Viral Fever: Causes, Symptoms, and Treatment Options
Introduction
Fever is one of the body’s natural defence mechanisms, which signals that something is wrong in our body. Fever can happen due to infection, inflammation, or injury. When fever is caused by a virus, it is called viral fever. Our body raises its temperature as an immune response, which fights the virus in the body1,2.For unknown or unexplained fevers, especially short-term fevers, the cause is usually viral3.
Fever can be continuous or intermittent and might vary in pattern based on which virus is affecting you. In viral fever, although fever is the main symptom, other symptoms may also be present, depending on the virus. In this blog, we will discuss in detail the causes of viral fever, viral fever symptoms, and its treatment1,2.
What Is Viral Fever?
Viral fever is an increase in body temperature caused by a virus entering our body. Viruses are extremely tiny microbes that can’t grow by themselves, so they enter living cells in our body and start replicating2,4,5.
Once the virus multiplies inside the cells, it releases substances that can harm the body and cause illness. Our immune system works to fight this virus by sending immune cells called macrophages to attack the virus and release certain proteins to stop the virus’s activity. This triggers an increase in body temperature, causing fever. The high temperature makes it hard for the virus to grow and helps the body fight the infection5,6.
A person is said to have a fever if their oral temperature is above 37.2°C in the early morning, or above 37.7°C at any time during the day1.
Fever is a common symptom in viral infections, with its severity varying by virus type and individual response. In the next section, we will see the different types of viruses causing different types of viral fever6.
Types of Viral Fever
Viral fevers can be caused by viruses from different families and can spread in many different ways, e.g., through the air, insect bites, contact with infected people, or contaminated water. Each type of virus can cause a different kind of illness in the body7.
The most common types of viral fever are:
Flu: The influenza virus is responsible for flu and is the most common cause of viral fever. It affects the upper parts of the respiratory system (e.g., the nose and throat). It spreads through the air and causes fever, cough, sore throat, runny nose, and body pain. Sometimes, it can become severe and lead to a lung infection8.
Dengue: It is caused by a virus belonging to the Flavivirus family. When a mosquito is infected with this virus, it can transmit the virus to a human being through a bite. The dengue virus then enters the human body, multiplies, and enters the blood, causing fever and body pain. In some cases, it can become severe, leading to bleeding, shock, and even death9.
COVID-19: It is an infection caused by severe acute respiratory syndrome Coronavirus 2. It spreads easily through droplets emitted while talking, coughing, or sneezing. It can cause flu-like symptoms, but in some cases, it can become severe and lead to breathing difficulty and lung damage10.
Chikungunya fever: Chikungunya fever is caused by the Chikungunya virus. It spreads through the bite of an Aedes mosquito infected with the virus. The illness can cause symptoms like fever, skin rash, and severe joint pain. In some people, the joint pain and swelling can last for weeks or months11.
Hepatitis: When viruses like hepatitis A and hepatitis E enter your body through contaminated food or water, they can affect your liver. The symptoms usually start with fever, and the eyes and skin may turn yellowish. Most people recover within weeks, but in some cases, it can become severe and lead to liver failure12.
Viral fevers may also affect the stomach (e.g., rotavirus), eyes (e.g., adenovirus), skin (e.g., measles virus), or even the brain (like Japanese encephalitis), causing different viral fever symptoms based on the type and severity of the infection7.
These viral fevers spread in different ways depending on the virus, which brings us to the next part – how are viral fevers transmitted?
How Do You Get a Viral Fever?
Viral fevers spread through different modes, depending on the virus type.
Through the air: Respiratory viruses like influenza, COVID-19, and common cold viruses spread through droplets or aerosols from an infected person’s cough, sneeze, or when talking.
Touching surfaces: Respiratory viruses also spread when you touch surfaces or objects that are contaminated with the virus and then touch your face, mouth, or nose.
Mosquito bites: Some types of fevers, like chikungunya or dengue, spread when an infected mosquito bites you.
Contaminated food or water: Hepatitis A and E viruses spread when you eat food or drink water contaminated with the virus.
From person to person: Some viruses spread through sexual contact or from a pregnant mother to her baby4,7.
Once the virus enters your body, it can trigger certain symptoms as part of your body’s natural response.
