Final answer:
Three common types of bacteria are spherical, rod-shaped, and curved. They can be transmitted through direct contact, the fecal-oral route, or vector-borne transmission.
Step-by-step explanation:
There are many types of bacteria, but three common types are:
- Spherical (coccus): These bacteria are round or spherical in shape. Examples include Streptococcus pneumoniae, which can cause pneumonia, and Staphylococcus aureus, which can cause skin infections.
- Rod-shaped (bacillus): These bacteria are shaped like rods. Examples include Escherichia coli, which can cause food poisoning, and Bacillus anthracis, which causes anthrax.
- Curved (spirillum or spirochete): These bacteria have a curved or spiral shape. Examples include Treponema pallidum, which causes syphilis, and Vibrio cholerae, which causes cholera.
These bacteria can be transmitted through various means:
- Direct contact: Bacteria can spread from person to person through touching, coughing, or sneezing.
- Fecal-oral route: Bacteria can spread through contaminated food or water. For example, E. coli can be transmitted through undercooked meat or contaminated water.
- Vector-borne transmission: Some bacteria can be transmitted through vectors, such as insects. For example, the bacteria that cause Lyme disease are transmitted through tick bites.