Spirochete (spiral) bacteria belonging to the genus Leptospira are responsible for causing Leptospirosis.
It is the commonest zoonotic disease (i.e. animal disease that can be transmitted to humans), and affects mammals, birds and reptiles alike.
Humans contract this infection via direct contact with infected animals, or infectious animal tissues or fluids. Unhealed cuts and scratches form the entry points for the bacteria. Ingestion of contaminated food and water is another mode by which the disease spreads to humans.
The disease has a greater incidence in regions that experience heavy rainfall. Though it affects both men and women of all ages, it is commonly observed in middle-aged men.
Alternative names: Weil’s Disease/Weil’s Syndrome, Icterohemorrhagic Fever, Swineherd's Disease, Rice-field Fever, Cane-cutter Fever, Swamp Fever, Mud Fever, Hemorrhagic Fever
Consultant/Specialist: Internal Medicine
Etio-patho-genesis (Causes and Mechanisms)
As stated before, Leptospira bacteria are the causative agents of the disease. The pathogen affects both animals and humans. It has a greater prevalence in regions that receive heavy and frequent rains. Such weather condition is favorable for its growth.
Mode of transmission
- Leptospirosis usually spread via consumption of water contaminated by an infected animal’s excreta and body fluids, e.g. sweat, urine, feces, semen, etc Muddy riverbanks, ditches and lakes are the common sites of such contamination because of their frequent use by animals.
- Mice are the primary hosts, i.e. they are the first to be infected by the bacteria. They act as carriers of the disease, and transmit it further.
- Humans are infected by the bacteria when they are exposed to infected animals, or their body fluids or tissues. Splashing contaminated water into the eyes, the nose and open wounds, and consuming food or water infected by animal excreta are ways by which Leptospirosis is transferred to humans. It is not known to spread from one person to another.
- Individuals who are exposed to infected animals, e.g. veterinarians, pet-shop owners, people working at a slaughter house, etc.
- Open wounds, as infected pets can lick them
- Areas with high probability of infection such as muddy banks and gullies, especially during the rainy season
Presentation (Signs & Symptoms)
In case of humans, about 1-2 weeks elapse between the initial exposure and the appearance of the first symptoms (incubation period). Leptospirosis is biphasic, i.e. the disease re-manifests itself after an apparent resolution of the initial symptoms. The presentations in the second phase of the disease are generally more severe than earlier ones.
Primary symptoms include:
- Red eyes
- Stomach pain
- Muscle pain
Secondary symptoms include:
- Stiffness in the neck
- Abdominal pain
- Meningitis (inflammation of covering of the brain)
- Kidney failure
- Liver damage, resulting in jaundice
- All or some of the primary symptoms
- Bacterial culture: Leptospira bacteria remain in the blood of the host for 7-10 days post exposure. After 10 days of initial exposure, the pathogen is visible in the urine as well. Thus, blood and urine samples are used for growing the bacteria in controlled laboratory conditions.
- Kidney function and liver function tests help check for the effect of the disease of the functioning of the respective organs.
- Kidney biopsy (involves examining a sample of nephritic tissue)
- ELISA (Enzyme-linked Immunosorbent Assay), PCR (polymerase chain reaction) and MAT (microscopic agglutinations test) help detect the presence of specific antibodies. These antibodies are the proteins which are produced by the body’s defense system in response to the infection or foreign bodies.
- The treatment strategy for Leptospirosis involves suppressing the causative agent and tackling the possible complications.
- Antibiotics such as Cefotaxime, Doxycycline, Penicillin, Ampicillin and Amoxicillin help suppress the bacteria. Doxycycline is primarily used for prophylaxis.
- Corticosteroids such as Prednisolone help in some hemorrhagic cases.
The following herbs help speed up the recovery, and prevent the complications of Leptospirosis:
- Sitopaladi churna
Supportive therapy is prescribed for fever, headaches and dehydration. Dehydration is treated via normal painkillers such as Ibuprofen, and restoration of electrolyte balance.
- Organ-specific therapy is undertaken in case of complications related to the liver, the kidney, the heart, etc.
- Detoxification and electrolyte neutralization are necessary in case the kidneys are severely affected.
- Increase in serum potassium level is corrected via dialysis or oral administration of Calcium Carbonate. It should be ensured that the serum calcium level is not high.
The duration and severity of infection determine its prognosis. Early diagnosis and proper treatment help alleviate the disease before it results in complications.
- Extreme fatigue
- Respiratory distress
- Vasculitis (inflammation of vessels), resulting in edema
- Bleeding problems
- Hearing loss
- Liver failure
- Kidney failure
- Allergic reaction (if the patient is allergic to penicillin)
At present, the only vaccines available are those that prevent the occurrence of Leptospirosis in animals.
Some measures to avoid Leptospira infection:
- Not contacting animal excreta and contaminated water
- Regularly vaccinating pets
- Keeping the house neat and clean
- Avoiding places where the probability of contracting the disease is high, e.g. slaughter houses
- Taking Doxycycline before going to regions where the disease is prevalent