VPH - Final 4

drraythe's version from 2016-04-25 13:36

Zoonotic Arboviruses: WNV

Question Answer
What kinda virus is WNV?RNA Arbovirus: acronym for ARthropod-BOrne viruses (Flaviviridae - bc nile water is flavorful)
What are the 2 proteins which give WNV its biological propertiesE & M
*What does the E protein of WNV do?Mediates virus-host cell binding (E for ENTER)
**Which surface protein of WNV elicits most virus-neutralizing antibodies, which means it is useful for Vxs?E. It is the MAJOR antigenic protein!
(e for enter & e for EEEEK! Abs, attack!!)
*Is WNV reportable?No bc its endemic (she'll use this as an distraction)
What’s the WNV vector?Mosquitos, esp. the sp. Culex (not all sp competent vectors)
What’s the WNV maintenance host?Wild birds, esp. Birds of the Corvidae (ravens, jays, crows)
Occasionally poultry, mainly geese & ostriches
Are birds affected by WNV?Some can die from systemic infxn w/ myocarditis & encephalitis, most survive, develop life-long immunity & then can become carriers
What are accidental/dead end hosts of WNV?Horses & humans
**How do humans get WNV?Bite from mosquito 99% of exposures
(technically, can also get from transfusions, transplants, Mother-to-Child. During pregnancy & breastfeeding rarely, Laboratory-acquired human infxns)
But you can't get it from casual contact or just touching an infected person/horse
Can humans get WNV from horses?No
Can humans get WNV from humans?No
*What is WNV dz like in humans?Typically develop symptoms 3-14 days after they are bitten by the infected mosquito. Majority are asymptomatic. Some develop mild symptoms:
Some get severe dz like CNS signs inclding encephalitis
*Which age is a risk factor for getting a severe WNV infxn?AGE, Elderly are more at risk
How’s WNV dz like in horses?Differences in susceptibility of individual horses to neurologic dz following infxn. Strains of WNV vary in their virulence to horses...Many asymptomatic, others…CNS signs. 33% mortality, die spontaneously or are slaughtered/euthanized to avoid excessive suffering
In a horse, DDxs for WNV?Rabies
What is dz like in birds w/ WNV?Not pathogenic in many species of birds. ↑ mortality in some spp. of wild birds in the US, like American crow & other corvids (ravens, jays) ← these birds are the ones that develop ↑ viremia & transmit the virus on to uninfected mosquitoes
How do you detect WNV (Dx) in horses/humans?ELISA Serological detection of IgM antibody (IgM is M is upside down W)
Is there a WNV Vx for horses?Yes (DOSENT prevent infxn tho)
Downside to the WNV Vx in horses?Vxd horses & foals from vxd mares may also test positive bc of IgM formed from the Vx
If you cannot differentiate the Vx from exposure of WNV, what must vets do?Vet must consider not only the serology results, but the clinical symptoms & the possibility of other CNS dzs including Rabies, EEE, WEE & EPM (Equine Protozoal Myeloencephalitis)
Is there a human Vx for WNV?No (Therefore, prevention of arboviral dz depends on efforts to reduce vector densities)
What kinda precautions should VETS be taking w/ WNV?Vets & others performing necropsies or handling specimens from infected animals that may shed the virus in oral, respiratory secretions, urine or feces. WEAR protective clothing, gloves & respiratory protection
When do you wanna Vx horses for WNV?Immunization should be timed to maximize protection during the summer & fall when virus exposure is greatest (i.e., mosquito season)

