The four types of pathogens - virus, bacteria, fungi and protozoa

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  1. Pathogen are microorganisms that enters the body and causes diseases in a human body. They are four kinds of pathogens, these are virus, bacteria, fungi and protozoa. They enters the through the gas exchange.








They are very thin and its size it is about 1/100th size of a bacteria

Are microscopic organisms that come in many shapes and sizes. The largest ones are only 10 micrometres long - 1 micrometre = 1 millionth of a metre

very simple single-celled organisms

They are very larger they also, fungi include moulds and mushrooms

Are large and single-celled organisms. can be up to 1 mm in size


They produce many other copies of themselves

bacteria have been used in the production of cheese

They cause infections to the surface of the body

They cause parasitic infections in humans. If not treated can even cause death.


They provides information on the mechanisms by which viruses enter the cell, repeat, package their DNA into capsids and mature into new virions.

They can grow and damage some cells inside the body. they helps to recycle nutrients

They helps to save lives by producing the antibiotic that is called penicillin.

protozoa help digest the raw sewage



This is a disease that is caused by the bacteria that produces a watery diarrhoea that can rapidly lead to dehydration.


Usually this occurs because there is too much water lost or not enough water taken in. It is most common and also a combination of the two.

Symptoms and signs:

A very smelly diarrhoea that look like rice water and may lead to signs of dehydration. For example vomiting, wrinkled skin, low blood pressure, dry mouth and rapid heart rate.


It is normally spread by water sources contaminated with the causative bacterium called Vibrio cholerae.


Cholera is an infectious disease, it can be treated by an antibiotics in which dehydration occurs. The diagnosis of cholera ranges from excellent to poor. Rapid treatment with fluid and electrolytes result in better outcomes.


Cholera can be prevented with appropriate measures such as safe drinking water and non-contaminated foods, some protection can be obtained from oral vaccines while avoiding areas where cholera commonly occurs or has had a recent outbreak.

After treated it can take up to five days for the infection to clear up.


According to NHS Choices athlete’s foot it is a common fungal infection that usually occurs on the foot. Its appearance look like a red itchy rash that develops in between the toes. The skin begins to crack and can be very itchy.

Spread of infection

Athlete’s foot often develops betweenthe little toe and the one next to it. If the infection does not treated early, it can spread on the bottom and sides of the feet. The infection can also spread to thetoenails. This can cause them to become dry and crumbly.

Scratching the infected skin and then touching other parts of the body canspread the infection. It is very important to treat the infection promptly. Always wash your hands thoroughly after touching the rash.


  • Wash your feet regularly and thoroughly using soap and water.
  • After washing, dry your feet, paying particular attention to the areas between your toes.
  • Wear clean cotton socks.
  • Change your shoes and socks regularly to help keep your feet dry.
  • Don't share towels and wash your towels regularly


  • Wash your feet thoroughly every day, especially between the toes.
  • Reduce foot perspiration by using talcum powder on your feet.
  • Avoid wearing tight-fitting footwear, particularly during the summer as they will sweat.


This is a mosquito infectious disease caused by protozoa.

Symptoms of malaria

Candevelop as quickly as seven days after you arecome in contact with an infected mosquito. The symptoms areflu-like and a high temperature, headache, sweats, chills and vomiting.


Malaria is caused by the plasmodium parasite. These type of parasite can be spread to humans through the bites of infected mosquitoes. The types of parasites are Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale.


Malaria is transmitted completely through the bites of Anopheles mosquito. Transmission also depends on climatic conditions that may affect the number and survival of mosquitoes such as rainfall patterns, temperature and humidity.


When travelling to high risk areas, make sure you prevent it before travel.

  • Use mosquito net at night time.
  • Close the windows and doors properly.
  • Use insect repellent on your skin and in sleeping environments.
  • Wear trousers or long sleeve clothes


Is an infectious and common viral illness spread by coughs and sneezes.


It takes up to three days to show up and the temperature will go high, headache, chest cough, tiredness, sore throat, diarrhoea and sneezing.


Usually it can disappear without medication, all you have to do is to keep yourself warm, get enough rest and drink plenty of water to avoid dehydration.

For fever and other symptoms you can take pain killers like paracetamol and ibuprofen.

For chest infection antibiotics will be prescribed by the GPs or Doctors and other prescribers.


  • Thorough and frequent hand washing is the best way to prevent many common infections. Scrub your hands strongly for at least 15 seconds or use alcohol-based hand sanitizers if soap and water are not available.
  • Cover your mouth and nose when you sneeze or cough.
  • To avoid contaminating your hands, cough or sneeze into a tissue or into the inner crook of your elbow.
  • Flu spreads easily wherever people congregate, in nurseries, schools, office buildings, auditoriums and public transportation. By avoiding crowds during peak flu season, you will reduce the chances of infection.


See Cross infection power point


What is cross infection? defined it as the transferring of harmful microorganisms.

What the types are of cross infections?

  • bacteria
  • fungi
  • parasites
  • viruses

What can causes cross infection?

  • Not sterilising all the medical equipment used
  • By not washing hands or holding mouth when coughing and sneezing
  • the transmission of viruses through human contact
  • touching contaminated objects
  • dirty bedding

How can cross infection be controlled?

