1/21/99
Microbiology
II
Neurotrophic--Nervous
System
Polio,
Rabies, Encephalitis
Table
11.1--know all infections and diseases well
Equine
encephalitits--mosquintes p682-3 (Arbovirus/Togaviridae)
Polio
Virus
-pico--one
trillionth of a meter
-5nm in
size
-permanent
house guest of nervous system for life, particularly anterior horn cells
-can
become airborne and released in nasal secretions and saliva
-transmitted
through droplet route
-respiratory
tract, GI tract
-5
distinct phases that a person goes through
-non-immune
who does not have ab is the one who goes through phases
1.
entry--virus enters
2.
alimentary--multiples in GI tract mucosa, may cause GI disturbance,
nothing serious at this stage
3.
lymphatic--enters lymphatic system RES, multiples in lymphatic
glands(nodes),(reticulo endothelial system) fever, aches and pains
4.
viremic--virus in blood, fever, aches and pains more severe, person may
need a doctor, can't diagnose at polio, mild symptoms
5.
neurologic--entry of virus into CNS and brain, brain parenchyma cells
attacked, esp. motor cortex and neurons, where a person suffers from the
clinical symptoms of polio, permanent disabling of muscle, motor functionis
lost, happens in a few weeks, most serious consequence depends upon which
neurons are infected and damaged, any paralysis existing after a few months is
permanent p 689, occurs in those not immunized, 99% the people go through the
1st four stages and not the 5th, about 1% experience the 5th phase
-history--a
lot of bad news
-have
had outbreaks where 1000's of people have been crippled and 1000's have died
-do not
know why some years are worst than others
-development
of vaccine occured about 1952
-difficulties
in development of vaccine
1.
could not be cultured (a pure form)
-Enders, Weller, and Robins cultivate on
non-neural tissue
-2 vaccines Salk and Sabin
Salk is killed
Sabin is alived attenuated vaccine, more
effective but more
dangerous
-many
cases seen today are linked to vaccination
-b/c
faulty vaccine preparation where live vaccination was used
-100-120 cases over the last 10 years