Final answer:
Spirochetes are spiral-shaped bacteria including pathogens like Treponema pallidum, which causes syphilis, and others that cause diseases like Lyme disease. They are characterized by their unique shape and may require special microscopy techniques for observation.
Step-by-step explanation:
Spirochetes: Spiral-Shaped Bacteria
Spirochetes are a group of spiral-shaped bacteria that can be characterized by their long, thin, and corkscrew-like appearance. They belong to a larger category of bacteria defined by their shape, which also includes spherical (cocci), rod-shaped (bacillus), and other curved forms such as spirillum and vibrio. One of the key features of spirochetes is that they often require darkfield microscopy to be viewed due to their thin structure and gram-negative-like qualities.
Pathogenic Spirochetes
The group of spirochetes includes several genera that contain human pathogens responsible for serious diseases. Syphilis is caused by the pathogen Treponema pallidum, of which there are several subspecies. T. pallidum pallidum is the subspecies responsible for syphilis, a sexually transmitted disease.
Other diseases caused by spirochetes include Lyme disease, often spread by tick bites, and leptospirosis. While many members of the spirochetes species are free-living anaerobes, some are notably pathogenic and can cause significant human illness.