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Chapter14InfectiousDiseasesandSTDs.pptx

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The Basics Health

13th edition

Chapter 14

Protecting against Infectious Diseases and Sexually Transmitted Infections

The Process of Infection

Disease-causing agents called pathogens are found in air and food and on nearly every object or person.

An epidemic is a disease outbreak that affects many people in a community or region at the same time.

A pandemic is a global epidemic of a disease.

When a pathogen is virulent, it is strong enough to overcome host resistance and cause disease.

One becomes immunocompromised when the immune system is impaired.

Routes of Transmission

Direct contact: kissing or touching an infected person

Indirect contact: touching something that the infected person has touched

You may also autoinoculate yourself by transmitting a pathogen from one part of your body to another.

Animal-borne (zoonotic) infections are spread by domestic and wild animals.

Interspecies transmission is rare but does occur.

Risk Factors You Can Control

Too much stress

Inadequate nutrition

Low fitness level

Lack of sleep

Misuse or abuse of drugs

Poor personal hygiene

High-risk behaviors

Routes of Disease Transmission

Hard to Control Risk Factors

Heredity

Age

Environmental conditions

Organism virulence and resistance

Your Body's Defenses against Infection

Physical and chemical defenses

Skin

Enzymes in body secretions

Internal linings of the body

Immune system defenses

The Body's Defenses against Disease- Causing Pathogens

How the Immune System Works

Immunity: Being able to resist a particular disease by counteracting the substance that produces the disease

Antigens: Substances capable of triggering an immune response. Examples include a virus, a bacteria, a fungus, a parasite, a toxin or tissue from another organism.

Antibodies: Specific responses to antigens

How the Immune System Works (cont.)

Humoral immune response: The body's major defense against many bacteria and the poisonous substances, toxins, they produce

Cell-mediated immunity

Lymphocytes

B lymphocytes

T lymphocytes

Macrophages

The Cell-Mediated Immune Response

When the Autoimmune System Misfires

Autoimmune diseases

Sometimes the body makes a mistake and targets its own tissues.

Common autoimmune disorders are rheumatoid arthritis, systemic lupus erythematosus (SLE), type 1 diabetes, celiac disease, and multiple sclerosis.

Inflammatory response, pain, and fever

Four cardinal signs of inflammation: redness, swelling, pain, and heat

Fever is another indicator of inflammation.

High temperatures can destroy some disease-causing organisms.

Stimulates more white blood cell production.

Vaccines Bolster Immunity

Vaccines consist of killed or weakened versions of the disease-causing microorganism or an antigen that is similar to but less dangerous than the disease antigen.

Artificially acquired active immunity: Given orally or by injection

Vaccination schedules have been established for various population groups

College students are particularly at risk

Recommended Vaccinations for Teens and College Students

Recommended Adult Immunization Schedule, by Vaccine and Age Group, 2015

Types of Pathogens and the Diseases They Cause

Bacteria are single-celled organisms.

Diseases caused by bacteria can be treated with antibiotics.

Staphylococcal infections

Methicillin-resistant Staphylococcus aureus (MRSA)

Clostridium difficile

Streptococcal infections

Meningitis

Pneumonia

Tuberculosis (TB)

Tick-borne bacterial diseases

Escherichia coli O157:H7

Examples of Five Major Types of Pathogens

Viruses

Viruses are the smallest known pathogens.

Consist of a protein structure that contains either ribonucleic acid (RNA) or deoxyribonucleic acid (DNA).

Incapable of carrying out any life processes on their own; to reproduce must invade and inject their own RNA or DNA into a host cell.

Diagnosis can be difficult because some viruses have incubation periods (the time from infection to symptoms) that can last years.

Drugs powerful enough to kill viruses generally kill the host cells.

Viruses (cont.)

The common cold

Influenza

Hepatitis: three different types

A (HAV)

B (HBV)

C (HCV)

Other Pathogens

Fungi

Candidiasis

Ringworm

Jock itch

Toenail fungus

Protozoans

Giardia

Parasitic worms

Pinworms to large tapeworms

Prions

Bovine spongiform encephalopathy (BSE—mad cow disease)

Emerging and Resurgent Diseases

Measles and mumps

The most well-known symptom for mumps is swollen salivary glands. It can cause hearing loss or male sterility.

Measles is known for high fever, and itchy red rash. It is increasingly common, particularly on college campuses. Many have not been vaccinated against measles.

ABC News Video: A Brief History: Measles in America

Emerging and Resurgent Diseases (cont.)

West Nile virus

Several thousand cases occur each year. Symptoms are flu-like.

Avian (bird) flu

As of March, 2016, there were 859 cases of bird flu in humans, with 453 deaths.

Swine (pig) flu A (H1N1)

2009-10, 60 million cases of a variant of the H1N1 virus in the United States, killing nearly 12.5 thousand people.

Contains combined elements of a human flu virus and the pig virus

Powassan virus

Viral disease related to West Nile

Attacks the brain of those bitten, causing encephalitis.

ABC News Video: CDC Issuing New Alert on MERS

Sexually Transmitted Infections (STIs)

Every year, there are at least 20 million new cases of sexually transmitted infections (STIs),

Many go unreported due to lack of symptoms

Left untreated, some STIs can cause sterility, blindness, central nervous system destruction, disfigurement, and death.

What's your risk?

The more sexual partners you have, the higher your risk for an STI.

Casual attitude toward sex in spite of infection

Ignorance about infections/symptoms

Continuum of Disease Risk for Various Sexual Behaviors

Routes of Transmission

Intimate sexual contact

Mouth-to-mouth contact

Contact with fluids from body sores

STI pathogens have both a pathogen-specific incubation period and periods of communicability—times during which transmission is most likely.

