Infectious Disease And Sexually Transmitted Infections

Question 1

Infection

Answer 1

When a microorganism (bacteria, virus, fungi, protozoan) invades the body of a host

Question 2

Latent period

Answer 2

The time between infection and the development of symptoms/signs.

Question 3

Pathogens: Agents of infection

Answer 3

1. Bacteria (most are helpful)
   * 1% are pathogens, disease-causing; cause harm by releasing enzymes and toxins that do damage inside host

Antibiotics - kill bacteria (many are now resistant to multiple antibiotics

2. Viruses
   * acellular pathogens that invade living cells (can’t survive without host)

Antiviral drugs: typically reduce severity or duration of viral infections

3. More examples include Fungi, Protozoa, parasitic worms

Question 4

How to ‘catch’ an infection

Answer 4

People:
* direct or indirect contact

Food:
* e.g. E. coli, Salmonella

Water:
* contaminated water can carry pathogens

Animals and Insects = vector transmission
* mosquitos - Zola virus, malaria
* rats/fleas - plague

Question 5

Examples of good bacteria

Answer 5

Trillions of bacteria live in your digestive tract

Ex. Aid in digestion and vitamin absorption, compete with and exclude harmful microbes

Question 6

First line of defense

Answer 6

Includes various physical and chemical barriers

• skin
• Epidermis
• Cilia
• Mucus
• Elevated boy temperature
• cough, tears, saliva

Question 7

Antigen

Answer 7

A chemical structure that your immune cells recognize as different from your own and therefore foreign and we need to amount a response to

Question 8

Second line of defense

Answer 8

Specialized cells including macrophages, T cells, and B cells launch an immune response to eliminate the pathogen

Question 9

Immune system: T cells & macrophages

Answer 9

Macrophages (big eaters):
* surround and digest foreign matter
* aid immunity by engulfing antibody-bound pathogens

T-cells:
* fight parasites, fungi, cancer cells, infected cells
* thousands of T-cells work together to kill pathogens

Question 10

Immune system: B cells & antibodies

Answer 10

Antibodies (Abs):
* made by B-cells
* Abs are proteins that stick to specific antigens on pathogens (humoural response)

Abs coat pathogens and make them clump together so that pathogens:

• cannot infect new cells
• can be more effectively ‘eaten’ by macrophages

Question 11

The chain of infection & ways to break the chain

Answer 11

• pathogen - disinfectants, chlorinations of water
• reservoir (long term host)- medical treatment and testing, quarantine
• portal of exit - masks, condoms
• means of transmission - sanitary practices, safer sex
• portal of entry - masks, insect repellant
• new host - immunization, health promotion, medical treatment

Question 12

Chain of infection: Influenza

Answer 12

Pathogen - Influenza virus
Human reservoir - Human #1 infected
portal of exit - human #1 sneezes; pathogen exits mouth or nose
Transmission - Airborne droplets or indirect transfer through a surface
portal of entry - human #2 inhales; pathogen enters nose or mouth
New host - Human #2 infected

Question 13

Vaccination

Answer 13

Small quantity of inactive pathogen injected to create memory cells (T- and B-cells)

• when you encounter the actual pathogen, your immune system can fight it off (with antibodies)
• eliminates pathogen before signs/symptoms experienced

Question 14

Smallpox

Answer 14

A virus that plagued humans throughout history
* killed more people than every infectious disease combined

Vaccination has led to the eradication of smallpox (~35% mortality)

Question 15

Measles

Answer 15

Causes inflammation of the brain, brain damage, seizures, deafness, and for 150000 cases per year globally, it leads to death

“Most deadly of all childhood rash/fever illnesses” - WHO

Question 16

Difference between T-Cells & B-Cells

Answer 16

B-Cells: produce antibodies that are used to attack invading bacteria, viruses, and toxins

T-Cells: destroy the own body’s cells that have been taken over by viruses or become cancerous

Question 17

Infectious Disease in Canada

Answer 17

1. Colds
2. Influenza
3. Hepatitis
4. Meningitis
5. Reproductive & Urinary infections
6. Sexually transmitted infections

Question 18

Common cold (rhinovirus, coronavirus)

Answer 18

Spread by coughs, sneezes, direct, indirect contact
~200 types (so you keep getting it)

Prevention: washing hands
Cure: Your immune system
* rest, fluids, mild exercise, nutrition
* medications mask symptoms

Question 19

Flu (Influenza virus)

Answer 19

More severe symptoms (aches, chills, dry cough, weakness) that last longer than a cold

1918 Spanish flu outbreak:
* killed 50-100 million people
* 50% of worlds population infected
* killed those with the healthiest immune systems (typically ages 18-40)

Question 20

Hepatitis (virus)

Answer 20

Symptoms: fever, headaches, fatigue, diarrhea, vomiting, aching joints

• Viruses (A-G) cause inflammation of the liver
• Viruses (A & E) transmitted by contaminated water
• Viruses (B,C,D) transmitted through sexual contact

