LEPTOSPIROSIS

What is Leptospirosis?

It is an infection caused by corkscrew shaped bacteria called Leptospira interrogans. There are 13 different genetic types of Leptospira can cause infection to Humans.

Mode of Transmission

• Transmitted mainly by the urine of infected animals mainly Rodents such as Rats, mice, Moles. The urine is contagious until it is moist.
• Humans become infected through contact with water, food, or soil that contains urine from these infected animals. This may happen by swallowing contaminated food or water or through direct contact with break in skin, eye, ear, nose contact. The disease is not known to spread between humans,
• Pet dogs also transmit infection if they lick the urine of the infected rodents in homes.

Vulnerable Groups

Slaughter House workers can contract the disease through contact with infected blood or body fluids, farmers, veterinarians, sailors on rivers, sewer maintenance workers, waste disposal facility workers, Homeless people are more vulnerable to get infection.

Incubation period

usually 7 to 12 days, with a range of 2 to 30 days

Pathophysiology

• Once the bacteria appear in the blood, it invades all tissues and organs particularly affecting the liver and kidney. Eventually they get cleared from the body by the host's immune response.
• In some condition bacteria settles in the convoluted tubules of the kidneys shed in the urine for a few weeks to several months or longer .subsequently they are cleared from the kidneys and other organs (may persist in the eyes for much longer)
• When the bacteria persist in blood, Produces endotoxins attach onto the endothelial cells that results capillary Vasculitis (endothelial necrosis and lymphocytic infiltration).
• Vasculitis & Leakage causes petechiae, intraparenchymal bleeding and bleeding along serosa and mucosa.
• Movement of fluids into the third space causes hypovolemic shock and vascular collapse

Clinical manifestations/Signs & Symptoms

• The signs & symptoms start to appear after the incubation period
• It causes range of clinical signs and symptoms in two phases, i.e. First & Second phase.
• First phase lasts up to 3 to 7days. During the period patient will have

1. fever accompanied by chills,
2. intense headache,
3. severe myalgia (muscle ache),
4. abdominal pain,
5. conjunctival suffusion (red eye), and
6. Occasionally a skin rash.

• These symptoms will disappear once the antibodies are produced against the Leptospira and results in disappearance of Leptospira in blood stream.

Then the patient is Asymptomatic for little period of 3 to 4 days before the second phase of disease starts with followings manifestations.

1. Again Fever,
2. Classic signs of Meningitis
3. Acute Respiratory symptoms
4. Weil's disease, which is characterized by liver damage (causing jaundice), kidney failure, and abnormal bleeding.

Diagnostic Investigations

• Microscopic Agglutination Test (MAT). It is a ‘gold standard’ serological test for diagnosing Leptospirosis.
• Leptospirosis can also be confirmed with tests such as enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction.
• Microorganism can be seen Cerebrospinal Fluid in initial period of 7 to 10 days.
• Renal Function Test (BUN, Serum Urea, Serum Creatinine)
• Liver Function Tests (Aspartate Aminotransferase, Alanine Aminotransferase, Gamm Glutamyltransferase, Sr.Bilirubin etc)

Treatment

• Effective use of Antibiotics such as Penicillin G, Ampicillin, Doxycycline and in cases of more severe condition cephalosporin like Cefotaxime, ceftriaxone followed for course.
• Adequate fluid & Electrolyte Replacement.
• Correction of Hyperkalemia
• In cases of severe cases, dialysis is done to treat renal failure and to correct hyperphosphatemia.

Preventive Aspects

1. Avoiding the contact of contaminated:- Avoiding swimming and walking in contaminated water that might contain infection by the urine of infected animals.
2. Keep away from the animals
3. Avoid travelling to the epidemic areas
4. Wash hands properly after touching contaminated water, pets.
5. Wear protective gears while gardening, or during building renovations.
6. Keep your home environment clean and free from rodents

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