Micro Winter 3 Arbovirus

Front 1

all of the arbo virus are spread by what? what is the exception. when are these viruses spread

Back 1

mosquitoes, except colorado TICK fever

**spread in summer/fall

Arbovirus means ARthropodBOrn

Front 2

what diseases so arbovirus cause? how do we treat

Back 2

1. Aseptic meningitis- fever, HA, stiff neck, mild disease

2. Encephalitis- seizure, altered mental status, pararlysis

we CANOT combat the arbovirus, we can only prevent (wear bug spray, stay inside etc)
3. meningoencephalitis- combination

Front 3

what are some general features of arbovirus (genome, structure, transmission, hosts)

Back 3

RNA
enveloped, inactivated by solvents
from mosquito bite

infect lots of things like birds and small animals, we are usually dead end hosts

**the arbo are are transmitted the same but lots of vairation in structure and gemone expression/replication

Front 4

ok so an arbo can cause meningitis, encephalitis or a combination, what determiens the outcome

Back 4

1. specific viral agent
age of pt
3. extent of encephalitis

**mostly infections are subclinnical- flu like with no CNS.
**in severe causes there is sudden fever, vomit, HA, vertigo etc. cant recover or not- 50/50

Front 5

what is recovery after arbovirus

Back 5

ehh, you might you might not

Kids- deafness, psychomotor diffuculty, learning disability

**recall polio- paralysis worst at 2-3 days then recover was max at 6 weeks

Front 6

how is arbovirus dx

Back 6

ehh, often its not. (not the specific virus)

**epidemics create high index of suspicison

**IgM AB detection- test CSF or serum with elisa

Front 7

tell me about IgM AB capture with arbovirus

Back 7

use ELISA, lots of cross talk

**test CSF is best but perhaps can just get serum (serum + may not indicate whats going on it spinal cord)

**test for AB EARLY! and look for 4x increase in titer

Front 8

ok so we can run IgM ELISA to test for arbovirus adn look for 4x increase in titer, what about viral cultures

Back 8

not usually done for arbo virus

**collect specimen early

Front 9

for what arbovirus is an indirect AB test good?

Back 9

colorado tick fever, (common in transfusions)

BHK21 cells are infected and stained with AB

Front 10

other than IgM elisa and indirect AB test, what else can be dont to detect arbovirus

Back 10

reverse transcriptase PCR

**keep in mind only a minority of cases have hte exact virus ID

Front 11

how are arboviruss monitored In the environment

Back 11

mosquite trapping (or bird but its harder)

**when its high in them its likely a human will get it

Front 12

what are hte dx clues for an arbovirus

how do we treat

Back 12

time- season (late summer/fall)
place- endemic area
person- 90% its a person under 30

**no tx for arbovirus (viral meningoencephalitis) supportive measures only

Front 13

arbovirus encephalitis resevoire

Back 13

zoonotic diseases, WIDE resevoire- mostly mosquitoes, vertebrates, rodents, birds, amphibians (crocidile)

humans are typically a dead end host

Front 14

what type of virus uses arthropod as a TRUE biological vector

Back 14

arbo

Virus infects and multiplies in gut, disseminates in the hemolymph, and ultimately establishes a persistent infection in the salivary glands where it may be transmitted. infected vestor shows no disease nad no amplification of virus occurs here

Front 15

tell me about arbovirus amplificaiton

Back 15

wont happen in the vector BUT>..

say there is a bird nad mosquitoes feed on it. the bird is uninfected and gets bit by an infected mostuito, the bird is now infected and can pass the virus along to uninfected mosquitoes that feed on that bird

Front 16

arbo epidemics are associated with what

Back 16

seasionality- late summer/fall. changes each year

**large vector pops--> increased disease

Front 17

describe the sylvatic cycle of arbo virus

Back 17

from a mosquito to a bord and back and forth- the mostioto accidently passes it to us. we are dead end host for the virus.

*we are accidental host, amplification will NOT occur in us (contrast to urban where a human can pass back to mosquito)

Front 18

what is the urban cycle associated with arbo virus

Back 18

lots of humans and lots of mosquitoes

**humans have enough viremia to sustain life cycle. human--> mosquito--> human. st louis encephalitis, yellow fever

**contrast to sylavatic cycle where humans were dead end

Front 19

what type of cycle do ellow fever and st louis encephalitis have

Back 19

urban- humans have sustained viremia and are part of cycle

**contrast to sylvatic where humans are dead end accidnetal hosts

Front 20

can we prevent arbo virus

Back 20

not with vaccine- they are in SO many other things than humans so vaccine wont work

**best thing to prevent it to stop chain of transmission

1. kill the vector
2. avoid exposure
3. immunization of horse/pig NON HUMAN AMPLIFYING HOSTS

Front 21

so we prevent arbo we can control arthropod vectors, prevent exposure and vaccinate amplifying hosts t or F

Back 21

True

Front 22

what is the family, structure, etc of arbo

how it inhibits host

Back 22

todaviridae group (toga= cloak= enveloped)
ss + RNA
Hemagluttinin is in envelope
Repliacated in cytoplasm (like LCMV- rodents)

causes pathology in host bc it stops translation of mRNA

Front 23

what are hte 2 basic groups of hte togavirus

Back 23

togavirus- arbo

1. Alpha
EEE, WEE, VEE

2. Flavivirus
St louis, West Nile, Yellow fever

**LOTS of cross talk, IgM tests are hard to intrepret

Front 24

wht virus causes california encephalitis

Back 24

Bunyaviridae

ss - RNA
envelope (all arbo)

Front 25

tell me about EEE (eastern equine encephalitis)

where
when
who

Back 25

Eastern US (N and S)

summer fall (June-Oct)

**in Fl its all year!

SUPER deadly but not very common

**less than 15 yo, older than 55

**swamp

**often inapperant

Front 26

a person from Rhode Island got encephalitis in July. The pt was 10 and his 80 yo granddad got it to after fishing in a swamp

which one?
what vector? resevoire?

