unit 9 part 2 Flashcards
vaccines and their effects on the incidence of measles and mumps
MMR or MMRV (measles, mumps, rubella, varicella-zoster virus)
–> after 2 doses it is 97% effective in preventing
lead to 99% decrease in cases
clinical manifestations of the mumps virus
prodromal period of nonspecific symptoms then parotitis (swollen parotid glands)
pathogenesis of the parainfluenza viruses
causes infection in the upper respiratory tract that can descend to the lower respiratory tract
most common cause of the croup
PIV-1
age group in which respiratory syncytial virus causes a life threatening pneumonia
most common in infants under the age of 1
pathogenesis of RSV
upper respiratory tract infection that commonly descends to lower respiratory tract due to syncytia (fusion of cells in 1 big one)
months of the year when RSV is most often isolated
precedes the influenza season and occurs early fall into early winter
RSV vs human metapneumovirus
RSV has a higher risk and infection rate in younger children than hmpv
most common cause of lower respiratory tract infections in young children
RSV
unique features of retrovirus replication
reverse transcribe RNA into DNA of host cell to infect it
taxonomy of HIV
disease descended from apes
two types of HIV (HIV-1 and HIV-2)
–> HIV-1 has groups M,N,O,P (m is most common)
–> HIV-2 has groups A-I
tropism of HIV
CD4+ cells as well as monocytes, macrophages, microglia, and dendritic cells
how are CD4+ cells attacked by HIV
gp120 on envelope binds to it and gp41 fuses membrane
secondary receptors of HIV
CCR5 (t cells) CXCR4 (t helper cells)
pathology of HIV (modes of transmission and receptor sites)
how does HIV affect the immune system
cell-free spread in which there is rapid viral replication
-> decrease in T helper cell because they are attacked by CD8 cells
–> leads to AIDS
–> neurologic diseases
CD4 count in AIDS
less than 200
clinical stages of HIV
acute phase: asymptomatic or flu/mono like symptoms (associated with high viral load)
chronic infection: latency
clinical latency of HIV
no symptoms or manifestations but HIV can still be transmitted
HIV vs AIDs
progression to aids takes 10 years
–> causes recurrent/prolonged respiratory infections
oppurtunistic infections and carcinomas associated with AIDS
candidiasis, fungal infections, pneumonia, toxoplasmosis
kaposi’s sarcoma, cervical cancer
epidemiology of AIDS and the region with the greatest incidence
african region remains most severly affected by AIDS (gay/bisexual men)
principles of the serologic tests used to screen for HIV antigens
seroconversion used to detect antibodies
–> rapid Ab test as preliminary and 4th generation AB test detects p24 antigen
then sent for confirmatory testing
ratio of CD4 counts in HIV infections
decrease in CD4+ is directly associated with increase in HIV RNA or viral load (and presence of symptoms)
timeline when HIV serologic markers are detectable
algorithm for HIV testing
HIV1-2 Ag/Ab immunoassay, if positive then HIV 1-2 Ag/Ab differentiation immunoassay, if undetectable then HIV- NAt
treatment of HIV
highly active antiretroviral therapy (HAART) which is a 3-4 drug regimen to maximize effectiveness of reducing HIV
classes of anti HIV drigs
- fusion inhibitors (prevents binding)
- nucleoside reverse transcriptase inhibitor (prevents binding)
- protease inhibitor (prevents cleaving)
- integrase inhibitors (prevents integration of viral genome)
evaluate methods of determining HIV drug resistance
genotyping by performing RT-PCr and DNA sequencing to determine which drugs the virus is sensitive to
–> prevents resistance to drugs before initiation of therapy
potential reasons for treatment failures in HIV patients
drug resistance
