HIV and Infectious Diseases Quiz

Immunity and Infection - Chapter 14

• The immune system is the body's collective defenses, including surface barriers and specialized cells, tissues, and organs.
• It protects against pathogens (disease-causing organisms) and cancer.
• Physical and chemical barriers include skin, mucous membranes, and cilia lining the respiratory tract.

The Body's Defense System

• The immune system operates through a network of white blood cells, including two interacting systems: innate and adaptive immune systems.

The Immune System: Cells, Tissues, and Organs 1

• The innate immune system is the first to respond.
• Innate immune system cells include neutrophils, eosinophils, macrophages, natural killer cells, and dendritic cells.

The Immune System: Cells, Tissues, and Organs 2

• The adaptive immune system involves lymphocytes (T cells and B cells).
• B cells produce antibodies that neutralize specific invaders.
• T cells differentiate into helper, killer, or suppressor T cells.

The Immune System: Cells, Tissues, and Organs 3

• Macrophages engulf invaders and alert other cells.
• Inflammation is a response that causes blood vessels to dilate and fluid to move into injured tissue, often leading to pus formation.

The Immune System: Cells, Tissues, and Organs 4

• The immune response has four phases: recognition, proliferation, elimination, and slowdown.
• Dendritic cells initiate recognition. Helper T cells multiply. Killer T cells eliminate infected cells, and memory T and B cells remain.
• Cytokines are chemical messengers.

The Immune Response (Figure 14.1)

• The immune response is a complex series of body reactions to destroy invaders.
• Processes include recognition, proliferation via helper T and B cell production, pathogen elimination by killer T cells and antibodies, and finally a slowdown in response by memory T and B cells.

Immunity

• Immunity refers to the body's ability to resist the same pathogen.
• Adaptive immunity is developed through antigen-specific lymphocyte activation. Memory T and B cells circulate in the lymphatic systems.

The Lymphatic System

• The lymphatic system includes vessels that carry lymph and organs like the spleen and lymph nodes.
• Lymph nodes filter excess fluid from tissues, and those involved in fighting infection may swell.

Immunization 1

• Immunizations prime the body to remember a specific antigen.
• Vaccination rates impact disease outbreaks, with international travel playing a role in infectious disease spread.
• Vaccines include weakened organisms (attenuated) and killed viruses. A recent advancement is mRNA vaccines.

Immunization 2

• Vaccines have contributed to increased American life spans.
• Vaccine efficacy depends on individual responses, highlighting the importance of consistently high vaccination rates.
• Vaccination approvals are rigorous, with rare and usually mild side effects.

Allergy: A Case of Mistaken Identity 1

• Allergies occur when the immune system reacts to harmless substances as if they were harmful pathogens. Common allergens include pollen, animal dander, dust mites, molds, foods, and insect stings.

Allergy: A Case of Mistaken Identity 2

• Allergic responses may cause an asthma attack.
• Anaphylaxis is a serious allergic reaction with symptoms including swelling, low blood pressure, and potentially life-threatening complications. Epinephrine injection is crucial treatment.

Allergy: A Case of Mistaken Identity 3

• Climate change can exacerbate allergy issues.
• Treatment options for allergies include avoidance, medication, and immunotherapy (desensitization).

The Spread of Disease: Symptoms and Contagion

• The first phase of infection, the incubation period, may not demonstrate symptoms but may be contagious.
• The prodromal period marks the onset of symptoms.
• Many symptoms arise from the immune system's response to the infection. Transmission may occur before symptoms.

The Chain of Infection

• Pathogens initiate the infectious disease cycle.
• The natural environment is the reservoir.
• Portals of exit include discharges.
• Transmission is direct or indirect via vectors.
• Entry portals include skin penetration, inhalation, and ingestion, potentially causing systemic infection.