  • Always be aware of it
  • Wash our hands properly
  • By advising patients not to share things like razors and shaving machines
  • Advising visitors to wash their hands using alcohol gel at their time of visit
  • By wearing protective clothing such as cloves and aprons when doing things like dressings of wounds
  • Wash your hands every time after and before helping a patient Use two buckets for mopping – one for detergent and the other for rinsing.
  • Mops and buckets should be cleaned, disinfected and dried after each use.
  • Use two buckets for mopping for example one for detergent and the other for rinsing.
  • Mops and buckets should be cleaned every time with disinfectant and dried after each use.
  • Have to make sure that the kitchen surfaces are always clean.

How does cross infection spreads?

  • Germs can be passed from one person to another by touching unclean equipment orsurfaces
  • Coughing or sneezing near another person may pass on the viruses
  • Our hands play a very big part in spreading infection
  • Infection can be spread through inhalation

How to prevent cross infections in hospitals?

  • By receiving good training
  • Effective communication for both health care workers, patients and visitors
  • using personal protective equipment
  • safe handling and disposal of sharps
  • safe handling and disposal of clinical waste
  • managing blood and bodily fluids


ESSAY: How does the body defends itself against pathogens which cause infectious diseases.

This essay is going to discuss about how the body defends itself against pathogens which causes infectious diseases. It will talk about what are these pathogens and how they enter the body. In addition, the essay will look on how these pathogens affect the immune. It will draw more attention to the difference between the primary and the secondary responses to infections. In conclusion the essay will discuss what the specific and non-specific defences are and what they do to protect the body against infections.

Pathogens are micro-organisms that causes diseases. The human body has a unique way of defending itself from pathogens that may causes infections like bacteria, fungi, viruses and other organisms. Bacteria are living organisms and they easily multiplied. As soon as they enters the body they releases toxin that weakens the body and makes it ill. Viruses goes inside the cell and occupy until it burst. They travels via bloodstream airways. The body can be attacked in so many ways but the good thing is it is always protect itself. The body can be affected both outward and inward.

The body defends itself against diseases in stages. The first stage is passive immunity, this is where the body fights to stop pathogens from entering the body. The examples of the body’s passive immunity systems are the skin which acts as a physical barriers. In addition the skin contains glands which are secret lactic acid and fatty acids. They creates an acidic environment on the surface of the skin to prevent the growth of pathogens. Mucus and cilia which are found in the respiratory system which pretend and move the bacteria and lastly, the enzymes which are found in tears.

The second stage is called active immunity. This is where white blood cells come into action. They can ingest pathogens and destroy them. They are also in a position of producing antibodies that are also able to destroy pathogens and produce antitoxins. Antitoxins reduce the effect of toxins which produce pathogens. When something is not right in the body, the phagocytes send a message to other phagocytes in the body, telling them where antibodies are needed. If the bacteria enters in the skin, the phagocytes look for them and ingest them. Pathogens they contain antigens that are acts as foreign chemical to the body.

Lymphocytes are trusted of carrying a specific type of antibodies. This type is called protein. It has a chemical that fits on a specific antigen. On the gathering of lymphocyte and antigen they reproduce multiple antibodies that will help to destroy the pathogens. The way the human body were created it is very unique, its mechanism of defending itself from infectious diseases it is awesome. This mechanism is also known as non-specific defences which means they have their own way of protecting against other organisms. Nonspecific mechanisms acts as the body's primary defence against disease. When they fail protect the body they contact the second defence to take over. They are also other different mechanisms which is stated as specific defences. This specific immune allows the body to aim a certain pathogens and pathogen-infected cells for damage. This depends on particular white blood cells called lymphocytes and it also includes T-cells which is made from lymphocytes that developed in the thymus gland. B-cells are also formed from lymphocytes that developed in the bone marrow. They only targets a certain pathogens and other infected cells.

These two opposite mechanisms of the specific immune are the cell-mediated response. These cell-mediated response have the T-cells and they are in charge of directly destroying body cells that are infected with a virus or for activating other immune cells to be more efficient germ killers. The antibody-mediated response also have both T-cells and B-cells. This is very critical in attacking pathogens as well as the elimination of toxins. The antibody-mediated response come across when the lymphocytes activates specific B-cells to produce antibodies. These antibodies are connected to antigens on the surface of the pathogens.

The antibodies destroys pathogens in so many ways, they put them together and harm them. They also make them visible and ingested. Antitoxins and toxins that is released from lymphocytes they form pathogens and stop them from attacking the body. Antibiotics are there to also help the immune to fight against infections. Antibiotics are formed by microorganisms to kill or control the growth of other microorganisms by blocking specific metabolic pathways within the cell. Since bacteria are so different to human cells, antibiotics can be taken by humans to kill bacteria without harming the human cells. Viruses are different in a way as they do not carry out many metabolic processes for themselves. They also rely on a human cell to carry out these processes for them. Therefore, viruses cannot be treated with antibiotics as it is impossible to harm the virus without harming the human cells.






A specific type of immunity

Everyone born with this type of immunity, it protects from outside for example the skin. This is acquired upon exposure to a specific pathogen particularly in the course of an infection.


A specific type of immunity

This develops in lifetime and it is not a genetic immunity. It develops after being exposed to antigens. It is a specific immune in response to pathogens and this can be acquired naturally. it requires previous exposure to a is a specific type of immunity





Naturally and artificially acquired

This is the type of protection that the body receive from individual’s own immune system. It produces antigen specific defences. It lasts for a long period of time- can be a lifelong. It also protect the body form natural diseases. It develops when the body is exposed to diseases


Naturally and artificially acquired

This can be transferred from one person to another for example from mother to a baby. This does not last long, it comes and go. It protect the body against infections. Antibodies are produced by one individual and then acquired by another individual.