Leptospirosis
Introduction
Leptospirosis
is an infectious disease which occurs worldwide. It is more common in tropical
and sub-tropical areas. It is a zoonotic illness which means that organisms are
transmitted directly or indirectly from animals to humans. Leptospirosis
characteristically occurs during rainy weather or flooding. Between 1000 to
2000 patients are admitted to hospitals to take medication for rat fever on a
yearly basis. Incidence is highest among the [rice] paddy farmers.
According
to Dr. Jayantha Rajapakse of faculty of Veterinary Medicine and Animal Science
– University of Peradeniya, in Sri Lanka a total of 10,000 cases have been
reported and nearly 500 people have died. Most likely the disease is under-
diagnosed because of the non-specific initial presentation and difficulties in
laboratory diagnosis. Most number of patients detected as suffering from
leptospirosis are from Matara district. Also Gampaha and Kegalle districts have
recorded a higher incidence.
Pathogenic
bacteria called leptospirosis. They are found in the kidneys of certain animals
such as rodents like rats and bandicoots, canines, livestock, and wild mammals.
It is
transmitted to humans by exposure of abraded skin or mucous membranes (nasal,
oral or eye) to water or wet soil or food and water that has been contaminated
by urine from asymptomatic chronically infected animals, especially rodents.
After infection the organisms enter the blood and invade all tissues and
organs. Patient can develop symptoms about 1 – 2 weeks following exposure.
Initial
symptoms are abrupt onset of fever, chills, muscle pain especially in calf
muscles and back, headache, cough, nausea, vomiting and diarrhea.
Characteristically conjunctiva suffusion i.e. red eyes and tenderness of
muscles occur.
The 2nd
phase of disease occurs after a short period of relative wellbeing which is due
to immunological response to the infection. They can present with aseptic
meningitis (Inflammation of brain coverings), myocarditis (Inflammation of
heart muscles), pneumonia (Inflammation of lungs), nephritis (Inflammation of
kidneys) and hepatitis (Inflammation of liver) with jaundice (yellow eyes).
More than 90% of patients have a self-limited illness but some develop severe
disease with kidney and liver failure.
Kidney
failure, heart failure and wide spread haemorrhage (bleeding) are the main
causes of death. Rarely liver failure contributes. Case fatality rate is
reported to range from 5 – 30% according to data from Epidemiology unit.
High
index of suspicion is essential to diagnose especially if there is an
occupational and recreational exposure. Confirmation is mainly by detecting
anti bodies.
Leptospirosis
is a potentially serious but treatable disease. Treatment with effective
antibiotics should be initiated as soon as the disease is suspected without
waiting for laboratory results. Supportive care with strict attention to fluid
and electrolyte balance is essential. Dialysis is indicated in renal failure.
If you
are involved in occupations such as farming, mining, cleaning drains and canals
etc. please inform your area MOH or PHI. They will explain how to prevent you
getting the disease. The following specific measures can help to prevent
leptospirosis.
Keeping
areas around human habitation clean to control rodents
Keep
animals away from gardens, playgrounds and other places where children play.
Where
there can be recreational and occupational exposure, protective clothing,
knee-high boots, gloves etc should be worn and wounds covered with waterproof
dressing.
Use
boiled and cooled water to drink. Never drink stagnant water directly from
rivers and lakes.
Avoid
walking in flood water
Doxycycline
has been reported to give some protection against infection and disease.
Organisms mainly found in the kidneys of rodents like rats and bandicoots.
 |
| Leptospira interrogans 3D electron microscope view. |
 |
| Image of human conjunctival suffusion. |