Epidemics and Pandemics 1, 2

• Epidemics are rapidly spreading diseases exceeding normal occurrences.
• Pandemics involve widespread infectious diseases, such as the bubonic plague, smallpox, influenza, and COVID-19.
• Endemic diseases are habitually present in a region.

Pathogens, Diseases, and Treatment: Bacteria 1, 2

• Bacteria are microscopic single-celled organisms.
• Diseases include pneumonia, meningitis, strep throat, toxic shock syndrome, tuberculosis, and others.
• Antibiotics either inhibit bacterial growth or kill bacteria, affecting cell wall synthesis, DNA replication, and protein production., Antibiotics have been misused leading to antibiotic resistance. Usage must follow instructions, and not all illnesses are treated effectively by antibiotics.

Pathogens, Diseases, and Treatment: Viruses

• Viruses are microscopic organisms replicating inside other organisms' cells.
• They cause diseases like the common cold, influenza, measles, mumps, rubella, chickenpox, herpes, viral hepatitis, and HPV.
• There are antiviral drugs available for some viruses.

Pathogens, Diseases, and Treatment: Other Pathogens

• Fungi reproduce via spores.
• Yeast infections, athlete's foot, jock itch, and ringworm are fungal infections.
• Protozoa are single-celled organisms; malaria and giardiasis are examples.
• Parasitic worms include tapeworms, hookworms, and pinworms.

Emerging Infectious Diseases 1, 2

• Diseases of concern include Zika, Ebola, West Nile virus, and pathogenic E. coli.
• Factors contributing to emerging infections include drug resistance, poverty, population growth, urbanization, overcrowding, migration, breakdowns in public health measures, travel and commerce, food production and distribution, human behaviors, and climate change.

Immune Disorders

• Autoimmune diseases arise when the immune system attacks the body's own tissues.
• Some cancers suppress immune responses.

Supporting Your Immune System

• General guidelines include adequate sleep, regular eating, frequent handwashing, avoiding exposure to contagious individuals and carriers, and maintaining current vaccinations.

The Major STIs

• Sexually transmitted infections (STIs) spread through sexual activity.
• Common STIs include HIV/AIDS, chlamydia, gonorrhea, HPV, herpes, hepatitis, and syphilis.

HIV and AIDS 1, 2, 3

• HIV is a virus that causes AIDS (acquired immunodeficiency syndrome).
• HIV attacks and progressively damages the body's immune system by invading CD4 T-cells, macrophages, etc.
• HIV converts its RNA into DNA.
• AIDS emerges when the CD4 count drops below certain levels, opening the way for opportunistic infections.
• HIV infections can remain asymptomatic for years.

HIV: Transmitting the Virus

• HIV only replicates within cells like blood products, semen, vaginal secretions, and breast milk.
• It cannot live outside the body.
• Transmission occurs through sexual contact, exposure to infected blood, and transmission from mother to child.

HIV: Key Populations Affected by HIV

• In 2020, 20% of new HIV diagnoses were among young people.
• Young African American, Latino gay, and other men who have sex with men are disproportionately affected.
• Sexual activity between men is a primary transmission route.

HIV: Routes of HIV Transmission

• Distribution figures (like the pie chart) illustrate the prevalence of transmission through various means.

HIV: What's Risky and What's Not

• Relative risks of HIV transmission are associated with different sexual activities.

HIV: Symptoms

• Primary HIV infection is marked by flu-like symptoms.
• After the initial phase, symptoms may diminish, leaving people asymptomatic for extended periods.
• As the immune system weakens, opportunistic infections frequently arise, such as pneumonia, Kaposi's sarcoma, vaginal yeast infections, and tuberculosis cases.

HIV: Diagnosis

• HIV diagnoses involve antibody tests, combination HIV antigen/antibody tests, and nucleic acid tests (NATs).
• Viral load monitoring is critical to assessing disease progression and severity.
• AIDS diagnosis is made when serious immune system damage and opportunistic infections manifest.

