Viruses are unique organisms because they cannot reproduce without a host cell. After contacting a host cell, a virus will insert genetic material into the host and take over the host’s functions. The cell, now infected, continues to reproduce, but it reproduces more viral protein and genetic material instead of its usual products.

It is this process that earns viruses the classification of “parasite”.

A short video on how viruses cause infections

Viral infections

Many common infections of the nose, throat, sinuses, ears, and chest are caused by viruses. Flu-like illnesses are also caused by viruses.

Diarrhea and/or vomiting are often due to a viral infection of the gut.

If you are normally well, your immune (defence) system is good at fighting off many types of viral infection.

An antibiotic is not needed if a virus is causing an infection.  This is because:

• Antibiotics do not kill viruses. Antibiotics only kill bacteria.
• Antibiotics may cause side-effects such as diarrhea, rashes, feeling sick, etc.
• Overuse of antibiotics when they have not been necessary has led to some bacteria becoming resistant to them. This means that some antibiotics might not be as effective when they are really needed.

You may feel unwell for several days or more until a viral infection clears. Treatment aims to ease symptoms and common management protocols advised for viral infections include the following:

• Paracetamol or ibuprofen to reduce a high temperature (fever), and to ease aches, pains, and headaches.
• Make sure you drink enough to prevent mild dehydration. Dehydration may develop if you have a high temperature, and it can make a headache and tiredness much worse.
• Do not wrap up, but try to cool down if you have a high temperature. This is particularly important in children. If a child has a high temperature, then take their clothes off (in a warm, but not hot, room) and consider giving some paracetamol.
• Other advice may be given for specific symptoms. For example, decongestants for a blocked nose, etc. Ask a pharmacist for advice.

What about bacterial infections?

A person’s immune system can eradicate most bacterial infections.  Studies have demonstrated that antibiotics usually do little to speed up recovery of bronchitis, or most ear, nose, and throat infections that are caused by bacteria. However, you do need antibiotics if you have certain serious infections caused by bacteria, such as meningitis or pneumonia. When you are ill, doctors are skilled at checking you over to rule out serious illness, and to advise if an antibiotic is needed.

What if symptoms change?

Occasionally, a viral infection or minor bacterial infection develops into a more serious infection. See a doctor to review the situation if the illness appears to change, becomes worse, does not go after a few days, or if you are worried about any new symptom that develops.

References

• Antimicrobial Resistance, Health Protection Agency (2007)
• Antibiotic resistance. Department of Health. Various documents, various dates.
• Antimicrobial Resistance. European Centre for Disease Prevention and Control. Various documents, various dates.

 Measles is a serious and highly infectious viral disease that can make people very sick and can lead to hospitalisation or, in rare cases, death.

The infection is spread by contact with droplets from the nose, mouth, or throat of an infected person. Sneezing and coughing can put contaminated droplets into the air. Just being in the same room as someone with measles can lead to infection if you are not immunised. One person with measles can pass on the disease to 13 other people who have not been immunised. If you are not immunised you could have measles and spread it without even knowing it. Those who have had an active measles infection or who have been vaccinated against the measles have immunity to the disease which prevents them from getting very sick. Before widespread vaccination, measles was so common during childhood that most people became sick with the disease by age 20. The number of measles cases dropped over the last several decades to almost none in theU.S. and Canada. However, rates have started to rise again recently.

 What might happen if I get measles?

A person may be developing measles and not be aware until they actually feel ill – symptoms usually take about 10 days to develop but it might take as long as 18 days.

Symptoms may include:

• Bloodshot eyes
• Cough
• Fever
• Light sensitivity
• Muscle pain
• Rash
• Usually appears 3 – 5 days after the first signs of being sick
• May last 4 – 7 days
• Usually starts on the head and spreads to other areas, moving down the body
• Rash may appear as flat, discoloured areas (macules) and solid, red, raised areas (papules) that later join together
• Itchy
• Redness and irritation of the eyes (conjunctivitis)
• Runny nose
• Sore throat
• Tiny white spots inside the mouth (Koplik’s spots)

Complications<

Up to one in three people may develop complications of measles infection may include:

• Bronchitis – chest infection
• Encephalitis (about 1 out of 1,000 measles cases) – infection around the brain
• Ear infection (otitis media)
• Pneumonia

Acute encephalitis (brain inflammation) develops in 1 in 1000 cases, some of whom die and more than one third are left with permanent brain damage.

One in 1000 people with measles may die.

One in 10 cases will end up in hospital.

Who is at risk of getting measles?

If you were born after January 1969, and haven’t had two doses of measles vaccine, or have not had measles already, you are at risk of catching the disease.

It is not just babies – older children, teenagers and adults who are not immunised are also at risk from getting sick from measles.

Maori children in theAucklandregion are particularly at risk as the percentage of 18 month old Tamariki who have received one dose of MMR is only 67%.

The percentage of children who have received one dose of MMR by age 18 months in theAucklandregion is low at 79%. Anyone with a weakened immune system (for example, people who are receiving chemotherapy or radiotherapy for cancer or people who take high-dose steroid medications) is at risk of measles infection. Pregnant women who are not immunised and who get measles are at risk of miscarriage, still birth and low birth weights for their babies. Non immune pregnant women should not be immunised but it is very important their family and close contacts are immunised to protect the pregnant mother and unborn baby.

When measles is widespread a very small proportion of people who have been immunised may also get measles.

Signs and tests

• Measles serology – blood test
• Viral culture (throat swab )

Treatment

There is no specific treatment for the measles.  However, the following may relieve symptoms:

• Isolate
• Paracetamol
• Bed rest
• Humidified air

Some children may need vitamin A supplements.

The only thing that can stop you or your child catching measles is getting immunised. If you suspect you or your child is sick with measles phone your GP or Healthline on 0800 611 116. For more information on immunisation, please call the Immunisation Advisory Centre free on 0800 IMMUNE (0800 466 863) or visit their website http://www.immune.org.nz

Dr Richard Parker

Dr Lalani Udalamatta

Dr Lize Upton