14 Exotic and Emerging viral diseases Flashcards
what are the henipaviruses
- Hendra virus
- Nipah virus
what are the flaviviruses
- Dengue virus
- West Nile virus
- Yellow fever virus
- Zika virus
what are the emerging viruses
- newly appeared in population
- not previously recognised in man (new to host)
what are the re-emerging viruses
- existed previously
- rapid increase in incidence
- rapid increase in geographical range (new to region)
- rapid increase in human host range
what are the drivers of emergence - changes in host ecology
- urbanisation (movement of people to places that were animal only)
- intensive farming (movement of animals)
- climate change (change in vectors)
what are the driver of emergence - changes in host behaviour
- patterns of sexual behaviour
- local and global travel (HIV AIDS)
- IV drugs use (HIV AIDS)
what are the drivers of emergence
changes in host ecology
changes in host behaviour
changes in host phenotype or genetics
changes in virus phenotype or genetics (think Flu A, drift and shift)
what are the drivers and locations of emergence events for zoonotic infectious diseases in humans
- international travel and commerce,
- changes in human demographics and behaviour
- changes in the medical industry
- climate and weather, breakdown of public health measures
what is the virus RNA of henipavirus like
(-)ssRNA
what group is henipavirus
V
what type of disease is henipavirus
zoonotic
what is the henipavirus transmission
Pteropus (fruit bat) Feed on fruit pulp and nectar Bat spits out fruit pulp (contaminated) Bat urine contaminated Bat faeces contaminated
are humans infected by henipavirus
rare
what are the initial symptoms of nipah henipavirus
- headaches
- disorientation
what is the progression of nipah henipavirus
- respiratory failure
- renal failure
- cardiac arrest
what are the effects of 20% of patients chronic damage - nipah henipavirus
neurological defects, personality changes
relapse can occur
what is the mortality of nipah henipavirus
40%
what leads to mortality in nipah henipavirus
- haemorrhaging and oedema of lungs
- brain (encephalitis)
how can henipavirus be diagnosed
TEM, IHC (immunohistochemistry)
Serology (using AB - ELISA assay)
PCR
what is the henipavirus treatment
ribavirin (RNA analogue)
effect of ribavirin
reduced mortality (from 54 to 32%) in NiV
what is the RNA od flavivirus
(+)ssRNA
what is the group of flavivirus
IV
what do ticks and mosquitoes cause
- yellow fever
- west nile
- dengue
what is CDC
dengue fever virus
what causes the increased transmission by Aedes aegypti
- rapid population growth
- rural-urban human migration
- inadequate basic urban infrastructure
- increase in volume of solid waste, items which provide larval habitats
what is the geographical expansion of mosquitoes aided by
- international trade (used tyres)
- increased air travel
- breakdown of vector control measures
how is dengue virus transmitted
Urban Mosquito Aedes aegypti
- Acquired and Transmitted during blood feed (of female mosquito)
Tropical and subtropical climates
Jungle cycle and urban cycle
how many serotypes for dengue fever have
dengue fever virus 5 serotypes
dengue fever virus 5 serotypes effect
re-infection with other serotype
what are the clinical findings of dengue fever
- fever
- headache
- muscle/joint pain
- measles-like skin rash
what has dengue fever got the potential to progress to
DV haemorrhagic fever
> Bleeding, blood plasma leakage, loss of platelets
what is the mortality of dengue shock syndrome
20% without treatment
what does dengue fever cause
-low blood pressure, decreased blood to vital organs
what is the treatment for dengue fever
no specific treatment
- symptomatic/nursing: reduces mortality
why is it important to understand the vector for dengue
vector control
- understand habitat
- urban habitats: breeds mainly in man-made containers
how can the dengue vector be controlled
GM moquitoes
what type of virus is yellow fever
acute viral haemorrhagic disease
mortality caused by yellow fever
up to 50%
why is there declining immunity to infection
urbanisation
population movements
climate change
how is yellow fever transmitted
mosquitoes-borne
what is the natural host of yellow fever
monkey
what is the sylvatic cycle
money-mosquito-monkey
what is the urban cycle
human-mosquito-human
what can accidental exposure in sylvatic cycle be
human in jungle
what can semi-domestic mosquitoes in yellow fever be
monkey and human feeder
what is the yellow fever virus treatment/control
ribavirin
what is the the oldest live virus vaccine
yellow fever
what is important for innate immune protection
OAS gene - important for protection
- oligoadenylate synthetase
what is causes west nile virus
mosquito borne
what does west nile virus affect - reservoir
birds
- primary host
- reservoir
what is the host for west nile virus
humans
horses
can humans transmit west nile virus
not amplified in human
no transmission
what does west nile virus cause high mortality in
birds