Symptoms of Viral Fever
Viral fever often begins suddenly and presents with symptoms common to many infections. These include:
High body temperature (fever)
Headache and body pain
Muscle and joint aches
Feeling tired or weak
Nausea, vomiting, or diarrhoea
Skin rash (in some infections)
Cough, sore throat, or runny nose (in respiratory infections)
In some cases, viral fever symptoms can be more specific to a particular infection:
Joint pain like in chikungunya
Bleeding or bruising as seen in dengue or Ebola
Neck stiffness or confusion that can happen in brain infections like encephalitis
Birth defects, possible if some viruses (like Zika) infect pregnant women
The exact symptoms of a viral infection depend on the type of virus and how your body responds to it13.
How Long Does Viral Fever Last?
The duration of viral fever varies depending on the type of infection and your body’s immune response. Most viral fevers are self-limiting and last between 3 to 7 days.
Viral infections that affect the respiratory tract usually cause fever that lasts 3 to 5 days but may also last up to 7 days14.
Dengue and chikungunya fevers typically last 4 to 5 days, but in severe dengue cases, fever may continue for 6 to 10 days. With chikungunya, even though the fever lasts around 4 to 5 days, joint pain can continue for a longer time15.
In COVID-19, fever can last around 8 to 10 days, especially in moderate-to-severe cases16.
In gastrointestinal viral infections, the fever is often low-grade and lasts about 1 to 3 days14.
Since most viral fevers resolve on their own, it’s important to know whether your fever is due to a virus or something more serious like a bacterial infection.
Viral vs. Bacterial Fever: How to Tell the Difference
Viral and bacterial fevers may look similar at first, but they differ in symptoms, how long the fever lasts, and how they respond to antibiotics. Here is how to understand the difference:
Feature
Viral Fever
Bacterial Fever
Symptoms
Viral fever often causes symptoms that involve many body parts, like cough body pain or tiredness17.
Bacterial fever usually causes symptoms in one area, like redness, swelling, or pain in a specific part17.
Duration
Most viral fevers last less than 7 days.
Bacterial fevers can last longer than 2 weeks if not treated.
Response to Antibiotics
Antibiotics do not work for viral fevers and should not be used 1,14.
Bacterial fevers usually improve with antibiotics1,14.
Blood Tests
CRP is usually at normal levels, and WBC count is normal or slightly raised2,16.
Viral fever is diagnosed by the doctor by checking your viral fever symptoms, asking about your health history, and doing tests if necessary.
Symptoms: You will be asked about common viral fever symptoms like high fever, body pain, cold, sore throat, and tiredness. These are usually seen in the first 3 to 5 days.
History: You will be asked if you have travelled recently or have had close contact with anyone sick. If fever occurs within 1 to 21 days of such contact, it may be viral.
Day-wise pattern: In the early days, symptoms are general. But after 5 days, some individuals may show specific signs like bleeding or confusion, depending on the severity of the infection.
Medical tests: In the first few days of illness, doctors may use tests like PCR or antigen tests to directly find the virus in your body. After a few days, your body produces antibodies to fight the virus, so blood tests for IgM and IgG antibodies may be used to check your immune response. These tests help confirm if the fever is due to a viral infection and its stage13.
This structured approach can help the doctor to diagnose the viral fever, assess its severity, and plan the viral fever treatment.
Treatment of Viral Fever
Your doctor may give medicines based on your symptoms and the type of viral fever. Although viral fever may get better by itself, it is important to manage the symptoms and take good care of the body for faster recovery.
Fever/Body Pain: You may need to take paracetamol or stronger painkillers like NSAIDs to help relieve fever and body pain.
Dehydration: Drink plenty of fluids. In severe cases, fluids may be given through the vein.
Diarrhoea: Rest and fluids may help, but for severe diarrhoea, medicines may need to be given.
Nausea/Vomiting: A bland diet is advised and anti-nausea medicine may be given.
Sore Throat/Runny Nose: Drink warm fluids, do a salt water gargle, and take any other medicines as advised by the doctor.
Antiviral Medicines: May be given in specific viral infections like influenza or herpes under medical supervision.
Antibiotics: Are not useful against viruses and should be used only if the doctor suspects a bacterial infection18.
Diet During Viral Fever
When you have viral fever, it’s better to eat soft foods that are easy to digest. Your diet should include:
High protein
More liquids
Soft, non-oily, non-spicy foods
Examples:
Coconut water, lemon water, juices, and soups that are rich in vitamins and minerals to help balance electrolytes
Soft foods like vegetable poha, upma, sewai, and porridge
Paneer sandwich with fruits
Khichdi (rice and pulses), green vegetables, curd, and paneer-based dishes
Make sure you get enough rest and keep yourself well-hydrated by drinking a lot of fluids19.
