A pathogen is a microorganism that causes a disease. Pathogens spread communicable diseases meaning that they are transmitted person to person and are infectious.
Types of pathogens include bacteria, fungi, viruses and protists. Not all microorganisms are pathogens but here are some examples of microorganisms which are harmful.
Bacteria: Salmonella
Salmonella is a bacteria that causes food poisoning.
· Symptoms: Vomiting, diarrhoea, and abdominal cramps.
· Transmission: It is spread by eating uncooked meat, egg, and chicken.
· Prevention: Food should be cooked properly in hygienic kitchens.

Fungi: Athletes food
Athletes foot is a rash caused by fungi growing in between the toes.
· Symptoms: Dry, flaky, white skin in between toes.
· Transmission: Touching infected skin or surface. Often found in swimming pool changing rooms or gyms.
· Prevention: Keeping feel dry and clean helps prevent athletes’ foot. Treatment is by antifungal creams.

Virus: HIV
HIV stands for Human Immunodeficiency Virus which can lead to AIDS (acquired immune deficiency syndrome).
· Symptoms: In AIDS, the virus attacks the body’s immune system leading to more infections.
· Transmission: HIV is a sexually transmitted disease and is transmitted by bodily fluids. HIV can be spread by unprotected sex and sharing needles.
· Prevention: There is currently no cure for AIDS, although antivirals are used to slow the progression of HIV to AIDS and to prevent HIV.

Protist: Malaria
Protists are single celled organisms that have a nucleus (eukaryotic).
· Symptoms of malaria are a fever, headache, vomit and diarrhoea.
· Transmission: Malaria is a disease that is spread by mosquitos which have the protist called plasmodium. The mosquitos are called vectors because they are not ill but can transmit the disease. Malaria is found in hot countries such as in Asia and Africa where there are a lot of mosquitos.
· Prevention: Vaccines, anti-malarial tablets and mosquito nets are used to prevent malaria.

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