By Dr Ritesh Kohli, MD (Internal Medicine Specialist)
What is leptospirosis?
Leptospirosis is a bacterial disease that af-fects humans and animals. In humans it causes a wide range of symptoms, and some infected persons may have no symptoms at all. Symptoms of leptospirosis include high fever, severe headaches, chills, muscle aches and vomiting, and may include jaundice (yellow skin and eyes), red eyes, abdominal pain, diarrhoea, or a rash. If the disease is not treated, the patient could develop kidney damage, meningitis (inflammation of the membrane around the brain and spinal cord), liver failure, and respiratory distress. The rate of persons dying is high with complicated leptospirosis.
How is leptospirosis transmitted?
Outbreaks of leptospirosis are usually caused by exposure to water contaminated with the urine of infected animals. Many different kinds of animals carry the bacterium; they may become sick but sometimes have no symptoms. Leptospira organisms have been found in rodents, cattle, pigs, horses, dogs, and wild animals. Humans become infected through contact with water, food, or soil containing urine from these infected animals. This may happen by swallowing contaminated food or water or through skin contact, especially with mucosal surfaces, such as the eyes or nose, or with broken skin. Flooding after heavy rainfall helps spread the bacteria in the environment. The disease is not known to be spread from person to person.
How long is it between the time
of exposure and when people become sick?
The time between a person’s exposure to a contaminated source and becoming sick is 2 days to 4 weeks. Illness usually begins abruptly with fever and other symptoms. Leptospirosis may occur in two phases; after the first phase, with fever, chills, headache, muscle aches, vomiting or diarrhoea, the patient may recover for a time but become ill again. If a second phase occurs, it is more severe; the person may have kidney or liver failure or meningitis. This phase is also called Weil’s disease.
The illness lasts from a few days to 3 weeks or longer. Without treatment, recovery may take several months.
Where is leptospirosis found?
Leptospirosis occurs wor-ldwide but is most common in temperate or tropical climates. It is an occupational hazard for many people who work outdoors or with animals, and it is a recreational hazard for campers or those who participate in outdoor sports in contaminated areas and has been associated with swimming and wading in contaminated lakes and rivers.
How is leptospirosis diagnosed?
Laboratory diagnosis with specific tests is a must for proper diagnosis of leptospirosis. Under circumstances of limited access (eg, developing countries) to specific diagnostic means, close attention must be paid to clinical history of the patient. Factors like certain dwelling areas, seasonality and contact with stagnant, contaminated water (bathing, swimming, working in flooded fields, etc) and/or rodents in the medical history support the leptospirosis hypothesis and serve as indications for specific tests.
On infection the micro-organism can be found in the blood for the first seven to ten days (invoking serologically identifiable reactions) and then moves to the kidneys. Hence, early diagnosis is done using serologic tests. After seven to ten days the micro-organism can be found in fresh urine. It is also possible to culture the micro-organism from blood, serum, fresh urine and possibly a fresh kidney biopsy. However, a culture is used only for research purposes and not for diagnosis, as a positive culture results take three weeks to three months.
The diagnosis of leptospirosis is confirmed with tests such as Enzyme-Linked Immunosorbent Assay (ELISA) and PCR. The microscopic agglutination test (MAT) is considered the gold standard for serologic diagnosis. The ELISA test is widely used and helps in rapid diagnosis.
How is leptospirosis treated?
Leptospirosis is treated with antibiotics, such as doxycycline or penicillin, which should be given early in the course of the disease. Intravenous antibiotics may be required for persons with more severe symptoms. Persons with symptoms suggestive of leptospirosis should contact a health care provider.
What is the outcome of leptospirosis during pregnancy?
Leptospirosis during pregnancy may cause a miscarriage or foetal death.
Who is at risk for leptospirosis?
Leptospirosis outbreaks occur during the rainy season or in times of flooding.
Farmers, workers in rice fields, sewer workers, and others whose jobs involve contact with water or mud that is contaminated by animal urine, especially the urine of rodents are especially at risk.
Veterinarians and others in contact with leptospirosis-affected animals are also at risk.
Can leptospirosis be prevented?
The risk of acquiring leptospirosis can be greatly reduced by not swimming or wading in water that might be contaminated with animal urine. Protective clothing or footwear should be worn by those exposed to contaminated water or soil because of their job or recreational activities. The major control measure available for humans is to avoid potential sources of infection such as stagnant water and water derived from run-off from animal farms, rodent control and protection of food from animal contamination. Doxycycline tablet prophylaxis was effective in preventing some cases of leptospirosis, although further studies are awaited.
Prognosis
Most patients with Leptospirosis recover if treated in early stages. Long term follow-up of patients with kidney and liver failure has shown good recovery from leptospirosis.
