BACTERIA AND VIRUSES

The Good: BACTERIA Are Prokaryotic Unicellular organisms Has a role in maintaining health by inhabiting our intestine to aid in digestion and producing vitamins that our bodies need Remove waste from water Used in medicine

The Bad: Bacteria BACTERIA CAN CAUSE DISEASE ARE TREATED WITH ANTIBIOTICS Tooth Decay Tetanus Diphtheria

The Ugly: Viruses Non living “organisms” that can only reproduce inside a living cell Unique Structure Causes disease specific to a host

Question.. What is the most common threat to a host organism posed by an invading virus? A Production of viral fluids in the bloodstream B Fermentation of acids in the digestive system C Destruction of cells by viral reproduction D Stimulation of muscle tone in the heart

The Ugly: Viruses Continued Capsid/Head Fiber Tails Base Plate

Question The photograph shows a virus attacking a human T cell (immune cell). Which disease could result if many T cells are destroyed in this manner? A AIDS B Tuberculosis C Chicken pox D Multiple sclerosis

The Ugly: More about viruses Invade other cells by attaching to a cell and injecting their genes or by being swallowed up by the cell. Responsible for many human diseases Can result in death

The Ugly Rabies Smallpox AIDS

Terms Pathogen Microorganism Usually a bacterium, virus, or fungi play an important role in many ecosystems Life cycles of microorganisms are studied in order to better understand diseases Pathogen A bacterium, virus, or other microorganism that can cause disease

AIDS: Acquired immune deficiency syndrome What do they stand for? AIDS: Acquired immune deficiency syndrome HIV: Human Immunodeficiency Virus

Glycoprotein: binds to receptor molecules on the host cell membrane Viral Envelope: made of 2 layers of fatty acids Reverse transcriptase: Makes DNA from RNA Capsid: Protective protein coat

Basic facts about HIV/AIDS HIV is a retrovirus HIV is the virus that causes AIDS HIV attacks T-cells (specifically called CD4 cells) HIV/AIDS is treatable, but not curable You can’t tell by looking if a person is living with HIV, the only way to know is by taking an HIV antibody test.

Origin descendant of a Simian Immunodeficiency Virus because certain strains of SIVs bear a very close resemblance to HIV-1 and HIV-2, the two types of HIV. Sooty mangabey (also known as the White- collared monkey)

How could HIV have crossed species? The 'hunter' theory chimps being killed and eaten or their blood getting into cuts or wounds on the hunter The oral polio vaccine (OPV) theory journalist Edward Hooper suggests that HIV can be traced to the testing of an oral polio vaccine called Chat, given to about a million people in the Belgian Congo, Ruanda and Urundi in the late 1950s. To be reproduced, live polio vaccine needs to be cultivated in living tissue, and Hooper's belief is that Chat was grown in kidney cells taken from local chimps infected with SIVcmz. This, he claims, would have resulted in the contamination of the vaccine with chimp SIV

How could HIV have crossed species? The contaminated needle theory likely that one single syringe would have been used to inject multiple patients without any sterilization in between. This would rapidly have transferred any viral particles (within a hunter's blood for example) from one person to another

Four of the earliest known instances of HIV infection are as follows: A plasma sample taken in 1959 from an adult male living in what is now the Democratic Republic of the Congo. A lymph node sample taken in 1960 from an adult female, also from the Democratic Republic of the Congo. HIV found in tissue samples from an American teenager who died in St. Louis in 1969. HIV found in tissue samples from a Norwegian sailor who died around 1976.

The 4 Fluids Blood Semen Breast Milk Vaginal Fluids These are the four fluids that transmit HIV. The key to protecting yourself from infection is to avoid these four bodily fluids. Do: Clarify that semen includes “pre-cum” and the ejaculation. Even if it does not come up, please point out that no other fluids transmit HIV.

Transmitting HIV HIV is transmitted when one or more of the four fluids is transferred from one person to another. The most common ways HIV is transmitted is by: Unprotected sex Sharing needles Breastfeeding from infected mother to baby

HIV is not spread by casual contact. It dies quickly outside the body and is easily killed by soap and by common disinfectants such as bleach. There is no risk of HIV infection from: donating blood mosquito bites toilet seats shaking hands hugging sharing eating utensils food or objects handled by people with HIV or AIDS spending time in the same house, business, or public place with a person with HIV/AIDS.

Preventing HIV: Sharing Needles/Breastfeeding Needles should never be shared. When getting tattoos or piercings, make sure that new needles and new ink bottles are used. Injection drug users should never share works. Works can be cleaned using bleach and water. Do: Explain how sharing needles puts people at risk for contracting HIV. Be sure to discuss how needles used for medications (insulin) can also be a risk. Sharing needles is never a good idea. Mothers living with HIV should not breastfeed babies; prenatal care can help reduce the chance that babies of HIV-infected mothers are born with HIV.

HIV Transmission Activity On separate sheet of paper, put your name, date, class period. Copy table below Person’s Name Infected? 1 2 3

Total students in class: Total that were “infected”: Percent that “got infected”:

Follow-Up Questions 1. Did every person in the room become infected? Why/why not? 2. If we continued to do this activity, would everyone eventually get HIV? Explain. 3. Name at least two other viral diseases besides HIV/AIDS. 4. List 4 fluids that can transmit HIV. 5. Discuss at least two ways the spread of HIV/AIDS can be prevented. 6. What is the difference between HIV and AIDS? 7. What does a person with HIV look like? Can you recognize someone with this virus?