• Leptospirosis has emerged as an important infectious disease in the world today.
  • It is a potentially fatal zoonotic bacterial disease that tends to have large outbreaks after heavy rain or flooding.



  • This disease is more prevalent in warm, humid countries and in both urban and rural areas.
  • It affects an estimated 1.03 million people every year, killing around 60,000.
  • In India, thousands of people are affected by leptospirosis every year.
  • However, the numbers at the global and regional levels are not exact because of:
    • misdiagnosis (its symptoms mimic those of dengue, malaria, and hepatitis)
    • limited access to reliable diagnostics
    • lack of awareness among treating physicians
    • lack of environmental surveillance.
  • Within India, studies have found that leptospirosis is more common in the south, although this could be due to the region’s better healthcare and thus better disease detection.


  • The disease is caused by a bacterium called Leptospira interrogans, or leptospira.
  • It is a contagious disease in animals but is occasionally transmitted to humans in certain environmental conditions.
  • The carriers of the disease can be either wild or domestic animals, including rodents, cattle, pigs, and dogs.
  • The cycle of disease transmission begins with the shedding of leptospira, usually in the urine of infected animals.

Vulnerable sections

  • Humans become part of the cycle when they come in direct contact with this urine or indirectly, through soil and water that contain leptospira bacteria.
  • A person is more likely to contract leptospirosis if they have cuts or abrasions on their skin.
  • The disease is also considered an occupational hazard for people working in agricultural settings, with animals, or in sanitary services that bring them into contact with contaminated water.
  • Recreational activities in contaminated lakes and rivers are also reported to increase the risk of leptospirosis.


  • The severity of a leptospirosis infection ranges from a mild flu-like illness to being life-threatening.
  • The infection can affect many organs, reflecting the systemic nature of the disease.
    • This is also why the signs and symptoms of leptospirosis are often mistaken for other diseases.
  • In milder cases, patients could experience a sudden onset of fever, chills, and headache – or no symptoms at all.
  • But in severe cases, the disease can be characterised by the dysfunction of multiple organs, including the liver, kidneys, lungs, and the brain.
  • Animals exhibit a variety of clinical symptoms and indications.
  • In cattle and pigs, the disease can potentially cause reproductive failure, stillbirths, and weak calves or piglets.

Misconceptions About the disease

  • The disease has been called:
    • ili jwara” in Kannada
    • eli pani” in Malayalam
  • Both the above terms mean “rat fever”.
  • It is a common belief that rats are the sole cause of the disease.
  • However, this is not true as Leptospirosis has a spectrum of reservoir hosts, including pigs, cattle, water buffaloes, goats, dogs, horses, and sheep.
  • Seasonal patterns such as the onset of the monsoon can also potentially facilitate the disease’s incidence and transmission.
  • Ambient air that is more humid can help the pathogenic leptospira survive longer in the environment, thus increasing the risk of disease exposure in the community.
  • The incidence of the disease is also linked to extreme weather events like floods and hurricanes, when people are exposed to contaminated water.
  • Similarly, poor waste management, a high density of stray animals, faulty drainage systems, and unhygienic sanitation facilities are major drivers of the disease in urban areas.
  • In rural parts, these are contaminated paddy fields, dirty livestock shelters, and poor water-quality and sanitation.

Preventing leptospirosis

  • Leptospirosis control can benefit from a ‘One Health’ approach.
  • ‘One Health’ is an interdisciplinary approach that recognises the interconnections between the health of humans, animals, plants, and their shared environment.
  • People who frequently interact with animals or their urine should exercise particular caution, such as by wearing personal protective equipment like gloves and boots.
  • Preventing animals from getting infected is also important to reduce the risk of leptospirosis spreading and to limit farmers’ economic losses.
  • This in turn requires sanitary animal-keeping conditions, which is also desirable to improve the animals’ health and to prevent the spread of many diseases.
  • Given the spike in leptospirosis during the monsoons, it is best to take precautions, including washing one’s arms and legs with an antiseptic liquid after handling animal waste and after working in water.

Way forward

In sum, with ‘One Health’ in mind, public health professionals must work closely with the animal husbandry department to familiarise people about the dangers of leptospirosis, and create countermeasures that work for the health of both people and animals.


Bacterial Diseases

  • Bacterial diseases are diseases caused by bacteria.
  • A variety of bacteria do not cause any infections and are known as “good bacteria”.
  • The bacteria that cause diseases in humans are called “harmful bacteria”.
  • There are thousands of bacteria present in the gut that are beneficial for humans.
  • The pathogenic bacteria in humans account for less than a hundred species.
  • Bacterial diseases are communicable diseases and spread from one person to another.
  • Bacterial diseases are infectious diseases and are transmitted through water, air, food, vectors, body fluids, etc.
  • Bacterial disease in humans is one of the major causes of death to humans, even after so much advancement in medical research.

Some bacterial diseases

  • Diphtheria
  • Anthrax
  • Pneumonia
  • Leprosy
  • Tuberculosis
  • Plague– Yersinia pestis is a zoonotic bacterium that is typically found in small mammals and the fleas that live on them. This bacterium is responsible for the transmission of the plague.
  • Meningitis– An infection of the tissues that cover and protect the brain and spinal cord is known as meningitis. Viral infections, bacterial infections, and fungal infections can all cause meningitis.
  • Cholera
  • Tetanus
  • Typhoid fever
  • Lyme disease
  • Whooping cough
  • Gonorrhea –It is a disease that can be passed on through sexual contact. A bacterium known as the gonococcus, Neisseria gonorrhoeae, is responsible for causing this condition.
  • Syphilis – a disease that affects the entire body and is brought on by the spirochete bacterium known as Treponema pallidum.
    • In most cases, the disease is passed on through sexual contact; however, it can also be contracted by coming into direct non-sexual contact with an infected person, and it is also possible for an unborn child to contract the disease from their mother if she is infected with it.