Bat flight and zoonotic viruses paper Flashcards
What is the main hypothesis of this article?
Flight-Fever Hypothesis: That flight provides an intensive selective force for bats’ coe-existence with viral parasites through a daily cycle that elevates metabolism and body temperature to levels analagous to those seen in a mammalian febrile response.
(while mammals reach high metabolic rates and body temperatures when infected, bats operate at these levels on a consistent day to day basis anyway due to flight. And this is a selective force for why they co-exist with viruses).
What fact does the article state about bat increase in metabolic rate during flight?
increased metabolic rate estimated to be 15-16 fold,
in comparison with 7 fold increase in metabolic rate of rodents or
2 fold increase of most flying birds
What does the article state about mice that are bred for higher metabolic rates?
They show stronger immune responses too immune challenge
leukocyte counts and mass of lymphatic organs (source of immune cells) are elevated in mice with higher metabolic rates.
When confronted with a viral antigen what is the metabolic cost for a non volant small mammal vs a bat?
The immune response of a non volant mammal has a metabolic cost of increasing resting metabolic rate to be approximately 10-30% higher.
Bat: when raising an immune response against a viral antigen, the proportional increase in metabolism may be trivial compared with the large increase in metabolism that occurs on a day to day basis during flight.
what is their metabolic hypothesis
the higher metabolic rates during flight in bats might subsidise any inherent cost of raising metabolism to activate an immune response.
(basically raising metabolism against infection isn’t a big deal for bats because they already raise it really high during flight anyway)
They are arguing that tthe reason bat’s can act as viral reservoirs is because when they get infected and the immune response causes a raise in metabolism , bat’s aren’t bothered by this as they are already used to having metabolism raised loads when they fly.
What does this paper say about elevated body temperatures?
During fever, mammalian core body temperatures raise to 38041 degrees.
The high metabolic demands of flight result in a common body temperature in bat within the same range (38-41).
So common daily high body temperatures might arm bats against some pathogens during infection.
Why is raising body temps good for a bat?
1) raising to a certain point can help eliminate a pathogen
2) if a pathogen is particularly infectious and causes temps to be raised even higher, unlike mamals which would suffer from this immunopathology, bats don’t because the energy intensive nature of flight has selected for mechanisms that help them deal with it.
