Diseases caused by protists and fungi

• Rose black spot is a fungal disease of rose leaves which turn yellow and drop early, so less photosynthesis can take place and the plant does not flower well
• The spores of the fungus are carried by the wind and raindrops splashing from one leaf to another
• Gardeners prevent spread by removing affected leaves and using chemical fungicides but it is not very effective
• Protists, a type of single-celled organism, cause a range of diseases in animals and plants. Disease caused by protists usually involve a vector that transfers the protist to the host
• Malaria is a disease caused by protist pathogens that are parasites - they live and feed on other living organisms
• The life cycle of the protists includes time in the human body and time in the body of a female Anopheles mosquito
• The mosquitos act as vectors (they pass it on) of the disease. The female needs two meals of human blood before she can lay her eggs, and this is when the protists are passed into the human bloodstream
• The protists travel around the human body in the circulatory system. They damage the liver and damage red blood cells, and it can be fatal
• Some drugs are effective if given early but protists are becoming resistant
• Several hundred million cases of malaria occur each year and around 660,000 people die from the disease
• The spread of malaria can be prevented by:

  • Using insecticide impregnated mosquito nets to prevent mosquitos biting humans and passing on the protist
  • Using insecticides to kill the mosquitoes
  • Preventing the mosquitoes from breeding by removing standing water and spraying insecticide to kill the larvae
  • Travellers can take anti-malarial drugs that kill the parasites in the blood if they are bitten by an infected mosquito
• Malaria can be treated by drugs that kill the parasite, but it can be fatal if not treated