9 common viral illnesses you should know

Viral infections are among the most common causes of illness worldwide. They occur when viruses enter the body and multiply, affecting different organs and body systems. Depending on the virus involved, an infection may affect the respiratory tract, digestive system, skin or nervous system.

Some viral illnesses cause mild symptoms that resolve without specific treatment, while others can lead to serious complications, particularly in young children, older adults, pregnant women and people with weakened immune systems.

Although many viral infections share symptoms such as fever, fatigue and body aches, they differ in how they spread, the symptoms they cause and the care they require. 

Understanding these differences can help people recognise when to seek medical attention and how to reduce the risk of infection.

In this article, Tribune Online highlights nine common viral illnesses, their symptoms and important facts you should know.

Influenza (Flu)

Influenza , commonly called the flu, is a contagious respiratory illness caused by influenza viruses. It affects the nose, throat and sometimes the lungs. Unlike the common cold, which often develops gradually, influenza typically begins suddenly. 

Symptoms may include fever, chills, headache, muscle aches, dry cough, sore throat and extreme tiredness. Some people also experience a runny nose, nasal congestion and loss of appetite. Although most people recover within a few days to two weeks, influenza can cause complications such as pneumonia, particularly in people at higher risk.

Treatment usually involves rest, adequate fluid intake and medicines to relieve symptoms. Antiviral medicines may be prescribed for people with severe illness or those at increased risk of complications. They generally work best when started early. Annual influenza vaccination is an important way to reduce the risk of infection and severe illness.

Common Cold

The common cold is a viral infection of the upper respiratory tract. It can be caused by several viruses, with rhinoviruses among the most common. It usually spreads through respiratory droplets, close contact with an infected person or touching contaminated surfaces and then touching the eyes, nose or mouth.

Common symptoms include sneezing, a runny or blocked nose, sore throat, mild cough and occasional headache. Some people may experience a low-grade fever, although fever is less common in adults. Most people begin to feel better within seven to 10 days, although a cough may last longer.

There is no specific cure for the common cold. Rest, adequate fluids and appropriate medicines for symptom relief can help manage discomfort. Antibiotics do not treat the viruses responsible for colds.

COVID-19

COVID-19 is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The infection primarily affects the respiratory system, although it can involve other organs. It spreads mainly through infectious respiratory particles released when an infected person breathes, talks, coughs or sneezes.

Symptoms vary from one person to another. They may include fever, cough, sore throat, fatigue, headache, muscle aches and nasal congestion. Some people experience shortness of breath or changes in their sense of taste or smell.

While many people develop mild illness, COVID-19 can cause severe complications, including pneumonia and respiratory failure. Older adults and people with certain underlying medical conditions are more likely to develop severe illness.

Management depends on the severity of the infection and the patient’s risk factors. People at increased risk of severe disease should seek medical advice promptly because specific antiviral treatments may be available and are most effective when started early. Vaccination, good ventilation, hand hygiene and staying away from others when ill can help reduce transmission and the risk of severe disease.

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Viral Gastroenteritis

Viral gastroenteritis, sometimes called stomach flu, is an infection that causes inflammation of the stomach and intestines. Despite its common name, it is not caused by influenza viruses. Norovirus and rotavirus are among the viruses responsible for this condition. Infection can spread through contaminated food or water, contact with an infected person or contaminated surfaces.

Symptoms include watery diarrhoea, vomiting, nausea and abdominal cramps. Some people also develop fever, headache and body aches.

Most cases improve within a few days. However, frequent vomiting and diarrhoea can lead to dehydration, which is particularly dangerous for young children, older adults and people with underlying health conditions.

Oral rehydration solution (ORS) helps replace fluids and essential salts lost through diarrhoea and vomiting. Small, frequent sips may be easier to tolerate when nausea is present.

Medical attention is necessary if there are signs of severe dehydration, blood in the stool, persistent vomiting or worsening symptoms.

Dengue

Dengue  is a mosquito-borne viral infection transmitted mainly through the bites of infected Aedes mosquitoes. It is common in tropical and subtropical regions and can cause illness ranging from mild fever to severe, potentially life-threatening disease.

