India’s annual southwestern monsoon has arrived. It is caused by the temperature difference between land and ocean. During summer, the land becomes very hot while the ocean stays relatively cooler, creating a low-pressure area over the land and a high-pressure area over the ocean. This temperature contrast leads to the formation of monsoon winds that blow from the Arabian Sea and the Bay of Bengal toward the subcontinent. These very winds carry vapour from the ocean, and, upon reaching land, rise and cool down. They help in bringing relief from scorching summer temperatures and nourish the land with abundant rainfall, consequently supporting agriculture and the overall ecosystem. However, a surge in various sicknesses and other challenges (notably the disastrous 2018 Kerala floods) is observed throughout the nation during this period. The combination of increased atmospheric moisture (humidity), stagnant water, and favourable breeding grounds for disease vectors create an environment conducive to the spread of numerous illnesses.

Disease Vectors are vexatious living organisms, such as insects and other animals (pests), that can transmit infectious pathogens (viruses, bacteria, parasites) from one host to another. These vectors act as carriers and facilitate the spread of diseases. Their control and prevention are key in mitigating the persistence of diseases. Various respiratory illnesses are also prominent at this time of the year. This article shall delve into the diseases commonly associated with the south-westerly monsoon of India, and how to prevent their symptoms from arising.

Vector Diseases:-

  • Malaria: Malaria is a mosquito-borne disease caused by the Plasmodium The monsoon provides an ideal environment for mosquito breeding due to the accumulation of stagnant water. Mosquitoes breed on stagnant water by laying their eggs on the water’s surface, which then hatch into larvae and develop into adult mosquitoes in the aquatic habitat. The disease is prevalent in several parts of India during the monsoon season. Symptoms include high fever, chills, body aches, and fatigue. Prompt diagnosis and treatment are crucial to prevent malaria.


  • Dengue Fever: Transmitted by the Aedes mosquito, is a significant concern during the monsoon season. The increased humidity and water accumulation provide breeding grounds for these insects. Symptoms range from mild fever, severe joint & muscle pain, rashes; and, in severe cases, progress to dengue hemorrhagic fever or dengue shock syndrome. Apt medical intervention and vector control measures are vital in curbing dengue outbreaks.


  • Chikungunya: Like dengue, chikungunya is also transferred by the Aedes mosquito. The rainy season contributes to an upsurge in chikungunya cases, especially in regions with poor sanitation and inadequate waste management. Symptoms consist of high-grade fever, severe joint pain, headache, and rash. Although seldom life-threatening, it can cause long-term joint pain and disability in some cases.


  • Leptospirosis: Commonly known as rat fever, it is caused by the Leptospira During the monsoon, flooding and waterlogging provide an ideal environment for the bacteria to thrive. Humans can contract the disease via contact with contaminated water and soil, especially through open wounds. Symptoms include high fever, headache, muscle pain, and in harsh circumstances, liver & kidney damage. Proper sanitation, wearing protective attire, and avoiding contact with contaminated water can help prevent leptospirosis.


  • Typhoid Fever: Caused by the Salmonella Typhi bacteria, it is primarily spread through contaminated food and water. Symptoms include prolonged high fever, headache, abdominal pain, and diarrhea. Maintaining proper hygiene, making sure drinking water is safe, and eating well-cooked food (which will kill any possible bacteria) are essential preventive measures.


  • Pure Waterborne Diseases & Respiratory Illnesses:

 Pure waterborne diseases are caused by ingesting or encountering contaminated water containing pathogenic microorganisms, such as bacteria, viruses, or parasites. Examples of pure waterborne diseases include cholera, hepatitis A, gastroenteritis, and typhoid fever. These diseases chiefly affect the gastrointestinal system and can lead to symptoms like diarrhea, vomiting, abdominal pain, and dehydration.

Contrastingly, respiratory illnesses during the monsoon season are predominantly caused by airborne pathogens, such as viruses and bacteria, that are spread through respiratory droplets during precipitation. These illnesses affect the respiratory tract, leading to symptoms such as coughing, wheezing, sneezing, runny/stuffy nose, sore throat, and difficulty breathing. Common respiratory illnesses during the monsoon include the common cold, influenza (flu), respiratory syncytial virus (RSV) infection, asthma exacerbation, & allergic rhinitis (hay fever).

 Note:- Boiling water (thus killing bacteria present), using water purifiers, washing hands before eating, and consuming hygienically prepared food can help prevent waterborne & respiratory illnesses.

While India’s southwest monsoon brings respite from the blazing heat and rejuvenates god’s own country, it also brings an upsurge in a multitude of diseases across the land. Malaria, dengue fever, chikungunya, leptospirosis, typhoid fever, waterborne diseases, and respiratory illnesses are namely common health concerns during this season. Prevention and control strategies such as vector control measures, proper sanitation methods, maintaining hygiene, and public awareness campaigns are crucial in reducing the impact of these diseases. By adopting precautionary measures and seeking timely medical attention, Keralites can safeguard their health and well-being during the rainy season.

Article Credits
Rohan Panicker, Content Writer, CareMithra