viral zoonoses I and II Flashcards
molluscum contagiosum
a poxvirus
wart-like lesions on face, butt, and back in kids
spread via towels/lockerrooms, contact, and sexually
self limiting after 4-6 months with secondary attacks
molluscum contagiosum
orf lesion
vessicular lesion caused by poxvirus of (ruminants) sheeps or goats, copox, or vaccinia
vaccinia virus vaccination for _____ also immunizes against what rare poxvirus?
smallpox and monkey pox
what animals can carry monkeypox?
african rodents (giant rat, prairie dogs)
brickshaped (dogbone) organisms in cytoplasm
poxvirus
rabies
rhabdovirus, envelped, negative sense ssRNA
ONLY virus shaped like a bullet
reservoirs = racoons, skunks, coyotes, and bats
causes acute encephalitis - fatal if untreated
rabies
the only bullet-shaped virus
negri bodies
eosinophilic cytoplasmic inclusion bodies
sign of RABIES!
For persons who have never been vaccinated against rabies, post-exposure anti-rabies vaccination should always include administration of both ____ and ____
passive antibody (HRIG/human rabies immunoglobin) and vaccine
100% effective
SARS coronavirus
SARS = severe acute respiratory syndrome
respiratory coronavirus
reservoir is bats
begins like a cold –> severe atypical pneumonia
xray resembles pneumonia or ARDS (acute respiratory distress syndrome)
***risks: travel to SE asia, lab/healthcare worker
MERS-CoV
middle east respiratory syndrome coronavirus
carried in camels
hendra and nipah viruses
paramyxoviruses
bats(carrier) to farm/domestic animals –> humans
BSL-4 restricted (same biosafety level as ebola)
symptoms –> causes widespread multisystem vasculitis (thrombosis, ischemia, and necrosis), pneumonitis and/or encephalitis
2 filoviruses?
2 arenaviruses?
3 bunyaviruses?
Filoviruses = ebola and marbug
arenaviruses = lassa fever, S. american hemorrhagic fevers
bunyaviruses = CCHF (congo-crimean hemorrhagic fever), rift valley fever (RVF), and hantaviruses (HRFS and HPS)
arboviruses and rodent borne viruses are all _________ and _____
one exception?
RNA viruses and enveloped
reovirus (colorado tick fever) is non enveloped
Lassa fever
west africa; reservoir is multimammate rate (mastomys)
transmitted via animal urine and feces
symptoms = fever and malaise at day 10, + myalgia and prostration(exhaustion/lying), N/V/D/C/abdpain, cough, retrosternal pain
can cause deafness
arenaviruses
virion appearance?
genome?
virions are enveloped with grain appearance d/t ribosomes from host cells
ambisense dsRNA (+ and - strands together; L and S)
—LCMV (lymphocytic choriomeningitis virus), lassa fever, and S american HFs
LCMV
lymphocytic choriomeningitis virus
A biphasic febrile illness: Initial phase (a week) has fever, malaise, anorexia, aches, headache. A few days of remission, then….
Second phase: meningitis (fever, headache, and a stiff neck) or encephalitis (drowsiness, confusion, sensory disturbances, motor abnormalities, paralysis).
spread by the common house mouse, Mus musculus and hamsters.
virus spread by mice/hamsters
LCMV
hantavirus
rodent borne bunyavirus
enveloped ssRNA virus
genome has 3 negative sense RNA segments (L, M, and S)
transmission: inhalation of rodent excrement
HFRS = hemorrhagic fever with renal symptoms
symptoms = fever, headache, hemorrhage, and acute renal failure
hanta virus
enveloped ssRNA virus
hantavirus 2 diseases and their symtoms
HFRS = hemorrhagic fever with renal symptoms
symptoms = fever, HA, hemorrhage, and acute renal failure; capillary vasodilation, congestion with hemorrage
HPS (hantavirus pulmonary syndrome) = sin nombre virus in four corners area of US
–damage to capillaries in the lungs rather than kidneys
vector for arboviruses?