Back 26

EEE- eastern, fall/summer, extremes of age

Resevoir: horse, bird
Vector: mosquito* needs bridge vector bc the mosquite that spreads it is only a bird one

**

Front 27

which arbo has a high case fatality rate,

who
where
vector, resevoire

Back 27

EEE

1. old, young, in the east, swamp, summer/fall
2. vector- mosquito (bridge vector) resevoire- horse, bird

**young children have better survival than adults

**concern that more mosquite spp will increase infections

Front 28

which encephalitis wiped out turkey farms

Back 28

EEE- old and young, swams, horse/bird/mosquite.eastern, fall/summer

Front 29

whats WEE

where
when
resevoire
vector
who

Back 29

west of Mississippi, irrigated pastures, flooded grounds (no fish)
Summer Fall: wont see it then it explodes
Resevoire: bird, horse, small mammal
Vector: mosquito
KIDS under 10 (most often subclinical)

Front 30

what disease affects kids in a burst where there are flooded pastures

Back 30

WEE

mosquito- bird, horse, small mammal

Front 31

in what disease are horses huge in the amplification process nad we shoudl prbly vaccineate them

Back 31

Venezuelan Equine Encephalitis

**benign usually but with outbreaks with apparent disease. most human VEE have apparent disease

**disease of "place" central/sounth america, texas, everglades.

*soliders

**spread until the horse dies

Front 32

whats VEE

Back 32

ususally benign but thwn a horse gets it it can be HUGE for amplification. ppl get it til the horse dies

infection of place- texas, everglades, central/S america

**horse is amplifier

Front 33

what is venezuelan Equine Encephalitis

Back 33

benign usually- can have outbreaks
Rapid spread til horses are dead or we get dry enough weather that the mosquitoes die

Central/S america, US everglades, texas

**horses are amplifying hosts

**most human VEE infections result in apparent disease

Front 34

what is st louis encephalitis

where, when?

who

Back 34

wide distrubution, conc in Midwest US and california (Oh/MS river basin, gulf coast)

Summer Fall (aug/sept)

can have seasons with HIGE numbers of outbreaks and then just a few

aaffects adults over 40

**bird resevoire, mosquito vector

Front 35

what encephalitis effects adults over 40 in the summer where there is lots of agriculture and ppl are low SES and hand out outside inthe evening

Back 35

st louis encephalitis

Bird resevoire , mosquite vector

Front 36

if you have a honkey tonk 40 yo who likes birds and hangs out outside in the summer evenings in your home in OH/MS what encephalitis are you at risk for

Back 36

st louis

low ses, hang outside in evening, agriculture places (OH/MS/CA)

Front 37

tell me a bit about west nile virus

who is at greatest risk
common in US

Back 37

largest risk is old ppl (>50)
not common, its an EMERGING disease (not known how long its been here)

**neuroinvasive paralytic syndrome simliar to poliomylitis

Front 38

west nile gives encephalitis simliar to what other neuroinvasive disease

Back 38

poliomylitis

Front 39

what is the west nile virus transmission cycle

Back 39

bird resevoir --> mosquito vector

**the mostoito can then infect us and livestock as indicental infections

Front 40

how is west nile dx

Back 40

IgM ELISA with serum or CSF- lots of cross reaction with St Louis or Yellow fever

**plaque reduction neurtralization test may be used to confirm

Front 41

what % of west nile infections result in disease

*8what predisposes you to getting the bad effects

Back 41

20%

About 1:150 total infections result in severe neurological (neuro-invasive) disease

Most important predictive factors for severe disease/death is advanced age (>50 years) or immune system dysfunction

Front 42

The flaccid paralysis syndrome (West Nile poliomyelitis) is _____ (more or less) common than encephalitis or meningitis

Back 42

less

Front 43

who might you suspect has west nile virus

Back 43

Consider WNV in any patient with unexplained encephalitis or meningitis

Front 44

what does it mean if a person has IgM west nile + in serum but - in CSF

Back 44

well we get lots of cross talk so a + serum can be a recent infection/vaccination against st louis or yellow fever

**CSF is only + if the infection is in the CSF- IgM cant cross BBB

Front 45

what is the most important cause of mild encephalitis, what serotype are most cases caused by

Back 45

california encephalitic, most common by LaCrosse serogroup

Front 46

who is affected by california encephalitis

Back 46

summer/fall

school ages boys

**commonly caused by LaCrosse serogroup
**important cause of mild encephalitis- daytme mosquite feedings

Front 47

what is the reservoir for california encephalitis

Back 47

small mammels

**mosquitoes are the vector as with ALL arbo virus. there is daytime mosquito feedings

Front 48

what arbo is common in NW US

Back 48

CO tock fever

reovirus, with 12 segments of ds RNA

Front 49

what arbo has a sadlebacked fever pattern (up and down)

Back 49

colorado tick fever

**most individuals have a history of tick sttachment or exposire

March- Oct in mountinous regions of NW US

Front 50

what arbo virus has restrictions on blood donations

Back 50

colorado tick fever, dont donate for like 6 months after infection (virus seeds progenitor cells)

**recall its a reovirus with 12 segemnts of dsRNA, common in NW US