Presentation on theme: "Disease-Causing Viruses and Microorganisms Disease-Causing Viruses & Microorganisms (pathogens) Viruses Structure of Viruses- genetic material surrounded."— Presentation transcript:
Disease-Causing Viruses and Microorganisms
Disease-Causing Viruses & Microorganisms (pathogens) Viruses Structure of Viruses- genetic material surrounded by protein shell Protein shell (capsid) Viral DNA/RNA
Viruses View from a microscope (Capsid) Another kind of viral structure
Viruses Much smaller than bacteria
Viruses Not considered to be living because they cannot survive alone They can reproduce only inside of other living things. A single infected cell may replicate thousands of viruses. The new viruses go on to infect other cells.
Mutations of Viruses- Some viruses’ DNA can mutate at a very high rate, making it difficult to treat them with medicines. This is why new medicines and vaccines have to be discovered constantly.
Examples of Viruses HIV- causes AIDS; attacks white blood cells/immune system; death usually occurs from getting sick from another disease; high rate of mutation Kaposi’s sarcoma
HIV: the AIDS Virus Transmitted by: Blood-contaminated products Contaminated blood Sexual intercourse Origins: Scientists are still uncertain where the virus came from, but have noted a similar virus (SIV) in monkeys, which may have mutated. Patient 0: a Canadian flight attendant E:\Biology\HIV_and_AIDS. asf
Examples of Viruses Influenza- many different strains; high mutation rate; fever, muscle aches, chills, extreme fatigue
Influenza Virus Flu Epidemics: First epidemic recorded in Europe? 1173 Russian Flu ( )- 1 million deaths Spanish Flu ( )- over 50 million died Asian Flu Pandemic ( )- about 2 million deaths Hong Kong Flu Pandemic ( )- about 1 million deaths Avian Flu discovered (1996) E:\Biology\The_Influenza_Pandemic_of_1918.asf
Should you get a flu shot? Flu vaccines are chancy. They include parts of dead flu viruses that scientists believe are the “most likely suspects” to cause the flu this year. Your immune system learns to recognize them and fight them. (You can actually feel a little sick after getting the shot.) However, the flu virus mutates quickly, and may look nothing like anything in the shot. Effectiveness of the vaccine varies from year to year. Doctors recommend it for young children, the elderly, and those with compromised immune systems.
Examples of Viruses Smallpox- once eradicated; may come back via bioterrorism. Vaccine is being developed again; causes fever, fatigue, body ache, rash, pustules
Examples of Viruses Herpes Simplex- two types; type I causes cold sores; type II causes genital herpes It is transmitted by sexual intercourse. Currently there is no cure for Herpes.
Examples of Viruses Chicken pox- small red, itching spots; can recur in adults as Shingles Children in the U.S. may now be vaccinated for chicken pox.
Examples of Viruses West Nile Virus- carried by mosquitos; may show no symptoms (80%) or fever, headache, vomiting, coma, tremors, vision loss, paralysis (20%)
Examples of Viruses Rabies- transmitted by bite of rabid animal; fatigue, headache, fever, disorientation, hallucinations, seizures, death or coma After bitten, victim must be treated with a series of vaccinations.
Other Nasty Viruses Ebola Hemorrhagic Fever- one strain is 90% fatal, extremely virulent, liquefies internal organs, patients “bleed out” of every orifice
Other Nasty Viruses Hantavirus- carried by mice (mice feces), 50% fatal, one strain causes respiratory infection & failure, another causes hemorrhagic fever (SW U.S. has had cases!)
Other Nasty Viruses Lassa Fever- carried by rats, 50% fatal, can cause fever, hearing loss, vomiting, diarrhea, abdominal pain, facial swelling, mucosal bleeding, tremors.
Bacteria Mutations of Bacteria – bacteria that are repeatedly exposed to antibiotics are likely to mutate and become resistant (Show Video clip- HHMI Infectious Diseases- Bacterial Growth)
Examples of Bacteria Streptococcus/strep throat – severe and sudden sore throat without coughing or sneezing, fever, white or yellow spots on throat/tonsils Strepto = chain Coccus = round
Examples of Bacteria E.coli – watery/bloody diarrhea, abdominal pain, fever, anemia; 2-6 days; usually results from eating undercooked beef meat Most strains of E.coli are harmless, and live in large intestines of humans and animals. A few strains cause the food poisoning above. Movie: see Fast Food Nation
Examples of Bacteria Salmonella – usually results from eating undercooked chicken/eggs or egg products, diarrhea and vomiting for 2 weeks. Also found on some turtles!
Examples of Bacteria Botulism – bacteria produces toxin; home- canned foods and honey (infants); flaccid muscles, double/blurred vision, slurred speech; toxin is used for cosmetic purposes (botox) Do not open cans/canned food that looks “inflated”.
Examples of Bacteria Anthrax – produces white spores; 3 types 1. Cutaneous (skin) – itchy bump, then pustule with black center; usually contracted from hides and wool; 20% fatal if not treated Often affects animal (livestock) handlers- aka “Ragpicker’s Disease” or “Wool sorter’s Disease”
Examples of Bacteria Anthrax types: 2. Inhalational – agent of bioterrorism; flu symptoms (muscle aches, fever), then difficulty breathing, shock, usually death X-ray of infected lungs
Examples of Bacteria Anthrax types: 3. Gastrointestinal – contaminated meat; nausea, vomiting (w/ blood), severe diarrhea
Examples of Bacteria Tetanus – “rusty nail”; bacteria lives in soil; lockjaw, difficulty swallowing, muscle spasms, continual contracting of muscles, airway obstruction
Examples of Bacteria Cholera – caused by drinking water contaminated with feces; explosive diarrhea, rice- water stool, dehydration Can also be caused by eating undercooked shellfish Cholera bed
Examples of Bacteria Lyme Disease – carried by ticks; rash (sometimes fades to a bull’s eye shape), fever, chills, muscle ache, fatigue, sometimes irregular or slow heart beat
Other Nasty Bacteria Typhoid fever- Salmonella typhi, causes abdominal pain, blinding headache, rash, high fever, the tale of Typhoid Mary- some people can be carriers & not get sick Typhoid Mary
Other Nasty Bacteria Tuberculosis- Mycobacterium tuberculosis, most common form is pulmonary TB, spread by airborne droplets, causes bloody cough, pain, & breathlessness, victims waste away.
Examples of Protists Giardia – contracted by drinking contaminated water (rivers, lakes, etc.) – USE A GOOD WATER FILTER AND/OR BOIL WATER IF BACKPACKING!); diarrhea, bloating, farting, stomach cramps, fatigue, and weight loss Giardia is a parasite!
Fungus Examples: Athlete’s foot – itching and burning feet, skin peeling, cracking, pain, and bleeding; usually associated with locker rooms; up to 70% of the population will have it sometime in their lives!; can be treated with OTC (over the counter) meds
Examples of Fungus Ringworm – itchy, red scaly patches that may blister or ooze; redder on outside with normal skin tone inside (like a ring) “Barber’s itch”