Contents
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
- Meningitis,(asceptic)
- Myocarditis
- Hearing loss
- Respiratory distress
- Renal failure
- Liver failure
- DIC
- CCF
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
- 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
- Murtagh’s General Practice. 6th Ed. (2015) John Murtagh, Jill Rosenblatt
- Oxford Handbook of General Practice. 3rd Ed. (2010) Simon, C., Everitt, H., van Drop, F.
- Beers, MH., Porter RS., Jones, TV., Kaplan JL., Berkwits, M. The Merck Manual of Diagnosis and Therapy