Module 8 - Viral Infections Flashcards
Creation of Influenza Vaccination:
-jan-may = virus selection
-june-july = fda testing
-aug = filling/packaging
-sep = product release and shipping
-oct-now = vaccination begins
Structure of Influenza:
-2 internal structural proteins: nucleocapsid (NP) and matrix (M) protein
-nucleocapsid proteins = dna packaging and protection
-matrix proteins = assembly release of viral particles
-influenza A/B viruses further subdivided based on surface antigen of 2 different types of protein spikes: hemagglutinin and neuraminidase
Hemagglutinin:
-binds to the target cell surface receptor (sialic acid) to initiate infection
-influenza
-antibody against the hemagglutinin neutralises the infectivity of the virus and prevents disease - therefore it is useful in vaccines
Neuraminidase:
-divides/cuts (sialic acid) to release virus from the infected cell
-degrades the protective layer of mucus in the respiratory tract
-enhances the ability of the virus to infect the respiratory epithelium
-antibody against the neuraminidase does not neutralise infectivity but does reduce disease
-flu antivirals target neurminidase
Influenza Antigenic Variation:
antigenicdrift/shift
-influenza viruses (especially 1A) show changes in the antigenicity (ability to bind to b/t cells) of their hemagglutinin and neuraminidase proteins - this can cause devastating worldwide epidemics
Two Types of Antigenic Changes:
(strains combine to become worse)
- Antigenic shifts: major/abrupt changes based on the re-assortment of segments of the 2 genomes , influenza A only
2.Antigenic drifts: minor/gradual changes based on mutations in the genome RNA, a and b
Influenza and Target Hosts:
Influenza type A viruses:
-can infect people, birds, pigs, horses
-wild birds are the natural hosts for these viruses
-most of severe epidemics and pandemics are type A
Influenza type B viruses:
-usually found only in humans
-it can cause morbidity and mortality among humans
-are associated with less severe epidemics than influenza A viruses
Influenza type C viruses:
-cause mild illness in humans and do not cause epidemics or pandemics
Influenza Virus Prevention:
-majority of currently used vaccines are inactivated (killed) preparations derived from influenza A and B viruses that circulated during the previous influenza season (in late season)
-the overall health risk following influenza outweighs the small potential risk associated with vaccination
-herd immunity provided by vaccination population is thought to prevent spread, and protect unvaccinated individuals
Abbreviations
DNA
CMV: cytomegalovirus
HSV: herpes simplex virus (HSV types 1 and 2)
VZV: varicella-zoster virus
EBV: epstein-barr virus
HEP: hepatitis virus
RNA
HEP: hepatitis virus
HTLV: human t lymphotropic virus (type 1)
HIV: human immunodeficiency virus (rubella)
ZIKV: zika virus
Latency and Herpes Viruses:
-in health individuals, HSV provoked by: certain febrile illness (common cold, pneumonia), direct sunlight, stress, trauma, menstruation, immunocompromised
Primary Causes of Chronic Liver Disease:
-hep c virus and alcohol
Recall how HIV Gets in and Replicates:
slide 45
Case Study: 6 month pregnant client has an outbreak of chicken pox in her students. What would you advise?
-ask and check if she’s been vaccinated for chickenpox (IGg immunoglobulin test to see if they have antibodies)
-if no antibodies, stay home because it transmits very easily, it is life threatening to baby as it can cross placenta
Influenza
-ssrna
-type a (human outbreak) also b and c
-through aerosols such as cough/sneeze
-cause fever, cough, sore throat, muscle ache
-can cause 2ndary lunge infection such as pneumonia
-antivirals for A/B
=zarimaivir (relenza) and oseltamivir (tamiflu)
-no transfer ti fetus
influenza vaccine is safe in prenancy and baby gets antivirals
HSV1
-Herpes Simplex Virus
-cold sores name
-dsDNA
-dindirect/direct contact
-latent, can reactivate in pregnancy
-causes cold sores
-in utero/perinatal is rare
-postnantl is yes
-rash/fever in infant
-antiviral acyclivir for mom and baby
–> decreases outbreak time, helps sores heal, less painful
