Biology II Diseases caused by Bacteria and Viruses

Diseases by Bacteria and Viruses Pathogens- Disease causing agents Bacterial Disease Viral Disease

Bacteria Most bacteria in out body are harmless A few species cause infectious diseases – Cholera – Syphilis – Anthrax – Leprosy – Bubonic plague

Diseases caused by Bacteria How does bacteria produce disease? – Damage the cells and tissues by breaking down the cells for food – Releasing toxins (poisons into the body)

One of the most common bacteria is streptococcus pyrogenes which is strep throat. Other bacteria diseases – Salmonella- the bacteria that causes food poisoning in humans – E. Coli- bacteria that live in intestins, and are the sources of many food poisoning outbreaks

Controlling Bacteria Sterilization Disinfectants Proper food storage

Antibiotics Antibiotics are chemicals which either kill bacteria or prevent their growth and reproduction Bacteria and other microbes produce antibiotics to reduce competition from other organisms

Penicillin was the first to be used to fight diseases Two scientist Walter Florey and Ernst Chain determined how to use penicillin to treat disease in 1939 The discovery of antibiotics revolutionized the treatment of disease

How Antibiotics Works Antibiotics effect bacteria, but not eukaryotic cells Antibiotics attack bacteria in 5 ways – Damage the cell walls or prevent cells walls from forming – Damage the cell membrane – Prevent protein synthesis – Prevent DNA from being Copied – Interfere with bacterial Metabolism

Diseases caused by Viruses Viruses disrupt the body’s normal equilibrium Cannot be treated with antibiotic Viruses can infect humans and plants

How do they Spread Carried by blood sucking insects Spread by coughing and sneezing Passed from person to person contact Sexual contact Exposure to infected blood

How to Eliminate the virus Viral infections provoke an immune response- – This will eliminate the infecting virus The immune system is made of white blood cells- the body’s army Vaccines- are very specific to which virus they protect our body’s against

Viruses and Disease Adenovirus- virus that causes colds, spread through the air Influenza- virus that causes flu; many different strains of this virus Herpes simplex virus- virus that causes herpes infections Bacteriophage- viruses that infect bacteria cells

HIV/AIDS HIV is the virus that cause AIDS. HIV attacks the body’s immune system making it weak and prone to infection It is hard to find a cure or vaccine for AIDS because it is constantly evolving and can live in a person’s cell for year

Viruslike Partilces Viroid – single stranded RNA molecules with no capsid – They cause diseases in plants – Infect cell and produce more viroid by disrupting the plant metabolism

Prions- contain only protein; no DNA or RNA – They cause diseases in animals and humans – Prions clump and cause normal protein to clump with it- creating new prions