Module 4 Flashcards
What is the risk of being infected with a blood borne pathogen when stuck with a used needle and no gloves?
HIV- 0.3%
HCV- 3.0%
HBV- 30.0%
How much is your risk of infection decreased if you’re wearing gloves?
50%
Why is the presence of HIV antibodies in the blood not good news?
The virus is hiding inside cells of the cellular immune system so the cells will be destroyed and the immune system compromised.
What is hepatitis and its symptoms?
Liver inflammation caused by a virus.
Symptoms: jaundice, dark urine, pale feces (build up of bilirubin and bile).
What are the more common types of hepatitis?
A & E- through food (AtE them)
B, C, D- blood and other bodily fluids
What are the characteristics of HAV?
Naked virus, replicates in the oral lining epithelium and intestine first
Usually symptomatic
No evidence of chronic carriers or chronic liver damage
Transmitted by fecal-oral route, not between mother and child, not sexually
Immunization recommended for travellers, replaced immune globulin
Diagnosed by anti-HAV presence
What are the characteristics of HBV?
Enveloped virus, stable due to protein coat
About 50% asymptomatic, 5-10% are carriers, fluids infective for 6-7yrs
Fulminant- rapid, sudden, severe
Transmitted by contaminated body fluids, usually into blood stream
Chronic liver damage possible
Can be transferred from mom to child
Vaccine available also HBIG immune globulin
Diagnosed by testing HBsAg
What are the antigenic areas associated with the HBV virus?
Hep B surface antigen (HBsAg), surface envelope
Core antigen (HBcAg)
E antigen (HBeAg)
What does chronic viral infection predispose people to?
Hepatocellular carcinoma
How can healthcare workers prevent infection of HBV?
Routine precautions
Immunization
Immune globulin within 48hrs of exposure
What are the characteristics of HCV?
Enveloped virus
Most people are asymptomatic (80%) and 60-90% become chronic carriers
Chronic liver damage occurs
Transmitted through contaminated blood/products, associated with IV drug use, not often spread from mother to child or sexually
No vaccine or immune globulin, treated with interferon, ribavirin, other antivirals
Diagnosed by anti-HCV presence or NAT
What do many chronic HCV patients develop?
Cirrhosis
Increased risk of hepatic cancer
What blood borne pathogens are of greatest concern?
HBV, HCV and HIV(AIDS)
What are the characteristics of HDV?
Can only replicate in combination with HBV
Associated with progressive liver damage and fulminant hepatitis
Spreads in blood, stool, semen and vaginal secretions
Immunization against HBV
What are the characteristics of HEV?
Spread fecal-orally
Mortality rate higher than in HAV
Describe the virus that causes HIV.
HIV is an RNA retrovirus which has a lipid envelope.
Not a hardy virus, routine sterilization, disinfection and cleaning methods don’t need to be altered.
How does HIV viral replication take place?
Binding to a host cell with a receptor for gp120 (T-lymph a or CD4 cells)
Penetration
Reverse transcription
Dormant period- infected with no symptoms
Viral replication- host cell activated, parts are synthesized and assembled, form bud to infect another cell
What effect does the HIV virus have on host cells?
Kills CD4 and helper T-lymphs
If too many are lost the clinical symptoms of AIDS occur
Dysfunctional immune system, host is susceptible
How is HIV diagnosed?
Screen for antigens not routine
Screen for antibodies but it takes 4-12 weeks for them to appear so the test may come back negative
Why do false positives occur in the screening for HIV antibodies?
There is another antibody similar in structure that is detected.
How is an HIV diagnosis confirmed?
Western blot
What is the progression of HIV infection?
Contact
Primary (1 month)- flu-like/no symptoms, test may be neg
Latent period (2yrs)- no symptoms, slow destruction of CD4 cells, test pos
Clinical AIDS- virus becomes active, variety of opportunistic infections, CD4
What is the treatment for HIV/AIDS?
ZDV- slows replication, prolongs latent period by interfering with viral enzymes
Highly active antiretroviral therapy (HAART)
Multi drug regime
How is HIV transmitted?
Blood is the most infectious fluid.
Virus must contact with blood or mucous membrane of host.
Infective dose required is large.
What are the risks of HIV associated with healthcare workers?
Accidental needle sticks
Blood splashes
Blood contact
How is HIV prevented in the hospital?
Routine practices
What if a healthcare worker is HIV positive?
Not legally responsible to disclose.
Little chance of transmitting HIV to patient.
What is the protocol for significant exposure to blood?
Treat exposure site
Notify (incident report)
Blood test (healthcare worker and patient)
Treatment
Follow up
What recent viral infections are of concern to Canada?
SARS
West Nile
H1N1
MERS Corona virus
Ebola
