Viruses and Diseases in the Civil War Miss Sabia

 Be able to summarize both the lytic and lysogenic cycle.  Be able to compare the structure and characteristics of viruses and bacteria.  Be able to properly perform a swab technique. Objectives

 Typhoid  Pneumonia  Measles  Tuberculosis  malaria The Main Killers

 Microbes that cause diseases… VIRUSES and BACTERIA Pathogens

 Earliest form of life (3 billion years ago)  Prokaryotic cells (no organelles, no nucleus)  Single celled  have a cell wall Bacteria

 3 shapes:  Cocci (spherical)  Bacilli (rod shaped)  Spirilla (spirals) Bacteria

 Use flagella to “swim” or produce thick coats of slime to “slide” around Bacteria

 Give off chemicals called toxins that can make us sick  Our body fights off bacterial infections using antibodies How Bacteria Infect

 Single-celled  Not considered living  Cannot reproduce on their own  They are not made up of cells  They cannot respond to the external environment  Cannot move on their own  Called “particles” or “agents”  About 4,000 different types of viruses Viruses

 Have genetic material (DNA or RNA) enclosed in a capsid  Some viruses have a viral envelope covering their capsid (taken from host cell)  sneaky Viruses

 Lytic cycle  1. entry into cell  2. replicate DNA  3. make viral proteins  4. assemble new generation  5. exit from infected cell—host cell bursts open (lyses) and virus is released into the environment, host cell dies  How Viruses Infect

 Lysogenic cycle (sneaky!)  1. entry into cell  2. DNA incorporated into host cell’s DNA  3. host cell copies chromosomes  4. host cell divides and replicates—all new cells have virus’ DNA incorporated into their own  5. steps 3-5 from lytic cycle  tm tm How Viruses Infect

 Swab Demo: ohttp:// o  Note: we will not be wetting our swabs in distilled de- ionized water as the video says Microbiology Lab—Microbes Around Us