Possible Complications of Viral Fever
Viral fever usually gets better with proper rest and taking plenty of fluids along with medicine as per the doctor’s advice. But in some cases, it can lead to complications like dehydration, long-lasting tiredness, breathing trouble, low platelets (like in dengue), or sometimes the heart or brain may also be affected. If the fever doesn’t settle in 3–4 days or new symptoms appear, you should see the doctor without delay.
When to See a Doctor
If you have viral fever and experience these symptoms, you need to see a doctor immediately:
A very bad headache
Bright lights hurt your eyes
A stiff neck
Feeling confused or too sleepy
Trouble breathing
Vomiting
Skin rash that is unusual
Stomach pain
Fits or muscle jerks
Seeing or hearing things that aren’t real (hallucinations)
For children, take them to the hospital quickly if they:
Viral fever can spread easily, but by taking a few simple steps, you can protect yourself and others from getting sick.
Wash your hands with soap often, especially before eating or after coughing or sneezing.
Avoid close proximity to a sick person.
Wear a mask in crowded or enclosed places.
Drink clean water and eat food that is cooked properly.
Keep the surfaces and things you touch often clean.
Use mosquito repellent and wear full-sleeved clothes to prevent viruses spread by mosquito bites22.
Take vaccines as recommended by your doctor based on your health and age. Some important vaccines that help prevent viral fevers are:
The flu vaccine protects against seasonal flu and should be taken once every year before flu season.
The COVID-19 vaccine protects against coronavirus and you should take at least 1 dose (or 2 doses if you are more than 65 years of age).
The MMR vaccine protects against measles, mumps, and rubella and is given in 1–2 doses if not already vaccinated.
The chickenpox vaccine protects against varicella and should be taken as 2 doses if you are 45 years of age or younger.
The RSV vaccine protects against respiratory syncytial virus and is taken as 1 dose if you are 75+ years of age or pregnant during RSV season23.
Conclusion
Viral fever is usually mild and goes away with proper rest and fluids in most people. However, sometimes it can become serious and needs medical attention. By addressing the symptoms early and getting viral fever treatment, the recovery is faster. Also, follow proper hygiene, get vaccinated, and follow the prevention steps to keep yourself safe from viral fever.
Frequently Asked Questions (FAQs)
How long should I stay away from people to avoid spreading the flu infection?
Once your symptoms improve and you’ve been fever-free for at least 24 hours without medication, it’s best to avoid close contact with others for another 5 days, as you may still be contagious24.
Who is at greater risk of getting seriously ill from viral fever?
People who are very old, very young (like babies and small children), have weak immunity, or are pregnant, are more likely to get very sick if they catch a viral fever25.
Can my child get a seizure when they have a viral fever?
Yes, some children can have a seizure when the body temperature rises quickly during a viral fever. This may happen in children who are 6 months to 6 years old.
Can I take a cold bath or sponge during a viral fever?
No, this will make you feel more uncomfortable. Wear light cotton clothes and don’t use heavy bedding as it can make your body heat up more. Keep the room at a normal cool temperature21.
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Belon L, Skidmore P, Mehra R, Walter E. Effect of a fever in viral infections — the “Goldilocks” phenomenon?. World Journal of Clinical Cases [Internet]. 2021 Jan 16;9(2):296–307. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7812885/
Chi-Chung Cheng V, Fuk-Woo Chan J, FN Hung I, Yuen KY. Viral Infections, an Overview with a Focus on Prevention of Transmission. Reference Module in Biomedical Sciences [Internet]. 2016; Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7157453/
Ojeda Rodriguez JA, Haftel A, Walker III. Chikungunya Fever [Internet]. PubMed. Treasure Island (FL): StatPearls Publishing; 2021. Available from: https://www.ncbi.nlm.nih.gov/books/NBK534224/
Gupta N, Boodman C, Christelle Genevieve Jouego, Van S. Duration of Fever in Patients with Dengue: A Systematic Review and Meta-Analysis. The American journal of tropical medicine and hygiene. 2024 May 14; Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC11229643/
Foster J. Understanding Long-Term Effects of Viral Infections: Epidemiological Insights into Post-Infection Syndromes. Insight into Epidemiology [Internet]. 2024 Oct 30;1(1). Available from: https://docentra.com/longterm-viral-infections
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