What Are The Common Causes Of Febrile Illness?


Febrile illness refers to a prominent rise in body temperature above the normal average value of 37 degrees Fahrenheit or 98.6 degrees Celcius. Febrile illness occurs in children and adults most likely due to infection by various pathogenic microorganisms such as bacteria, viruses, fungi and protozoa. The fever persists for at least 4 – 7 days in many instances, while in some cases, it prolongs for even up to 2 – 3 weeks wherein it termed as acute febrile illness (AFI) or short febrile illness (SFI).

Typical Symptoms Of Febrile Illness:

Apart from having a constant fever, numerous other symptoms are also experienced during febrile illness. These happen due to heightened inflammatory responses and immune system activity in the body, induced by the attack of harmful microbes on normal, healthy cells and tissues. People affected by febrile illness often have prominent red rashes on their skin, with irritation, swelling, itching. They also display grave problematic signs of haemorrhages i.e. bleeding from an injured blood vessel, excruciating muscle pain, soreness or myalgia, decline in liver functions from jaundice and aching joints termed as arthralgia.

Frequently Occurring General Causes Of Febrile Illness:

The common factors that prompt febrile illness in people of a specific region depend upon the geographical location in which they reside. However, statistics from epidemiological and medical experts in many different countries and continents report that infectious diseases from bacteria, protozoa, viruses are the primary reasons that trigger febrile illness in individuals of all age groups. Among the several infectious sicknesses, the following are the five most common conditions that result in febrile illness.


This is triggered by the Dengue Fever Virus type 1, 2, 3, 4, denoted as DENV-1, DENV-2, DENV-3 and DENV-4. It is transmitted from an infected person to a healthy individual through a carrier or vector, the female Aedes mosquito. Treatment comprises prescription medications of analgesics to relieve body pain and antipyretics, which bring down elevated body temperature and cure fevers.


Typhoid is a bacterial infection prompted by the Salmonella typhi species of pathogenic microbes. This illness is dispersed across a group of people by consuming contaminated food and water. In localities where typhoid fever occurs rampantly, preventive vaccines are given. When affected by typhoid fever, the treatment consists of pertinent antibiotics and intake of ample fluids.


Also known as the flu, influenza is a contagious viral infection and spreads from a sick person to a healthy individual through air droplets when coughing, sneezing, talking. It is induced by influenza viruses and attacks the respiratory system – nose, throat, lungs. Preventive flu shots shield the body from infection, while treatment entails taking complete rest, ingestion of large volumes of fluids, and prescription antiviral drugs.


Malaria is an infectious ailment triggered by the Plasmodium parasite, which spreads from an afflicted person to a healthy individual by means of an insect vector – the female Anopheles mosquito. This illness is treated by prescription antimalarial drugs, which are taken orally in situations of a slight fever and administered intravenously in severe cases, to combat the parasitic infection in the body.


Leptospirosis is caused by the bacterial pathogenic microbe known as Leptospira interrogans. This ailment is zoonotic, as the bacteria is initially present in the kidneys of afflicted animals and is excreted via their urine. It then invades the human body through openings in the skin, either by direct contact with infected animals or through contaminated soil, food, water. Treatment involves taking appropriate antibiotics to resolve the infection.