HIV: Treatment

• Medications, that block HIV replication or prevent infection of other cells. Include reverse transcriptase inhibitors, protease inhibitors, integrase inhibitors, and entry inhibitors.
• Combination drug therapies are used to treat HIV and reduce opportunistic infection risk.
• Postexposure prophylaxis (PEP) is a treatment option after possible HIV exposure.

HIV: Prevention

• Research continues on effective HIV vaccines.
• Protecting against HIV involves making responsible sexual choices, not sharing drug needles, considering pre-exposure prophylaxis (PrEP) for individuals at risk of exposure, and participating in HIV/STI risk reduction education.

Chlamydia

• Chlamydia is a prevalent bacterial STI caused by Chlamydia trachomatis.
• Untreated infections in women can lead to PID and infertility.
• Infants may contract chlamydia from mothers who have it.
• Diagnosis is done through laboratory tests, and antibiotics are the standard treatment. Both partners should be tested and treated.

Gonorrhea

• Gonorrhea is caused by Neisseria gonorrhoeae; often transmitted sexually from infected mucous membranes.
• Symptoms vary, sometimes absent in women.
• Treatment is with ceftriaxone. Partners need treatment.

Pelvic Inflammatory Disease (PID)

• PID is a serious complication of untreated chlamydia or gonorrhea.
• Initial infection spreads from the cervix to the uterus, fallopian tubes, ovaries, and pelvic cavity.
• Symptoms are diverse and can range from asymptomatic to severe abdominal pain, fever, chills, nausea, vomiting and abnormal vaginal bleeding.
• Treatment is prompt antibiotics and possible laparoscopy. Sexual partners must be treated as well.

Human Papillomavirus (HPV)

• HPV causes common warts, genital warts, and genital cancers, particularly cervical cancer.
• Most sexually active individuals will be exposed to HPV at some point.
• HPV can be asymptomatic or cause visible warts.
• Vaccination is recommended for both girls and boys. Pap smears can also aid detection.

Genital Herpes

• Genital herpes is caused by HSV 1 and HSV 2.
• Symptoms in 90% of cases aren't obvious; a primary outbreak after exposure may occur.
• Triggers include stress, illness, fatigue, sun exposure, sexual contact, and menstruation.
• Antiviral drugs can manage symptoms.

Hepatitis A, B, and C 1, 2

• Hepatitis is a liver inflammation.
• HBV is transmitted through certain body secretions (blood, semen, saliva, urine, vaginal secretions. Sexual contact or injection drug use are high-risk behaviors.
• HAV is of particular concern for some sexual behaviour. More transmission likely than HIV.
• HCV is associated with increased risk sexual activity.
• Hepatitis symptoms range from mild (flu-like) to severe and acute to chronic.
• Diagnosis is done by blood tests to analyze liver function and detect the virus.

Syphilis

• Syphilis is caused by Treponema pallidum.
• Transmission is through sexual contact, with potential placental transmission to an unborn child.
• Stages involve different initial symptoms (chancre), skin rash, and eventual system damage (dementia, cardiovascular damage, blindness). Antibiotics treat the infection in all stages.

Other Sexually Transmitted Infections 1, 2

• Trichomoniasis is a prevalent nonviral STI, highly transmissible during vaginal and penile sex.
• Prompt treatment is crucial, to avoid increased HIV risk in pregnant people and to avoid premature delivery.
• Bacterial vaginosis (BV) is characterized by abnormal vaginal discharge.
• Public lice and scabies are contagious parasitic infections.

What You Can Do about Sexually Transmitted Infections

• Education on symptoms, vaccination, testing, informing partners, and treatment are pivotal for successful STI management.
• Prevention involves responsible sexual behaviour.

Review 1, 2

• Review topics include body defenses against infection, disease transmission, pathogen identification, treatment options, and preventative measures, including personal immune system support.
• Review sexually transmitted infections symptoms, risks, and treatment(including available treatment options).
• Strategies are provided for infection prevention.