Symptoms usually include sudden high fever, severe headache, pain behind the eyes, muscle and joint pain, nausea and skin rash. Some people may also experience vomiting and weakness.

Most people recover within one to two weeks. However, a small proportion develop severe dengue, which can cause plasma leakage, severe bleeding, shock and organ impairment.

A particularly important warning is that severe dengue may develop around the time the fever begins to subside. Severe abdominal pain, persistent vomiting, bleeding, unusual tiredness or restlessness should therefore not be ignored.

There is no specific antiviral treatment for dengue. Management focuses on careful monitoring and supportive care, including adequate fluid replacement. People with suspected dengue should avoid aspirin and non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, because these medicines may increase the risk of bleeding.

Chickenpox

Chickenpox is a contagious viral infection caused by the varicella-zoster virus. It is characterised by an itchy rash that develops into fluid-filled blisters before drying and forming scabs. The rash often begins on the chest, back or face before spreading to other parts of the body. New spots may continue to appear over several days, meaning that blisters and scabs can be present at the same time.

Other symptoms include fever, tiredness, headache and loss of appetite. Chickenpox is usually mild in children, but it can be more serious in adults, pregnant women, newborn babies and people with weakened immune systems. Possible complications include bacterial skin infections, pneumonia and inflammation of the brain.

Treatment generally involves relieving itching, managing fever and maintaining adequate fluid intake. Antiviral medicines may be recommended for people at increased risk of complications. The varicella vaccine provides protection against chickenpox and helps reduce the risk of severe disease.

Measles

Measles is a highly contagious viral disease caused by the measles virus. It spreads through infectious respiratory particles and can remain in the air for some time after an infected person has left an area.

The illness often begins with a high fever, cough, runny nose and red, watery eyes. Small white spots, known as Koplik spots, may also appear inside the mouth before the characteristic skin rash develops.

The rash usually starts on the face before spreading downwards to the neck, trunk, arms and legs.

Although some people recover without major complications, measles can cause serious health problems, including ear infections, diarrhoea, pneumonia and encephalitis (inflammation of the brain).

Young children, particularly those who are malnourished or have vitamin A deficiency, are at increased risk of severe complications.

There is no specific antiviral treatment for uncomplicated measles. Care focuses on managing symptoms and treating complications. Vitamin A supplementation may also be recommended for children with measles under appropriate medical supervision.

Vaccination with a measles-containing vaccine remains the most effective way to prevent the disease.

Mumps

Mumps is a contagious viral illness caused by the mumps virus. It mainly affects the salivary glands, particularly the parotid glands located near the ears and cheeks. One of its most recognisable symptoms is painful swelling around the cheeks and jaw. The swelling may occur on one or both sides of the face.

Other symptoms include fever, headache, muscle aches, tiredness and loss of appetite. Some infected people may have mild symptoms or no noticeable symptoms at all.

Although most people recover, mumps can occasionally cause complications. These include inflammation of the testicles (orchitis), ovaries (oophoritis), pancreas (pancreatitis) or the membranes surrounding the brain and spinal cord (meningitis).

Treatment is generally supportive and may involve rest, fluids and appropriate pain or fever relief. The measles, mumps and rubella (MMR) vaccine protects against mumps and helps reduce its spread.

Hand, foot and mouth disease

Hand, foot and mouth disease is a contagious viral infection that commonly affects infants and young children, although adults can also develop it. It is usually caused by enteroviruses, particularly coxsackieviruses. The infection can spread through contact with respiratory secretions, fluid from blisters, faeces and contaminated surfaces.

Early symptoms may include fever, sore throat, reduced appetite and general discomfort. Painful sores may then develop inside the mouth, while small red spots or blisters may appear on the palms of the hands, soles of the feet and sometimes the buttocks.

Most cases are mild and improve within seven to 10 days without specific treatment. However, painful mouth sores may make it difficult for children to eat or drink, increasing the risk of dehydration. Treatment focuses on relieving discomfort and maintaining adequate fluid intake. Children who cannot drink enough, become unusually weak or show signs of dehydration should be assessed by a healthcare professional.