Causes and Spread of infection

Understand the causes of infection

Q1.1 Identify the differences between bacteria, viruses, fungi and parasites

All 4 are different types of pathogens

Bacteria is a single celled organism that multiply by themselves. They live within and on most living and non-living things. The majority of bacteria are harmless and beneficial to the human body but some can cause infectious diseases. A bacterium usually affects one part of the body and doesn’t spread across or through the body. Bacterial infections are normally treated with a course of antibiotics.

Viruses are made up of genes and proteins that spread throughout the body by invading the body’s own cells so they can reproduce and multiply in the body. They use the body’s cells as a host because they are unable to multiply on their own. They are normally spread directly from human to human. Viruses can be very tough and there are not many effective medicines available for viral diseases.
There are currently 21 families of viruses known to cause disease in humans.

Fungi like to grow in warm, moist places. Some fungi can be beneficial to us such as penicillin, but certain types of fungi can be harmful to our health. Like bacteria and viruses, some fungi can act as pathogens. Human fungal diseases can occur due to infection or fungal toxins. Symptoms of fungal diseases can be as common as itching, coughing, fever, wheezing, but they can also be as serious as meningitis or even death.
Parasites are organisms that need other organism for their survival. They draw nourishment and other needs from their host organism. Parasites that cause infection and disease are known as Pathogenic parasites

Parasites are those micro-organisms which depend on other organisms (hosts) for their survival. Both virus and bacteria could be parasites.

Q1.2 Identify common illnesses and infections caused by bacteria, viruses, fungi and parasites

Illnesses/infections caused by :

Bacteria: Salmonellosis, tuberculosis, MRSA, coccidiosis, food poisoning, dysentery, bronchitis, ear infections, strep throat/tonsilitis, pneumonia, gonorrhea, syphilis, chlamydia

Viruses: Influenza, common cold, stomach flu, pneumonia, ear infections, HIV/AIDS, herpes, warts, dengue, West Nile Virus, encephalitis

Fungi: Valley fever, athlete's foot, ringworm, yeast infection

Parasites: Worms, schistosomiasis, malaria, sleeping sickness (trypanosomiasis), leishmaniasis

Q1.3 Describe what is meant by 'infection' and 'colonisation'?

Colonisation occurs whenever any one or more species populate an area and infection is the invasion of body tissues by disease-causing microorganisms, their multiplication and the reaction of body tissues to these microorganisms and the toxins that they produce

Q1.4 Explain what is meant by systemic infection and localised infection?

Systemic means it's in the blood stream and is spreading/has spread through the body. Septicaemia is an example of a systemic infection.

Localised means the infection is restricted to one small area only. An infected cut or ulcer is an example of this.

A localised infection can spread and become systemic.

Q2.1 Explain the conditions needed for the growth of microorganisms?

a place to grow food moisture warmth time

Q2.2 Explain the ways an infective agent might enter the body

Q2.3