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1.19.3.11 - Host-Virus Interactions - Coggle Diagram
1.19.3.11 - Host-Virus Interactions
interactions between virus and host cells
whether infection occurs
type of infection that established
persistance
clearance
outcome of he virus/host encounter
depends on pathogenicity of the infecting virus
depends on the susceptibility or resistance of the host
pathogenesis of viral infection
morphological
lysis, rounding and detachment from surface
functional
inhibition or stimulation of cell division
biochemical
activation of cell signaling pathways, induction of immune responses
metabolic reprogramming
to support viral replication and rapid cell growth
immunological
key strategies that could lead to resistance or infection- Immune system is central to host-virus interactions
Viruses are obligate intracellular microorganisms that rely on host cell machinery to survive
virus lifecycle
Invade the host, through skin or mucus membranes
At the cellular level, infect susceptible cells (tropism)
Overcome local defences, i.e. innate immune responses, to replicate in permissive cells
Virus assembly and spread from the site of infection often via the bloodstream to other organs
undergo further rounds of replication
exit/ shedding from the host in high numbers (titre) to infect other susceptible hosts to ensure spread and maintenance
routes - urine, faeces, skin, respiratory tract- coughing, sneezing, semen, milk, blood
innate vs adaptive immunity
immunity is a combination of innate and adaptive immune response mechanisms
innate
- non-specific and rapid response against viral infection
adaptive
- develops after previous exposure to a virus and is specific to that pathogen and related strains
The principal function of the immune system is to protect the host against pathogen invasion
The continuous interactions between host and pathogen have shaped the immune system, during the co-evolution of viruses with their host species
Viruses have manipulated host immune control defence mechanisms and in turn, the host has developed diverse strategies to overcome viral infections
diseases occur
when host encounters a new virus
when immune system is suppressed
e.g. immunosuppressive drugs
factors affecting emergence of viral infections
virus adaptation and change
international travel
economic status
climate change
public health measures and deficiencies in response and infrastructure
host susceptibility to infection
human demographics and behaviour
urbanisation
increased interactions between reservoir species and host
population growth
changing ecosystems
exploitation of host cell machinery
counteract host antiviral defences
hijack host cell resurces
shut down host cell function