Virology (week 8)

Enveloped, ss – sense, RNA viruses

Non-enveloped, ss – sense, RNA viruses

Enveloped, ss + sense, RNA viruses

Enveloped, ds – sense, RNA viruses

Non-nveloped, ss + sense, RNA viruses

Haemagglutinin and Neuraminidase protein

Nucleocapsid phosphoprotein and Neuraminidase protein

Hernagglutinin and Neuraminidase protein

Haemagglutinin and Nucleocapsid phosphoprotein

~ 5 days

~ 10 days

~ 9 days

~ 15 days

~ 2 days

“cleavability” and activation of the F protein

“cleavability” and activation of the Haemagglutinin protein

“cleavability” and activation of the Neuraminidase protein

“cleavability” and activation of the Haemagglutinin/Neuraminidase protein

Severe fatal disease with haemorrhagic intestinal lesions and bright green diarrhoea (mortality 90-100%)

Respiratory signs: tachypnoea, gasping, rales, oedema of head/neck. Progresses to nervous signs: tremors, paralysis, torticollis (mortality 10-20% in adults)

Coughing, weight loss, reduced egg production (mortality ~10% - usually young birds)

Mainly subclinical

Mainly subclinical

Coughing, weight loss, reduced egg production (mortality ~10% - usually young birds)

Respiratory signs: tachypnoea, gasping, rales, oedema of head/neck. Progresses to nervous signs: tremors, paralysis, torticollis (mortality 10-20% in adults)

Severe fatal disease with haemorrhagic intestinal lesions and bright green diarrhoea (mortality 90-100%)

Coughing, weight loss, reduced egg production (mortality ~10% - usually young birds)

Mainly subclinical

Respiratory signs: tachypnoea, gasping, rales, oedema of head/neck. Progresses to nervous signs: tremors, paralysis, torticollis (mortality 10-20% in adults)

Severe fatal disease with haemorrhagic intestinal lesions and bright green diarrhoea (mortality 90-100%)

Mainly subclinical

Coughing, weight loss, reduced egg production (mortality ~10% - usually young birds)

Respiratory signs: tachypnoea, gasping, rales, oedema of head/neck. Progresses to nervous signs: tremors, paralysis, torticollis (mortality 10-20% in adults)

Severe fatal disease with haemorrhagic intestinal lesions and bright green diarrhoea (mortality 90-100%)

2011

1998

1972

2001

2014

Pyrexia, inflammation and necrosis of the mucous membranes

Diarrhoea and fever

Abortion and reproductive failure

Neurological symptoms (encephalitis)

High morbidity and high mortality

High morbidity and low mortality

Low morbidity and high mortality

Low morbidity and low mortality

3 – 5 days

6 – 9 days

1 – 2 days

1 – 4 days

Within 12 days

Within 2 days

Within 5 days

Within 9 days

Pest de Petit Ruminants

Newcastles disease

Bovine vascular disease

Canine Distemper

3- 6 days

5- 9 days

1- 2 days

9- 10 days

Maternal antibodies and vaccination

Test and kill

Vaccinate to kill

Wild birds

Flying foxes (Fruit bats)

Rodents

Arthropods

1994

1995

1998

1991

Nipah virus

African Horse Sickness

Japanese Encephalitis

Enveloped, segmented, ss, - sense RNA

Non-enveloped, segmented, ss, - sense RNA

Non-enveloped, segmented, ds, - sense RNA

Enveloped, segmented, ss, + sense RNA

Orbivirus

Influenzavirus B

Thogotovirus

Quaranjavirus

Isavirus

Influenzavirus A

Influenzavirus C

17 HA subtypes and 9 NA subtypes

7 HA subtypes and 5 NA subtypes

17 HA subtypes and 4 NA subtypes

9 HA subtypes and 17 NA subtypes

H7H7

H3N8

H1N1

H2N3

1-3 days

5-7 days

7-9 days

4-5 days

Twice

Once

Three times

It is endemic to Australia

2-3 weeks for well-rested, mildly affected horses and up to 6 months in the
most severe cases

2-3 months for well-rested, mildly affected horses and up to 6 months in the
most severe cases

2-3 weeks for well-rested, mildly affected horses and up to 3 months in the
most severe cases

2-3 months for well-rested, mildly affected horses and up to 9 months in the
most severe cases

Mortality rates in HPAI are nearly 100% compared to 3-15% iin LPAI

Mortality rates in HPAI are nearly 100% compared to 40% iin LPAI

Mortality rates in HPAI are nearly 100% compared to 30-50% iin LPAI

Attachment, Fusion and Antigenicity

Attachment, Fusion and Disattachment

Attachment, Fusion and Exclusion

cleaves sialic acid (also known as neuraminic acid) from glycoproteins and glycolipids and removes sialic acid from newly formed virions to prevent their aggregation and promote their release from infected cells

Attachment of the virion to the host cell

Breakdown of the host cell so that the new virions can leave

Non-enveloped, Icosahedral ss + sense RNA

Enveloped, Icosahedral ss + sense RNA

Non-enveloped, Icosahedral ds - sense RNA

Non-enveloped, Icosahedral ss - sense RNA

Enveloped, Icosahedral ss - sense RNA

Foot and Mouth Disease

Encephalomyocarditis virus

Equine Rhinitis A virus

Porcine enterovirus 1

Poliomyelitis

Swine vesicular disease virus

High mortality

Dramatic reduction in production

Infertility

Zoonotic

Lost milk production for remainder of lactation and subsequent lactations - mastitis 25% loss of milk

Reduced growth rate

Reproductive dysfunction

2 – 8 days

1 – 2 days

9 – 12 days

Infects cloven hoofed animals

Infects birds (eg. chickens)

Infects horses

Infects carnivores

Via the respiratory tract- Inhalation of aerosolised droplets

Via the skin (broken or damaged skin, direct contact)

Venereal transmission

Vector transmission

Faecal-oral route

Pharyngeal mucosa and draining lymph nodes

The GIT

The LRT

Birds

Cattle

Sheep

Goats

Horses

Pigs

7

3

4

2

9

An upper respiratory tract disease in horses

A reproductive disease in horses

A GIT disease in horses

A lower respiratory tract disease in horses

Swine

Cattle

Horses

Sheep

Fever, depression, anorexia followed by tremors and ataxia, the hind limbs show neurological
signs first, progressing to paralysis, convulsions, coma and death

Odd behaviour (tongue lolling, salivation, head bobbing) which returns to normal when the virus is cleared

Pulmonary and myocardial oedema

4 weeks

3 days

6 months

2 weeks

4 months

Faecal – oral route of transmission

Respiratory droplets

Vector transmission

Vertical transmission