Zoonotic Arboviruses: EEE/WEE/VEE

Question Answer
Eastern/Western/Venezuelan Equine Encephalomyelitis → czd by what kinda virus?Zoonotic RNA viruses, Alphavirus (Family Togaviridae) (all these acronyms are an α-pain in my butt)
EEE/WEE/VEE are what category?Category B
Essential reservoir host for EEE?Birds
Essential reservoir host for WEE?Birds
**Essential reservoir host for VEE?RODENTS, NOT BIRDS!! (Venezuela must be full of rats or something)
Biological vector for EEE?Mosquito
Biological vector for WEE?Mosquito
Biological vector for VEE?Mosquito
*How do the accidental/dead end hosts differ btwn EEE/WEE/VEE?In EEE/WEE, HORSES & PEOPLE are dead end hosts. However, in VEE, only people are dead end hosts & horses are AMPLIFIER hosts
*Which Arbovirus has horses as an amplifier host?VEE
Which Arbovirus doesnt have birds as a maintenance host? What IS the maintenance host?VEE, RODENTS
*Which Arbovirus is reportable?VEE
Dz in Horses w/ infxns of EEE/WEE?Fever
Seizures & coma in fatal cases
EEE dz in humansEncephalitis. No specific Tx
Symptomatic illness may CS:
Significant CNS damage in most survivors
*Most severe mosquito-xmitted dzs in the US?EEE
Is there a Vx for EEE/WEE/VEE for humans?No
Is there Vx for EEE/WEE in horses?Yes
Is there a horse Vx for VEE?Yes

Bats: Henipaviruses

Question Answer
***Henipaviruses encompass what 2 viruses? What kinda viruses are they?Hendra & Nipah viruses. Zoonotic Paramyxoviruses (henipavirs & "O" in henipa so its not orthmyxo!!)
**Hendra & Nipah viruses are harbored by what kinda bats?Fruit bats (Flying Foxes)
Intermediate host for Hendra?Horses (hendra horses)
Intermediate host for Nipah?Pigs (Nipah, pigs)
How do humans get infected w/ Hendra/Nipah?Contact w/ INTERMEDIATE host (horse/pig)
3 recently discovered zoonotic viruses carried by bats in AustraliaHendra virus
Australian bat Lyssavirus
Menangle (another Paramyxo)
Is there a Vx for Hendra?Yes, for horses! (Vx consists of Hendra virus surface protein, G, known target for triggering host immune response.)
How does a human play into the role of the lifecycle of Hendra?Accidental dead-end hosts
How is Hendra NOT xmitted?No evidence of bat-human, human-human or human-horse xmission
How does a person get infected w/ Hendravirus?Contact w/ infected HORSE! Horses serve as amplifiers to infect humans (no contact w/ bats will lead to infxn in humans)
**What is the reservoir host in Hendra virus & how is the virus shed?Pteropid (FRUIT BAT/Flying Foxes) res. host → shed virus in saliva, urine, semen, feces
(specifically: Little Red Flying-Fox, Black Flying-Fox, Grey-Headed Flying-Fox, Spectacled Flying-Fox)
Do fruit bats show signs of Hendra virus?No
Who can bats spread Hendra virus to?HORSES & other bats (stress factors)
Who can horses spread Hendra to?HUMANS & also other horses (but this is limited)
How can horses be infected w/ Hendra from bats?Could be from ingesting food/water/pasture tainted w/ bat feces/urine/saliva/birthing fluids/ other bodily fluids
How does Hendra usually spread from bat to bat?Virus shed in bat feces, urine, saliva → spread easily w/in a bat colony. More likely to be spread during repro/nutritional stress
How does a horse xmit Hendra to a horse?RARE, but can happen. Close contact, virus shed in oral secretions & urine & can be Aerosol xmission in a contaminated environment
How can a horse infect a human w/ Hendra?Cutaneous from infected horse saliva to human
Aerosol at necropsy (result of direct exposure to infected or dead horses)
(usually need close contact xmission to humans is not very efficient)
How does Hendra present in a horse?Deteriorate quickly ~75% die
+/-CNS signs
Can a horse have a carrier state of Hendra?No
What is Hendra dz like in humans?Self-limiting flu-like + severe pneumonia & death. Aseptic meningitis w/ recovery, then death from encephalitis 13 months later
HeV (Hendravirus) control in flying fox populations unfeasible due to...Size of their populations
Geographical range
Migratory activity - which is beyond Australian borders
**What are some ways to prevent horse-to-human xmission of Hendra?Isolation of ill horses
Quarantine horses who were exposed to horses testing + for HeV
Australian government determines fate! Euthanize? VX HORSES!
**What’s the mortality rate of Hendra in humans?50% human mortality rate but dz rare
The natural host for Hendra virus is the...Flying fox (Fruit Bats)
**Which Henipavirus has a CDC category for bioterrorism & what is it?Nipah, Category C (Nipah is as dangerous as C4)
**What BSL (biosafety level) are Hendra & Nipah?Level 4 (Highest category, super dangerous, Nipah is as dangerous as C4)
****Which Henipavirus has human-human spread?Nipah!
**Which Henipavirus has a Vx?HENDRA
Does Nipah affect the pigs?YES bad for them too, High economic loss for pig farmers
Do bats show signs of Nipah virus?NO, they are natural hosts & asymptomatic
Hosts of Nipah virus?Fruit Bats (The Island Flying-Fox, Malayan Flying Fox)
How do bats shed Nipah virus?Virus found in urine, saliva, uterine fluids of bats
How do pigs shed Nipah virus?Pigs shed virus in respiratory secretions, saliva, urine
How do humans relate to the life cycle of Nipah virus?They are accidental hosts - NOT dead end hosts, as some human-human in Bangladesh
Who can pigs spread Nipah virus to?Other pigs & humans!!
Who can bats spread Nipah virus to?To PIGS & in Bangladesh & India, also to humans (drinking date palm juice tainted w/ bat saliva/feces)
Can humans spread Nipah virus?Limited evidence of human-human huge pandemic implications
How do pigs usually spread Nipah to other pigs?Aerosol (coughing) due to virus being shed in secretions
How do bats xmit Nipah to pigs?Increasing overlap btwn bat habitats & piggeries mean Pigs eat fruit from trees near piggeries. Fruit may be contaminated w/ bat saliva+urine
How do pigs spread Nipah to humans?DIRECT CONTACT w/ PIGS. Aerosolization or direct contact w/ respiratory secretions, urine or saliva from infected pigs
Which virus may spread human-human & how?NIPAH, Aerosol, Btwn friends/family members who cared for cases, Ingestion via saliva? Care providers shared eating utensils/leftover food & shared beds w/ PTx
How do humans present when infected w/ Nipah?Fever
Encephalitis (may relapse after recovery)
Neurologic deficits
Death (some will have seizures & become comatose)
How do pigs present when infected w/ Nipah virus?Porcine respiratory & neurologic syndrome also known as BARKING PIG SYNDROME! Also CNS, twitching/trembling, hind limb paresis, death after onset of respiratory distress, & some affected pigs may be asymptomatic
How do bats present when infected w/ Nipah virus?NO CS


