The monsoon ushers in a host of infections. The increased humidity and waterlogged conditions provide an ideal environment for pathogens to thrive. One such common infection occurring during the rainy season is leptospirosis, a widespread zoonotic condition transmitted by animals to humans. Also known as Weil’s disease, the bacterial infection has been observed in several Indian states like Kerala and Gujarat, especially after floods.
With Cyclone Biparjoy, the fear of leptospirosis has come to the forefront again. However, experts opine that barring a few cases, the infection hasn’t given rise to an outbreak.
How is leptospirosis transmitted?
“Leptospirosis is caused by a bacteria called Leptospira, commonly found in the kidneys of rats, which gets expelled when the infected animal urinates,” says Dr Netto George, assistant professor (infectious diseases), Government Medical College, Kottayam, Kerala.
Rats tend to dwell in unhygienic conditions. “An individual can contract the infection by coming in contact with the infected animal’s urine, either directly or indirectly through soil or water contaminated by it,” says Dr Netto.
He further adds that the bacteria usually enter the human body through cuts and abrasions on the skin, especially the feet. They can also enter through mucous membranes like the eyes, nose and mouth. The bacteria, on entering the body, get localised in the kidneys.
While several animals like cattle, dogs, horses, pigs and birds can serve as hosts for the bacteria, rats are the most common hosts in India, notes Dr Netto.
Monsoons can trigger leptospirosis
According to Dr Vikas Desai, former professor and HOD, community medicine, Government Medical College, Surat, leptospirosis is seen during the monsoon season (when there is a lot of flowing water along with water logging and floods), as there is an increased exposure to contaminated water.
People in certain professions are more susceptible to contracting leptospirosis than others.
“Those working in wet environments or involved in professions like agriculture and livestock farming, sewer cleaning, cattle care, veterinarians, etc. are more susceptible to contracting the bacterial infection because of the possibility of coming in contact with the infected animal or the infected urine,” says Dr Desai, who’s also the additional director of Family Welfare in Gujarat.
According to The Centers for Disease Control and Prevention (CDC), while leptospirosis occurs worldwide, it is most common in temperate or tropical climatic regions, including South and Southeast Asia, Oceania, the Caribbean, parts of sub-Saharan Africa and parts of Latin America.
“Hot and humid temperatures along with soil alkalinity facilitate the survival of bacteria for months,” notes Dr Desai.
Leptospirosis in India
Outbreaks of leptospirosis have been increasing in India for the past three decades. Factors like rapid urbanisation, climate change, poor sanitation and improper waste management have resulted in increased reporting of leptospirosis outbreaks in the past few years, notes the Royal Society of Tropical Medicine and Hygiene.
“In Indian states like Kerala, Tamil Nadu, Gujarat, Maharashtra, Karnataka and Andaman & Nicobar Islands, leptospirosis has acquired endemic status,” says Dr Desai.
The state of Kerala saw an upsurge in leptospirosis cases post the 2018 floods.
Dr Netto says that the monsoons trigger leptospirosis cases in Kerala, as the paddy fields experiencing heavy rainfall offer a conducive environment for bacterial transmission.
Symptoms of leptospirosis
Leptospirosis can initially present with mild symptoms, which can escalate to severe complications like organ damage, making timely diagnosis and treatment important. Dr Netto lists the typical early signs of leptospirosis, which include:
- Fever
- Myalgia (muscle pain, especially in the calf muscles)
- Red eyes
- Jaundice
Advanced symptoms include organ damage that can involve the kidneys, liver and lungs. “The bacteria can enter the kidney, causing an increase in creatinine levels and eventually lowering the urine output. The person may also require two to three dialysis sessions until the infection comes under control,” says Dr Netto.
According to him, the liver can also be affected, causing jaundice, characterised by yellow discolouration of the eyes and skin. It can also lead to liver failure.
He further points out that the lungs being affected can be a cause for concern.
“When the lungs get affected, the person experiences breathing difficulties, coughing out blood, pulmonary hemorrhage [bleeding in the lungs], etc. They may require mechanical ventilation,” says Dr Netto. “In rare cases, it can also affect the brain and heart,” he adds.
“The host animal can also suffer from ill effects like abortions and mastitis,” says Dr Desai.
Treatment and prevention
Dr Netto says that leptospirosis is treated with antibiotics like doxycycline or penicillin.
“The symptoms usually settle within a week. In case of organ damage, appropriate supportive therapy is provided,” he adds.
“Wearing appropriate protective gear [like boots and gloves], monitoring and managing infections in cattle before the onset of monsoons and avoiding wading into contaminated waters can help prevent the infection,” says Dr Desai.
Takeaways
- Leptospirosis is a bacterial infection transmitted from animals (especially rats) to humans.
- Infection can occur through direct or indirect contact with the contaminated urine of the infected animal. Bacteria can enter the human body through cuts and abrasions on the skin as well as through mucous membranes like the eyes, mouth and nose.
- Wearing appropriate protective gear, monitoring and managing infections in cattle and avoiding wading into contaminated waters can help prevent the infection.
