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How infections spread
The chain of infection
The chain of infection
The chain of infection refers to the way in which germs spread. All the steps in the chain need to occur for germs to spread from one person to another. By breaking the chain you can prevent and control infections. You can break the chain of infection at any stage.
The 3 steps in the chain of infection
1 - The germ has a source
People can pick up germs directly from an infected person, or from the environment. A person with an infection may or may not show any signs of illness. They may be infectious before they become unwell, during their illness or after they have recovered.
For example, in cases of gastroenteritis, tamariki and staff who no longer have runny poos (diarrhoea) may still have the germs that cause the illness in their poos for some time. This means that they can still spread the gastroenteritis germ.
2 - The germ spreads from the source
Germs can spread in a number of ways, including through:
- the air by droplets (sneezing)
- contact with poos and then contact with mouths
- direct contact with skin
- contact with other body secretions (urine, saliva, discharges or blood).
Some germs can spread directly from person to person, others can spread from the infected person to the environment. Many germs can survive on hands, and on objects such as toys, door handles and bench tops. The length of time a germ can survive on a surface (including the skin) depends on the germ itself, the type of surface it has contaminated and how often the surface is cleaned. Washing hands and surfaces regularly with detergent and water is a very effective way of removing germs and preventing them spreading through the environment.
3 - The germ infects another person
When the germ has reached the next person it may enter the body through the mouth, respiratory tract, eyes, genitals, or broken or grazed skin. Whether a person becomes ill after the germ has entered the body depends on both the germ and the person’s immunity.
Illness can be prevented at this stage by stopping the germ from entering the body, for example, by:
- making sure that all toys that tamariki put in their mouths are clean
- washing tamariki hands and by covering wounds
- having immunisation against the particular germ.
Ways to break the chain of infection
The most important ways to break the chain of infection and stop the spread of diseases are:
- effective hand hygiene
- exclusion of ill tamariki and staff
- immunisation.
Other strategies to prevent infection include:
- coughing and sneezing safely
- using gloves correctly
- good cleaning processes
- personal hygiene.
Coughing and sneezing safely
Many germs can be spread through the air by droplets. By covering your mouth and nose when you cough or sneeze, you reduce how far the droplets can travel and stop them from contaminating other surfaces. In the past, people were encouraged to cover their coughs and sneezes with their hands but if you do not clean your hands immediately, germs stay on your hands and can be transferred to other surfaces.
Ways germs can spread in early learning services
Ways germs can spread in early learning services
Whether or not a person becomes ill in an early learning service depends on 3 things.
- The type of germ - some viruses, such as measles and norovirus, are very infectious. others, such as hepatitis B, hepatitis C and human immunodeficiency virus (HIV) are very difficult to spread in early learning services.
- The opportunity for transmission - germs have a greater chance of spreading if, for example, there are inadequate hand-washing facilities, or ill tamariki are not excluded from the early learning service.
- The person’s immunity - people who have been immunised against a particular disease, or who have had that disease before, are unlikely to become ill if they come in contact with the disease. People who have not been immunised, or who do not have natural immunity to that disease, have a much higher risk of becoming infected and developing the disease.
The way in which a germ spreads is known as its mode of transmission. These are the modes of transmission that are most likely to affect early learning services.
Coughing or sneezing (droplet transmission)
When an infected person sneezes or coughs, tiny droplets are spread into the air and onto surrounding surfaces. A sneeze can spread droplets as far as 2 metres away. The droplets may be breathed in directly by another person, or another person may touch a surface contaminated with the droplets, then touch their mouth, eyes or nose. Examples of a germs spreading by droplets is the flu virus and meningococcus.
Breathing contaminated air (airborne transmission)
Airborne transmission is different from droplet transmission because the germs are in even smaller particles than droplets, and they can be infectious over time and distance. These very small particles are created when an infected person breathes, talks, coughs or sneezes. The particles can be carried on air currents and through ventilation or air-conditioning systems, so they can infect people who have not had close contact with the source. Examples of airborne germs are the measles virus and the chickenpox.
Direct contact (contact transmission)
Some germs can spread through touching alone. These include head lice (head-to-head contact), scabies and fungal infections of the skin (skin-to-skin contact).
Germs can spread through contact with infectious body fluids, such as mucus, saliva, vomit, blood, urine and poos. They can enter the body by being swallowed, or through damaged skin or mucous membranes. This means that they can spread if a person touches infectious body fluid then puts their hands in their mouth, or if they prepare and eat food without first washing their hands.
