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How knowledge of avian coronavirus infectious bronchitis virus in poultry relates to COVID-19 in humans
* from P6
When the spike protein
insufficient protection.
It can be a fast track to finding a vaccine candi- date, but the safety of these live vaccines must
ery from one type does not immunise the bird against another type.
These and many other potential antivirals are presently being tested by several companies.
is removed from the vi- rus envelope or when it is expressed in a labora- tory system, those con- formationally dependent epitopes are not faithfully reproduced.
be rigorously tested. Fortunately, it is not all
For this reason, we have had to develop a number of different IBV vaccines, such as Ark, Mass, Conn, DE, etc., to control the disease.
Two drugs currently in the news, chloroquine and hydroxychloroquine are being examined for their ability to ameliorate COVID-19 infections.
Thus, vectors such as fowl pox and herpesvi- rus of turkeys have not been suitable vaccine platforms for expressing coronavirus spikes.
a bird is very different from that of a human.
These drugs have been used against malaria, lu- pus and rheumatoid ar- thritis for many years.
Spike protein produc- tion by the virus in a natural infection is very specific and difficult to mimic, thus other recom- binant vaccines, such as DNA vaccines, RNA vaccines and subunit vac- cines, do not accurately reproduce spike.
In addition, financially wecandoalotmorein development and delivery of vaccines in humans than in poultry, where tight margins make it necessary for vaccines to improve the welfare of the flock while still yield- ing a satisfactory return on investment.
A number of mutations have been observed, but none appear to be main- tained at this time, which suggests they are not im- portant for transmission or virulence.
However, until con- trolled clinical trials are conducted, their effective- ness against COVID-19 remains in question.
bad news.
The immune system of
Fortunately, there ap- pears to be only one type of COVID-19 virus circu- lating in humans.
What doesn’t work in poultry may actually work well in humans.
However, full genome sequencing has shown that the virus is changing.
Preliminary data out of China indicate that the drugs stop the spread of the COVID-19 virus in cell culture and are some- what effective in treating humans.
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Additionally, these vaccines usually do not stimulate adequate local immunity and have to be given many times to pro- vide any protection.
The goals and perform- ance parameters for hu- man vaccines are obvi- ously much different than production agriculture.
From a vaccine stand- point, only one type of COVID-19 virus circulat- ing in humans means that only one vaccine type should be needed to pro- tect against this disease. Are there treatments for coronaviruses?
It is likely that this pan- demic will not be over anytime soon.
Then there are geneti- cally altered coronavirus vaccines derived from in- fectious clones.
Currently, there are many different corona- virus vaccines and plat- forms being developed or optimized for human use. How do different sero- types or genetic types of coronavirus complicate vaccine development?
For humans, we have antiviral drugs for in- fluenza, but there have not been any successful drugs developed specifi- cally for coronaviruses.
In the meantime, follow government and World Health Organization rec- ommendations to protect yourself and your family.
Making changes to the genome of the pathogenic virus to create a safe, at- tenuated live coronavirus vaccine that is still capa- ble of inducing an effec- tive immune response is complex and often results in non-viable viruses or
In poultry, there are many types – serotypes or genetic – of IBV that do not cross protect.
Drugs against the viral- encoded proteases have been tried, as well as drugs that interfere with entry and egress of the virus from the host cell.
Poultry flocks do not appear to be at risk. Mark W. Jackwood, MS, Ph.D. Department of Population Health, Poultry Diagnostic
Consequently, recov-
and Research Centre, College of Veterinary Medicine, University of Georgia
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National Poultry Newspaper, April 2020 – Page 7