lect 10 Flashcards
etiology of Acute Respiratory Diseases (ARD), the common cold
- rhinovirus (25%)
- coronaviruses (10%)
- adenovirus and unknown viruses 30-40%
rhinovirus infections occur what time of year
hyperendemic in Winter
rhinovirus infections primarily affects what patient population
children an young adults
route of transmission of rhinovirus infections
- Hands are a major vector; person to person transmission
- *Handwashing and disinfection of objects are best means of control
rhinovirus treatment
- Primarily symptomatic relief
- An anti-rhinovirus compound, zinc gluconate, is used in OTC treatments such as “Cold Eeze” and Zicam. (Zicam has been withdrawn from the market)
-
Picovir (Pleconaril) – inhibits virus infective process by binding in rhinovirus virion canyon
- Not yet approved for mass use in U.S.
There are three types of influenza (A,B,C), which is the most problematic
A
Large numbers of subtypes of influenza are recognized based on what two envelope proteins
- H hemagglutinin (viral attachment)
- N neuraminidase (viral penetration and release from infected cells)
How does influenza cause such bad complications
Viral destruction of respiratory tract ciliated epithelium (mucociliary escalatory system), sets stage for complications
List the major complications of influenza
- pulmonary
- secondary (bacterial) PNA
- Reyes syndrome
- Guillain-Barre syndrome
Reyes syndrome is associated with what medication and commonly seen in what age group
- Primarily observed in children aged 6 months-15 years
- Correlated with Influenza A/B or chickenpox infection treated with aspirin
etiology of secondary bacterial PNA (after influenza)
- Streptococcus pneumoniae
- Staphylococcus aureus
- Haemophilus influenzae type B (Hib)
how is influenza diagnosed
-
Rapid antigen detection kits are now available for in-office confirmation
- rapid tests sometimes fail
- False negatives – early in course of disease, antigens levels may be below detection limits
What two meds were used in the treatment of influenza by being effective against the type A viruses only, but resistance has emerged recently and their use has been halted
Amantadine and Rimantadine
Which two drugs are neuraminidase inhibitors approved for use in 1999 for treatment of influenza. Stops virus release/spreading Effective against both type A and B viruses
Osetamivir (Tamiflu) and Zanamivir (Relenza)
describe the trivalent vaccine used for influenza
- contains the two type A and one type B viruses predicted most likely to be dominant.
- Two basic forms of vaccine are now in wide use – inactivated and a live, attenuated vaccine (“FluMist”)
recommendation of flu vaccine for Children under age 9 without history of prior influenza infection
require two administrations of vaccine to attain maximum degree of protection.
Recently, flu vaccines have changed to what
- Quadrivalent forms: 2 type A and 2 type B viruses
- TIV -> IIV
- intradermal application
influenza vaccine target groups
- >65 yo
- residents of chronic care housing facilities
- chronic pulmonary or CV disorders
- children with asthma
- immunosuppression
describe influenza antigenic drift
point mutations of H or N proteins
describe influenza antigenic shift
recombination involving entire genome segments encoding H or N gene
describe influenza nomeclature
ex: A/Hong Kong/68/H2N1
A/Hong Kong/68/H2N1
type/location of discovery/year of isolation/antigenic type
when are influenza vaccines typically provided
around October
- *must be repeated each season
What are two Chlamydiae strains that cause respiratory illness
- chlamydia trachomatis
- Chlamydophila pneumoniae
describe chlamydiae
- Obligate intracellular parasites
- Biochemically restricted, energy parasites
- Remove ATP from host since they have no means to synthesize it
chlamydiae assumes what two forms
- elementary body: infectious, nongrowing form, responsible for dispersal
- Reticulate body: growing (vegetative) form
Chlamydia trachomatis is the caustive agent of what infant conditon
- Infant pneumonia
- Onset 3 weeks after birth
risk factor of infant getting Chlamydia trachomatis
infected mother , child aspirates agent during birth
What condition is associated with infant PNA caused by C. trachomatis
Reiter’s syndrome may follow infection with this agent
Chlamydophila pneumoniae causes what conditions
- Widely distributed - causes bronchitis, pneumonia, sinusitis
- associated with atherosclerosis