Question 21

Meningitis (bacterial or viral)

Answer 21

Infection of the membranes surrounding the brain and spinal cord

Symptoms: fever, drowsiness, confusion, headache, nausea, vomiting

• viral meningitis clears up on its own
• bacterial meningitis is very serious and requires antibiotics immediately

Question 22

Reproductive and Urinary tract infections

Answer 22

Vaginal infections:
* symptoms include itching, burning, discharge

Penile infections:
* symptoms include redness, irritation, pain during urination or intercourse, discharge

Urinary tract infections (UTIs):
* typically caused by bacteria
* symptoms include burning sensation while urinating, chills, fever, fatigue, blood in urine
* more common in females

Question 23

Ways to support your immune system

Answer 23

• washing your hands
• adequate sleep and exercise
• a balanced diet

Question 24

Bacterial STIs

Answer 24

• chlamydia
• gonorrhea
• infectious syphillis
• pelvic inflammatory disease (PID)

Question 25

Viral STIs

Answer 25

* human papillomavirus (HPV) * Genital Herpes (HSV 1 and HSV 2) * human immunodeficiency virus (HIV) * Hepatitis B (HBV)

Question 26

Chlamydia (most common bacterial STI in Canada)

Answer 26

Caused by chlamydia trachomatis * it is common and easily treatable with antibiotics * 2x more common in females then males * if left untreated, can lead to ectopic pregnancy; sterility in females (and males) Symptoms (often asymptomatic): * discharge * burning when urinating

Question 27

Gonorrhea

Answer 27

Caused by Neissaria gonorrhoeae * often asymptomatic * in females can cause PID * in males can cause inflammation of the urethra, prostate, epididymis

Question 28

Syphillis

Answer 28

Caused by Treponema pallidum * transmitted through a break in the skin, via kissing, oral, vaginal, or anal sex **Primary**: ulcer at site of infection (days to weeks after contact); not usually painful; contains high numbers of bacteria and highly contagious **Secondary**: flu-like symptoms; rash over the body, hands and feet; ~ 2 months later **Tertiary**: neurological and cardiovascular effects; blindness; years to decades later Treatment: antibiotics if early enough

Question 29

Human Papilloma Virus (most common viral STI in North America)

Answer 29

> 100 types of HPV Cause common warts, genital warts, genital cancers * all cervical cancers caused by HPV * spread by sexual contact Immune system often clears the infection (some cases infection persists to cause genital warts or cancer) Prevention: Gardasil vaccination HPV Progression: Long latency provides ample opportunity to remove pre-cancerous cells

Question 30

Herpes Simplex Virus 1 & 2

Answer 30

Travels along nerves and lays dormant in nerve cells; infection is life-long * commonly transmitted through oral sex * prevention is difficult * outbreaks can be triggered by stress, illness, fatigue, sun exposure, intercourse, and menstruation Prevention: condom use Treatment: antivirals like acyclovir can lessen symptoms; there is no cure

Question 31

Human Immunodeficiency virus (HIV)

Answer 31

Transmission: * not spread by casual contact; requires blood-blood or fluid-blood contact Most common: unprotected sex

Question 32

HIV and AIDS

Answer 32

HIV infects immune cells (T-cells) The immune system launches a response but: * HIV “hides” inside immune cells (and slowly kills them) * HIV replicates too fast for the immune system to fight it * HIV mutates (changing its antigens) and avoids elimination An untreated HIV infection typically leads to **AIDS** within 10 years Severely compromised immune system * death due to **opportunistic infections** Main treatment: * highly active antiretroviral therapy (HAART) Combination of (usually) 3 different kinds of drugs that target various stages of the HIV viral life cycle

Question 33

Key takeaway from HIV in Canada

Answer 33

It does not discriminate * shown in heterosexual individuals **(33%)**, gay individuals **(50%)**, and intravenous drug users **(17%)**

Question 34

Opportunistic infection

Answer 34

An infection caused by pathogens (bacteria, viruses, fungi, or parasites) that take advantage of an opportunity not normally available Ex. A host with a weakened immune system

Question 35

Steps to the immune response

Answer 35

Phase 1: Recognition - when a pathogen breaches the body’s physical and chemical barriers it initiates the first phase of the immune response Phase 2: Proliferation: the activated helper and killer T-cells multiply, thereby amplifying the immune response to the pathogen Phase 3: Elimination: the activated T and B cells then undergo a transformation to become either memory cells or effector cells. Phase 4: Slowdown: Regulatory T cells inhibit lymphocyte proliferation and induce lymphocyte death, causing a slowdown of the immune response

Question 36

Pelvic Inflammatory Disease

Answer 36

Usually a complication of untreated gonorrhea or chlamydia * is an ascending infection that progresses from the vagina to the cervix to the uterus, oviducts, and pelvic cavity * it can lead to infertility, ectopic pregnancy, and chronic pelvic pain