Surfaces such as benches, tables, door handles, toys, bedding and toilets can be contaminated when a person with an infectious disease touches them, or coughs or sneezes on them. If a person touches a contaminated surface and then touches their mouth, eyes or nose, they can become infected.
Food
Germs can live and reproduce in food. If the food is not heated or chilled properly, the germs can spread to the people eating the food and make them ill. Hand washing and following food preparation procedures are important to make sure that germs are not spread through food.
Animals
Contact with animals can spread disease. Germs can be present on the skin, hair, feathers and scales of animals, and in their poos, urine and saliva. These germs may not cause disease in the animal, but they may cause disease in humans. Some germs can multiply in insects such as mosquitoes and fleas and spread through the insect’s bite; these insects that carry the germs are known as ‘vectors’.
Different germs spread in different ways
Airborne
The virus that causes measles can stay in the air for up to 2 hours after an infected person has left the room. This means that people can be exposed to the virus without having direct contact with the infected person.
Contact
Germs such as norovirus and rotavirus can cause gastroenteritis, leading to symptoms of runny poos (diarrhoea) and throwing up (vomiting). It may be obvious that a person can spread the disease while they are unwell, but what is not so well known is that a person may still be contagious up to 10 days after the symptoms have stopped.
Droplet
The bacteria that cause meningococcal disease can be present in people’s throats. If an infected person coughs or sneezes, the droplets they produce can infect other people nearby.
Note
This content is based on material provided by the Australian National Health and Medical Research Council.
Exclusion of sick children and staff
The aim of exclusion is to reduce the spread of infectious disease. The less contact there is between people who have an infectious disease and people who are at risk of catching the disease, the less chance the disease has of spreading. Excluding ill tamariki and staff is an effective way to limit the spread of infection in early learning services.
The following resources explain how long people should stay away from others depending on their illness.
Notify public health of a gastro or respiratory illness outbreak
You should notify public health if there is a suspected gastro, and in some areas a respiratory illness, outbreak in your:
- early learning service
- Kōhanga Reo
- school.
Hand hygiene
Clean hands are an effective way to reduce getting sick and spreading illnesses.
Wash your hands with soap and water
Wash your hands with soap and water
Regularly washing hands prevents the spread of a range of illnesses including colds, flu and tummy bugs.
Wash your hands before preparing or eating food and after blowing your nose, coughing and sneezing, and visiting the toilet.
- Wash your hands for at least 20 seconds with soap and warm water - this removes both dirt and germs from your hands.
- Dry your hands for 20 seconds with a dry towel or paper towel.
If soap and water are not available, use hand sanitiser.
Use hand sanitiser if soap and water are not available
Use hand sanitiser if soap and water are not available
If soap and water are not available, use hand sanitiser. Look for one with 60-80% alcohol. Hand sanitiser is a good alternative however it is not as effective against viruses as soap and water. Hand sanitisers are useful when multi-tasking and hands can potentially become contaminated, for example:
- when helping children with eating
- when on outings
- in the playground
- in other situations where soap and water are not always available.
Hand sanitisers are safe to use as directed, but tamariki may be at risk if they:
- eat or drink it
- breathe it in (inhale it)
- splash it into their eyes or mouth.
Hand sanitisers should be kept well out of reach of tamariki and only used with adult supervision. It is a good idea to place hand sanitiser at the entrance to your early learning service, this can help remind parents, tamariki as well as staff to have clean hands when they enter the centre.
Gloves can provide a protective barrier against germs
Gloves can provide a protective barrier against germs
Gloves provide a protective barrier against germs. When staff wear gloves correctly, they protect both themselves and the tamariki in their care from potential infection. It is important to remember that using gloves correctly will reduce the spread of germs, but will not eliminate it.
Wearing gloves is not compulsory, centres may require staff to use gloves when changing nappies, we recommend that you check with staff management and read policies.
Disposable (single-use only) gloves are made of natural rubber latex, nitrile or vinyl. Latex gloves are preferable, but nitrile gloves can be used by staff who have a latex allergy, or with tamariki who have latex allergies. Wear disposable gloves if you are likely to come in contact with body fluids or excretions, such as when changing nappies or cleaning up vomit or blood.
Wearing gloves does not replace the need to wash your hands and you should make sure you wash and dry your hands thoroughly before using gloves.
Wash your hands before wearing gloves
Wash your hands before putting on gloves so that you remove as many germs as possible from your hands. Otherwise, when you reach into the box of gloves, you can contaminate the other gloves in the box.
