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27 Cards in this Set

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describe the pathogenic genera and species.
rhino (cold), entero (includes polio, coxsackie, echo, and entero), parecho (similar to echo in entero genera), and hepato (hepatitis A)
describe picorna morphology.
no envelope, icos with VP1 - VP4, canyon between VP1,2,3 for binding to cell, pos ssRNA
two common characteristics of rhinovirus?
sensitivity to acid pH and optimal temp for replication is 33 deg C. This can determine the kinds of diseases that these viruses cause - stays in URT bc it is too warm LRT and cannot get into the gut.
how many serotypes of rhinovirus exist?
over 100, thus you will be infected a lot
what may a cold predispose you to?
secondary bac infections like sinusitis and otitis media
properties of enterovirus?
replicate in the GI tract, usually causes asympto infections, can cause viremia, occasionally infect the CNS, stable at acidic pH
the confusing as hell classification of the enteroviruses has settled on what?
4 species, A, B, C, D… these include all the enteros
spread of enterovirus?
primarilly fecal oral, but can occur via inhalation of resp droplets, majority of infections are in children, like the warm weather of summer and fall
describe the pathogenesis of the enteroviruses
replicate in the mucosa of oropharynx and URT, released into oral secretions and swallowed, go to the intestines, GI replication and shedding in feces, can go to bloodstream to establish a primary viremia, spread depends upon virus tropism, sx then appear with a second viremia, note that no syndrome is uniquely associated with one virus, it can occur in many
# of serotypes of poliovirus?
3
describe progression of poliovirus infection signs, syptoms and disease.
general flu sx for 5 days once it hits the GI tract. If it does not prgress beyond GI, it is abortive polio. Note most ppl are asympto, viremia occurs in a minority of sympto cases, can hit the CNS and get second phase comprised of aseptic meningitis - second fever, and all meningitis sx. in less than 1% of these cases, paralytic poliomyelitis occurs, paralysis is usually flacid due to destruction of motor neurons in the anterior horns (spinal poliomyelitis), bulbar paralysis from damaged neurons in the brainstem can lead to inability to swallow and breathe and is often fatal. encephalitis may be caused by replication in the motor corex, note coxsackie A7 and entero 71 can cause a polio like illness
describe post polio syndrome
occurs decades after recovery from paralytic polio, no virus present in the patient. Fatigue, new muscle weakness, pain in muscles and joints, note that it does not stay latent in the body, it is thought to be due to instability of renervation
describe aseptic meningitis seen in polio.
enteroviruses are most common cause of epidemic aseptic meningitis in the US. Highest attack rates in infants, not as fatal as septic meningitis
deescribe the enterovirus syndrome of pleurodyna (epidemic mylagia, bornholm disease)
abrupt onset of fever, intense chest or upper abdominal pain (intercostal muscles), spasmodic pain that can last for 30 mins, rapid shallow breathing, lasts one to 3 days, chest X ray to differentiate from pneumonia, complete recovery
describe herpangina caused by enteroviruses
young kids, abrupt fever, sore throat, dysphagia, drooling, can be ab issues, GRAY PAPULOVESICULAR lesions on the fauces, throat, tonsitls, or tongue, surrounded byy erythema, ulcerate and last for a few days, complete recovery
describe hand foot and mouth disease caused by enteroviruses
children, lasts one week, flu like, then enanthem in the mouth - red spots on buccal mucosa and tongue, ulcerates, then an exanthem - vesicular lesions on the fingers, palms, toes, and soles, usually complete recovery, enterovirus 71 does this, note that there have been deaths in foreign countries due to CNS issues and myocarditis, but none in the US
describe the respiratory illness caused by enteroviruses
mild URT illness in children, cannot be distinguished from rhino, parainfluenza, RSV, or adeno, except that it likes warmer weather where as the others like cooler, enterovirus 68 is the only one that causes pneumonia and bronchiolitis
describe the eye diseases caused by enterovirus
enterovirus 70 causes epidemics of acute hemorrhagic conjunctivitis, can be discrete petechiae to large blotches, recovery is usally complete wi 10 days
describe the cardiac diseases associated with enteroviruses
acute myocarditis mainly hits 20 to 40 yo, is fatal in infants though. Dilated cardiomyopathy (enlargement of the ventricles) is seen in older ppl and has a high mortality rate in 2 yrs. Cytopathology in both is caused partly by the virus and partly by an autoimmune response
describe the neonatal disease caused by enteroviruses
congenital or neonates infection can get hepatitis, myocarditis or asept meningitis, can be fatal, and heart problems can be seen later in life
describe the minor illnesses sometimes associated with enteroviruses
short fevers, possible rash, some gastroenteritis, usually in fall or summer
describe the diagnostic methods for enterovirus and some reasons for diagnosing
collect specimens from stool, rectal swabs, throat swabs, urine, CSF. Used to do a culture then neutralization rxns with antisera, but now do RT PCR. This will tell you if it is an enterovirus, not species, if need to know species, need to sequence the VP1 gene. dx is sometimes needed to rule out other diseases, getting entero patients home and out of hospital beds, and for epidemiologic studies
describe poliomyelitis epidemiology
endemic, epidemic, and vaccine era. Endemic era was poor hygeine era, thus infants got it at 6 mos or so while still protected with maternal Ab's. Epidemics started to occur as urbanization and higeine improved thus you got infected later and thus lotsa cases of paralysis
what are the four factors that made the development of polio vaccine possible?
how to grow polio in human tissue culture cells not derived from nervous tissue, confirmation that there were only 3 viral serological types, realization that the virus reaches the CNS throught the bloodstream not the nerves, discovery that a formalin inactivated vaccine protects monkeys
describe the oral polio vaccine versus the injectable attenuated virus.
oral is live virus that can replicate in the GI tract, but it does not spread to the nervous system, replication induces a secretory IgA response and the resulting mucosal immunity in the GI tract is a crucial argument in favor of OPV. IPV (injection) is dead virus with the antibodies. problem is if infected with wild type and had the IPV then the wild type will shed in feces and can infect others. Oral does not do this, the viruses it sheds are the avirulent ones, it cannot be infected with wildtype bc of the IgA that is made. problem with oral is that ab 10 ppl per year got vaccine associated paralytic polio from the virus converting back to an active form in the gut. Went back and forth over which one to use, until 1996 it was OPV, then it was sequential use of IPV and OPV, now it is IPV alone, get shots at 2 mo, 4mo, 6-18 mo, and 4 to 6 yrs
give some facts about the fight to try to eradicate polio.
use OPV WW bc it is cheaper, still mainly endemic in nigeria, cause dumb state of KANO tried to prevent immunization as some US conspiracy to give everyone AIDS. Only type 1 polio spread from nigeria, so they used a type 1 OPV later
reasons we should not discontinue vaccinating if polio is erradicated.
it can be stable in sewage, there are asymptomatic long term secretors, possibility for coxsackievirus to mutate and cause polio, polio can be made from scratch in the lab and that has bioterrorism potential