Viruses& Human Health ‏ Human Health ‏ June 23, 20091SBI3C

September 4, 2015SBI3C2 Viral diseases are difficult to treat because: 1.No drug is available to kill viruses in the body 2. Some viruses are lysogenic  can remain dormant for years (hide inside cells) ex. a) Herpes Simplex Virus I (HSV I) (cold sores ) b) HIV 3.some viruses are cause cells to become cancerous 2 (AIDS) ex. Human Papiloma Virus (HPV) (genital warts) (cervical cancer)

September 4, 2015SBI3C3 3 vaccines: only true protection against viral diseases people are given a dead or weakened form of the virus builds up an army of WBC’s & antibodies to kill the living virus immediately before it can reproduce ex. polio vaccine, hepatitis B vaccine Protection Against Viral Diseases

September 4, 2015SBI3C Viral Vectors Viruses can be used for gene therapy as “carriers” Viral core is removed & desired human gene is added Virus is mixed with living cells Virus attaches to human host cell & injects the human gene i.e. acts like a microscopic hypodermic needle Viral Uses In Medicine

SOME EXTRA INFO ON HIV… September 4, 20155

SBI3C6 Worldwide HIV Distribution Note: Total exceeds 100 percent due to rounding. Source: UNAIDS, 2006 Report on the Global AIDS Epidemic, 2006.

SBI3C7 Structure of HIV

September 4, 2015SBI3C8 8 AIDS HIV (Human Immunodeficiency Virus) virus that causes AIDS RNA core (retrovirus) can only infect helper T cells (type of white blood cell) cannot survive outside the body because glycoprotein membrane around its capsid dries out can only be transmitted from 1 bodily fluid to another ex. 1. blood to blood: needles, transfusions, toothbrushes 2. semen & vaginal secretions 3.breast milk

SBI3C9 Transmission of AIDS (Worldwide) ‏ HIV in Body Fluids Semen 11,000 Vaginal Fluid 7,000 Blood 18,000 Amniotic Fluid 4,000 Saliva 1 Average number of HIV particles in 1 mL of these body fluids

SBI3C 10 Life Cycle of HIV Lysogenic Cycle HIV + Lytic Cycle AIDS

September 4, HIV positive: virus is in its lysogenic cycle (dormant) patient is not sick, but is a carrier of the virus can infect others AIDS (Acquired Immunodeficiency Syndrome) patient has symptoms of the disease (begins when HIV enters the lytic cycle) WBC’s are being destroyed Early symptoms: night sweats, diarrhea, cold symptoms SBI3C11

September 4, 2015SBI3C12SBI3C12 AIDS Associated Disease Late Symptoms Gastrointestinal: Cause most of illness and death of late AIDS Symptoms: Wasting (extreme weight loss) ‏ Abdominal pain Infections of the mouth and esophagus Respiratory: 70% of AIDS patients develop serious respiratory problems Bronchitis Pneumonia Tuberculosis Lung cancer

September 4, 2015SBI3C13SBI3C13 More AIDS Associated Disease Skin Disorders: 90% of AIDS patients develop skin or mucous membrane disorders Herpes Thrush Eye Infections: 50-75% patients develop eye conditions. Dry eye syndrome

September 4, 2015SBI3C14 The ultimate fate of a patient with AIDS patient dies from other infections due to a lack of immune response ex. pneumonia cancer

SBI3C15 Transmission of AIDS (Worldwide) ‏

SBI3C16 “When you have sex with someone, you are having sex with everyone they have ever had sex with.” Former US Surgeon General C. Everett Koop

September 4,

SBI3C18 Reverse Transcriptase Inhibitors: Competitive enzyme inhibitors. Example: AZT, ddI, ddC Protease Inhibitors: Inhibit the viral proteases. Prevent viral maturation Problem with individual drug treatments: Resistance Drug Cocktails: A combination of: One or two reverse transcriptase inhibitors One or two protease inhibitors Drug cocktails have been very effective in suppressing HIV replication and prolonging the life of HIV infected individuals, but are not considered to be a cure Drug Therapy

Homework Read ‘Sex Slaves for Science’ article Answer questions 1 – 11 September 4,

September 4, Oncolytic viruses used in targeted cancer treatment Choose a nonpathogenic virus that can infect human cells is chosen ex. Vaccinia (cowpox) Allow this virus to attack human tumour cells After reproducing, viruses released kill host cancer cell i.e. lytic cycle New viruses infect neighbouring tumour cells Also stimulate immune system, bringing WBC’s in to help kill cancer cells Note: cancer  is caused by a mutated ‘stop’ gene  results in uncontrollable cell division SBI3C20 Viral Uses In Medicine

September 4, SBI3C21

September 4, 2015SBI3C22SBI3C22 AIDS History 1950s: Blood samples from Africa have HIV antibodies 1976: First known AIDS patient died 1980: First human retrovirus isolated (HTLV-1) ‏ 1981: First reports of “Acquired Immuno- deficiency Syndrome” 1983: Virus first isolated in France (LAV) ‏ 1984: Virus isolated in the U.S. 1985: Development and implementation of antibody test to screen blood donors

September 4, SBI3C : Consensus name Human Immunodeficiency Virus (HIV-1) ‏ Related virus (HIV-2) identified 1992: AIDS becomes the leading cause of death among adults ages in the U.S. 1997: Mortality rates of AIDS starts to decline due to the introduction of new drug cocktails 2005: World Health Organization (WHO) predicts up to 40 million infected individuals More than 22 million have already died History - continued

SBI3C24 Source: UNAIDS, 2006 Report on the Global AIDS Epidemic, 2006 HIV Prevalence Worldwide Adults Ages with HIV 15.01% % 5.01% % 1.01% - 5.0% 0.51% - 1.0% 0.0% - 0.5% Not available