Chennai (previously known as Madras), is the capital of this southern state of Tamil Nadu. The weather is so hot that the British have a dish named after this city called Chicken Madras. Despite being dry most of the year, many infectious disease are prevalent throughout the year, only that some are more common during the rainy season. Infections are an important reason for high temperatures in the city.

The 5 common endemic infections in Chennai are:

1. Malaria – Vivax malaria is seen more often compared to falciparum malaria and typically cause high fevers with intense shivering (rigors). A person suffering typically experiences a cold phase with shivering, a hot phase with high fever and a sweating phase with drenching sweating. This happens periodically once a day or once in 2-3 days.

2. Typhoid fever (Enteric fever) – this is food borne infection caused by salmonella gastroenteritis. This can present variously but what is usual is that there would be some degree of a gastrointestinal upset. The patient could present with fever,shivering, body pains, headache,rash etc.

3. Dengue Fever – is another mosquito borne viral infection spread by the day biting Aedes aegypti (tiger mosquito – with white stripes on it) which is believed to bite below the knee. Fever can be high with shivering and severe back pain. A rash is also possible in light skinned patients.

4. Leptospirosis or Rat fever is caused by a family of 400 bacteria and causes fever with severe body pains. Some subtypes can cause jaundice, bleeding tendencies along with the fever whereas some others can cause kidney failure. This bacteria enters the body when water contaminated by rat urine (containing the bacteria) comes in contact with the body of the patient.

5. Scrub Typhus -happens due to a organism called Rickettsia and is a mite borne infection. The bite usually occurs in people who travel to heavily wooded areas such as IIT Madras or Raj Bhavan. The fever can be very high and the patient can have a very severe headache. Usually a black ulcer is found in the flexures of the body (under the breasts and in the groins)

The number one fever in Chennai over the last 2 years has been Covid 19. Patients usually have a fever with upper respiratory symptoms such as a headache, sore throat, runny nose, sneezing and cough with some phlegm production. A small proportion of patients develop a severe immune mediated pneumonia during the second week of the infection.

Urine infections, Intestinal infections, Skin infections are other common causes for fever. These infections are usually easily treated.Early diagnosis will help ensuring an early cure and rapid return to normal living.