Lecture 28 - Emerging Viruses Flashcards
What is an emerging virus (definition)?
new/recently identified virus to humans
What is a reemerging virus (definition)?
virus under control from public health perspective; making a comeback/reappearance and increasing in incidence/geographical range of exposed human populations
What are the 3 characteristics of emerging viruses?
expanded host-range w/ increase in disease | virus transmission from animals to humans | cross-species infection = can establish new virus in population
What are the 5 forces that drive viral emergence?
human population/social behavior (ie: travel) | climate/environmental changes | ecological factors | genetic/biological factors | microbial evolution/adaptation
What are the 4 host-virus interactions?
stable, evolving, dead-end, resistant
What is the stable host-virus interaction?
virus is maintained in the ecosystem
What is the evolving host-virus interaction?
passage of virus to naive population (same or different host)
What is the dead-end host-virus interaction?
one-way passage of virus to a different species
What is the resistant host-virus interaction?
viral infection is blocked
What are the 3 characteristics of a stable host-virus interaction?
both participants (host and virus) survive and multiply | some interactions are effectively permanent | may include infection +1 species
What are the 2 characteristics of an evolving host-virus interaction?
hallmarks = instability an unpredictability | infection outcome ranges from benign to death
What are 3 characteristics of a dead-end host-virus interaction?
frequent outcome of cross-species infection | new infected host may not transmit virus to others of same species | contributes little to spread of a natural infection
What type of host-virus interaction do West Nile Viruses have?
stable (generally) | large mammals = dead-end hosts
What are 5 characteristics of West Nile Virus?
brain-related severe illness | neurological symptoms = 10% = severe brain damage/die | RNA, flavivirus
What mosquito can help spread West Nile Virus and what are its biting habits?
Culex | dusk to dawn
What are characteristics of Zika virus?
1st outbreak in Yap = infected 78% population, 18% = symptoms | strong preference for maternofetal transmission and adverse fetal outcomes
What mosquito spreads Zika virus and what are its biting habits?
Aedes | daytime
What are 2 diseases/conditions as a result of Zika virus infection?
microcephaly | neuological disorders (motor weakness)
How is Zika virus spread person-to-person?
congenitally | sexually
What are the hosts for Yellow Fever virus?
humans and primates
What mosquito spreads Yellow Fever virus?
Aedes
What is the transmission of Poliovirus?
fecal-oral | via contaminated water
What is the H7N9 influenza virus?
lasted only 2013 | 8 of viral genes = closely related to viruses found in domestic ducks and poultry and wild birds in Asia
What disease does Nipah virus cause to humans?
respiratory and neurological disease due to pig farms
What animal spreads Nipah virus but is unaffected?
fruit bats = excrete virus in urine
Which animals spread Nipah virus to humans?
pigs and bats
What are 3 characteristics of Hantavirus?
virus excreted in mouse feces | humans not natural host | hantavirus pulmonary syndrome
What are the symptoms of SARS?
fever, chills, malaise, myalgia, dyspnea, dry cough
What disease does SARS cause?
severe atypical pneumonia
What method of treatment could be used against SARS?
mechanical ventilation
What type of virus is MERS-CoV?
emerging
What happened within 6 months of discovery of MERS-CoV?
isolated and studied via 1-step growth analysis | genome cloned and sequence determined | infectious DNA clone used to make viral mutants | identified receptor | immunofluorescence to study infection of various cell types | serological assays used to determine origin of virus
What is the Mayaro virus characterized by?
fever, rash, aches, pains (FRAP)
What spreads Mayaro virus?
Aedes mosquito
What can Mayaro virus cause in humans?
arthralgia; can persist for months, can be incapacitating
What animal host does MERS-CoV infect?
camels, may have been infected by bats
What cells does Ebola infect?
mucosal
What does Ebola induce in the body?
inflammatory cytokines
How does Ebola cause internal bleeding/hemorrhaging?
all coagulation proteins and platelets get consumed | small blood clots in vessels
What does liver dysfunction due to Ebola infection cause?
increase liver enzymes
What is AFM?
Acute Flaccid Myelitis
What does AFM affect?
nervous system, esp. spinal cord
What does AFM cause?
weakens muscles and reflexes, may cause paralysis
Which individuals are mostly affected by AFM?
children
What virus or type of virus causes AFM (assumed)?
enterovirus
What virus/disease is similar to what causes AFM?
polio
