Leptospirosis
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Leptospirosis: also known as Weil’s Disease

Organism

Spirochaete bacterium called Leptospira spp
incubation: 7-14 days

Transmission

  • Via the urine of an infected animal (contagious as long as it is still moist)
  • Rats, mice, and moles are important primary hosts
  • Humans become infected through contact with water, food, or soil containing urine (ingestion/skin contact)
  • Incidence related to rainfall – seasonal in temperate climates and year-round in tropical climates.

Epidemiology

  • Uncommon in the UK (fewer than 40 cases/yr in England and Wales, approx. 2-3 of these die from the disease/yr)
  • Significant number affected by disease in eastern and southern Europe, Australia and New Zealand.
  • Those at risk include sewage workers, travellers (i.e. swimming in contaminated water), farmers, vets, abattoir workers, rodent control workers, among others.

 

Pathogenesis

  • Leptospires enter through broken skin/ mucous membranes/ inhalation
  • The motile organisms  disseminate throughout the body
  • Multiply in small blood vessel endothelium
  • Release products which cause damage and vasculitis affecting almost any organ
  • Capillary leak.
  • Organism multiply and septicaemia persists until host develops targeted immunoglobulin
  • Rapid clearance from bloodstream but leptospires remain in immunologically privelidges sites (i.e. renal tubules)

 

Clinical features

Infection can be asymptomatic, cause a mild flu-like illness, or severe, life-threatening illness.
Disease is usually self-limiting( Most recover fully within 2-6 weeks)

Disease usually  presents in 2 phases:
ACUTE/SEPTICAEMIC phase:

IMMUNE phase: (follows 5-7 days later)
Associated with antibody production and excretion of the organism in urine
Patients suffer from severe systemic manifestations i.e. renal failure/ hepatic failure/pulmonary haemorrhages..

*Liver and renal dysfunction are usually reversible, with resolution over 1-2 months.
*immunity develops following infection, but may not fully protect against infection with other strains.

Complications

 

Diagnosis

(leptospires can be found in blood and CSF for the first 7 -10 days and then moves to the kidneys)

  • ELISA and PCR
  • Culture (blood/CSF/Kidney biopsy)
  • Microscopy of fresh urine (after 7-10 days)

 

Treatment

Antibiotics

  • Cefotaxime/doxycycline/penicillin
  • Supportive measures (i.e.some patients require dialysis)

Prevention

  • Prophylaxis (i.e. high risk occupations/activities for short period) can be given, usually Doxycycline
  • No human vaccine available; (animal vaccines exist)
  • Reduction of rodent populations, e.g. by clearing rubbish and preventing rodent access into buildings.
  • Avoidance of swimming/wading in water that might be contaminated with animal urine.

References

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) currently works as a GP Registrar and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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