Question Answer
What’s SARS even mean?Severe Acute Respiratory Syndrome
What kinda virus is SARS?Family Coronaviridae, so a Coronavirus (CoV) (RNA virus) (not King (Corona is crown) Saul, it's kind SARS)
*How does SARS exemplify species jumping?SARS isolated in civets, bats, then sustained human-human via aerosol (Sars, species jumping, sustained)
What is SARS related to?ANIMAL Coronaviruses, not human ones!
Most initial cases of ppl who were infected w/ SARS were in what kinda environment?Most cases had regular contact w/ live animals bred for restaurant consumption (At "wet markets")
**Main Reservoir Hosts of SARS CoV?Microbats, predominately horseshoe bats
Do bats show signs of SARS?NO
What were some market species in which evidence of SARS CoV isolates were found?Domestic cat
Red fox
Chinese ferret badger
Raccoon dogs
Can humans get SARS from bats?The virus could not infect human cells directly implying that adaptation had taken place through palm civets +/-other intermediate hosts
*How is SARS xmitted from human to human?Aerosol: Readily xmitted human-human via close contact
**What are the symptoms of SARS (in ppl)↑ fever
Body aches
Some people get mild respiratory symptoms
Most PTx develop pneumonia
What does MERS even mean?Middle East Respiratory Syndrome
What kinda virus is MERS?Another Coronavirus (CoV) (RNA)
Symptoms of MERS?Fever
Severe respiratory dz
Persons w/ pre-existing medical conditions (diabetes, renal..) more likely to get other complications (GIT, death)
How is MERS spread from human to human?Spread from ill people to others through close contact, such as caring for or living w/ an infected person
What is the pattern of how MERS is spreading indicate how it is happening?The currently observed pattern of dz occurrence consistent w/ ongoing xmission in an animal reservoir & sporadic spillover into humans
Who is the most likely host for MERS?CAMELS (was in camels, mutated, able to infect humans from camels)
What are precautions for people to protect themselves against MERS? (3)(1) Avoid contact w/ camels
(2) Do not drink raw camel milk or raw camel urine
(3) Do not eat undercooked meat, particularly camel meat