objective 4.2 (3) Flashcards
- Tiny micoroorganism that can replicate only inside the living cells of
organisms; defense mechanism - Find a host and take it over to grow and reproduce; intracellular parasites
Simplest of all organisms; usually many times smaller than bacteria - Not suppressed by antibiotics; damage takes place within the cell
virus
mature virus particle
virion
what are the 4 ways a virus enters the body?
- Inhalation through the respiratory tract
- Ingestion via gastrointestinal tract
- Placenta via placental circulation – from mom to babe
- Inoculation via skin or mucous membranes; occurs various ways
including sexual contact, blood transfusions, sharing of syringes
or needles, organ transplants or bites
what are the prominant viral illnesses affecting humans>
- Smallpox (poxviruses)
- Sore throat and conjunctivitis (adenoviruses)
- Warts (papovaviruses)
- Influenza (orthomyxoviruses)
- Respiratory infections (coronaviruses, rhinoviruses)
- Gastroenteritis (rotaviruses, Norwalk-like viruses)
- HIV/AIDS (retroviruses)
- Herpes (herpesviruses)
- Hepatitis (hepadnaviruses)
HSV-1
oral herpes
HSV-2
genital herpes
- Both highly transmissible through close physical contact
- Painful skin lesions with periods of dormancy vs acute outbreaks
- Antivirals do not cure but can speed up the process of remission and
reduce the duration of painful symptoms - Can be life threatening in immunocompromised individuals and
neonates
herpes simplex virus
is highly contagious with transmission
occurring from weeping lesions or droplet inhalation; usually
non invasive but can become complicated if Reye’s syndrome
(condition causing fatty liver and encephalopathy) develops as
a result; usually only treat when immunocompromised; vaccine
helps maintain prevalence
chicken pox or varicella
is caused by the reactivation of VZV from its
dormant state; lesions appear along dermatomes (nerve
tracts); very painful; treated with acyclovir which will work best
if started within 72 hours of symptom onset
zoster or shingles
are chemicals that kill or suppress viruses by destroying the virions or
by inhibiting their ability to replicate.
* Immune system can potentially control or eliminate a viral infection when the ability
of the virus to replicate itself is suppressed
* Work best in individuals with competent immune systems
* Those with immune systems which are compromised or are immunocompromised
are more susceptible to opportunistic infections which are infections that would not
normally harm an immunocompetent person
antiviral drugs
are virucides used to clean equipment and the
body during invasive procedures
disinfectants
are concentrated antibodies that attack and destroy viruses; more
commonly thought of as immunity drugs; derived from human or animal blood
immunoglobullns
what are the MOAs of antiviral drugs
- Interferes with the ability of the virus to carry out its reproductive functions, hence
reducing replication - Must enter the cell and act at the site of infection to be effective
- Stops the virus from growing but does not kill it; lowers viral concentrations to allow
for elimination of virus by the patient’s immune system - Cannot cure only lesson symptoms
what are the indications of antiviral drugs?
- Treat a variety of common conditions caused by different viruses
- Herpes zoster, herpes simplex, genital herpes, varicella and some influenza infections
what are the adverse effects of antiviral drugs?
- Each has its own specific adverse effect profile
- Selective killing is difficult so many healthy cells are killed in the process, therefore
more serious toxicities for these drugs - Table 45.2 Lists adverse effects by drugs
- Acyclovir- nausea, vomiting, diarrhea, headache, burning when applied topically