insects
arboviruses: compare genome and structure
1) bunyaviruses
2) reoviruses
3) rhabdoviruses
1) ssRNA 3 segments, enveloped, round
2) dsRNA 12 segments, NOT enveloped, round
3) bullet shaped ssRNA, enveloped
colorado tick fever virus
a reovirus, no envelope, dsRNA, 12 segments
vector = wood tick (spring to fall) in west/northwest
pathogenesis = infects erythroid precursors; hemorrhagic disease when it infects the vascular endothelium
diagnose by IF for viral antigen on blood smear
symptoms = resembles dengue; incubation 3-6 days and then fevers, chills, headache, myalgia, athralgia, photophobia, and lethargy
aedes mosquito transmits what two bunyaviruses
california encephalitis and La Crosse virus
La Crosse virus
a bunyavirus transmitted by aedes mosquito
causes pediatric arbovirus encephalitis in midwest states
presentation of WEE/EEE/VEE
flu like
can progress to encephalitis 3-10 days after infection
usually resolves fine but can possibly lead to paralysis, mental issues, and death
EEE WEE VEE
eastern, western and venezuelan equine encephalitis
arboviruses (transmitted by insects or ticks) – bird to mosquito to human
only VEE can pass from horse to human
they infect NERVOUS TISSUE
VEE
transmission: appears to be rodents and mosquitoes, not birds
Acute fever 2 – 6 days post-infection with pronounced systemic symptoms, neurologic involvement less common and less severe than with EEE/WEE, but again, more common in children
WEE
mosquito-bird cycle
Neurologic involvement more common in kids
60% of survivors with neurologic impairment.
EEE
mosquito-bird cycle
Neurologic involvement is lestimated at: ~1 in 23.
death may occur in 3-5 days of onset of severe disease.
Case/fatality rate ~50% among all age groups.
three togaviruses (alpha viruses) transmitted by insects
EEE, WEE, VEE
dengue
Symptoms: high fever, lymphadenopathy, myalgia, bone/joint pains, headache, and a maculopapular rash.
Severe cases may present with hemorraghic fever and shock with a mortality of 5-10% (Dengue HF or Dengue shock syndrome) –> usually in those previously infected with a different serotype = immunopathogenic mechanism
No specific antiviral therapy is available. Supportive care.
Prevention in endemic areas depends on mosquito eradication
dengue
transmission?
what is facilitating global spread?
aedes mosquito
air travel
4 serotypes –> why vaccines are hard to create!
**the biggest arbovirus problem in the world today (SE asia, africa, A america, and carribean)
yellow fever
west africa and s america
2 major forms: urban and jungle
Jungle YF is the natural reservoir of the disease in a cycle of primates and forest mosquitoes. Humans incidentally infected upon venturing into jungle.
Urban YF is transmitted between humans by the Aedes aegypti mosquito.
symptoms = chills, fever, and headache, generalized myalgias and GI complaints (N+V). GI haemorrhage leads to “black vomit” and liver involvement causes jaundice.
There is no specific antiviral treatment
An effective live attenuated vaccine (17D) is available and is used for persons living in or travelling to endemic areas.
japanese encephalitis
SE asia
transmission involves culex mosquitoes, birds and pigs.
Most subclinical: 1 in 300 develops a life-threatening encephalitis
No specific therapy is available.
Since Culex has a flight range of 20km, local control measures fail.
An effective vaccine (killed virus) is available.
west nile virus
flavivirus, +sense ssRNA
transmission = culex mosquito; reservoir is birds
causes ecephalitis, fever
poxviruses
exceptional features?
vaccines?
human diseases?
biggest virus
only DNA virus that replicates in the cytoplasm
there IS a smallpox vaccine
hydrophobia/inability to drink water is a sign of
rabies!
copious salivation too/drools to avoid swallowing
