infectious disease 2 Flashcards
Tuberculosis
An infectious, inflammatory systemic disease that affects that lungs and may disseminate to involve lymph nodes and other organs
Caused by Mycobacterium tuberculosis
Infection most commonly occurs through inhaled droplets
Mycobacterial infections
Mycobacteria are small, slow-growing aerobic bacteria distinguished by a complex, lipid-rich cell envelope
Diseases caused by mycobacteria include tuberculosis and leprosy
Tuberculosis pathogenesis
Once a susceptible person inhales an infected droplet, the bacteria become established in the lungs and a proliferation of epithelial cells surrounds and encapsulates the multiplying organisms in an attempt to wall them off
The granulomas eventually become necrotic in the center leading to fibrosis and calcification of tissues. In later stages of the disease, the bacteria is able to enter the blood and lymph circulation and ultimately colonize distant sites.
TB kills 3 million people per year (worldwide)
Leading infectious disease cause of death
Represents 1/3 of world’s preventable deaths
TB S&S
Fever night-time seating Loss of weight Persistent cough Constant tiredness loss of appetite
TB DX and TX
Diagnosis - culture sputum; tuberculim skin test
Treatment - antibiotic cocktail
Prevention - vaccination
Viral infections
Viruses are the smallest microorganisims. They are always pathogens. They depend completely on cells to reproduce. They have an outer cover of protein, and sometimes lipid, and an RNA or DNA core. For infection to occur the virus first attaches to the host cell.
The viral DNA or RNA then separates from the outer cover (uncoating) and replicates inside the host cell in a process that requires specific enzymes
The host cell typically dies, releasing new viruses that infect other host cells
Viral Infection examples
Rubella - caused by rubella virus AIDS- caused by HIV Flu- caused by influenza virus Cold-caused by rhinovirus Pneumonia Measles Hepatitis
Herpesvirus
Family of DNA viruses that cause active or latent infections Herpes simplex 1 (HSV-1) Mouth Herpes simplex 2 (HSV-2) below waist Varicella-zoster virus (VZV) chicken pox Epstein-Barr virus (EBV) Mono Cytomegalovirus (CMV) Torch
Herpes Simplex
Causes oral herpes - cold sores (most common)
Causes genital herpes (second most common)
Easily transmitted via direct contact but can also be transmitted via indirect contact
HSV transmittion
Can be transmitted through contact with lesion or with contact of bodily fluids
Can also be transmitted during asymptomatic periods (asymptomatic viral shedding)
Can be transmitted from mother to child via birth canal
HSV S&S
Symptomatic phase includes sores on face, mouth, genitals, hands,
Symptomatic phase alternates with periods of remission
Virus tends to burn out over time
No treatment or vaccine
Symptoms antiviral meds
Prevention - condoms
Varicella-zoster virus
Causes chicken pox
Can persist in peripheral nervous system as latent infection
Reactivated as shingles in adults
chicken pox characterized by small, itchy vesicles all over body
In children, usually benign self-limiting disease
VZV
Can develop into life threatening encephalitis or pneumonia
Chicken pox in adults generally more painful, more scarring
Infection generally confers life long immunity
Prevention vaccination
VZV
Shingles aka herpes zoster
Characterized by unilateral painful blisters
Treatment - antiviral meds, painkillers
Prognosis - usually self -limiting within 5 weeks
EBV
Epstein-Barr virus
Cause infectious mononucleosis (‘mono’ or the “kissing disease”)
Characterized by fatigue, malaise, sore throat
Mild except for in IC compromised people, elderly, newborns
