Infections Bacterial And Viral

Overview

An infection happens when tiny living things (germs) get into your body and start to multiply. The two most common types are bacterial infections and viral infections. Bacteria are tiny single-celled living things. Many live harmlessly on your skin and in your gut, and only some cause illness. Viruses are much smaller than bacteria. They are not really alive on their own — they need to get inside your body's cells to make copies of themselves. This is why antibiotics (medicines that kill bacteria) do not work on viruses. Knowing which type you have helps your doctor choose the right treatment — and helps you avoid taking medicine you do not need.

Very common. Almost everyone gets several infections a year, especially colds and coughs. Children often catch eight to ten viral infections a year, which is normal and helps build their immune system.

Everyone can get infections. Babies and young children, older adults, pregnant women, and people with a weakened immune system (the body's defence system) or a long-term health condition tend to get more infections and may become more unwell. People who work in healthcare, schools, or crowded places are also exposed more often.

Symptoms

Common symptoms

• A high temperature, feeling hot and shivery, or feeling cold and clammy
• Cough, sore throat, runny or blocked nose, or sneezing
• Feeling very tired, achy, or having a headache
• Swollen glands in the neck, armpit, or groin
• Feeling sick, being sick, or loose stools (diarrhoea)
• A rash, red or warm skin, or a wound that is sore and weeping
• Burning or stinging when you pass urine, or needing to go more often
• Loss of appetite and not feeling like eating or drinking

Symptoms in children

• Being fussy or clingy, crying more than usual, or being hard to settle
• Not feeding or drinking as much, or fewer wet nappies
• Being sleepier than usual or harder to wake
• Pulling at an ear, or complaining of ear pain
• Vomiting or loose stools
• A rash, or skin that looks mottled or pale
• Breathing faster than usual, or finding it hard to feed and breathe at the same time

Symptoms in older adults

• Sudden confusion or a change in behaviour, which can be the first sign of infection
• A fall or trouble with balance that is new
• A lower body temperature than normal rather than a fever
• Feeling weak, very tired, or unusually sleepy
• Poor appetite and drinking less, leading to dehydration
• Not being able to pass urine, or leaking urine

Causes

Main causes

• Viruses and bacteria passing from person to person in tiny droplets when someone coughs or sneezes
• Touching surfaces or hands that have germs on them, then touching your eyes, nose, or mouth
• Contaminated food or water
• Bites from insects such as mosquitoes or ticks
• Close physical contact, including sexual contact
• Germs that normally live harmlessly on your body getting into a cut, or into a place they should not be

Risk factors

• Being very young or over 65
• A weakened immune system, from illness or from certain medical treatments
• Long-term conditions such as diabetes, lung disease, or heart disease
• Not being up to date with recommended vaccines
• Living in crowded or close-contact settings such as shared housing or dormitories
• Smoking, which damages the lungs and makes chest infections more likely
• Poor hand hygiene or not having clean water to wash with
• Travel to areas where certain infections are common

When to see a doctor

See a doctor urgently if:

• You or your child has any of the emergency warning signs listed above — call your local emergency number right away
• A fever in a baby under three months old
• Symptoms that are getting worse quickly, or that are severe enough that you cannot manage at home
• You are pregnant and have a fever, or you have a long-term condition or weakened immune system and become unwell

Book a routine appointment if:

• Symptoms have not started to improve after about a week, or are slowly getting worse
• You keep getting infections, or the same problem keeps coming back
• You are worried and would like advice — it is always okay to ask
• You want to check whether you need any tests or vaccines

Diagnosis

A doctor or nurse will usually start by asking about your symptoms, how long you have had them, and whether anyone else around you is unwell. They may check your temperature, look in your throat and ears, listen to your chest, and feel your neck for swollen glands. In many cases this is enough to tell whether an infection is likely to be viral or bacterial, and how serious it seems. Most people do not need any tests.

Tests that may be done

• A swab: a soft cotton bud is wiped on the back of your throat or inside your nose and sent to a lab
• A blood test to look for signs of infection and to check how your body is coping
• A urine test (a sample of your pee) if you have pain or burning when passing urine
• A stool (poo) sample if you have ongoing diarrhoea
• A small sample of fluid or tissue from a wound, or a sputum sample if you are coughing up phlegm
• A chest X-ray or a scan if a chest or deeper infection is suspected
• A rapid test done in the clinic, which can give an answer within minutes for some infections

What to expect at your appointment

Tests are quick and usually painless, though a blood test feels like a small scratch. Results from swabs and blood tests often take a day or two. While you wait, your doctor may advise rest, fluids, and simple comfort measures, and will tell you what to look out for. Sometimes treatment starts before results come back, and is changed later if needed.

Treatment

Treatment depends on whether the infection is viral or bacterial, how unwell you are, and where the infection is. Most viral infections, like colds and mild flu, get better on their own with rest, fluids, and time. Bacterial infections may need antibiotics, which only a healthcare professional can prescribe. Some viral infections, such as certain long-lasting ones, can be treated with antiviral medicines. In every case, the goal is to help your body recover and to prevent the infection from spreading to others.

