Download Animal pathogens: viruses

Animal pathogens:
viruses
Topic 11
Ms Sherina Kamal
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Types of diseases
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Foot and mouth
Hog Cholera
New Castle
Avian Influenza
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Foot and mouth disease (FMD)
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an infectious disease affecting cloven-hoofed
animals
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Cattle
Sheep
Pigs
Goats
Deer
Other ruminants: deer and some zoo animalscamelids (camels, llamas, alpacas, guanaco) and
elephants can also be affected
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Foot and mouth disease (FMD)
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serious for animal health and for the
economics of the livestock industry
not normally fatal to adult animals
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it is debilitating and causes significant loss of
productivity
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milk yields may drop or the animals may become lame
In young animals it can be fatal on a large scale
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Foot and mouth disease (FMD)
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A picornavirus is a virus belonging to the
family Picornaviridae
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Laboratory analysis
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Hog cholera/Swine fever/Classical
swine fever
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serious and often fatal viral disease of swine
Characterized by high fever and exhaustion
The disease is transmitted from infected pigs via numerous
carrier agents
 including vehicles in which pigs are conveyed from place
to place
 dealers who journey from farm to farm
 farm attendants
The virus may be present in garbage used for swine feed but
is destroyed by cooking
It affects no other species
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Hog cholera/Swine fever/Classical
swine fever
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Hog cholera/Swine fever/Classical
swine fever
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Diagnosis
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CSF is a rapid spreading disease with high mortality
There are characteristic post-mortem changes with
haemorrhagic lymph nodes, dead patches in the
spleen, multiple small haemorrhages in the kidneys
and so-called "button ulcers" in the gut
Laboratory tests
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identification of viral antigen
isolation of the virus and the presence of antibodies in
serum
In most countries CSF is notifiable
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Hog cholera/Swine fever/Classical
swine fever
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Larynx of pig with swine fever, note
haemorrhaging (red and dark black areas)
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Hog cholera/Swine fever/Classical
swine fever
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Kidneys showing small pinpoint
heammorrahges
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Hog cholera/Swine fever/Classical
swine fever
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Haemmorrhaging inside chest cavity
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Hog cholera/Swine fever/Classical
swine fever
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Haemorrhaging in bladder of pig with swine
fever
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New Castle disease
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viral disease that can affect a wide variety of
avian species
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wild birds
domestic fowl
The disease is of great concern throughout
much of the world's agricultural community
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it is highly contagious
can cause severe disease in poultry
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New Castle disease
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Strains that produce mild and moderate forms
of the disease are sometimes found in
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domestic poultry
pigeons
The most severe forms- velogenic Newcastle
disease (VND)
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caused by highly pathogenic strains of the virus
can cause severe mortality in chickens
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New Castle disease
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conjunctiva
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New Castle disease
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signs of the disease in wild birds occur mainly in the
young and include:
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clenched toes
high number of sudden deaths in wild birds, particularly
cormorants (wild aquatic, migratory birds)
inability to walk or fly
lack of muscular coordination
muscle tremors
paralysis of one or both legs or wings
twisting of the head and neck
walking in circles
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New Castle disease
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Prevention
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Vaccines are available
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Chickens
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Turkeys
Pigeons
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used to induce an antibody response
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so vaccinated bids must be exposed to a larger dose of
NDV to be infected
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Avian influenza
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refers to the disease caused by infection with
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avian (bird) influenza (flu) Type A viruses
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A(H5N1)
A(H7N9)
occur naturally among wild aquatic birds worldwide
and can infect domestic poultry and other bird and
animal species
Avian flu viruses do not normally infect humans
However, sporadic human infections with avian flu
viruses have occurred
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Avian influenza
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outbreaks of AI in poultry may raise global public
health concerns due to their effect on poultry
populations
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can seriously impact local and global economies and
international trade
The majority of human cases of A(H5N1) and
A(H7N9) infection have been associated with direct
or indirect contact with infected live or dead
poultry
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Avian influenza
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avian influenza A viruses are very contagious
among birds
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some of these viruses can sicken and even kill
certain domesticated bird species:
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Chickens
Ducks
Turkeys
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Avian influenza
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Infected birds can shed avian influenza A viruses in
their:
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Saliva
nasal secretions
feces
Susceptible birds become infected when they have
contact with the virus as it is shed by infected birds
They can also become infected by coming in contact
with surfaces that are contaminated with virus from
infected birds
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Avian influenza
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Laboratory analysis
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Direct RNA
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RT-PCR techniques
Preferred rRt-PCR (modification of RT-PCR that
reduces the time for both identification of virus
subtype and sequencing)
Antigen detection
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AC-ELISA kit (immunoassays; use antibody against
the nucleoprotein)
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Can detect the presence of influenza A viruses in poultry
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END OF LECTURE
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QUIZ
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