Chapter 19 diseases Flashcards
What causes folliculitis?
genus staphylococcus
what causes Rocky Mountain spotted fever?
Rickettsia rickettsii
what causes chickenpox/shingles?
Varicella-Zoster
what causes measles?
messes virus (rebeola)
what are characteristics of Staphylococcus?
Facultatively anaerobic, Gram positive cocci in clusters
what are characteristics of Rickettsia rickettsii?
Intracellular, Gram negative coccobacillus
what are the characteristics of Varicella-Zoster (herpesvirus)?
Icosahedral, enveloped, DNA virus
what are the characteristics of the measles virus?
helical nucleocapsids surrounded by an envelope
what is the reservoir of folliculitis?
humans
what is the reservoir of Rocky Mountain Spotted Fever?
rodents (zoonosis)
what is the reservoir of chickenpox/shingles?
humans
what is the reservoir of measles?
humans
Folliculitis mode of transmission?
direct contact and fomites
RMSF mode of transmission?
hard ticks of the genus Dermacentor
chickenpox/shingles mode of transmission?
direct contact or droplet
measles mode of transmission?
droplet and airborne transmission
Portal of entry for folliculitis?
skin and mucous membranes
Portal of entry for RMSF?
parenteral
Portal of entry for chickenpox/shingles
upper respiratory tract or the conjunctiva
Portal of entry for measles?
respiratory tract
folliculitis virulence factors?
-Enzymes
-structural defenses
-toxins
RMSF virulence factors?
not killed by host cells
chickenpox/shingles virulence factors?
Is able to establish a latent varicella-zoster viral infection in the dorsal root ganglia which allows the infection to reemerge at a later time
measles virulence factors?
-adhesion proteins: attach to host cell
-fusion protein: enter and spread between cells by promoting direct membrane fusion
How does folliculitis affect body functions?
Organism grows into hair follicles and invades sebaceous glands; follicle enlarges and fills with pus
How does RMSF affect body functions?
Causes damage to blood vessels which results in loss of fluid, low blood volume, reduced blood flow to organs, disordered tissue function, and thrombocytopenia
How does chickenpox/shingles affect body function?
Infection begins in the mucous membranes of respiratory tract; spreads to liver, spleen, and lymph nodes; 2 weeks later, a second wave of viruses spread via blood throughout body and to skin; infects cells of dermis and produces a rash
How does measles affect body function?
Infects cells in the respiratory tract; spreads throughout the body via blood and lymph; CTLs kill infected cells, but causes most of the symptoms
Signs and Symptoms of folliculitis?
inflammation and fever develop, pustule, sty, furuncle, carbuncle
Signs and Symptoms of RMSF?
Non-itchy, spotted rash and petechiae
Signs and Symptoms of Chickenpox/shingles?
Red macules, fever, malaise, rash
can become latent in sensory nerves and reactivate (shingles) painful rash near distal end of nerve, burning, numbness, itchiness, pain
Signs and Symptoms of measles?
-Fever, sore throat, headache, dry cough and conjunctivitis (initial)
-2-3 days later Koplik spots develop on the mucous membranes of the mouth (crystals of salt surrounded by a red halo)
-4th day: raised lesions appear on the head and spread over the body (lasts 3-5 days)
Epidemiology of Folliculitis?
S. epidermidis is ubiquitous on human skin (seldom causes disease because it lacks virulence factors; can be an opportunistic pathogen)
S. aureus is not a permanent resident but does grow on skin and mucous membranes (transferred from the face to other locations)
Epidemiology of RMSF?
More common in Appalachia, Oklahoma, and the southeastern U.S.
Epidemiology of chickenpox/shingles?
Seen more in children, 15-20 percent of people who had chickenpox develop shingles as adults, shingles can spread virus to a person who has never had chickenpox
Epidemiology of Measles?
Highly contagious
Only infects humans
Pts. Infectious until 2-4 days after rash development
Can be serious and fatal for small children
Diagnosis for Folliculitis?
-Detection of Gram-positive bacteria in grapelike arrangements isolated from pus.
-Positive coagulase test for S. aureus
-Coagulase-negative staphylococci are usually S. epidermidis and not indicative of a Staphylococcal infection
Diagnosis for RMSF?
Rash on palms and soles, sudden fever, headache following tick exposure
Diagnosis for chickenpox/shingles?
-Characteristic appearance of lesions
-shingles is more difficult to diagnose
-localization of lesions with band of skin on one side of body
-There are antibody tests available
Diagnosis for measles?
-Diagnosis via signs (kopliks spots)
-Serological testing confirms the presence of measles antigen
treatment for folliculitis?
-Topical mupirocin
-It is critical to clean and drain abscesses of pus before topical therapy
treatment for RMSF?
Remove tick; administer doxycycline, tetracycline, or chloramphenicol
treatment for chickenpox/shingles?
Chickenpox: self-limiting, no tx required
Shingles: management of symptoms, bedrest, and oral acyclovir; light fitting clothing, nonadherent dressings
treatment for measles?
-Supportive therapy
-Administration of vitamin A, antibodies against the measles virus, and ribavirin
prevention of folliculitis?
-People with Staph lesions should refrain from working with food, pts. with open wounds, immunocompromised pts., and women in labor.
-Use proper aseptic techniques
prevention of RMSF?
Avoid tick infested areas and frequent tick checks
prevention of chickenpox/shingles
-Attenuated vaccine that protects against chickenpox
-Recombinant vaccine that protects against shingles
prevention of
