AS

Fungal and Protist Diseases

Fungal Diseases

  • Fungi and protists are important pathogens, though less known than bacteria and viruses.
  • Fungal diseases affecting humans are relatively few.
    • Athlete's foot is a common, minor skin condition.
    • Some fungal diseases can be fatal if they attack the lungs or brains, particularly in already ill individuals.
    • Damaged heart valves can develop serious fungal infections, but these are rare.
    • Antifungal drugs are effective against skin fungi, but deep-seated tissue infections are harder to treat.
  • Fungal diseases are common and devastating in plants.
    • Huge crop losses occur annually due to fungal infections like stem rusts and rotting diseases, affecting cereals and bananas.

Rose Black Spot

  • Rose black spot is a fungal disease affecting rose leaves, causing purple or black spots.
  • It is a nuisance for gardeners and commercial flower growers.
  • Leaves often turn yellow and drop early, weakening the plant by reducing photosynthesis.
  • Reduced photosynthesis leads to poor flowering, which is the main reason for growing roses.
  • The spores spread via wind and water (splashing from one leaf to another during rain).
  • Spores remain dormant over winter on dead leaves and stems.
  • Prevention methods:
    • Removing and burning affected leaves and stems.
    • Using chemical fungicides.
    • Horticulturists have bred roses with resistance to black spot, but the disease cannot be fully prevented or cured.

Diseases Caused by Protists

  • Protists are single-celled organisms that cause various diseases in animals and plants.
  • They are relatively rare pathogens, but the diseases they cause are often serious.
  • These diseases usually involve a vector that transfers the protist to the host.
  • Malaria is a well-known and globally serious protist disease.

Malaria

  • Malaria is caused by protist pathogens that are parasites (living and feeding on other organisms).
  • The life cycle includes time in the human body and in the body of a female Anopheles mosquito.
  • The mosquito transfers the protist to the human host.
  • Symptoms include bouts of fever, and malaria can be fatal if untreated.