Chlamydia

In 2015, there were just over 1.5 million reported cases.

Many people display no symptoms, but men may experience painful and difficult urination and penile discharge. Women are more likely to be asymptomatic.

Complications can lead to injury to the prostate gland, seminal vesicles, bulbourethral glands; inflammatory damage to the blood vessels and heart, and arthritis-like symptoms in men.

In women, damage to the cervix or fallopian tubes can cause sterility and lead to pelvic inflammatory disease.

Chlamydia may be responsible for one type of conjunctivitis, an eye infection.

If detected early, it is easily treatable with antibiotics.

Gonorrhea

Gonorrhea, surpassed only by chlamydia, is one of the most common bacterial STIs in the United States.

Nearly 400,000 new infections each year.

Symptoms in men are white, milky discharge and painful urination.

Most women do not experience symptoms, but occasionally vaginal discharge and a burning sensation occur while urinating.

Complications, if not treated, include scarring resulting in PID and sterility.

May (through blood) infect the joints, heart valves, or brain.

During delivery, possibly transmitted to baby

If detected early, it is easily treatable with antibiotics but, as with other diseases, is becoming resistant

Gonorrhea

Syphilis

Syphilis is caused by a bacterium called Treponema pallidum.

Known as the "great imitator" because symptoms often resemble other STIs.

Sometimes there are no symptoms.

nearly 75,000 reported new cases of syphilis in 2014, up significantly from the 17,375 cases in 2013

Four stages of syphilis

Primary: Chancre develops and then disappears in 3–6 weeks.

Secondary: A rash or white patches appear on the skin or mucous membranes.

Latent: Invades the organs and causes lesions called gummas.

Tertiary/late: Heart and central nervous system damage, along with loss of senses and motor ability.

Easily treated with antibiotics, except in the late stage.

Syphilis

Herpes

The herpes family of diseases is not transmitted exclusively by sexual contact.

Genital herpes (HSV-2) affects about 16 percent of the population

HSV-1 affects about half the population with mouth cold sores

Infection begins with burning sensation and redness at site and then turns into a blister full of the virus.

In blistering stage, there it is possible to spread the virus through autoinoculation.

If left undisturbed, the site will clear and the virus will go dormant, but can reoccur during periods throughout life.

Herpes (cont.)

Herpes can be spread from mother to child during birth.

There is no cure for herpes, but there are drugs that can treat symptoms and reduce viral shedding.

Herpes

Human Papillomavirus (HPV) and Genital Warts

Over 150 different types of HPV

People infected with low-risk HPV may develop genital warts. HPV can cause cervical cancer; cancer of the vulva, penis, anus, vagina, back of the throat, and tongue.

Complications

Dysplasia: Change in cells that may lead to a precancerous condition

Treatment

Available only for the low-risk forms of HPV

Most warts can be treated with topical medication or can be frozen.

Genital Warts

Sexually Transmitted Infections (cont.)

Candidiasis (moniliasis) or yeast infection

Caused by a yeast-like fungus

Symptoms include severe itching, burning, and swelling.

Antifungal drugs can cure candidiasis in just a few days.

Trichomoniasis

Caused by a protozoan

Symptoms in women include an unpleasant-smelling discharge accompanied by a burning sensation, itching, and painful urination.

Most men do not experience symptoms.

Usually transmitted by sexual contact or toilet seats, wet towels, or other items with discharged fluids on them.

Pubic Lice

Informally called "crabs."

Symptoms include itchiness in the pubic hair, bluish gray skin color, and sores in the genital area.

Treatment includes thorough washing of clothing, furniture, and linens.

Takes 2 to 3 weeks to kill all larval forms.

Usually transmitted sexually but can also be caught from lying on sheets or sitting on a toilet seat that an infected person has used.

Pubic Lice

HIV/AIDS

Acquired immunodeficiency syndrome (AIDS)

Human immunodeficiency virus (HIV)

There are approximately 37 million people worldwide living with HIV.

2.1 million new infections and 1.1 million deaths in 2015.

78 million people worldwide have become infected with HIV and 35 million have died.

Globally, the number of people living with HIV, and new infections have decreased.

How HIV Is Transmitted

Engaging in high-risk behaviors

Exchange of body fluids

Contaminated needles

Mother-to-child (perinatal) transmission

Estimates of New HIV Diagnoses in the United States for Most Affected Subpopulations, 2015

Symptoms of HIV/AIDS

Incubation time varies greatly.

For HIV-positive adults who receive no medical treatment, AIDS will develop in 8 to 10 years.

Opportunistic infections are characteristic of the disease.

An AIDS diagnosis occurs when a person has a dangerously low CD4 count (below 200 cells per cubic milliliter of blood) or contracts one or more opportunistic infections (e.g., Kaposi's sarcoma or Pneumocystis carinii pneumonia).

Testing for HIV

Antibody tests – accurate if window period has been long enough

Antibody test provides results from blood in 30 minutes, and the OraQuick test kit can provide results within 20 minutes.

The Home Access HIV-1 Test System requires a finger prick of blood to be sent to a lab.

Combo or Fourth-Generation Tests

Look for antibodies and antigens

Shorter window period

Nucleic Acid Tests (NAT) and HIV p24 Antigen Test

Quicker, but not recommended for initial a screening

HIV/AIDS

New hope and treatments

New drugs slow progression of virus.

Current treatments combine selected drugs such as protease inhibitors and reverse transcriptase inhibitors.

There is no treatment effective for all cases.

Preventing HIV infection

Reduce risk by responsible choices and behaviors.

If you don't exchange bodily fluids, you won't get the disease.

Abstinence or safe sexual practices

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