When changing a nappy, it is very important to wash your hands before you put on gloves, so that when you have finished changing the tamaiti, you can remove the dirty gloves and dress the tamaiti without needing to interrupt the nappy-changing procedure to wash your hands before dressing the tamaiti.
Wash your hands after wearing gloves
When you have finished a procedure that requires you to wear gloves, it is important to wash your hands thoroughly after removing the gloves, because any germs on your hands may have multiplied significantly while you were wearing the gloves. There may also be microscopic tears or holes in the gloves that can allow germs to contaminate your skin. When taking off the gloves, you may contaminate your hands with the dirty gloves - therefore, it is essential that you wash your hands.
Hand care
Hand care
Skin that is intact (has no cuts, scratches, abrasions, cracks or dryness) provides a barrier against germs. Frequent hand hygiene can cause some people’s skin to become damaged (known as dermatitis) and allow germs to enter the body.
The most common form of dermatitis is irritant contact dermatitis. This is mainly due to frequent and repeated use of hand hygiene products, especially soaps and other detergents, and paper towels which cause the skin to dry out. Symptoms may include dryness, irritation, itching, cracking and bleeding, and can range from mild to severe.
Allergic contact dermatitis is rare and is caused by an allergy to one or more ingredients in a hand hygiene product.
Hand care products containing soothing ingredients (emollients) are readily available and can reduce irritant contact dermatitis. Regularly moisturising hands can also help reduce dryness and irritation.
Factors that may contribute to dermatitis include:
- using products containing fragrances and preservatives - these should be kept to a minimum or eliminated
- not wetting hands before applying soap
- washing hands with soap and water immediately before or after using an alcohol-based hand rub
- putting on gloves while hands are still wet from either hand washing or using an alcohol-based hand rub
- using hot water for hand washing
- allowing skin to dry out
- using rough paper towels.
When buying hand sanitisers, soaps and moisturising lotions, make sure they are chemically compatible, this will minimise skin reactions and make sure that the hand hygiene products work effectively together. It is advisable to buy hand hygiene and hand care products from a range made by a single manufacturer, as this may help to make sure that the products are compatible. Speak to your supplier for advice on chemically compatible products.
Resources
Immunisation
Immunisation is a reliable way to prevent some infections.
Tamariki immunisation information
Tamariki immunisation information
Staff should ask all parents to provide a copy of their tamaiti immunisation records. If the tamaiti has not been immunised tell the parents that their tamaiti will be excluded from care during outbreaks of some infectious diseases such as measles and pertussis, even if their tamaiti is well. A statement about excluding tamariki that are not immunised should be included in the early learning service immunisation policy.
National immunisation schedule - Health Information and Services (external link)
Immunisation registers are available in our resources section.
Staff immunisations
Staff immunisations
The Immunisation Handbook recommends early learning service are vaccinated to protect them against common diseases.
- Pertussis (whooping cough) - this is especially important for staff caring for the youngest tamariki who are not fully immunised. Even if the adult was immunised in childhood, a booster may be necessary because immunity to whooping cough decreases over time. Protection from immunisation lasts about 5 to 7 years. The adult booster immunisation also provides protection against tetanus and diphtheria.
- Measles–mumps–rubella (MMR) - people born in New Zealand before 1969 are assumed to be protected from measles as measles occurred frequently during this time. People born after 1969 need to have had two doses of a measles containing vaccine after 12 months of age or had measles diagnosed by a doctor to be protected against measles.
- Hepatitis B - as staff may come in contact with blood and body fluids during their work. Staff born in New Zealand after 1974 are likely to be protected as the hepatitis B has been given to babies in New Zealand since 1988, with a catch up programme in 1990 for tamariki up to 16 years of age. Protection against hepatitis B is checked during pregnancy. If you are unsure your doctor can do a blood test to see if you have protection.
- Hepatitis A - is recommended because young tamariki can be infectious even if they are not showing any symptoms.
- Varicella vaccine (chicken pox) - for staff who have not previously had chicken pox, especially if they were born or lived in a tropical country where chicken pox is less common.
- Influenza vaccine (flu) - all staff should also consider having yearly flu vaccinations. The flu is very infectious and can spread through the air by coughing and sneezing, as well as by hands, cups and other objects that have been in contact with an infected person’s mouth or nose.
Please note - The measles vaccine is free for anyone who does not have protection against measles. Please discuss the cost of other vaccines with your local medical centre as they are not funded.
Taonga Mokopuna video learning series
National Public Health Service - Wellington developed these videos to help keep early learning services healthy. They were developed based on experience working with and supporting early learning services.