offer critiques of the existing trials as well as potential areas for future exploration that may better define the epidemiology and yield a better evidence base for both travel medicine and public health efforts.

Freshwater sports and infectious diseases: A narrative review

Freshwater sports involve a wide range of practices leading to contact with soil and water that can entail exposure to agents of potential infectious diseases. The pathogens can be multiple (bacteria, parasites, viruses, fungi), and be either well-known or more unfamiliar and exotic. We conducted a literature review to describe various infections contracted following exposure to water and mud during freshwater sport activities. Out of the 1011 articles identified, 50 were finally included. Our findings encompassed bacterial infections (leptospirosis and gastrointestinal infections); parasitic infections (schistosomiasis, cercarial dermatitis); viral infections (norovirus and other gastrointestinal viruses; seaweed contamination; and fungal infections. These infections were reported in various countries worldwide among diverse freshwater sport activities, including swimming, surfing, kayaking, as well as extreme sports such as adventure races and mud runs. Water sports in freshwater can expose participants to infectious risks according to geographical location and type of sport. Because regular sport practice is beneficial for health, freshwater sports should not be avoided due to potential exposure to pathogens; that much said, certain precautions should be taken. In addition to adoption of preventive measures, participants should be informed about infectious risks and seek medical advice if symptoms appear after exposure. Current guidelines for assessment of bathing water quality do not suffice to ensure comprehensive evaluation of freshwater quality. Event organizers are called upon to pay close attention to environmental factors and meteorological events, to conduct timely sensitization campaigns, and to enforce appropriate safety measures.

The impact of genetic recombination on pathogenic Leptospira

Leptospirosis is the most common zoonosis worldwide, and is increasingly common in poor urban communities, where there is inadequate sewage disposal and abundance of domestic and peridomestic animals. There are many risk factors associated with the disease, such as contaminated water exposure, close contact with animals, floods, recreational activities related to water, wet agriculture. The symptoms of leptospirosis are common to other infectious diseases and, if not treated, it can lead to meningitis, liver failure, kidney damage and death. Leptospirosis is caused by 38 pathogenic species of Leptospira, which are divided in almost 30 serogroups and more than 300 serovars. The serological classification (serogroups and serovars) is based on the expression of distinct lipopolysaccharide (LPS) antigens. These antigens are also associated to protective immunity; antibodies against a serovar protect from any member of the same serovar. Serologic and phylogenetic analyses are not congruent probably due to genetic recombination of LPS genes among different leptospiral species. To analyze the importance of recombination in leptospiral evolution, we performed a gene-by-gene tree topology comparison on closed genomes available in public databases at two levels: among core genomes of pathogenic species (34 recombinant among 1213 core genes), and among core genomes of L. interrogans isolates (178/798). We found that most recombinant genes code for proteins involved in translation, ribosomal structure and biogenesis, but also for cell wall, membrane and envelope biogenesis. Besides, our final results showed that half of LPS genes are recombinant (18/36). This is relevant because serovar classification and vaccine development are based on these epitopes. The frequent recombination of LPS-associated genes suggests that natural selection is promoting the survival of recombinant lineages. These results may help understanding the factors that make Leptospira a successful pathogen.

Pica (Allotriophagy): An Underestimated Risk Factor for Severe Leptospirosis (Weil's Diseases)? Report of a Leptospira Septic Shock Successfully Managed with ECMO

Leptospirosis is a zoonosis caused by infection with pathogenic strains of the bacterium Leptospira. The disease can be complicated by pulmonary hemorrhages and acute respiratory distress syndrome, with the mortality rate increasing to 51–100%. We report the case of a 37-year-old man who was admitted to the emergency department with a 6-day history of fever, weakness, vomiting and diarrhea, followed by jaundice. On admission, he presented leukocytosis, thrombocytopenia and acute liver and kidney injuries. His clinical course was critical, as it was immediately complicated by sepsis and severe respiratory failure, requiring haemodialysis, mechanical ventilation and broad-spectrum antibiotic therapy. In the following days, a veno-venous extracorporeal membrane oxygenation (VV-ECMO) was started due to a dramatic deterioration in respiratory function; 20 h later, it was switched to veno-arterial ECMO because of refractory cardiogenic shock. Hantavirus or Leptospira infection etiology was suspected, so penicillin G and methylprednisolone were initiated as an empirical therapy and subsequently confirmed after a laboratory diagnosis of leptospirosis. Although the clinical course was further complicated by hemorrhagic pneumonia, a gradual, full recovery occurred, and the patient was discharged from the hospital. After excluding other sources of contact with Leptospira-infected material, an unsuspected abnormal eating behavior was identified as the most probable cause of the patient’s Leptospira infection.

Leptospirosis with pulmonary haemorrhage and multiple organ failure: a case report and literature review

Pulmonary haemorrhage is an important complication of leptospirosis. We herein report an uncommon case of severe pulmonary haemorrhage and multiple organ failure caused by leptospirosis in a 49-year-old man who was previously healthy. He was a farm worker who was admitted to the hospital because of haemoptysis. He had worked in a paddy field 4 days prior to admission. Chest computed tomography revealed pulmonary haemorrhage, which rapidly deteriorated into haemorrhagic shock and multiple organ failure. Based on the patient’s possible history of contact with contaminated water and the DNA sequence of Leptospira detected in his bronchoalveolar lavage fluid, the patient was diagnosed with pulmonary haemorrhagic leptospirosis. Despite the administration of a fluid bolus, norepinephrine, broad-spectrum antibiotics, and haemostatics, and even with administration of a blood transfusion and extracorporeal life support, the pulmonary haemorrhage could not be controlled effectively. The patient eventually died of haemorrhagic shock. Leptospirosis can be a life-threatening disease despite aggressive treatment, even with extracorporeal life support. Next-generation sequencing can provide important diagnostic clues for patients with atypical leptospirotic symptoms.

Evidence of Leptospiral Presence in the Cumberland Gap Region

BACKGROUND

Leptospirosis is a widespread zoonotic disease that causes reproductive losses and/or hepatorenal failure in a number of animal species. Wild reservoirs of the disease, such as rodents, harbor the causative bacterium, Leptospira spp., in their kidneys and contaminate the environment by excreting infected urine. In this study, we tested small wild mammals, environmental water, and livestock in the Cumberland Gap region of southeastern Appalachia for the presence of pathogenic Leptospira or leptospiral antibodies.

METHODS/RESULTS

Small wild mammals (n = 101) and environmental water samples (n = 89) were screened by a real time quantitative PCR that targets the pathogenic Leptospira-specific lipl32 gene. Kidneys from 63 small wild mammals (62.37%) and two water sources (2.25%) tested positive for leptospiral DNA. To identify the infecting leptospiral species in qPCR-positive water and kidney samples, a fragment of leptospiral rpoB gene was PCR amplified and sequenced. L. kirschneri and L. interrogans were the leptospiral species carried by small wild mammals. Furthermore, sera from livestock (n = 52; cattle and horses) were screened for leptospiral antibodies using microscopic agglutination test (MAT). Twenty sera (38.46%) from livestock had antibodies to one or more serovars of pathogenic Leptospira spp.

CONCLUSIONS

In conclusion, results from our study show exposure to leptospiral infection in farm animals and the presence of this zoonotic pathogen in the environmental water and kidneys of a significant number of small wild mammals. The public health implications of these findings remain to be assessed.