Self-care at home

• Rest as much as your body asks for, and try to sleep well
• Drink plenty of fluids — water, warm drinks, and soups — to stay hydrated
• Take small, frequent sips if you feel sick, rather than large amounts at once
• Ask your pharmacist about a fever or pain medicine that is suitable for you or your child, and follow the instructions on the packet
• A warm drink with honey and lemon can soothe a sore throat (do not give honey to babies under one year)
• Gargling with warm salt water may ease a sore throat
• Keep the room at a comfortable temperature and avoid smoke, which irritates the airways
• Stay home while you feel unwell, and wash your hands often, to protect other people
• Use a tissue to cover coughs and sneezes, then throw it away and wash your hands

Medical treatments

Your healthcare professional will decide what, if anything, is needed. For bacterial infections, they may prescribe antibiotics — medicines that kill bacteria or stop them growing. It is important to take them exactly as instructed and to finish the course, even if you feel better. Antibiotics do not work on viruses, and using them when they are not needed makes bacteria more resistant (harder to kill) in the future. For some viral infections, antiviral medicines may be used, particularly for people at higher risk of becoming very unwell. Other treatment is supportive: managing fever and pain, replacing fluids, and treating problems such as dehydration or breathing difficulty. If you are very unwell, you may need to be cared for in hospital.

When is surgery considered?

Surgery is only needed in a small number of cases — for example, if an abscess (a pocket of pus) needs draining, if an infected appendix or gallbladder needs removing, or if an infected joint or bone needs cleaning. Your medical team will explain the reasons clearly if this applies to you.

Living with this condition

While you are recovering, keep things simple. Rest when you need to, drink regularly, and do not push yourself back to full activity too quickly. It is normal to feel tired for a week or two after an infection, especially after flu or a chest infection. Build your activity back up gradually. Stay off work or school while you have a fever or are feeling very unwell, and check with your employer or school about when to return.

Lifestyle tips

• Wash your hands with soap and water for about 20 seconds, especially after using the toilet, before eating, and after coughing or sneezing
• Keep shared surfaces like kitchen counters, door handles, and phones clean
• Do not share cups, bottles, towels, or utensils when someone is unwell
• Open windows or ventilate rooms when people visit
• Avoid smoking and second-hand smoke, which make chest infections worse
• Get enough sleep and manage stress, both of which support your immune system
• Keep up to date with recommended vaccines for you and your family

Diet and exercise

There is no special diet that cures an infection, but eating regularly and drinking enough helps your body recover. Aim for simple, nourishing foods you feel like eating — soups, toast, rice, eggs, fruit, and yoghurt are all good options. If you have diarrhoea or vomiting, focus first on fluids and then reintroduce bland foods gently. Avoid alcohol while you are unwell. Rest is more important than exercise during the acute phase; once your fever has gone and you feel stronger, gentle walks and a gradual return to your normal routine are fine. Wait until you feel fully recovered before returning to intense exercise.

Mental health and emotional wellbeing

Being unwell can be unsettling and tiring, and it is normal to feel low, anxious, or frustrated — especially if you are missing work, school, or time with friends. Feeling worried about a fever or a poorly child is very common. If low mood or anxiety is lasting more than a couple of weeks or is affecting your daily life, please talk to a healthcare professional. If you ever have thoughts of harming yourself, contact your local emergency number or a crisis support service right away — help is available and you deserve it.

Prevention

You cannot avoid every infection, but you can greatly reduce your risk and the risk to others. Hand washing is the single most effective habit. Covering coughs and sneezes, staying home when unwell, cleaning shared surfaces, and ventilating rooms all help stop germs spreading. Food safety matters too: wash your hands before cooking, keep raw meat separate, and make sure food is cooked properly. Practising safer sex and using insect repellent and nets when travelling to areas with insect-borne infections also lowers risk.

Vaccines

Vaccines are one of the best ways to prevent serious infections, and they work by training your body's defences in advance. Routine childhood vaccines protect against diseases such as measles, mumps, rubella, whooping cough, and others. Adults may be offered vaccines too, including yearly flu vaccines, and vaccines against other infections depending on age, pregnancy, health conditions, or travel plans. Ask your doctor or pharmacist which vaccines are recommended for you and your family.

Screening programmes

There is no general screening test for infections. However, screening is offered in some situations — for example, certain infections are routinely checked for during pregnancy so they can be treated and passed on to the baby is prevented. If you are planning a pregnancy or are pregnant, ask your maternity team what is offered. If you have been exposed to a specific infection, or have a condition that weakens your immune system, your doctor can advise whether any testing is appropriate.

Complications

If left untreated

• A bacterial infection can spread from where it started — for example, from the ear to the brain, or from the skin into the blood
• Sepsis, a serious whole-body reaction to infection, which needs emergency treatment
• Chest infections can develop into pneumonia, especially in older adults
• Dehydration from fever, vomiting, or diarrhoea, which is particularly risky for babies and older people
• An abscess forming, which may need draining
• Long-lasting tiredness or a cough that takes several weeks to settle after a viral infection

Long-term outlook

The great majority of infections are mild and people recover fully. Colds and coughs usually settle within one to two weeks, and most bacterial infections clear up quickly once they are treated. Some people feel tired for a while afterwards, and this is normal. Serious complications are uncommon, and getting advice early — especially for babies, older adults, pregnant women, and anyone with a weakened immune system — means problems are usually caught and treated promptly. With rest, good hydration, and the right care, most people are back to normal before long.

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